But then she rears back; her forelimb dangles at a sickening angle.
|
|
Sometimes it took a week of digging to isolate a single femur or a forelimb.
|
|
The 2-year-old filly sustained a right forelimb lateral condylar fracture with medial sesamoid involvement.
|
|
The limusaurus also had a distinctive forelimb that may help explain how birds evolved to develop wings.
|
|
"We don't actually know what would have triggered a reduction in the forelimb in each individual lineage," he said.
|
|
"This Longobard male shows a remarkable survival after a forelimb amputation during pre-antibiotic era," write the researchers in the study.
|
|
The scientists recovered parts of its skull, lower jaw, neck and back vertebrae, ribs, shoulder and forelimb, back foot and osteoderms.
|
|
Trilobites Tyrannosaurus rex may have been king of the dinosaurs, but it was also president of the itty-bitty forelimb committee.
|
|
Here's what we know about this new titanosaur: Shingopana's forelimb was about 1.5 meters tall, which is just shy of five feet.
|
|
Earlier this year, our minds were blown when a forelimb or wing of a small theropod dinosaur was found preserved in amber.
|
|
Both had similar membranous wings and styliform, but Ambopteryx had a wider forelimb and a shorter tail with fused vertebrae at the tip, among other differences.
|
|
Remarkably, the paleontologists were able to uncover the animal's skull, lower jaw, some vertebrae, ribs, bits of the shoulder and forelimb, and a section of its hind foot.
|
|
Still, for a limited time, visitors of the museum can see real fossils of the dinosaur's forelimb and its 8-foot-long thigh bone alongside this humongous cast.
|
|
To survive during the healing period, the dinosaur likely fed on small prey that it was able to catch with its mouth or feet, or with its one good forelimb.
|
|
The discovery of a new dinosaur species in China suggests some of these pioneering flyers evolved webbed fingers and an elongated forelimb, allowing them to fly in a distinctly bat-like fashion.
|
|
But the team then found one type of branched structure, which looked like a curved painter's brush, on the neck, part of the forelimb and foot area and tail of one of the specimens.
|
|
If you've never seen a dog cover its nose with a forelimb or a sleeping cat covering its eyes with its paws, then navigate your way to the nearest online stream of adorable animal memes.
|
|
There is a volume in the upper midback and between the heads that resembles a third rudimentary medial forelimb, but X-ray images only suggest the presence of medial skeletal elements of the pectoral girdle (clavicle and scapulae) in this region.
|
|
The track veterinarian observed "the filly had suffered a right forelimb lateral condylar fracture with medical sesamoid involvement and, because of the severity of the injury, made the decision to humanely euthanize the horse," Santa Anita Park said in a statement.
|
|
Next, Dr. Golas considered the case of a dilophosaurus — a theropod, or the same dino order as T. Rex — that holds the current record for most injuries found in one forelimb: eight, ranging from a fractured scapula to abscesses on the hand.
|
|
Illustration: Andrey Atuchin/DMNS 2017Working in this high desert terrain, paleontologists from the Natural History Museum of Utah and the University of Utah managed to pull out a number of bones, including an immaculately preserved complete skull, bony armor (including neck rings and spiked plates), several vertebrae, a forelimb, various hindlimb bones, and nearly complete tail with the iconic ankylosaur club still attached.
|
|
Additionally, forelimb swellings appear to be correlated with development of the males' eye glands. Due to the dimorphism of forelimb swellings, It is thought that they could be correlated with mating behaviors.
|
|
One major difference in bat forearms is that their skeletal limb structures are elongated. This elongation of the forelimb skeleton is required to support the wing membrane. Comparative in situ hybridization studies have revealed that the expression domain of fgf8 in bat forelimb AER are expanded in comparison to the mouse forelimb, suggesting that expanded expression of fgf8 may contribute to the larger size of the bat forelimb. Because the mouse and bat orthologs are conserved, there is likely to be a regulatory change in fgf8.
|
|
The fragmentary skeleton known for Abrictosaurus has never been fully described, although the forelimb and manus were smaller than in Heterodontosaurus. Also, the fourth and fifth digits of the forelimb each bear one fewer phalanx bone.
|
|
Transplantation of the AER to flank mesoderm between the normal limb buds results in ectopic limbs. If the AER is transplanted closer to the forelimb bud, the ectopic limb develops like a forelimb. If the AER is transplanted closer to the hindlimb bud, the ectopic limb develops like a hindlimb. If the AER is transplanted near the middle, the ectopic limb has both forelimb and hindlimb features.
|
|
It connected via a long forward protrusion to the coracoid, which was rounded. Both shoulder blades were connected by a small furcula. The paired breast bones possibly were made of cartilage only. Right forelimb of Tyrannosaurus The forelimb or arm was very short.
|
|
The position of FGF10 expression is regulated by Wnt8c in the hindlimb and Wnt2b in the forelimb. The forelimb and the hindlimb are specified by their position along the anterior/posterior axis and possibly by two T-box containing transcription factors: Tbx5 and Tbx4, respectively.
|
|
The material includes cervical, dorsal, sacral and caudal vertebrae, the forelimb girdle, and the partial hindlimb.
|
|
The radius, ulna, fibula and tibia (the bones which make up the lower forelimb and lower hindlimb, respectively) are very short and very wide compared to the humerus and femur (which make up the upper forelimb and upper hindlimb). The carpal (wrist) and tarsal (ankle) bones are weakly developed.
|
|
Because it was a biped, it could have a more modified forelimb without affecting its ability to run.
|
|
Tbx5 is a gene that is located on the long arm of chromosome 12. Tbx5 produces a protein called T-box 5 that acts as a transcription factor. The Tbx5 gene is involved with forelimb and heart development. This gene impacts the early development of the forelimb by triggering fibroblast growth factor, FGF10.
|
|
LGP V006 contains neck vertebrae, the shoulder girdle and forelimb elements. Additionally numerous disarticulated bones from the quarries were referred.
|
|
Life restoration Alternate reconstruction Fragmentary remains of this animal, including an articulated left forelimb (holotype), skull fragments, teeth, vertebrae and ribs, have been found in terrestrial deposits of the Villar del Arzobispo Formation of Riodeva (Teruel Province, Spain). A forelimb from Portugal.Mateus, O. (2009). The sauropod Turiasaurus riodevensis in the Late Jurassic of Portugal.
|
|
Though the humerus (upper arm bone) and femur (thigh bone) were roughly equal in length, the entire forelimb would have been longer than the hindlimb, as can be inferred from the elongated forearm and metacarpus of other brachiosaurids. This resulted in an inclined trunk with the shoulder much higher than the hips, and the neck exiting the trunk at a steep angle. The overall build of Brachiosaurus resembles a giraffe more than any other living animal. In contrast, most other sauropods had a shorter forelimb than hindlimb; the forelimb is especially short in contemporaneous diplodocoids.
|
|
Continuing with the hind limbs, the tibiotarsal articulation roughly reaches between where the forelimb connects to the body to the nostrils.
|
|
Though clearly forelimb-based launchers, basal pterosaurs have hindlimbs well adapted for hopping, suggesting a connection with archosaurs such as Scleromochlus.
|
|
Juvenile sauropods tend to have proportionally shorter necks and tails, and a more pronounced forelimb-hindlimb disparity than found in adult sauropods.
|
|
In 1972, Ronald J. Racine developed a method to split the severity of seizures into stages: mouth and facial movement, head nodding, forelimb clonus, rearing with forelimb clonus, and rearing and falling with forelimb clonus. Racine stages can be used to determine at which stages the patient is experiencing a seizure and at what level of stimulus the patient is able to reach a certain stage. Over time, mapping of the stimulus level and the resulting seizure intensity can show damage to the stimulated area. Mappings for patients can be made by sending electrical signals at different strengths to measure the body's reaction.
|
|
There is dark band running from behind the eye to the insertion of the forelimb. The upper surface of the upper forelimb is orange- brown. The ventrum is pale with some speckling. The call comprises a pulsed chirp of 4–6 pulses and is followed by 2–6 evenly spaced double clicks, often ending with one or two single pulse clicks.
|
|
The forelimb of Patagosaurus is much more gracile and different from the robust later sauropods like Camarasaurus, and Apatosaurus, and instead resembles more Diplodocus.
|
|
This information can also be used to predict locomotion patterns for extinct primates in cases where forelimb and hind limb fossils have been found.
|
|
The ulnae is no wider than the radii are, and they are both 5 mm long. An unknown carpal bone, probably an intermedium as it is quite elongate, is preserved between the ulna and radius of the right forelimb and there are three rounded carpal elements preserved in the left forelimb, one of which is the ulnare. The phalangeal formula is not known due to incomplete preservation.
|
|
Throughout the rest of the century, paleontologists would be occupied with several controversies regarding ceratopsian paleobiology. One concerned the stance of the ceratopsid forelimbs. When Marsh first reconstructed the ceratopsid forelimb, he portrayed it in an erect posture. However, when later researchers like Sternberg and Osborn tried to mount the skeletons, they found that the forelimb bones apparently sprawled despite the hindlimbs standing straight up and down.
|
|
It is also the case that a backthrust may occur in an asymmetric fold geometry as shear across the forelimb due to rotation and migration of beds. Symmetric faults were essentially covered previously under the name ‘lift-off’ folds, see figure 4. Progressive limb rotation and lock-up in a symmetric fold induces shear at both the forelimb and backlimb of the fold which may then result in faults on both limbs causing lift-off. Like the asymmetric fold faulting, as progressive slip along the basal detachment occurs, either the forelimb or backlimb (the limb closest to the source of thrust) thrust may reconnect with the basal detachment.
|
|
Individual cases of seven to ten nipples are known. There are five digits on each forelimb and four on the back-leg, a total of 18.
|
|
Lü J., Huang D. and Qiu L., 2005, "The Pectoral Girdle and the Forelimb of Heyuannia (Dinosauria: Oviraptorosauria)". In: Carpenter (ed.). The Carnivorous Dinosaurs. Indiana University Press.
|
|
Forelimbs in mammals have varying functions but are all homologous. A forelimb is an anterior limb (front arm, front leg, or similar appendage) on a terrestrial vertebrate's body. With reference to quadrupeds, the term foreleg is often used instead. (A forearm, however, is the part of the human arm or forelimb between the elbow and the wrist.) All vertebrate forelimbs are homologous, meaning that they all evolved from the same structures.
|
|
Duty factors over 50% are considered a "walk", while those less than 50% are considered a run. Forelimb-hindlimb phase is the temporal relationship between the limb pairs. If the same-side forelimbs and hindlimbs initiate stance phase at the same time, the phase is 0 (or 100%). If the same-side forelimb contacts the ground half of the cycle later than the hindlimb, the phase is 50%.
|
|
It is innervated by the accessory nerve. Trapezius: originates on the supraspinous ligament and inserts on the spine of the scapula. Its function is to elevate and abduct the forelimb. It is innervated by the accessory nerve. Rhomboideus: originates on the nuchal crest of the occipital bone and inserts on the scapula. Its function is to elevate the forelimb. It is innervated by the ventral branches of the spinal nerves.
|
|
The lengthening of the glenoid corresponds with a flattening of the proximal end of the humerus, a feature common in the forelimbs of more advanced stem tetrapods. Although the pectoral limb bones and girdle were not strong enough to support the weight of Tinirau out of water, glenoid lengthening and other changes to the proximal forelimb were among the first steps in the transformation from pectoral fin to forelimb.
|
|
In most modern ungulates, the radius and ulna were fused along the length of the forelimb; early ungulates, such as the arctocyonids, did not share this unique skeletal structure.Christine M. Janis, Kathleen M. Scott, and Louis L. Jacobs, Evolution of Tertiary Mammals of North America, Volume 1. (Cambridge: Cambridge University Press, 1998), 322-23. The fusion of the radius and ulna prevents an ungulate from rotating its forelimb.
|
|
The head, limbs and tail are greyish to yellowish-brown, with the front of each forelimb covered with large, angular scales and each thigh featuring several enlarged tubercles.
|
|
Amplexus has been found to involve different muscles in both male and female amphibians. The forelimb muscles in both males and females have been identified as the key muscles for amplexus that most species use. These forelimb muscles that are used during amplexus are typically larger in males than females, and for males these muscles contain more oxidative fibers, which could mean that amplexus involves an increased rate of aerobic metabolism. In addition to those forelimb muscles being larger in males, male frogs also typically have keratin pads or nuptial pads, which are located on their thumbs and contribute to the success of amplexus by assisting in gripping the female for the duration of amplexus.
|
|
The known skeleton includes most of the forelimb, shoulder girdle, pelvis, hindlimb and ribs of the holotype, and one shoulder bone, a radius and some vertebrae of the paratype.
|
|
The holotype of Z. shepardi is IGM 100/1321, consisting of the posterior region of the skull and lower jaws with articulation with cervical vertebrae, forelimb elements and osteoderms.
|
|
Dorsum and lateral side of head have glandular warts. Lower flank is granular. Dorsal part of forelimb, thigh, shank, and foot are smooth. Throat and chest are granular, smooth.
|
|
The scapulocoracoid (shoulder blade) was quite large and broad unlike most other avemetatarsalians. On the other hand, the glenoid (shoulder socket) was directed somewhat backwards (rather than sideways), as is the case with other dinosauriforms. The forelimb bones (consisting of a humerus, ulna, and radius) were very slender and shorter than the leg bones, and the forelimb as a whole was about half the size of the hindlimb. No portion of the hand was preserved.
|
|
In dinosaurs the main bones of the pectoral girdle were the scapula (shoulder blade) and the coracoid, both of which directly articulated with the clavicle. The clavicle was present in saurischian dinosaurs but largely absent in ornithischian dinosaurs. The place on the scapula where it articulated with the humerus (upper bone of the forelimb) is called the glenoid. The scapula serves as the attachment site for a dinosaur's back and forelimb muscles.
|
|
The only specimen is a partial right forelimb, including shoulder blade, upper arm bone, the two bones of the lower arm (ulna and radius), and three metacarpals. These fossils (Field number MGUAN-PA-003) are stored in the Museu de Geologia of the Universidade Agostinho Neto in Luanda. The upper arm bone measures , the ulna in length. In general, the forelimb was less robust than in most of the more derived titanosaurs.
|
|
The relatively large, and slightly recurved, pointed ten- to thirteen- centimeter (four- to five-inch) hand claws were likely used in self-defence. Pectoral girdle of skeletal cast Falcarius is known from many specimens, including complete forelimb specimens. Most of the bones of the pectoral girdle and forelimb are known, although sternal bones are not preserved. Both a left and right scapula are preserved, and they are both mostly complete as well.
|
|
A study showed that deletion of Tbx5 in forelimbs causes disruption in the muscle and tendon patterning without affecting the skeletons development. Tbx5 expression is in the cells of the lateral plate mesoderm which form the forelimb bud and the cascade of limb initiation. In its absence no forelimb bud forms. Diseases and defects associated with this gene are Holt-Oram syndrome, both have to do with limb defects and several other abnormalities.
|
|
The shape of the humerus is similar to the shortness of Neuquensaurus, although overall the forelimb is long, as in Diplodocus and Cetiosaurus, being 69% of the femur length. The distal end is roughened for a large cartilage cap as found in some other eusauropods like "Cetiosauriscus" greppini. The radius and ulna are broken, but complete they would have been long. The hindlimb of Cetiosauriscus is about the length of the forelimb.
|
|
In dinosaurs the main bones of the pectoral girdle were the scapula (shoulder blade) and the coracoid, both of which directly articulated with the clavicle. The clavicle was present in saurischian dinosaurs but largely absent in ornithischian dinosaurs. The place on the scapula where it articulated with the humerus (upper bone of the forelimb) is the called the glenoid. The scapula served as the attachment site for a dinosaur's back and forelimb muscles.
|
|
Early genera had long forelimbs, about 60% the length of the hindlimb in Guanlong, with the typical three digits of coelurosaurs. The long forelimb persisted at least through the Early Cretaceous Eotyrannus, but is unknown in Appalachiosaurus. Derived tyrannosaurids have forelimbs strongly reduced in size, the most extreme example being Tarbosaurus from Mongolia, where the humerus was only one-quarter the length of the femur. The third digit of the forelimb was also reduced over time.
|
|
Restoration Skin impression As a sauropod, Haestasaurus would have been a large quadrupedal long-necked dinosaur. Little information is available about the specifics of its build because only a forelimb is known of the animal. An indication of the size of Haestasaurus is given by the length of the forelimb elements. The humerus is 599 millimetres long, the ulna 421 millimetres and the radius, situated next to the ulna in the lower arm, has a length of 404 millimetres.
|
|
Dorsal forelimb has glandular warts. Smooth granular skin on throat and underside of thigh, and rough granular skin on chest and belly. Flanks and feet are granular (Manamendra-Arachchi and Pethiyagoda 2005).
|
|
The coracoids reach widths of nearly 14 inches. The forelimb is compressed mediolaterally when compared to the hind limb as well as limbs of other plesiosaurs.O’Keefe FR. 2001. Ecomorphology of plesiosaur flipper geometry.
|
|
It has a plain face with no nose leaf and with moderately large brown ears which have a long narrow tragus. It weighs an average of 13.9g and the forelimb length is 49.5mm.
|
|
In 1936 Charles Gilmore noted that previous reconstructions of Apatosaurus forelimbs erroneously proposed that the radius and ulna could cross; in life they would have remained parallel. Apatosaurus had a single large claw on each forelimb, a feature shared by all sauropods more derived than Shunosaurus. The first three toes had claws on each hindlimb. The phalangeal formula is 2-1-1-1-1, meaning the innermost finger (phalanx) on the forelimb has two bones and the next has one.
|
|
Although the holotype is very fragmentary, it exhibits an unusual combination of features that reveal a novel phylogenetic position. The forelimb exhibits a bird-like morphology that includes, among other things, a robust ulna, while the hindlimb appears to have been adapted for a cursorial lifestyle. A "sickle-claw" similar to that of dromaeosaurs is also present. Both a flight-adapted forelimb and a cursorial hindlimb are present in Rahonavis, also from Gondwana, and the describers suggest the two are closely related taxa.
|
|
Males of the species have notably longer humerus length resulting in a longer forelimb length; It is believed to give them an advantage while coupling and while fighting other males of the same species.
|
|
The Centralian blue-tongue is of a very robust build, short body and slender tail, and is among the largest 1% of species in the family Scincidae. Both the forelimb and hindlimb have five digits.
|
|
The specimen was extracted from an unknown locality in the Lower Sakamena Formation, an Upper Permian geological formation in Madagascar. The Sakamena Formation was formed by coastal rift valleys, and can be characterized by a diverse assortment of aquatic, semiaquatic, and terrestrial animals, including many early diapsids. The Acerosodontosaurus specimen is a partial skeleton preserved as a compression fossil within a sandstone nodule. The skeleton is mostly but not entirely articulated, preserving most of the trunk, right forelimb, and small portions of the left forelimb and hindlimbs.
|
|
Skeleton of the lower forelimb A fetlock (a MCPJ or a MTPJ) is formed by the junction of the third metacarpal (in the forelimb) or metatarsal (in the hindlimb) bones, either of which are commonly called the cannon bones, proximad and the proximal phalanx distad, commonly called the pastern bone. Paired proximal sesamoid bones form the joint with the palmar or plantar distal surface of the third metacarpal or metatarsal bones, and are rigidly fixed to the proximo-palmar or -plantar edge of the proximal phalanx.
|
|
It has been suggested that the long, powerful forelimbs of Heterodontosaurus may have been useful for tearing into insect nests, similarly to modern anteaters. These forelimbs may have also functioned as digging tools, perhaps for roots and tubers. Tianyulong restoration The length of the forelimb compared to the hindlimb suggests that Heterodontosaurus might have been partially quadrupedal, and the prominent olecranon process and hyperextendable digits of the forelimb are found in many quadrupeds. However, the manus is clearly designed for grasping, not weight support.
|
|
Bannykus, along with Xiyunykus, fills a 70-million year gap in alvarezsaur evolution by exhibiting morphologies intermediate between the typical theropod forelimb of Haplocheirus and the highly reduced forelimbs and minute teeth of Late Cretaceous alvarezsaurids.
|
|
The outer toes of Eohippus are no longer present in Orohippus, hence on each forelimb there were four fingers (toes) and on each hind leg three toes. Species of Orohippus has also been referred to Protorohippus.
|
|
The finding led to the study of the use of the forelimb in feeding behavior across all vertebrate species with the conclusion that forelimb use in feeding is conserved and extends to the phylogenetically earliest vertebrates. He further proposes that forelimb use includes at least three movements, a reach that extends arm/hand in relation to the extrinsic (location) properties of objects, a grasp that is made in relation to the intrinsic (size/shape) features of objects, and a withdraw that carries a grasped object to the mouth. Each of the movements is proposed to feature its own neural pathway or channel from sensory receptors to motor effectors and its own evolutionary history, accounting for the wide variety of hand and finger use skills in vertebrates. This work was influential in developing Feeding in Vertebrates, a book co-authored with Vincent Bels.
|
|
Functional morphology of the forelimb of mormoopid bats. Journal of Mammalogy, 51:217-235. The aspect ratio of the wings of one bat were calculated as 6.23, similar to M. megalophylla.Smith, J. D., and Starrett, A. 1979.
|
|
Its rostrum is shorter and more square-shaped than other species of its subfamily, Stenodermatinae Tavares, V. D. C. and A. Tejedor. 2009.The forelimb swellings of Pygoderma bilabiatum (Chiroptera: Phyllostomidae). Chiroptera Neotropical, 15(1): 411-416.
|
|
A Kovalev, AE Filippov, SN Gorb (2014) Unzipping bird feathers. J. R. Soc. Interface 11 (92) 20130988. Pennaceous feathers on the forelimb or wing are often attached strongly due to stresses related to flight or other activities.
|
|
This strong attachment is accomplished by ligaments under the skin, which in some birds and other feathered dinosaurs results in raised bumps or marks along the rear forelimb bone (ulna). These bumps, called quill knobs (ulnar papillae), are often used as an indirect indication of strongly-attached forelimb feathers in fossil species, and can also indirectly indicate the number of secondary remiges in a given specimen. Flight feathers (remiges and rectrices) are specialized types of pennaceous feathers, adapted for high loadings and often strongly asymmetric for improved flight performance.
|
|
The stegosaurian forelimb has evidence for a sauropod−like metacarpal configuration This was a different evolutionary strategy than megafaunal mammals such as modern elephants. Therapsids started evolving diverse and specialized forelimbs 270 million years ago, during the Permian.
|
|
Marine mammals have evolved several times. Over the course of their evolution, they develop streamlined hydrodynamic bodies. The forelimb thus develops into a flipper. The forelimbs of cetaceans, pinnipeds, and sirenians presents a classic example of convergent evolution.
|
|
Xiyunykus, along with Bannykus, fills a 70-million year gap in alvarezsaur evolution by exhibiting cranial and postcranial morphologies intermediate between the typical theropod forelimb of Haplocheirus and the highly reduced forelimbs and minute teeth of Late Cretaceous alvarezsaurids.
|
|
When it cannot reach prey in tight crevices and hole with its jaws, it will instead extract prey by reaching for it with a forelimb and hooking it out with its claws, allowing it to exploit a wider range of niches.
|
|
A claw hand can result of injuries to the inferior brachial plexus (C8 - T1). The condition may arise from the limb being suddenly pulled upward. For example, Klumpke paralysis can occur from excessive pulling of the infant's forelimb during parturition.
|
|
Restoration. Leptoceratops could probably stand and run on their hind legs: analysis of forelimb function indicates that even though they could not pronate their hands, they could walk on four legs. Leptoceratops was around long and could have weighed between .
|
|
DKK1 was also demonstrated to antagonize the Wnt/β-catenin pathway via a reduction in β-catenin and an increase in OCT4 expression. This inhibition plays a key role in heart, head and forelimb development during anterior morphogenesis of the embryo.
|
|
Restored skeleton in Oxford University Museum Research done by Phil Senter of the Lamar State College in Orange, Texas has indicated that Bambiraptor may have had mutually opposable first and third fingers and a forelimb maneuverability that would allow the hand to reach its mouth.Senter, P., 2006, "Comparison of forelimb function between Deinonychus and Bambiraptor (Theropoda: Dromaeosauridae)", Journal of Vertebrate Paleontology, 26(4): 897-906 This would have given the animal the ability to "hold" food in its front limbs and place it in its mouth, in a similar manner to some modern-day small mammals.
|
|
Associated Genetic Factors: c-Met/HGF and LBX1 Mutations in these genetic factors causes a lack of migration. LBX1 is responsible for the development and organization of muscles in the dorsal forelimb as well as the movement of dorsal muscles into the limb following delamination. Without LBX1, limb muscles will fail to form properly; studies have shown that hindlimb muscles are severely affected by this deletion while only flexor muscles form in the forelimb muscles as a result of ventral muscle migration. c-Met is a tyrosine kinase receptor that is required for the survival and proliferation of migrating myoblasts.
|
|
According to Kennedy: "Three angular unconformities within the Merced and overlying Colma Formations have formed on the steeply dipping fold forelimb". Mid to later Holocene fluvial channel deposits inset into the Merced Formation along the forelimb of the fold seem to be deformed, illustrating that the folding is active. The Serra Fault is a low angle imbricate fault that has thrust older Franciscan Assemblage rocks and soils of the Merced Formation over the younger Colma Formation. The Serra Fault was originally zoned as potentially active by the State of California (California, 1974) under the mandated special studies for surface fault rupture.
|
|
Section, in the transverse plane through the human midbrain at the level of the superior colliculus, that shows the rough path of each nervus oculomotorius from its nucleus toward the eye and the relative location of the red nucleus. For reference, the bottom of the picture is where the front of the head is located.. The red nucleus (RN), a group of neurons composed of the parvocellular red nucleus (pRN) and the magnocellular red nucleus (mRN), contributes to movement and motor control within the forelimb. Primate studies have shown that more forelimb mRN neuron discharges are observed when the location of the target object a primate is reaching is on the right or above. This demonstrates that although forelimb mRN neurons are involved in grasping movements to the left, right, above, and below, they play a greater role when an organism is attempting to reach an object to the right or above.
|
|
Distinctive cranial and cervical innervation of wing muscles: new evidence for bat monophyly. Science, 251(4996), 934-937. The strength and mass of forelimb musculature also had to be increased to allow powerful upstrokes and downstrokes.Thewissen, J. G. M., & Babcock, S. K. (1992).
|
|
All birds walk using hindlimbs. They have the ability to dig in two opposite directions using the hindlimbs. They can easily find food that makes them adapt on their surroundings. A bird with a forelimb that is very primitive is the Archaeopteryx.
|
|
1257633] The forelimb in the Archaeopteryx could have been used for parental care of offspring because enlarged feathers were possibly used to shield offspring from the suns' rays and for flight. (Carey, J.R., and Adams. J (2001))Carey, J.R. and Adams, J. (2001).
|
|
A biomechanical study conducted by Phil Senter (2006) used articulated casts of the Ornitholestes type specimen's right forelimb to determine its range of motion.Senter (2006), p. 1029–1030 Senter found that the antebrachium (forearm) could swing freely within a 95° range.Senter (2006), p.
|
|
In the forelimb, the ulna is exceptionally robust with a large olecranon process. Of the three patches with skin impressions found near the left shoulder, one shows a pattern of large, eight to eleven millimetres wide, hexagonal scales surrounded by smaller triangular scales.
|
|
Klinkhamer, A.J., Mallison, H., Poropat, S.F., Sloan, T. & Wroe, S., 2018. Comparative three-dimensional moment arm analysis of the sauropod forelimb: implications for the transition to a wide- gauge stance in titanosaurs. Anatomical Record; available online 12 October 2018. both of which involve Diamantinasaurus matildae.
|
|
A bat wing, which is a highly modified forelimb Bats are the only mammal capable of true flight. Bats use flight for capturing prey, breeding, avoiding predators, and long-distance migration. Bat wing morphology is often highly specialized to the needs of the species.
|
|
Egerton, pp. 64–65.Menkhorst and Knight, p. 94. The gliding possums have membranes called "patagia" that extend from the fifth finger of their forelimb back to the first toe of their hind foot. These membranes, when outstretched, allow them to glide between trees.
|
|
However, the glenohumeral articulation suggests a more conservative forelimb and girdle morphology than that of the pelvic girdle. Evidence points toward a sprawling position of the forelimbs, with an emphasis on long-axis rotation. This likely allowed for manoeuvrability, while the hindlimbs powered the animal.
|
|
Figure 4. Schematic depicting faulting of a symmetric detachment fold. The result of continued limb rotation and compression is the formation of faults in the forelimb and backlimb of the fold. Eventually these faults reconnect with the detachment and a pop-up may occur.
|
|
Appendicular forelimb skeleton The appendicular skeleton contains the fore and hindlimbs. The hindlimb attaches to the vertebral column via the pelvis, while the forelimb does not directly attach to the spine (as a horse does not have a collar bone), and is instead suspended in place by muscles and tendons. This allows great mobility in the front limb, and is partially responsible for the horse's ability to fold his legs up when jumping. Although the hindlimb supports only about 40% of the weight of the animal, it creates most of the forward movement of the horse, and is stabilized through attachments to the spine.
|
|
In the case of the barrel field, the map is somatotopic - based on the arrangement of body parts. Areas corresponding to the nose and mouth are more rostral and lateral in the map, the forelimb, hindlimb and trunk are more medial, with the forelimb rostral of the hindlimb, and the whisker barrel subfields - the posteromedial barrel subfield, which corresponds to the major facial whiskers (the mystacial vibrissae), and the anteriolateral barrel subfield, which corresponds to the smaller whiskers of the face - are caudal and lateral. Although the whiskers make up a relatively small portion of the animal, they dominate the somatotopic map.Hoover et al.
|
|
The flexion test is less useful to evaluate for subclinical joint disease, since a significant number of sound, unaffected horses can produce slightly positive results.Busschers, E. and Van Weeren, P. R. (2001), Use of the Flexion Test of the Distal Forelimb in the Sound Horse: Repeatability and Effect of Age, Gender, Weight, Height and Fetlock Joint Range of Motion. Journal of Veterinary Medicine, Series A, 48: 413–427. Additionally, forelimb flexion tests have been shown to have poor predictive value for future soundness or unsoundness, and are best interpreted in cases of clinical lameness, joint effusion, reduced range of motion, or pain on palpation.
|
|
The lateral plate mesodermal cells secrete fibroblast growth factors (FGF7 and FGF10) to induce the overlying ectoderm to form an organizer at the end of the limb bud, called the apical ectodermal ridge (AER), which guides further development and controls cell death. The AER secretes further growth factors FGF8 and FGF4 which maintain the FGF10 signal and induce proliferation in the mesoderm. The position of FGF10 expression is regulated by two Wnt signaling pathways: Wnt8c in the hindlimb and Wnt2b in the forelimb. The forelimb and the hindlimb are specified by their position along the anterior/posterior axis and possibly by two transcription factors: Tbx5 and Tbx4, respectively.
|
|
In 1912, Osborn suggested that this skin envelope represented webbing between fingers and that the forelimb would have functioned as a paddle, which he considered a clear indication of an aquatic lifestyle for Trachodon (= Edmontosaurus) and presumably other representatives of the Trachodontidae (= Hadrosauridae). The webbing would not only have connected the fingers with each other, but would also have extended up to beyond the fingertips. Furthermore, Osborn noted the lack of clearly pronounced hooves and large fleshy foot pads on the forelimb—features to be expected in a primarily land-dwelling animal. With the Senckenberg mummy, another Trachodon specimen with supposed webbing was discovered in 1910.
|
|
7, showing His's drawing of the forelimb of a deer embryo developing a clef, compared with a similar drawing (Sakurai, 1906) showing the forelimb initially developing as a digital plate with rays. Richardson and Keuck say "Unfortunately His's embryos are mostly at later stages than the nearly identical early stage embryos illustrated by Haeckel [top row of Haeckel's drawing]. Thus they do not inform the debate and may themselves be disingenuous." p. 518. Robert J. Richards, in a paper published in 2008, defends the case for Haeckel, shedding doubt against the fraud accusations based on the material used for comparison with what Haeckel could access at the time.
|
|
The paw is characterised by thin, pigmented, keratinised, hairless epidermis covering subcutaneous collagenous and adipose tissue, which make up the pads. These pads act as a cushion for the load-bearing limbs of the animal. The paw consists of the large, heart-shaped metacarpal or palmar pad (forelimb) or metatarsal or plantar pad (rear limb), and generally four load-bearing digital pads, although there can be five or six toes in the case of domestic cats and bears (including giant panda). A carpal pad is also found on the forelimb which is used for additional traction when stopping or descending a slope in digitigrade species.
|
|
Scott Gilbert proposed that the morphogenetic field is a middle ground between genes and evolution. That is, genes act upon fields, which then act upon the developing organism. Jessica Bolker described morphogenetic fields not merely as incipient structures or organs, but as dynamic entities with their own localized development processes, which are central to the emerging field of Evolutionary developmental biology ("evo-devo"). In 2005, Sean B. Carroll and colleagues mention morphogenetic fields only as a concept proposed by early embryologists to explain the finding that a forelimb bud could be transplanted and still give rise to a forelimb; they define "field" simply as "a discrete region" in an embryo.
|
|
Cuesta Fidalgo, Elena, Ortega, F., Sanz, J. (2015). Ulnar bumps of Concavenator: Quill Knobs or Muscular scar? Myological Reconstruction of the forelimb of Concavenator corcovatus (Lower Cretaceous, Las Hoyas, Spain). Abstracts of papers of the 75th Annual Meeting of the Society of Vertebrate Paleontology: 111-112.
|
|
Despite the huge reduction in size, no taxa in Ceratosauria ever lost a digit or any critical elements of the forelimb. Some joint variation has also been observed in Ceratosauria, and it has been postulated that they may have had better shoulder mobility than other large theropods.
|
|
7, 2017, pp. Royal Society Open Science, 2017, Vol.4(7). There features are often recognized in Triassic Sauropterygians. According to paleontologist Surmik, the presence of decompression syndrome-related avascular necrosis in Pistosaurus forelimb suggested that Pistosaurus used to live in aquatic or semi-aquatic environment.
|
|
The hip area and tail base were stiffened by large numbers of ossified tendons. Leg of S. harrisonii The scapula was short with a moderately expanded upper end. The coracoid was circular in side view. The elements of the forelimb were generally moderately long, straight and stout.
|
|
Carlson: Human Embryology and Developmental Biology, 4th Edition. Copyright 2009 by Mosby. 184-205. Tbx4 is expressed in the hindlimb, whereas Tbx5 is expressed in the forelimb, heart, and dorsal side of the retina. Studies have shown that fibroblast growth factor (FGF) play a key role in limb initiation.
|
|
A hypothetical scale diagram showing the Argyrosaurus holotype forelimb compared to some humans, with known material in white. Argyrosaurus was a medium-sized sauropod which is estimated to measure long and weighing up to according to Paul.Paul, Gregory S. Dinosaurs: A Field Guide. London: A. & C. Black, 2010. Print.
|
|
SAM 7416, another paratype, consists of an articulated vertebral column composed of the last dozen presacrals, both sacrals and at least the first 15 caudal vertebrae, fragments of right forelimb, pelvic girdle, complete right femur, right crus and partial left crus, and right and left tarsi and pedes.
|
|
It is related to Goggia essexi from which it can be distinguished mainly by the dorsal and ventral scaling and the colour markings. Dimensions: Body length about 30 mm, tail length 30 mm, head length 6 to 7 mm, head breadth 5.2 mm, forelimb 9 mm, hindlimb 12 mm.
|
|
The skeleton of a bird's wing. Places of attachment of various groups of flight feathers are indicated. The mute swan with outstretched wings Wing of the white-tailed eagle The bird's wing is a paired forelimb in birds. The wings give the birds the ability to fly, creating lift.
|
|
In four-legged animals, the radius is the main load-bearing bone of the lower forelimb. Its structure is similar in most terrestrial tetrapods, but it may be fused with the ulna in some mammals (such as horses) and reduced or modified in animals with flippers or vestigial forelimbs.
|
|
The holotype specimen, LH 7777, part of the Las Hoyas Collection presently housed at the Museo de Cuenca, Cuenca, Spain, of Pelecanimimus was recovered at the La Hoyas locality in Cuenca Province, Spain, from lagerstätte beds within the Calizas de La Huérguina Formation dating to the Lower Barremian. The only known specimen consists of the articulated front half of a skeleton and includes the skull, lower jaws, all the neck vertebrae and most of the back vertebrae, ribs, sternum, the pectoral girdle, a complete right forelimb and most of the left forelimb. Remains of the soft parts are visible at the back of the skull, around the neck and around the front limbs.
|
|
Skeleton of the lower forelimb Each forelimb of the horse runs from the scapula or shoulder blade to the navicular bone. In between are the humerus (arm), radius (forearm), elbow joint, ulna (elbow), carpus (knee) bones and joint, large metacarpal (cannon), small metacarpal (splint), sesamoid, fetlock joint, first phalanx (long pastern), pastern joint, second phalanx (short pastern), coffin joint, outwardly evidenced by the coronary band, and the third phalanx (coffin or pedal) bones. Each hind limb of the horse runs from the pelvis to the navicular bone. After the pelvis come the femur (thigh), patella, stifle joint, tibia, fibula, tarsal (hock) bone and joint, large metatarsal (cannon) and small metatarsal (splint) bones.
|
|
Restoration of Acrocanthosaurus engaging in alt= Like those of most other non-avian theropods, Acrocanthosaurus forelimbs did not make contact with the ground and were not used for locomotion; instead, they served a predatory function. The discovery of a complete forelimb (NCSM 14345) allowed the first analysis of the function and range of motion of the forelimb in Acrocanthosaurus. The study examined the bone surfaces which would have articulated with other bones to determine how far the joints could move without dislocating. In many of the joints, the bones did not fit together exactly, indicating the presence of a considerable amount of cartilage in the joints, as is seen in many living archosaurs.
|
|
This specimen consists of large portions of the tail, left forelimb, hip, and hindlimbs. Other Marasuchus fossils are stored at the PVL as well. PVL 3870 includes skull material, the entire presacral vertebral column, and a nearly complete hip and hindlimbs. PVL 3872 is a braincase and associated cervical (neck) vertebrae.
|
|
While they are less active moving on land, assuming a hip- extended body posture, on water, they use a distinct swimming model including forelimb-propelled locomotion. This particular behaviour has also been inferred for Halszkaraptor, and seems to support a piscivorous and aquatic life-style similar to that of mergansers.
|
|
In 1964 he published a volume on the birds of the Soviet Union along with Aleksandr Ivanovich Ivanov. He also worked on molluscs and on the evolution of birds. In 1978 his work on the comparative anatomy of the avian forelimb was published posthumously with a preface by Walter Bock.
|
|
These hairs are most developed around the mouth, which has a large horseshoe-shaped upper lip forming a highly mobile muzzle. This muscular upper lip aids the dugong in foraging. Bones in the forelimb can fuse variously with age. The dugong's tail flukes and flippers are similar to those of dolphins.
|
|
Jeholochelys fossils are considered evidence that hyperphalangy evolved multiple times among turtles; other coexisting sinemydids did not have an additional phalanx bone. The proportions of the forelimb in Jeholochelys was similar to that in soft- shelled turtles, and it may have been adapted for aquatic habits to a similar degree.
|
|
The toes have rudimentary webbing. The dorsal colouration is brown, forming a distinct dorsolateral colour border with the dark brown flanks. A distinct light stripe runs from the forelimb insertion to (almost) the nostril. The throat is dark grey with a distinct pattern of white spots forming a median row.
|
|
Gobipteryx is believed to have been capable of flight. The scapula is long, and therefore, well suited for flight by having more area for muscle attachment. In addition, the forelimb of Gobipteryx is more than twice the length of the thorax, falling within the acceptable range observed in flying birds.
|
|
Though most material is highly incomplete, Bathornis is nonetheless known from a variety of skeletal elements: hindlimbs (most commonly tarso-metatarsals), forelimb elements (especially humeri), pelvises and skulls.Federico L. Agnolin (2009). "Sistemática y Filogenia de las Aves Fororracoideas (Gruiformes, Cariamae)" (PDF). Fundación de Historia Natural Felix de Azara: 1–79.
|
|
In the shoulder girdle, the coracoid has a rectangular profile, in contrast to the more rounded shape with Panoplosaurus. Two sternal plates are present, connected to sternal ribs. The forelimb is robust but relatively long. In Edmontonia longiceps and E. rugosidens the deltopectoral crest of the humerus is gradually rounded.
|
|
Carpenter, K. and Wilson, Y. (2008). "A new species of Camptosaurus (Ornithopoda: Dinosauria) from the Morrison Formation (Upper Jurassic) of Dinosaur National Moument, Utah, and a biomechanical analysis of its forelimb". Annals of the Carnegie Museum 76: 227–263. doi:10.2992/0097-4463(2008)76[227:ansoco]2.0.co;2.
|
|
Apsaravis is the most basal bird that possesses an extensor process. This is a bony projection on metacarpal I that develops at the insertion of the m.extensor metacarpi radialis muscle and the propatagial ligaments. This anatomy functions to "automate" extension of the manus during extension of the forelimb in Aves.
|
|
The only material belonging to Oradectes is a partial skeleton known as MCZ 2989. This skeleton includes a complete skull, neck vertebrae, a partial pectoral girdle, the right forelimb, and some ribs. The skull is robust with spade-shaped teeth lining the jaws. The front teeth of the lower jaw protrude outward.
|
|
This may be correlated with the larger jaw size of females. While both males and females have glands below the jaw and surrounding the eyes, the glands in males are generally larger. Males also have forelimb swellings, which are not seen in females. The size and presence of such swellings varies geographically.
|
|
Fugusuchus is an extinct genus of erythrosuchid archosauriform. It was one of the earliest and most basal erythrosuchids. The genus is known from a single fossil from the middle Early Triassic Heshankou Formation in Shanxi, China. The partial skeleton consists of an incomplete skull, parts of the right forelimb, and an intercentrum.
|
|
The jacanas Actophilornis and Irediparra have an expanded, blade-like radius. The extinct Xenicibis was unique in having an elongate forelimb and massive hand which likely functioned in combat or defence as a jointed club or flail. Swans, for instance, may strike with the bony spurs and bite when defending eggs or young.
|
|
Yates recognized them as a separate taxon and published a description several years later. The holotype, or original specimen, consists of several vertebrae and numerous bones from both forelimb and hind limb, all presumed to be from one individual. Five more limb bones from another smaller individual were also referred to the genus.
|
|
Unfortunately, a positive response to forelimb flexion tests is one reason horses may be deemed unsuitable for purchase during the prepurchase exam. The wide range of significance attributed to these tests varies according to opinion and the experience of the examiner. While there have been many purchase exams discontinued solely because a positive response to a flexion test in one or both forelimbs, there’s really nothing in the veterinary literature to support such an action. Due to the variable response to the test depending on such things as the force applied, duration of the test, age of the horse and the day of examination, discontinuation of a prepurchase examination based solely on a failed forelimb flexion test is probably unwarranted.
|
|
A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints extremely similar to human fingerprints) are often described as having "hands" instead of paws on their front limbs. The raccoon is usually described as having "hands" though opposable thumbs are lacking. Some evolutionary anatomists use the term hand to refer to the appendage of digits on the forelimb more generally — for example, in the context of whether the three digits of the bird hand involved the same homologous loss of two digits as in the dinosaur hand.
|
|
The cheek teeth were short-crowned (brachyodont), with the tubercles more-or-less completely fused into transverse ridges, or cross-crests (lophodont type), and the total number of teeth was in one case the typical 44, but in another was fewer. The vertebra of the neck unite on nearly flat surfaces, the humerus had lost the foramen, or perforation, at the lower end, and the third trochanter to the femur may have also been wanting. In the forelimb, the upper and lower series of carpal (finger) bones scarcely alternated, but in the hind foot, the astragalus overlapped the cuboid, while the fibula, which was quite distinct from the tibia (as was the radius from the ulna in the forelimb), articulated with both astragalus and calcaneum.
|
|
B. heteropa can reach a length of snout-to-vent, and its tail may be more than 1.5 times that long. Its limbs are very small relative to its body length. It has four digits on each forelimb, and two digits on each hindlimb. Its body is covered by rows of large, overlapping, hexagonal scales.
|
|
Parts of the skeleton, like the pectoral girdle, tibia, and pubis are more robust, while others, like the forelimb and ischium, are more gracile. The material of Patagosaurus is similar to closely related taxa like Cetiosaurus and Volkheimeria, more primitive genera such as Barapasaurus and Amygdalodon, and more derived sauropods like Diplodocus and Camarasaurus.
|
|
TEAD2 is selectively expressed in a subset of embryonic tissues including the cerebellum, testis, and distal portions of the forelimb and hindlimb buds, as well as the tail bud, but it is essentially absent from adult tissues. TEAD2 has also been shown to be expressed very early during development, i.e. from the 2-cell stage.
|
|
This would have allowed it to have better night vision for catching insects. It is notable for its relatively derived forelimb morphology, having shoulder blades and other pectoral girdle elements comparable to those of modern therians like opossums. It also had grasping hands. By contrast, however, the hindlimbs retained primitive characters, suggesting a sprawling stance.
|
|
The fifth metacarpal had been lost. In all species, the first to third fingers are much smaller than the fourth, the "wingfinger", and contain two, three and four phalanges respectively. The smaller fingers are clawed, with the ungual size varying among species. In nyctosaurids the forelimb digits besides the wingfinger have been lost altogether.
|
|
Although this usage was common in the sciences for much of the 20th century, it is now considered rare. More generally, the term can refer to anything with distinctly human characteristics or adaptations, such as possessing opposable anterior forelimb-appendages (i.e. thumbs), visible spectrum-binocular vision (i.e. having two eyes), or biomechanic plantigrade-bipedalism (i.e.
|
|
Prefrontal and agranular cingulate projections to the dorsal premotor areas F2 and F7 in the macaque monkey (Fig. 3). European Journal of Neuroscience, 17(3), 559-578. Based on single unit recording and microstimulation it has been established that the SEF is caudally contiguous with the parts of the SMA which represent orofacial, and forelimb movements.Schall, J. D. (1991).
|
|
This may serve to increase colony size in species where females return to their natal colony to breed. A young bat's ability to fly coincides with the development of an adult body and forelimb length. For the little brown bat, this occurs about eighteen days after birth. Weaning of young for most species takes place in under eighty days.
|
|
The type species, Argyrosaurus superbus, was formally described by Richard Lydekker in 1893. The holotype specimen of Argyrosaurus superbus is a huge left forelimb, MLP 77-V-29-1. found at Chico River, a Campanian/Maastrichtian horizon in the Lago Colhué Huapi Formation.Argyrosaurus in the Paleobiology Database The material includes the humerus, ulna, radius, and all five metacarpals.
|
|
It consists of a partial skeleton belonging to a subadult individual. It includes two cervical, one dorsal and two caudal vertebrae; a right scapula; a left forelimb only lacking the carpus; a partial right illium and a fragmented ischium and pubis; the right femur; both tibiae, a right fibula and partial metatarsals. No skull traces were found.
|
|
However, it also retained some curiously primitive traits in common with non-mammaliaform cynodonts. The body was compact and the legs were short and robust. The articulation of the distal humerus was particularly expanded, indicating strong muscles for either digging or swimming. The front paws were relatively short, and the bones of the forelimb were curved and laterally compressed.
|
|
It is shorter than the forelimb but is about as long as the foot. The toes are webbed three-quarters to two-thirds of the way, with the exception of the outer metatarsals, which may be separated almost to the base. The subarticular tubercles are small. They also possess discs at the tips like the fingers.
|
|
Their biggest find was a nearly complete skeleton of Uintatherium. Fossils of Unitatherium are relatively common, but the specimen uncovered by Gazin's expedition was exceptionally complete and in high quality preservation. The only parts missing from the skeleton were the neck vertebrae, part of one forelimb, and a hindlimb. The fossil was discovered on a steep hillside slope.
|
|
This gene is one of several homeobox HOXD genes located in a cluster on chromosome 2. Deletions that remove the entire HOXD gene cluster or the 5' end of this cluster have been associated with severe limb and genital abnormalities. The product of the mouse Hoxd12 gene plays a role in axial skeleton development and forelimb morphogenesis.
|
|
Others think the legs were more sprawling, as evidenced by the shape of the forelimb bones. Although not as fast, this posture would have been efficient for grazing vegetation on the ground. Less is known about bipedal pachycephalosaur locomotion, although they must have had a fairly broad girth in order to make room for their enlarged gut.
|
|
Charles Andrews elaborated on differences between elasmosaurids and pliosaurids in 1910 and 1913. He characterized elasmosaurids by their long necks and small heads, as well as by their rigid and well-developed scapulae (but atrophied or absent clavicles and interclavicles) for forelimb-driven locomotion. Meanwhile, pliosaurids had short necks but large heads, and used hindlimb-driven locomotion.
|
|
In mice, however, both hindlimbs and forelimbs can develop in the presence of either Tbx4 or Tbx5. In fact, it is the Pitx1 and Pitx2 genes that appears to be necessary for specification of the developing hindlimb, whereas their absence results in forelimb development.Tbx4 and Tbx5 appear to be important specifically for limb outgrowth in mice.
|
|
Opposed to previous hypothesis, the forelimb of Augustasaurus was greatly reduced compared to Plesiosaurus. Therefore, Pistosauroidea was removed from stem group Plesiosauria and becomes paraphyletic group to Plesiosauria. Avascular necrosis, also known as bone necrosis, is associated with decompression syndrome (DCS). It is caused by expose rapid decrease of external pressure as well as rapid ascent in water column.
|
|
5α-Reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength, which has been proposed to be due to lack of 5α-reductase type 1 expression in bone and muscle. In 5 alpha reductase type 2 deficient males, the type 1 isoenzyme is thought to be responsible for their virilization at puberty.
|
|
The yellow spots might have dark brown centers or edging. Most specimens have a brown or dark brown canthal stripe that runs from the nostril through the eye to at least the forelimb insertion, sometimes further to the inguinal region of the hind limb. The throat is canary yellow. The belly is grayish blue or white.
|
|
Despite its name, the finless porpoise has two fins, and several species of legless lizards have tiny useless legs, such as pygopodids which retain rudimentary flaps. Contrarily, the worm lizard Bipes as its scientific name suggests has two stubby forelimbs which actually assist in digging similar to a mole. All other amphisbaenians have reduced or absent forelimb girdles.
|
|
The type specimen was discovered in one of Syncrude Canada Ltd.'s open- pit oilsand mines near Fort McMurray, Alberta, in 1994. The fossil is on display at the Royal Tyrrell Museum of Palaeontology, missing only the left forelimb and scapula, lost when the specimen was discovered accidentally by 100-ton electric shovel operators Greg Fisher and Lorne Cundal.
|
|
Size compared with a human Deinonychus possessed large "hands" (manus) with three claws on each forelimb. The first digit was shortest and the second was longest. Each hind foot bore a sickle-shaped claw on the second digit, which was probably used during predation. No skin impressions have ever been found in association with fossils of Deinonychus.
|
|
A. Hardel, Caen, 114 p., 8 pl. which was also inserted next year in volume 6 of the "Mémoires de la Société Linnéenne Normandie". The holotype, which was housed in Musée de la Faculté des Sciences de Caen and destroyed during World War II, included gastralia, phalanges, a left forelimb, caudal vertebrae, chevrons, ribs and a hindlimb.
|
|
The odontoid may have been encased in a keratinous covering so that it could occlude with the teeth. Apart from the skull, the skeleton of Istiodactylus was similar to those of other ornithocheiroid pterosaurs. The vertebral column, forelimb, and trunk bones were pneumatised by air sacs. The neural arches of the vertebrae had tall, sloping laminae.
|
|
There was a dark stripe that ran from the eye to the base of the forelimb. The ventral surface (belly) was white with large patches of cream or pale yellow. The toes and fingers were light brown with pale brown flecking. The end of each digit had a small disc and the iris was dark brown.
|
|
This gene is one of several homeobox HOXD genes located in a cluster on chromosome 2. Deletions that remove the entire HOXD gene cluster or the 5' end of this cluster have been associated with severe limb and genital abnormalities. The product of the mouse Hoxd11 gene plays a role in axial skeleton development and forelimb morphogenesis.
|
|
Navajodactylus was tentatively assigned to the Azhdarchidae because of its geological age, however, it does not show any synapomorphies of the group. Indeed, it may not actually be an azhdarchid, as it lacks pneumacy in its forelimb elements, which is opposed to the extensive pneumacy seen in azhdarchids.Wilton, Mark P. (2013). Pterosaurs: Natural History, Evolution, Anatomy.
|
|
In dinosaurs the main bones of the pectoral girdle were the scapula (shoulder blade) and the coracoid, both of which directly articulated with the clavicle. The place on the scapula where it articulated with the humerus (upper bone of the forelimb) is called the glenoid. The glenoid is important because it defines the range of motion of the humerus.Martin, A.J. (2006).
|
|
Preserved portions of the shoulder girdle indicate that Cabarzia had a thin scapula with a convex front edge. The pelvis included an ilium with a long and low dorsal blade and a pubis with a small tubercule. The forelimb is short and robust relative to the long and slender hindlimb. The humerus in particular is thick, with a large entepicondyle.
|
|
Transcription factor LBX1 is a protein that in humans is encoded by the LBX1 gene. This gene and the orthologous mouse gene were found by their homology to the Drosophila lady bird early and late homeobox genes. In the mouse, this gene is a key regulator of muscle precursor cell migration and is required for the acquisition of dorsal identities of forelimb muscles.
|
|
All three are based on fragmentary material, and were regarded as indeterminate in the most recent review. M. browni is based on two cervical, two back, and three caudal vertebrae and miscellaneous hind limb elements. M. harriesi is known from a well-preserved forelimb and parts of a hindlimb. M. schwarzi is known from an incomplete hind limb and sacrum.
|
|
Relatives have been found in other parts of Italy and New Mexico and New Jersey as well, in similar woodlands. Drepanosaurus is much larger than its relatives, more than double the length of Megalancosaurus. All drepanosaurs are thought to be tree-dwelling insectivores with similar body structures to Drepanosaurus, except for minor differences usually dealing with forelimb configuration and head shape disparities.
|
|
In 2007, Xu et al. assigned Gigantoraptor to the Oviraptoridae, in a basal position. The anatomy of Gigantoraptor includes the diagnostic features of the Oviraptorosaurs. However, it also includes several features found in more derived eumaniraptoran dinosaurs, such as a forelimb/hindlimb ratio of 60%, a lack of expansion of the distal scapula and the lack of a fourth trochanter on the femur.
|
|
In 1988, a Tyrannosaurus rex known as "Devil Rex" (MOR 555) was unearthed in the Russell National Wildlife Refuge. The specimen skeleton was approximately 46 percent complete and included the first complete T. rex forelimb. Doctoral candidate Mary Schweitzer found heme, a biological form of iron that makes up hemoglobin (the red pigment in blood), within some bones of the fossil.Schontzler, Gail.
|
|
Evolution of the forelimb may be characterized by many trends. The number of digits, their characteristics, as well as the shape and alignment of radius, ulna, and humerus, have had major evolutionary implications. Changes in body size, foot posture, habitat, and substrate are frequently found to influence one another (and to connect to broader potential drivers, such as changing climate).
|
|
The lowland streaked tenrec (Hemicentetes semispinosus) belongs to the family Tenrecidae in the order Afrosoricida, and more specifically to the subfamily of the spiny tenrecs Tenrecinae.Endo, H., Oishi, M., Yonezawa, T., Rakotondraparany, F., & Hasegawa, M. (2007). The semifossorial function of the forelimb in the common rice tenrec (Oryzorictes hova) and the streaked tenrec (Hemicentetes hemispinosus). Anatomia, histologia, embryologia, 36(6), 413-418.
|
|
Aside from elongate hind limbs, Tianyuraptor is different from other members of Microraptorinae in regards to the relative lengths of the forelimb elements. The forelimbs of Tianyuraptor are proportionally much shorter than those of larger dromaeosaurids. For example, a similar-sized Velociraptor specimen shows an arm/leg length ratio of approximately 0.75., while Tianyuraptor has an arm/leg ratio of 0.53.
|
|
Comparison of the forelimb of Archaeopteryx (right) with that of Deinonychus (left) Modern paleontology has often classified Archaeopteryx as the most primitive bird. It is not thought to be a true ancestor of modern birds, but rather, a close relative of that ancestor. Nonetheless, Archaeopteryx was often used as a model of the true ancestral bird. Several authors have done so.
|
|
Skeletal anatomy of a harbor seal. 1. Skull. 2. Spine. 3. Tail. 4. Hindlimb. 5. Forelimb. 6. Shoulder. 7. Pelvis. 8. Rib cage. Paul de Vos:Two young seals on a beach The earless seals, phocids or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae .
|
|
There are numerous small dark brown blotches arranged in rows along the skin folds, except for the outermost ones. A dark streak passes from snout tip through the eye and the tympanum, ending behind the forelimb insertion. The upper lip and infra- tympanic ridge are pale. The tibia have 2–5 transverse bars, often narrowly interrupted by a tibial line.
|
|
Publishing House, Pyongyang, DPRK. A single species, "Proornis coreae", is known. Fossil remains of this animal, discovered in 1993 in Sinuiju series deposits at Sinuiju-si, consist of a skull, a few cervical vertebrae and a forelimb with feathers. Lee, Yuong-Nam; Yu, Kang-Min & Wood, Craig B. (2001): A review of vertebrate faunas from the Gyeongsang Supergroup (Cretaceous) in South Korea.
|
|
Limb skeleton of a lion, an example of an angulated bony column Even many terrestrial vertebrates exhibit differences in the scaling of limb dimension, limb coordination and magnitude of forelimb-hind limb loading, in the dog, horse and elephant the structure of the distal forelimb is similar to that of the distal hind limb. In the human, the structures of the hand are generally similar in shape and arrangement to those of the foot. Terrestrial vertebrate quadrupeds and bipeds generally possess distal limb and foot endoskeleton structures that are aligned in series, stacked in a relatively vertical orientation and arranged in a quasi- columnar fashion in the extended limb. In the dog and horse, the bones of the proximal limbs are oriented vertically, whereas the distal limb structures of the ankle and foot have an angulated orientation.
|
|
The limb field is a region specified by expression of certain Hox genes, a subset of homeotic genes, and T-box transcription factors – Tbx5 for forelimb or wing development, and Tbx4 for leg or hindlimb development. Establishment of the forelimb field (but not hindlimb field) requires retinoic acid signaling in the developing trunk of the embryo from which the limb buds emerge. Also, although excess retinoic acid can alter limb patterning by ectopically activating Shh or Meis1/Meis2 expression, genetic studies in mouse that eliminate retinoic acid synthesis have shown that RA is not required for limb patterning. The limb bud remains active throughout much of limb development as it stimulates the creation and positive feedback retention of two signaling regions: the AER and its subsequent creation of the zone of polarizing activity (ZPA) with the mesenchymal cells.
|
|
The shoulder and forelimb are broadly similar to those of Azendohsaurus, with a tall scapula that is concave along the front with an expanded tip, and an interclavicle with a long paddle-like process on the back and a short forward-pointing process (an unusual feature for archosauromorphs but also found in Azendohsaurus). The coracoid articulates with the scapula to form a glenoid (shoulder socket) that faces out to the sides and back, a feature in Azendohsaurus suggested to indicate the forelimb was held more upright than a full sprawl. The humerus is likewise similar, with broad ends and a narrow midshaft, and a very well-developed deltopectoral crest half as long as the whole bone, indicating powerful forelimbs. The ulna, however, can be distinguished by a lower olecranon process below the elbow than in Azendohsaurus.
|
|
Known material of the skull in multiple views Nasutoceratops is known from the holotype UMNH VP 16800, a partially associated nearly complete skull, a coronoid process, a syncervical, three partial anterior dorsal vertebrae, a shoulder girdle, an associated left forelimb, parts of the right forelimb and skin impressions. Two specimens were referred: UMNH VP 19466, a disarticulated adult skull consisting of an incomplete premaxilla, maxilla and nasal, and UMNH VP 19469, an isolated squamosal of a subadult. The holotype was discovered and collected in 2006 during the Kaiparowits Basin Project, initiated by the University of Utah in 2000. It was recovered from channel sandstone from the middle unit of the upper Kaiparowits Formation within the Grand Staircase-Escalante National Monument, in sediment that dates to the late Campanian stage of the Cretaceous period, approximately 75 million years ago.
|
|
Skeletal reconstruction showing known remains in white and light gray, and unknown in dark gray. The holotype specimen, ULBRA-PVT280, was discovered in the Buriol ravine in São João do Polêsine, Brazil. These rocks are part of the Santa Maria Formation, which dates to the Carnian epoch. The specimen consists of a single skeleton preserving parts of the skull, vertebrae, left forelimb, and left hindlimb.
|
|
Surveys of handlers indicates that about 1 in 3 dogs incur injuries from agility related activities. The most common types of injuries were (in order) strains, sprains and contusions. Locations most commonly injured were shoulders, back, phalanges (forelimb/hindlimb) and neck. Injuries were most commonly perceived as being caused by interactions with bar jumps (contact), A-frames and dog walk obstacles (contact and/or fall).
|
|
The forelimbs are moderately robust; the P. mephistocephalus holotype has a quite robust humerus and ulna, however. The hand is completely known, which is exceptional for ankylosaurids. It has five digits, and the phalangeal formula is 2-3-3-3-2, meaning that the innermost finger of the forelimb has two bones, the next has three, etc. The metatarsals are closely appressed and held vertical.
|
|
The order Chiroptera, comprising all bats, has evolved the unique mammalian adaptation of flight. Bat wings are modified tetrapod forelimbs. Because bats are mammals, the skeletal structures in their wings are morphologically homologous to the skeletal components found in other tetrapod forelimbs. Through adaptive evolution these structures in bats have undergone many morphological changes, such as webbed digits, elongation of the forelimb, and reduction in bone thickness.
|
|
Another major difference in bat forelimbs is in the density of their skeletal limbs. The bones found in their forelimbs are reduced to achieve a light body weight required for flight. In particular, their ulna is reduced in width and fused to the other zeugopod element, the radius. One of the possible molecular pathways involved in reduction of bat skeletal forelimb thickness is differences in SHH expression.
|
|
He also described another practically complete skeleton (including skull material) kept at the Bloemfontein Museum, a specimen now designated as NMQR 1483. He also mentioned a jaw fragment, now known as SAM- PK-2783.Most other analyses consider Uranocentrodon to be distinct from Rhinesuchus. Other known remains include TM 185 (a skull described by Broom in 1930), TM 208 (a right forelimb), and CGP 4095 (another skull).
|
|
Jixiangornis is a genus of primitive euavialans from the Early Cretaceous. Like later avialans, it had no teeth, but it also had a long tail, unlike modern birds. Since teeth were still present in some more advanced short- tailed avialans, Jixiangornis seems to have evolved its toothlessness independently of modern birds. The long forelimb (131% of hindlimb length) indicates at least some aerial ability.
|
|
Angolatitan ("Angolan giant") is a genus of sauropod dinosaur from the Upper Cretaceous and the first non-avian dinosaur discovered in Angola. Based on a forelimb, it was described in 2011 by Octávio Mateus and colleagues. The only species is Angolatitan adamastor. Angolatitan was a relict form of its time, being a basal titanosauriform sauropod in the Late Cretaceous, when more derived titanosaurs were far more common.
|
|
This pattern of retractor muscles points to an elephantine locomotion, consistent with columnar posture. Restoration of Euoplocephalus forelimbs demonstrate similarities to crocodilian forelimb musculature. The most well developed muscles in the pectoral region had more of a weight- bearing function than a rotational one. It has also been postulated that the carpals and metacarpals bear resemblance to those of tetrapods with fossorial (burrowing) habits.
|
|
As in Archaeopteryx, the skull of Sinornis has a proportionately short, toothed snout. There are broad nasal bones that expands caudally to the external nares, with a triangular caudal margin. The dorsal and central margins of the caudal half of the maxilla run parallel while its jugal ramus does not taper caudally. The postcranial skeleton features a separate carpus and manus in the forelimb.
|
|
The forelimbs of Appalachiosaurus are poorly known. Large tyrannosaurids are characterized by proportionally small forelimbs and hands with two functional digits each; except some reports of a humerus ascribed to Appalachiosaurus, no forelimb material are known. Early reconstructions gave it long arms with three fingers, but they are now thought to have been much shorter, with only two fingers. Museum mounts have been corrected accordingly.
|
|
Their hind limbs are in a plantigrade stance and are able to rotate under the body for quadrupedal locomotion and support. When swimming, there are two different types of movement: locomotion and diving. These seals swim primarily with forelimb propulsion due to their physiology. They have flexible joints between vertebrae for better maneuverability in the water as well as "greater muscular leverage" for pectoral strokes.
|
|
Although some of the phalanges are missing, it is believed that the phalanges formula is 2, 3, 4, 5, 3, 3. The femur is thought to be the longest bone. The tibia is more developed than the fibula, and they are 94% of the length of the femur. Taking all the bones into account, the forelimb is 91% the length of the hind limb.
|
|
Elbow flexion is usually only performed when joint abnormality is found during physical examination. Flexion may be performed by lifting the forelimb (antebrachium) so that it is parallel to the ground, while allowing the knee and distal limb to hang free to help prevent pressure on these joints. Unfortunately, elbow flexion often produces some flexion in the shoulder, and these joints are difficult to localize.
|
|
Dermal impressions are more widespread in the material of Tehuelchesaurus, where they are known from the areas of the forelimb, scapula and torso. There are no bony plates or nodules, to indicate armour, but there are several types of scales. Skin associated with the scapular blade is the largest, arranged in rosettes (spiral formations) with a smooth, hexagonal shape. These largest tubercles are , surrounded by smaller scales.
|
|
The dorsal claustrum has bi- directional connections with motor structures in the cortex. The relationship between animal's movement and how neurons in the dorsocaudal claustrum behaves are as follows: 70% of movement neurons are non-selective and can fire to do any push, pulls or turn movements in the forelimb, the rest were more discerning and did only one of the three movements listed above.
|
|
Pantosaurus possesses between 35 and 40 cervical vertebrae, which are very similar in proportion and morphology to those of Muraenosaurus leedsii from the Oxford Clay Formation (Callovian, Middle Jurassic) of England. The forelimb of Pantosaurus however can be differentiated from that of Muraenosaurus, such as the relatively large size of the radius and the corresponding humerus-radius articulation. No Pantosaurus cranial material has yet been discovered.
|
|
During the attack, it snaps at the object with its tongue or jaws and swallows it. Finally, it wipes its mouth with a forelimb. These actions constitute a series of well- defined behavioral patterns. One reason for this type of stimulus-response chain is that, unlike humans, toads do not have involuntary saccadic eye movements and they also cannot perform "tracking eye movements" (Ewert 1980).
|
|
Carpenter (2002) examined the bio-mechanics of theropods forelimbs and attempted to evaluate their usefulness in predation. He concluded that the forelimb of Coelophysis was flexible and had a good range of motion, but its bone structure suggested that it was comparatively weak. The "weak" forelimbs and small teeth in this genus, suggested that Coelophysis preyed upon animals that were substantially smaller than itself. Rinehart et al.
|
|
Another symptom of this syndrome is bone abnormalities in the fingers, wrists, or arms. An additional defect that Holt- Oram syndrome can cause is a conduction disease leading to abnormal heart rates and arrhythmias. Amelia syndrome is a condition where forelimb malformation occurs because FGF-10 is not triggered due to Tbx5 mutations. This condition can lead to the absence of one or both forelimbs.
|
|
Eight posterior dorsal vertebrae, a sacrum of six vertebrae and a tail of thirty-six vertebrae have been preserved, together with a partial ischium, a forelimb and a hindlimb. The describers considered Nanyangosaurus to be of Albian age because of its primitiveness, but the type horizon is now believed to be Turonian-Campanian in age based on plant and invertebrate fossils.Wang, D. et al., 2013.
|
|
The globular osteocyte lacunae become more flattened as you get closer and closer to the midshaft of the humerus. While the vasculature is present, the humerus contains no secondary osteons. The radii and ulnae of Thrinaxodon represent roughly the same histological patterns. In contrast to the humerii and femora, the parallel-fibred region is far more distinct in the distal bones of the forelimb.
|
|
Skeleton of "Saltillomimus" "Saltillomimus" is an informal name for an ornithomimid theropod from the Late Cretaceous (late Campanian) of the Cerro del Pueblo Formation in Mexico. It is known from a partial tail, most of a hindlimb, and forelimb bones that was given the name "Saltillomimus rapidus" by Martinez in 2010. Named in his thesis, the taxon name is an invalid nomen ex dissertatione.
|
|
Life restoration of Cetiosauriscus as a eusauropod Cetiosauriscus was originally classified by Huene as a genus in the family Cetiosauridae, within the subfamily Cardiodontidae. The subfamily, including the other taxa Cetiosaurus, Haplocanthosaurus, Dystrophaeus, Elosaurus and Rhoetosaurus, was founded upon the general basal features of elongate cervicals and shortened dorsals—both opisthocoelous, amphicoelous caudals that are rod-shaped distally, paired sternal plates, an ilium lacking the postacetabular process (region of the ilium behind the ischium joint and acetabulum), a very wide pubis, wide distal ischium, significantly shorter forelimb than hindlimb, fibula lacking the middle muscle attachment, and long metacarpals and short metatarsals. This classification was emmended in 1932 when Huene concluded Cetiosauriscus was closer to Haplocanthosaurus than Cetiosaurus in the family, because of forelimb and hindlimb proportions. Conversely, in 1956, Alfred Romer synonymised Cetiosauriscus and Cetiosaurus, a position that has not been followed by subsequent studies on the taxon.
|
|
Black-bellied fruit bats can weigh up to 63 grams, average 94.13 mm in length and have a forelimb average measurement of 59.99 mm. They have a unique counter shading pattern of a black underside and burnt orange backs. Research has determined that the black-bellied fruit bat is "strongly indicated as a sister taxon to all megachiropterans" and that they are likely a primitive form of the family Pteropodidae.
|
|
The interclavicle is spoon-shaped, concave from above and convex from below, although its true shape is unknown due to the rear portion being broken off. Overall it is more similar to those of paracrocodylomorphs rather than phytosaurs. The only portion of the forelimb known for this genus was the humerus (upper arm bone). Its medial edge was concave while the lateral edge was almost straight as in phytosaurs.
|
|
It consists of a skull and the anterior part of the postcranial skeleton: seven neck vertebrae, ten back vertebrae, the left shoulder girdle, the left forelimb, the two cervical halfrings and extensive armour in life position. The holotype is largely articulated. Referred specimens include ZPAL MgD-I/114 consisting of an undescribed fragmentary skull roof and associated armour, and an undescribed, almost complete skeleton with skull, specimen PIN 3142/251.
|
|
Its lower end is connected to a semicircular coracoid. The furcula is broad and more or less U-shaped with its two branches angled at 125°. The forelimb is rather long; its length is equal to 48% of the body length in front of the pelvis. Especially the hand is elongated as is typical for compsognathids; for a member of that group Scipionyx has a relatively short hand, however.
|
|
The ear is typical of the spotted hyena, as it is rounded. An image in the Le Gabillou Cave in Dordogne shows a deeply engraved zoomorphic figure with a head in frontal view and an elongated neck with part of the forelimb in profile. It has large round eyes and short, rounded ears which are set far from each other. It has a broad, line-like mouth that evokes a smile.
|
|
The successive discovery (1990) of a Middle Jurassic primitive ornithischian, Agilisaurus louderbacki, found in the Xiashaximiao Formation of Zigong, Sichuan Basin, China, has led to paleontologists learning more about the phylogeny of fabrosaurids. Fabrosaurids have many characters that are unique to their physiology, particularly unique tooth morphology and structure, and short forelimb lengths compared to hindlimbs.Galton, P. M. (1978). Fabrosauridae, the basal family of ornithischain dinosaurs (Reptilia: Ornithopoda). Palaontol.
|
|
Referred forelimb bone (humerus) from Potter Creek, USNM 21903 Several additional specimens were briefly described by Jensen in 1987. One of these finds, the humerus USNM 21903, was discovered in ca. 1943 by uranium prospectors Vivian and Daniel Jones in the Potter Creek Quarry in western Colorado, and donated to the Smithsonian Institution. Originally, this humerus was part of a poorly preserved partial skeleton that was not collected.
|
|
This would have made the limbs flipper-like. The forelimb flippers of Cartorhynchus were curved backwards, with the digits being tilted 50° relative to the axis of the long bones (zeugopodium), while the hindlimbs were curved forwards. The femur of Cartorhynchus was straight and not expanded at its bottom end. Sclerocormus had similar limbs, except they were better- ossified and their preserved curvature may not have been natural.
|
|
Close up skeletal of Fin whale flipper Whales and their relatives have a soft tissue flipper that encases most of the forelimb, and elongated digits with an increased number of phalanges. Hyperphalangy is an increase in the number of phalanges beyond the plesiomorphic mammal condition of three phalanges-per- digit. This trait is characteristic of secondarily aquatic vertebrates with flippers. Hyperphalangy was present among extinct ichthyosaurs, plesiosaurs, and mosasaurs.
|
|
In 1852, the collector Samuel Husband Beckles obtained a block of Wealden Sandstone that had become visible at low tide off the coast of East Sussex near Hastings. The precise location is today unknown. It proved to contain a large forelimb which was studied by Gideon Mantell. The same year, Mantell in a lecture named the find as a second species of Pelorosaurus: Pelorosaurus becklesii, the specific name honouring Beckles.
|
|
Also, not like the living crocodiles, the ulna and radius of Orthosuchus, or other typical archosaurs, are around 88% of the length of the humerus, while the radius and ulna in modern crocodiles are the shortest elements in the forelimb. It has two non-elongated carpals, with one of the elliptical shape. Orthosuchus appeared to have 5 digits. The first digit is the shortest and the fifth digit is the weakest.
|
|
As a result of the constant digging action, elements of the forelimb that are associated with those movements will begin to ossify. Some elements in the hands of Talpa europaea, formally described as distal phalanges, are actually the first to ossify. These elements build up a groove for the distal phalanges, but ultimately do not fuse with them. These bony elements develop directly, meaning they do not have any cartilaginous precursors.
|
|
The body and the long neck have spots, including the flanks. An image on a cave in Ariège shows an incompletely outlined and deeply engraved figure, representing a part of an elongated neck, smoothly passing into part of the animal's forelimb on the proximal side. Its head is in profile, with a possibly re-engraved muzzle. The ear is typical of the spotted hyena, as it is rounded.
|
|
The forelimb was more robust than the hindlimb. It was thought that the coracoid was longer than the scapula or shoulder blade, unlike most advanced pterosaurs, but the type specimen had a poorly-preserved coracoid and the second specimen showed this to not be the case. Zhenyuanopterus had relatively short cervical vertebrae compared to Feilongus. Several of the dorsal vertebrae are fused into a notarium, an indicator of maturity.
|
|
It is a large adult size frog with snout to vent length in males ranging between 55–69 mm and females being larger and up to 106 mm. The snout is obtusely pointed when observed from both dorsal and ventral planes and protrudes beyond the lower jaw. Tongue is spatulate and bifid without lingual papilla. Tympanum is distinct and a supra-tympanic fold from back of eye to forelimb is prominent.
|
|
The bones of the forelimb were slender and unspecialized, similar to those of Euparkeria rather than the robust structures of Erythrosuchus. The metacarpals were long and slender, but the hand was not complete enough to come to specific conclusions on its structure. The hindlimbs were also typical of generalized early archosauriforms, and the femur (thigh bone) had an apparent fourth trochanter. The metatarsals were also similar to those of Euparkeria.
|
|
For example, the flipper of a turtle or of a dolphin, the arm of a human, the foreleg of a horse, and the wings of both bats and birds are ultimately homologous, despite the large differences between them. Specific uses of the forelimbs may be analogous if they evolved from different sub-structures of the forelimb, such as the flippers of turtles and dolphins, and the wings of birds and bats.
|
|
Like most other tetrapods, the forelimb of birds consists of the shoulder (with the humerus), the forearm (with the ulna and the radius), and the hand. The bird's hand is strongly transformed: some of its bones have been reduced, and some others have merged with each other. Three bones of the metacarpus and part of the carpal bones merge into a carpometacarpus. The bones of three fingers are attached to it.
|
|
Eufalconimorphae is a proposed clade of birds, consisting of passerines, parrots, falcons, caracaras, and forest falcons (but not other raptors). It has whole-genome DNA support. The Eufalconimorphae is noted to produce aerodynamic force during the upstroke of the flight, this is supposed to help create a vertical flight pattern.Razmadze, Daria, et al. “Anatomy of the Forelimb Musculature and Ligaments of Psittacus Erithacus (Aves: Psittaciformes).” Journal of Anatomy, vol.
|
|
Within the infraorder he placed Deinocheiridae and Therizinosauridae, finding reason for the families to be united. In 1983, Barsbold elaborated, mentioning features uniting deinocheirids and therizinosaurids, mainly in the region of the hand and forelimb. He hypothesized that deinocheirosaurs would have had moderately- sized skull even though they were gigantic in size. Deinocheirus was mentioned and diagnosed as the only deinocheirid, while Therizinosaurus was mentioned to be the only therizinosaurid.
|
|
The thirteenth tail vertebra formed the transition point between the deep tail base and the middle tail that was stiffened by rather long front articulation processes. The underside of the trunk was covered by eighteen or nineteen pairs of segmented belly ribs. Furcula of specimen "Sue" The shoulder girdle was longer than the entire forelimb. The shoulder blade had a narrow shaft but was exceptionally expanded at its upper end.
|
|
In other cetaceans, the olfactory nerves are similarly present but strongly reduced. # The elbow joint is immobile, as shown by a single partial forelimb. placed Odobenocetopssidae in a large clade together with Phocoenidae (porpoises), Monodontidae (narwhal and beluga), and Albireonidae (an extinct group similar to porpoises). This clade originated in the Pacific Ocean in the Langhian (15–13 ma) and diversified from there during the Serravallian and Tortonian (13–7 ma).
|
|
It was discovered in 1971 during an uranium and thorium exploration by Kenny F. Larsen and was donated to the Dalhousie University in 2004. It was described but not named in 2008; by then it made its way into the collection of the Royal British Columbia Museum in Victoria. It was named in 2019. The holotype, RBCM P900 includes portions of the pectoral girdles, left forelimb, left hindlimb, and right pes.
|
|
Alan Gishlick, in a 2001 study of Deinonychus forelimb mechanics, found that even if large wing feathers were present, the grasping ability of the hand would not have been significantly hindered; rather, grasping would have been accomplished perpendicular to the wing, and objects likely would have been held by both hands simultaneously in a "bear hug" fashion, findings which have been supported by the later forelimb studies by Carpenter and Senter. In a 2001 study conducted by Bruce Rothschild and other paleontologists, 43 hand bones and 52 foot bones referred to Deinonychus were examined for signs of stress fracture; none were found.Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, pp. 331–336. The second phalanx of the second toe in the specimen YPM 5205 has a healed fracture.
|
|
It includes the (lower jaws), an incomplete , a complete and (lower arm bones), of the fingers, a forelimb (claw bone), an almost-complete , an incomplete right , six , ten from the front of the tail, fifteen from the hindmost part of the tail, the first , and fragments of the dorsal ribs. Two more specimens were designated as paratype specimens; specimen IGM 100/82 from the Khara Khutul locality includes a femur, and (leg bones), and , five toe phalanges including a foot ungual, rib fragments, complete , the upper portion of an , and the lower portion of a . Specimen IGM 100/83 includes a left (shoulder girdle), a radius, an ulna, forelimb unguals, and a fragment of a (neck) vertebra. In 1980, Perle and the paleontologist Rinchen Barsbold assigned another specimen to Segnosaurus; IGM 100/81 from the Amtgay locality included a left tibia and fibula. In 1983, Barsbold listed additional specimens GIN 100/87 and 100/88.
|
|
There was developed attachment for all the scapulohumeral muscles, particularly the deltoids. When extending the forelimbs, the deltoids may have raised the front side (anterior margin) of the humerus, and coracobrachialis muscle lowered the back side (posterior margin). When retracting the forelimb, the pectoralis muscle may have pushed the anterior margin down, and the subscapularis muscle pulled the posterior margin up. The pelvis joint has the usual ball-and-socket joint configuration.
|
|
In four- legged animals, the radius is the main load-bearing bone of the lower forelimb, and the ulna is important primarily for muscular attachment. In many mammals, the ulna is partially or wholly fused with the radius, and may therefore not exist as a separate bone. However, even in extreme cases of fusion, such as in horses, the olecranon process is still present, albeit as a projection from the upper radius.
|
|
Stress fractures to the hand are more likely to result from predatory behavior since injuries to the feet could be obtained while running or migrating. The researchers concluded that contact with struggling prey is the likely cause of a tendon avulsion found in the forelimb of the Tyrannosaurus specimen Sue. The authors concluded that the presence of stress fractures in theropods provide evidence for "very active" predation-based diets rather than obligate scavenging.
|
|
Iguanodon hand with spike The second, third, and fourth digits of the iguanodontid forelimb are close together. In some cases, it is possible that digits three and four were bound into a single structure by layers of skin, a specialized adaptation for quadruped locomotion. In addition, the wrist bones are fused into a block, and the thumb bones are fused into a spike-like point. In Iguanodon, the fifth digit is long, flexible, and opposable.
|
|
Trackways of sauropods like Brontosaurus show that the average range for them was around per day, and they could potentially reach a top speed of . The slow locomotion of sauropods may be due to the minimal muscling or recoil after strides. Various uses have been proposed for the single claw on the forelimb of sauropods. They were suggested to have been for defence, but the shape and size of them makes this unlikely.
|
|
The rear edge of the sternum has two pairs of thin rod-like structures. Although these structures are known in all but the most basal enantiornitheans, only IVPP 21711 has the inner pair extend the same distance as the outer pair. On the other hand, the V-shaped xiphoid region is similar to basal enantiornitheans such as Protopteryx and pengornithids. The forelimb is rather short, with a robust humerus possessing enantiornithean features.
|
|
Fabrosaurids were relatively small ornithischian dinosaurs, averaging about 1–2 meters in body length, with a triangular skull that had large circular orbits on the sides. This suggests that fabrosaurids had relatively huge eyes that faced laterally. The forelimbs of fabrosaurids are considerably shorter than their hindlimbs. A small forelimb such as those present in Fabrosauridae would not have been useful for locomotion, and it is evident that fabrosaurids were bipedal dinosaurs.
|
|
Retinoic acid is essential throughout an individual's lifetime, but it is most critical during pregnancy. Without the proper concentrations of ATRA, severe abnormalities can be present and even fatal to the growing fetus. Genetic loss-of-function studies in mouse and zebrafish embryos that eliminate ATRA synthesis or ATRA receptors (RARs) have revealed abnormal development of the somites, forelimb buds, heart, hindbrain, spinal cord, eye, forebrain basal ganglia, kidney, foregut endoderm, etc.
|
|
The ribs form antero-ventral and postero-dorsal flanges, which are for the muscle attachments. Orthosuchus has similar pectoral girdles and pelvic girdles compare to living crocodiles, with a long scapula and a shorter coracoid. The interclavicle is hypothesized to be cartilaginous. As for the forelimb, the fossil records showed that Orthosuchus has similar humerus, but the distal and proximal expansions does not lay on the same plane as the modern crocodiles.
|
|
The animal's leg is held in a flexed position for 30 seconds to up to 3 minutes (although most veterinarians do not go longer than a minute),Baxter, Gary (2011). Manual of Equine Lameness. Wiley-Blackwell. . and then the horse is immediately trotted off and its gait is analyzed for abnormalities and unevenness.Ramey, DW. Prospective Evaluation of Forelimb Flexion Tests in Practice: Clinical Response, Radiographic Correlations, and Predictive Value for Future Lameness. Proc.
|
|
In the appendicular regions, hadrosauromorphans the scapulae are not J shaped, instead having an overhanging projection. The lower forelimb bones are more slender in both hadrosauromorphans and Probactosaurus, unlike their more robust ancestors. Probactosaurus, however, possesses the basal condition of having a small, conical pollex, like in earlier ornithopods such as Iguanodon or Hypselospinus. This absence of a pollex is also linked to a reduction of the carpal bones, and a less mobile manus.
|
|
The holotype specimen, CCG 20020, was discovered in Sichuan, in a layer of the Xiashaximiao Formation dating from the Bathonian-Callovian. The specimen consists of a fragmentary skeleton lacking the skull. The holotype proper contains the intercentrum of the atlas and the third to ninth neck vertebrae. Other elements have been designated as a paratype, including fragmentary remains of the skull, nine teeth, elements of the pectoral girdle, a forelimb, and a hindlimb.
|
|
Comparing with Ceratosaurus itself, resulted in a body length of 730 centimetres, a hip height of 220 centimetres and a skull length of eighty centimetres. The thighbone length would then have been about eighty to eighty- seven centimetres, which indicates a body weight of 1160 to 1524 kilogrammes. Another method consisted in extrapolating from the known length of the forelimb. Applying the usual limb ratio indicated a hindlimb length of 198 centimetres.
|
|
In addition to motor deficits, adult Dab1-scm mutants are characterized by anomalies in grooming behavior, in particular shorter grooming bouts than non- ataxic controls of the same background strain, though they display the normal cephalocaudal sequence of grooming anterior body parts (face washing and forelimb licking) prior to posterior parts.Lalonde R, Lefebvre A, Jacquelin C, Strazielle C. Abnormal grooming activity in Dab1-scm (scrambler) mutant mice. Behav Brain Res 233: 24-28, 2012.
|
|
The earliest known tetrapod with specializations that adapted it for climbing trees was Suminia, a synapsid of the late Permian, about 260 million years ago. Some invertebrate animals are exclusively arboreal in habitat, for example, the tree snail. Brachiation (from brachium, Latin for "arm") is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms. During brachiation, the body is alternately supported under each forelimb.
|
|
Dinosaurs were not capable of more than semi-pronation of the wrist, though bipedal origins of all quadrupedal dinosaur clades could have allowed for greater disparity in forelimb posture than often considered. Monotremes have forearms that are not as dexterous as therians. Monotremes have a sprawling posture, and multiple elements in their pectoral girdles, which are ancestral traits for mammals. In birds, the forearm muscles supinate, pronate, flex and extend the distal wing.
|
|
Asymmetrical gaits are sometimes termed "leaping gaits", due to the presence of a suspended phase. The key variables for gait are the duty factor and the forelimb-hindlimb phase relationship. Duty factor is simply the percent of the total cycle which a given foot is on the ground. This value will usually be the same for forelimbs and hindlimbs unless the animal is moving with a specially trained gait or is accelerating or decelerating.
|
|
The holotype specimen's forelimb is represented by the proximal ends of the radius, ulna and humerus. Though missing, the shaft of the humerus was similar to those found in primitive protostegid species. The wide angle of divergence between the scapular processes is similar to a number of early protostegid and cheloniids. The wide wings along the entoplastron and its lack of fusion with the surrounding bones indicates that Longman's placement of the genus is accurate.
|
|
The fossils include only the holotype which are pieces of a crushed right forelimb. These pieces include a nearly complete right carpometacarpus, two phalanges, the radiale and ulnare of the wrist, and a fragment of the distal right humerus. The catalog number of these fossils are given multiple times as PIN 4499-1, but they are listed as PIN 44991-1 on page 3, where the holotype is formally listed. This is probably a misprint.
|
|
The forelimbs are not flattened into paddles as in metriorhynchids, but the ulna (lower arm bone) is reduced in length, indicating that forelimb reduction began at the lower limb and progressed upward (the humerus or upper arm bone of Zoneait not reduced). Taken together, the transitional features of Zoneait indicate that metriorhynchoids' adaptation of a marine lifestyle began with a shift in feeding ecology and only later involved changes in swimming locomotion.
|
|
They are now classified as the closest relatives to the mammals and this is supported by their high, flat, crested jaw, large zygomatic arches, well developed secondary palate, and specialized dentition. There have also been comparisons between the cranial nerves of Tritylodonts and mammals. The shoulder girdle and forelimb structures were suggestive of digging animals. These animals were extremely active and burrowed in leaf litter and dirt, which suggests characteristics of rodents and rabbits.
|
|
It is characterized by its nasal-rostral contact and moderately sized body. Its body has dorsal tubercles extending from the occiput and temporal regions to the back and tail base, but are lacking on the forelimb and thigh. It counts with 6–8 pre-cloacal pores in a continuous series in males, and a tail generally with two cloacal spurs on each side. Snout–vent length varied between among the males and females in the type series.
|
|
This feature is the presence of several large keels which run along the underside of each pleurocentrum. Although keels also run along the underside of the pleurocentra in synapsids, these keels are much closer to the midline in members of that group compared to in Westlothiana. The ribs of Westlothiana connect to the intercentra, and are present in every vertebra between the skull and the hip. The forelimb was significantly shorter than the hindlimb, a characteristic shared with lepospondyls.
|
|
Cryptoclidus was a plesiosaur whose specimens include adult and juvenile skeletons, and remains which have been found in various degrees of preservation in England, Northern France, Russia, and South America. Its name, meaning "hidden clavicles", refer to its small, practically invisible clavicles buried in its front limb girdle. The type species was initially described as Plesiosaurus eurymerus by Phillips (1871). The species name "wide femur" refers to the forelimb, which was mistaken for a hindlimb at the time.
|
|
Journal of Vertebrate Paleontology Vol. 27, No. 1. pp. 1-7 Adriosaurus includes three species: A. microbrachis (“micro”, meaning small, and “brachis”, meaning arm, referring to the vestigial forelimb composed of only the humerus), A skrbinensis (named after the location where they found the fossil, Skrbina, northwest of Komen, Slovenia) and A. suessi. However, A. microbrachis lacks many crucial characters to be qualified for cladistic analysis, thus it's not included in the list of terminal taxa.
|
|
A structure can be homologous at one level, but only analogous at another. Pterosaur, bird and bat wings are analogous as wings, but homologous as forelimbs because the organ served as a forearm (not a wing) in the last common ancestor of tetrapods, and evolved in different ways in the three groups. Thus, in the pterosaurs, the "wing" involves both the forelimb and the hindlimb. Analogy is called homoplasy in cladistics, and convergent or parallel evolution in evolutionary biology.
|
|
It has been proposed that sauropods possessed a four-chambered double pump heart, with one pump for oxygenated and one pump for deoxygenated blood. As in all Macronaria, the forelimbs of brachiosaurids are long relative to the hindlimbs, but this trait is more pronounced in brachiosaurids. The forelimbs were very slender for a sauropod and the metacarpal bones of the forelimb were elongated. These adaptations overall increased the stride length of the forelimbs, arguably resulting in an uneven gait.
|
|
A moderately developed fourth trochanter is placed proximally on the femur, unlike the well developed fourth trochanters of dinosaurs. The manus and pes are almost entirely missing, except for the calcanues of the ankle joint. The calcaneus indicates that Yarasuchus had a "crocodile-normal" ankle, which allowed for more rotation of the foot than the derived hinge-like avemetatarsalian ankle. The forelimb to hindlimb length ratio is roughly 3:5, with much longer back legs than the front.
|
|
The end is wide compared to the main spine, but approximately subequal in length and width. A partial forelimb, provisionally referred to Amphicoelias by Osborn & Mook in 1921, resembles Diplodocus but is more robust overall. The distal end of the scapula, while only partially preserved, show that the expansion of the was smaller than Camarasaurus but larger than Apatosaurus. long as preserved, the bone is noticeably thicker than in Diplodocus, but not quite as thick as in Camarasaurus.
|
|
In the forearm, the radius was longer than the ulna, and the , a bony extension on the upper end of the ulna that served for muscle attachment, was absent in Limusaurus. Both features are considered distinctive features of the genus. As in other ceratosaurians, ossified wrist bones were absent. Diagram of the forelimb and pectoral girdle As is typical for ceratosaurs, the arms and hands of Limusaurus were considerably reduced, even more so than in Ceratosaurus.
|
|
Gower and Schoch (2009), p. 109. The toe bones (phalanges) are poorly preserved and the only well known bone is a fifth metatarsal (bone in hindlimbs attached to the toe bones) which was hooked in shape. However, hypotheses suggest that probably each forelimb had four toes and each hindlimb five.Gower and Schoch (2009), p. 119 (Figure 8). Skull, Staatliches Museum für Naturkunde Stuttgart Batrachotomus had a tall and narrow skull estimated at in length.Gower (1999), p. 7.
|
|
Cistecephalus is an extinct genus of dicynodont therapsid from the Late Permian of southern Africa (South Africa and Zambia). It was a small, specialised, burrowing dicynodont, possibly with habits similar to a modern mole. The head was flattened and wedge-shaped, the body long, and the forelimbs very strong, with similarities in structure to the forelimb of modern burrowing mammals. It was one of the first genera of dicynodonts to be described, by Richard Owen, in 1876.
|
|
Associated Genetic Factors: PAX3, c-Met, Mox2, MSX1, Six, Myf5, and MyoD Mox2 (also referred to as MEOX-2) plays an important role in the induction of mesoderm and regional specification. Impairing the function of Mox2 will prevent the proliferation of myogenic precursors and will cause abnormal patterning of limb muscles. Specifically, studies have shown that hindlimbs are severely reduced in size while specific forelimb muscles will fail to form. Myf5 is required for proper myoblast proliferation.
|
|
It may have eaten ferns, cycadeoids, seed ferns, horsetails, and algae. Stevens and Parish (2005) speculate that these sauropods fed from riverbanks on submerged water plants. A 2015 study of the necks of Apatosaurus and Brontosaurus found many differences between them and other diplodocids, and that these variations may have shown that the necks of Apatosaurus and Brontosaurus were used for intraspecific combat. Various uses for the single claw on the forelimb of sauropods have been proposed.
|
|
Pectoral girdle and forelimb Linhevenator is a troodontid, a group of small, bird-like, gracile maniraptorans. All troodontids have many unique features of the skull, such as closely spaced teeth in the lower jaw, and large numbers of teeth. Troodontids have sickle-claws and raptorial hands, and some of the highest non-avian encephalization quotients, meaning they were behaviourally advanced and had keen senses. Linhevenator is a rather large troodontid with an estimated body weight of .
|
|
Since ants had not yet evolved at the time of Fruitafossor, it is assumed that these animals fed on termites, which were abundant – along with their relatives, the cockroaches. Fruitafossor has been nicknamed Popeye, after the cartoon sailor, because of its large front limbs. The features of the front limb indicate that the animal was fossorial, employing scratch digging like modern moles, gophers, and spiny anteaters. The olecranon process was highly enlarged indicating the forelimb had powerful muscles.
|
|
Using computer simulation and machine learning techniques, which found a combination of movements that minimised energy requirements, the digital Argentinosaurus learned to walk. The optimal gait found by the algorithms was close to a pace (forelimb and hind limb on the same side of the body move simultaneously). The model reached a top speed of just over 2 m/s (7.2 km/h, 5 mph). The authors concluded with its giant size, Argentinosaurus reached a functional limit.
|
|
The synonymization of Scolosaurus cutleri and Euoplocephalus tutus was generally accepted and thus NHMUK R.5161 was assigned to E. tutus. However, a redescription of Scolosaurus published in 2013 in the Canadian Journal of Earth Sciences by Paul Penkalski and William T. Blows suggested that the genus is a valid taxon. They concluded that Scolosaurus can be distinguished from Euoplocephalus by the form of their cervical armour, the details of other armour and the structure of the forelimb.
|
|
A species described by Wetmore in 1958, dating to the upper Oligocene deposits of South Dakota. It is relatively well studied at about 16 specimens, mostly of hindlimbs but also forelimb and shoulder girdle material. Though it was described as a smaller variant of B. cursor by Wetmore, it was actually similar to it in size, though it was still dwarfed by the larger B. geographicus and the larger Paracrax species, which would have co-existed with it.
|
|
Cratochelone berneyi is known only from one fossil, the holotype, specimen number "QM F14550". The specimen is composed of a grouping of disassociated post-cranial skeleton elements in a hard, fine-grained and "dirty-stone colored" sedimentary matrix. The bones include portions of the left side plastron, the shoulder girdle, and segments of a forelimb. The fossil is thought to have been recovered by F. L. Berney from outcrops of the Toolebuc Formation exposed in the Eromanga Basin.
|
|
DMNH EPV.59302, the referred humerus A long and slender humerus is the only forelimb bone safely assigned to Kwanasaurus, based on its similarity to that of Silesaurus and Diodorus. The proximal portion is slightly expanded, but the humeral head is not as thick or straight as that of other silesaurids. Unlike dinosaurs (but in line with other silesaurids), the deltopectoral crest is small and extends less than a third down the length of the shaft.
|
|
Additional findings comprising forelimb and hindlimb elements have been discovered during the 1960s-1980s. Therizinosaurus comprises the single species T. cheloniformis, which could grow up from long and weigh possibly over . It had the longest known claws of any land animal, reaching up to in length. Unlike other therizinosaurs, the claws were very stiff and elongated, but like other members, it would have been slow, long-necked/high browser herbivore equipped with a keratinous beak and a wide torso.
|
|
Unlike all other known dinosaurs, a long, pointed wrist bone known as a "styliform element", exceeding both the third finger and the ulna in length, extended backward from the forelimb bones. This styliform, an adaptation to help support the membrane, may have been a newly evolved wrist bone, or a calcified rod of cartilage. It was slightly curved and tapered at its outer end. The only known specimen of Yi qi preserved a heavy covering of feathers.
|
|
The pectoral girdle had a robust and U shaped wishbone, a slightly curved shoulder blade, a short and robust coracoid and a broad and deeply notched breastbone. The hips had an unfused illium, a slender and curved pubis with a small pubic foot and a strap like ischium which is shorter than the pubis. The hind limb was shorter than the forelimb. The forelimbs had a humerus and a radus which were straighter and shorter than the ulna.
|
|
Among macronarians, fossilized skin impressions are only known from Haestasaurus, Tehuelchesaurus and Saltasaurus. Both Tehuelchesaurus and Haestasaurus may be closely related to Europasaurus, and the characteristics of all sauropod skin impressions are similar. Haestasaurus, the first dinosaur known from skin impressions, preserved integument over a portion of the arm around the elbow joint. Dermal impressions are more widespread in the material of Tehuelchesaurus, where they are known from the areas of the forelimb, scapula and torso.
|
|
Charles M. Sternberg (1940) considered there to be multiple genera within the family, all sharing fully enamelled teeth, divided into two subfamilies, Hypsilophodontinae and Thescelosaurinae. Within Hypsilophodontinae–grouped by a longer scapula, thinner forelimb and femora shorter than tibiae–Sternberg included Hypsilophodon, Dysalotosaurus, and Parksosaurus (renaming of Thescelosaurus warreni). Only Thescelosaurus was included in Thescelosaurinae, as it had a tibia shorter than the femur. Peter M. Galton in 1972 re-studied the relationships of taxa within Ornithischia.
|
|
Guchengosuchus is an extinct genus of erythrosuchid archosauriform from the Early Triassic of China. It is known from a single holotype skeleton called IVPP V 8808, described in 1991 from the lower Ermaying Formation in Shanxi. The lower Ermaying Formation dates back to the Olenekian stage of the Early Triassic, making Guchengosuchus one of the earliest archosauriforms. IVPP V 8808 is a disarticulated skeleton including a partial skull, lower jaw, some vertebrae, a scapula, and forelimb bones.
|
|
Goyocephale is an extinct genus of pachycephalosaurian ornithischian that lived in Mongolia during the Late Cretaceous about 76 million years ago. It was first described in 1982 by Perle, Teresa Maryańska and Osmólska for a disarticulated skeleton with most of a skull, part of the forelimb and hindlimb, some of the pelvic girdle, and some vertebrae. Perle et al. named the remains Goyocephale lattimorei, from the Mongolian goyo, meaning "decorated", and the Ancient Greek kephale, for head.
|
|
They vary in size from the pygmy possum, weighing just , to the cat-sized common ringtail and brushtail possums. The sugar and squirrel gliders are common species of gliding possum, found in the eucalyptus forests of eastern Australia, while the feathertail glider is the smallest glider species. The gliding possums have membranes, called "patagia", that extend from the fifth finger of their forelimb back to the first toe of their hind foot. These membranes, when outstretched, allow them to glide between trees.
|
|
A skeletal diagram of Acherontiscus Adelospondyls share a variety of traits with other lepospondyls, although whether these traits are an example of convergent evolution is a controversial topic. Like the aïstopods and lysorophian "microsaurs", they had very elongated bodies similar to that of snakes and eels. In addition, they lacked limbs (similarly to the aïstopods), although forelimbs were supposedly found in various adelogyrinids in the late 1960s. Andrews & Carroll (1991) found that all cases of forelimb bones in adelogyrinids were actually misinterpretations.
|
|
The limbs are yellowish white below. The tail is light brown above, but has two rows of darker spots, and yellowish white below.Roux, 1907, pp. 301-302 Snout-to-vent length is 83 mm (3.3 in), head length 10 mm (0.39 in), head width 6.5 mm (0.26 in), length of the body 33 mm (1.3 in), length of the forelimb 15 mm (0.59 in), length of the hindlimb 23 mm (0.91 in), and length of the (incomplete) tail 40 mm (1.6 in).
|
|
Size comparison of P. cyrtocristatus (left, violet) and P. walkeri (right, blue) Restoration of P. walkeri Like most dinosaurs, the skeleton of Parasaurolophus is incompletely known. The length of the type specimen of P. walkeri is estimated at , and its weight is estimated at . Its skull is about long, including the crest, whereas the type skull of P. tubicen is over long, indicating a larger animal. Its single known forelimb was relatively short for a hadrosaurid, with a short but wide shoulder blade.
|
|
Two major concepts of comparative anatomy are: # Homologous structures - structures (body parts/anatomy) which are similar in different species because the species have common descent and have evolved, usually divergently, from a shared ancestor. They may or may not perform the same function. An example is the forelimb structure shared by cats and whales. # Analogous structures - structures similar in different organisms because, in convergent evolution, they evolved in a similar environment, rather than were inherited from a recent common ancestor.
|
|
Brachiating primates have long forelimbs and curved fingers Brachiation (from "brachium", Latin for "arm"), or arm swinging, is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms. During brachiation, the body is alternately supported under each forelimb. This form of locomotion is the primary means of locomotion for the small gibbons and siamangs of southeast Asia. Gibbons in particular use brachiation for as much as 80% of their locomotor activities.
|
|
Zby is suggested to be closely related to Turiasaurus riodevensis from Spain and Portugal, based on its tooth morphology, extreme anteroposterior compression of the proximal end of the radius, and strong beveling of the lateral half of the distal end of the radius, while some other forelimb traits distinguish these two genera. Nearly all other anatomical features suggest that Zby is a non-neosauropod eusauropod, confirming its position as a turiasaurian. Zby is estimated to measure around 16 to 18 metres in length.
|
|
One of the most unusual features of this genus lies in the shape of its bony sternum (breastplate). While most early birds had wide sternums, Eoalulavis had a very thin one, with an expanded front end tapering to a point as well as a rear tip with outward-pointing extensions. This form has been described as "spear-shaped" or "fish-shaped" by some. The morphology of the forelimb in Eoalulavis is remarkably primitive compared with that of other genera of enantiornithean birds.
|
|
The type species, Chrysocetus healyorum, is based on a single subadult specimen from the late middle or early late Eocene of Orangeburg County, South Carolina (, paleocoordinates ).. Retrieved April 2013. The holotype, SCSM 87.195, consists of a partial skull with lower jaws, ten teeth, and the hyoid apparatus; 21 vertebrae, some ribs and a sternum; a partial left forelimb; and partial innominates. A second species, Chrysocetus fouadassii, is known from Bartonian-age deposits in the Western Sahara.Philip D. Gingerich and Samir Zouhri (2015).
|
|
The degree of lameness can increase significantly with repeated flexions. Certain areas, such as tissues of the fetlock joint, are more sensitive to flexion tests over other tissues, such as those in the pastern and hoof.KEARNEY, C. M., Van WEEREN, P. R., CORNELISSEN, B. P. M., Den BOON, P. and BRAMA, P. A. J. (2010), Which anatomical region determines a positive flexion test of the distal aspect of a forelimb in a nonlame horse?. Equine Veterinary Journal, 42: 547–551.
|
|
77 The best- known examples are the American Mustang and the Australian Brumby, but there are many other populations worldwide. See also semi-feral horse (to which the term "feral" is often misapplied). ;fetlock :The joint above the pastern.Belknap Horsewords pp. 183–184 Anatomically, the metacarpophalangeal (front) and metatarsophalangeal (rear) joints of the horse, formed by the junction of the third metacarpal (forelimb) or metatarsal (hindlimb) bones (also known as the cannon bones) and the proximal phalanx distad (the pastern bone).
|
|
The limbs are salmon red to red, with the concealed parts of the thighs being bright orangish red. In adult females, the dorsal ground color varies from orangish brown to mustard yellow. The canthal region is dark brown in most individuals, and that coloration may extend from the posterior of the orbit to the forelimb insertion. The dorsum may be completely without patterns, or the patterns can resemble the males ones, or may include large brown blotches with neon yellowish green borders.
|
|
A few specimens indicate a maximum length of 11–30% greater than average and a mass of . The cervical vertebrae of Apatosaurus are less elongated and more heavily constructed than those of Diplodocus, a diplodocid like Apatosaurus, and the bones of the leg are much stockier despite being longer, implying that Apatosaurus was a more robust animal. The tail was held above the ground during normal locomotion. Apatosaurus had a single claw on each forelimb and three on each hindlimb.
|
|
Most of its postcranial skeleton is known. The skeletal material Jain and Bandyopadhyay found between 1984 and 1986 was "in associated and mostly articulated condition;" it included cervical, dorsal, sacral and caudal vertebrae, ribs, pelvis, scapula, coracoid, left forelimb and other bones, though skull, hindlimb and foot bones were missing. The site locality is Dongargaon Hill, which is in a Maastrichtian crevasse splay claystone in the Lameta Formation of India. Dongargaon Hill (20.212318N,79.090709E) is located near Warora, in Chandrapur District, Maharashtra.
|
|
The claws are deeply scooped on the underside to assist in digging in the ice of the natural habitat. Research of injury patterns in polar bear forelimbs found injuries to the right forelimb to be more frequent than those to the left, suggesting, perhaps, right-handedness. Unlike the brown bear, polar bears in captivity are rarely overweight or particularly large, possibly as a reaction to the warm conditions of most zoos. The 42 teeth of a polar bear reflect its highly carnivorous diet.
|
|
There are often dark brown triangular patterns between the eyes and sacrum, an irregular dark brown line running from the canthus rostralis through the eye and over the tympanum to the forelimb, dark brown spots or irregular lines on the flanks, and dark brown crossbars on the upper side of the limbs. Green or yellow flecks on the dorsum may also be present. All adults have a distinct white spot under the eye. The iris is red to reddish-brown.
|
|
The generic name combines the Latin prefix pro~ with the name of the genus Panoplosaurus because the new species lived earlier than — but resembled much — this already described nodosaurid. The specific name refers to Maryland. The holotype, USNM 540686, was found in the Patuxent Formation, dating from the late Aptian. It consists of the impressions of the back of the head together with a natural cast of the ribcage, some vertebrae, the right forelimb, the right femur and a right foot.
|
|
D. falkenbachi was a larger species that was found in northern Goshen, southeastern Platte Counties, Wyoming, and Nebraska. A smaller species, D. skinneri, was found in southern Wyoming. In one large species, D. robustum, the forelimb is elongated, making the adaptation for pursuing prey over open terrain very evident. The skeletal structure of D. robustum shows a predator that shares characteristics with highly evolved modern species—wolves and cheetahs—as well as large ambush wild cats (felids)—lions and tigers.
|
|
All the cervicals but the most posterior and axis/atlas have hypapophyses and those triangular neural spines; all characteristics that have been described in Megalancosaurus.Specifically, the type specimen has these features, and they are corroborated in other specimens, including a complete, articulated neck with dorsal series, pectoral girdle, and forelimb. This suggests that portions of Protoavis may be drepanosaurid in nature. Chatterjee presents the skull of Protoavis as complete, although only the caudal aspect of the cranium is represented in the available fossils.
|
|
Sunnybatrachus is a genus of extinct frog that lived during the Berriasian epoch of the Early Cretaceous of England. The only known material, including the holotype ilium as well as bones of the skull, vertebral column, forelimb, pelvis, and hindlimb was named Sunnybatrachus purbeckensis by Susan E. Evans and Gerard J. McGowan in 2002. The species name describes the Purbeck Limestone Group, while the genus name is for the Sunnydown Farm locality of the Lulworth Formation, where the fossils were found.
|
|
Of all the material, few is still preserved, although the gastralia, phalanges and forelimb were cast and now represent the plastotype, with casts in the Muséum National d'Histoire Naturelle (specimen MNHN 1897-2) and Yale Peabody Museum (specimen YPM 4938). The original material was uncovered in a layer of the Calcaire de Caen in Normandy, France. Poekilopleuron can be assigned to the middle Bathonian in age, about 167.7 to 166 million years ago. Megalosauroid neural arch and spine referred by Owen to Poekilopleuron.
|
|
The holotype, PIN 3386/8, is a skull, which is well preserved on the left side, as well as some postcranial material consisting of pieces of the hands, feet, shoulder and pelvic girdles. A more fragmentary skull was also recovered, associated with some ribs, fragmentary vertebrae, and a complete forelimb. A third specimen preserves many limb bones and a series of 34 tail vertebrae from a smaller individual. Two even smaller fragmentary skeletons, presumably of young individuals, were uncovered nearby.
|
|
While the three middle digits of each forelimb (digits II, III, & IV) were very thick and probably weight bearing, the outside fingers (digits I & V) were modified in different ways. The first digit was a simple sharp spike, as seen in Iguanodon. Aside from defense, the thumb spike could possibly have also been used for breaking the shells of seeds or fruit. The fifth digit was somewhat opposable to the rest of the hand and may have been useful for grasping food.
|
|
The encoded protein plays a major role in limb development, specifically during limb bud initiation. For instance, in chickens Tbx5 specifies forelimb status. The activation of Tbx5 and other T-box proteins by Hox genes activates signaling cascades that involve the Wnt signaling pathway and FGF signals in limb buds. Ultimately, Tbx5 leads to the development of apical ectodermal ridge (AER) and zone of polarizing activity (ZPA) signaling centers in the developing limb bud, which specify the orientation growth of the developing limb.
|
|
HOXD13 is the first of several HOXD genes located in a cluster on chromosome 2. Deletions that remove the entire HOXD gene cluster or the 5' end of this cluster have been associated with severe limb and genital abnormalities. The product of the mouse Hoxd13 gene plays a role in axial skeleton development and forelimb morphogenesis. Changes in the expression of the Hoxd13 gene in early lobe-finned fish may have also contributed to the evolution of the tetrapod limb.
|
|
In non-avian archosaurs, including crocodiles, the capitellum and the trochlea are no longer bordered by distinct etc.- and entepicondyles respectively, and the distal humerus consists two gently expanded condyles, one lateral and one medial, separated by a shallow groove and a supinator process. Romer (1976) homologizes the capitellum in Archosauromorphs with the groove separating the medial and lateral condyles. In birds, where forelimb anatomy has an adaptation for flight, its functional if not ontogenetic equivalent is the dorsal condyle of the humerus.
|
|
More recent studies of breeding place the mating season between February and June, as opposed to between February and March. Gestation lasts 21 days, and devils give birth to 20–30 young standing up, each weighing approximately . At birth, the front limb has well-developed digits with claws; unlike many marsupials, the claws of baby devils are not deciduous. As with most other marsupials, the forelimb is longer () than the rear limb (), the eyes are spots, and the body is pink.
|
|
Sphenosuchus is an extinct genus of Crocodylomorpha from the Early Jurassic Elliot Formation of South Africa, discovered and described early in the 20th century. The skull is preserved very well but other than elements of the forelimb and isolated parts of the hind limb, the Sphenosuchus material is incomplete. It was probably quadrupedal, but may have been a facultative biped. Sphenosuchus was first thoroughly described in 1972 by the British palaeontologist Alick Walker, in a paper in the journal Nature.
|
|
The type specimen or holotype of Latenivenatrix, CMN 12340, was originally described in 1969 by Dale Alan Russell and referred by him to the genus Stenonychosaurus. In 1987 it was referred to Troodon. It had been collected in 1968 by Irene Vanderloh in the Dinosaur Park Formation strata from Alberta, southern Canada. The specimen has preserved some skull bones (frontals, parietals, postorbital, basioccipital and basisphenoid), four vertebra and four ribs, some chevrons and gastralia, fairly complete forelimb and incomplete hindlimbs.
|
|
Boophis ankarafensis are small frogs: adult males measure and female (one specimen) in snout–vent length. The body is slender, with the head much wider than the body. The background colour of dorsum and limbs is light green, but the webbing, finger, and toe disks are green-yellow. There are speckles of reddish-brown and yellow pigment covering the dorsum and limbs, and thin yellow dorsolateral stripes running from behind the eye to the forelimb, then fading towards the mid-body.
|
|
The elongation of these structures continued until the middle of the tail. The spines may have held up some kind of low crest or sail of skin that was highest over its hips, lower and extending further to the back than that of Spinosaurus, in which the sail reached its highest peak over the dorsal vertebrae. This condition was more reduced in Baryonyx. Reconstructed forelimb and hand of Suchomimus, Museum of Ancient Life, Utah The furcula was V-shaped and indicates a high and narrow trunk.
|
|
North American river otters swim by quadrupedal paddling, forelimb paddling, alternate hind-limb paddling, simultaneous hind-limb paddling, or body and tail dorsoventral undulation. The tail, which is stout and larger in surface area than the limbs, is used for stability while swimming and for short bursts of rapid propulsion. While swimming at the surface, the dorsal portion of the North American river otter's head, including nostrils, ears, and eyes, is exposed above water. It must remain in motion to maintain its position at the surface.
|
|
Comparative studies have established that bat digits undergo a more rapid rate of chondrocyte proliferation. In addition to interdigit apoptosis, BMPs have been shown to affect chondrocyte proliferation and digit length in mice. Bmp-2 shows increased expression in the digits of bats compared with mice, suggesting that a change in the BMP pathway has occurred to give rise to longer bat digits. Simplified diagram showing expanded gene expression domains in developing bat forelimb potentially contributing to the morphological changes resulting in the bat wing.
|
|
Yueosaurus is known only from the holotype ZMNH M8620, an articulated, partial but well preserved postcranial skeleton which includes cervical, dorsal (back) and caudal vertebrae, scapula, rib, hip bones, partial forelimb and partial hindlimb. It was collected in Tiantai locality from the Liangtoutang Formation, dating to the Albian- Cenomanian stages of the latest Early Cretaceous and the earliest Late Cretaceous. Yueosaurus represents the southernmost basal ornithopod dinosaur from Asia, and the first one from China. It differs from other ornithischians by a combination of characters.
|
|
Skeletal restoration The remains of Erliansaurus were found near Sanhangobi in Inner Mongolia in 1999. The type species, Erliansaurus bellamanus, was described by Xu Xing, Zhang Xiaohong, Paul Sereno, Zhao Xijin, Kuang Xuewen, Han Jun and Tan Lin in 2002. The generic name refers to the town of Erlian and the specific name is derived from Latin bellus, "beautiful", and manus, "hand", in reference to the exquisite preservation of the forelimb. The holotype, LH V0002, was uncovered in the Iren Dabasu Formation dating from the Cenomanian stage.
|
|
Although its mass suggests a quadrupedal nature, Massospondylus would have been restricted to its hind legs for locomotion. Since the discovery of rudimentary and nonfunctional clavicles in ceratopsians, it was assumed that these shoulder bones were reduced in all dinosaurs that did not have true furculae. Robert Bakker (1987) suggested that this would have allowed the shoulder blades to swing with the forelimbs in quadrupedal dinosaurs, increasing their functional forelimb length. This would have reduced the discrepancy of length between fore- and hindlimbs in a quadrupedal Massospondylus.
|
|
The hindlimbs are strongly reduced and does not articulate with the vertebral column which lack true sacral vertebrae. Basilosaurid forelimbs have broad and fan-shaped scapulae attached to a humerus, radius, and ulna which are flattened into a plane to which the elbow joint was restricted, effectively making pronation and supination impossible. Because of a shortage of forelimb fossils from other arachaocetes, it is not known if this arrangement is unique to basilosaurids. Some of the characteristics of basilosaurids are also present in Georgiacetus.
|
|
Since Patagosaurus is known from many specimens, including at least one juvenile, its anatomy and growth are fairly well understood. Both ages exhibit the typical features of a sauropod, a long neck, small head, a long tail, and being quadrupedal. The juvenile exhibits features different from the adult in regions like the mandible, pectoral girdle, pelvis and hindlimb, although overall their anatomy is quite similar. The many known specimens help fill in gaps in the anatomy of the genus, such as the forelimb and skull.
|
|
Robertia is described as “solidly built, barrel-bodied animals.” It had developed postural limb musculature, a trochanter on the femur, diminished pre-acetabular iliac expansion relative to the post-acetabular, an anteriorly expanded pubis, and an abducted femur, which differentiate it from Diictodon. The radius and ulna are thin and about three-quarters the length of the humerus, articulating at right angles to the humerus. The antebrachium was also positioned at a right angle relative to the humerus, indicating a sprawling posture of the forelimb.
|
|
Gwyneddosaurus is a possibly invalid genus of extinct aquatic tanystropheid reptile. The type species, G. erici was described in 1945 by Wilhelm Bock, who identified it as a coelurosaurian dinosaur related to Podokesaurus (at the time, "podokesaurids" were thought to be coelurosaurians). Its remains were found in the Upper Triassic Lockatong Formation of Montgomery County, eastern Pennsylvania, and include skull fragments, several vertebra, ribs, gastralia, partial shoulder and hip bones, and several forelimb and hindlimb elements found in soft shale. The type specimen is ANSP 15072\.
|
|
Both the force applied and the time a flexion test is performed can affect outcome.Keg PR, van Weeren PR, Back W, Barneveid A. Influence of the force applied and its period of application on the outcome of the flexion test of the distal forelimb of the horse. The Veterinary Record 1997, 141(18):463-466. For this reason, it is best if the same person performs flexions of a joint on both legs, and for the same amount of time, to help standardize the response.
|
|
An image in the Le Gabillou Cave in Dordogne shows a deeply engraved zoomorphic figure with a head in frontal view and an elongated neck with part of the forelimb in profile. It has large round eyes and short, rounded ears which are set far from each other. It has a broad, line-like mouth that evokes a smile. Though originally thought to represent a composite or zoomorphic hybrid, it is probable it is a spotted hyena based on its broad muzzle and long neck.
|
|
It had no teeth in the front of its jaws, but instead had a beak-like tip that arched upwards. This would have allowed it to uproot plants in a similar manner to a modern pig. The peg-like teeth at the back of its mouth would have been suitable for chewing tough vegetation, including horsetails, ferns, and the newly evolved cycads. Restoration of S. robertsoni, based on Scott Hartman's skeletal A 2018 paper suggested that Stagonolepis olenkae's forelimb morphology is an adaptation for scratch-digging.
|
|
The other type of scales are very small, only between in diameter, and are preserved in small fragments from the forelimb and thoratic region. Ths skin types are overall more similar to those found in diplodocids and Haestasaurus than in the titanosaur embryos of Auca Mahuevo. As the shape and articulation of the preserved tubercles in these basal macronarians are similar in other taxa where skin is preserved, including specimens of Brontosaurus excelsus and intermediate diplodocoids, such dermal structures are probably widespread throughout Neosauropoda.
|
|
Associated Genetic Factors: LBX1 and Mox2 In specific muscle formation, mutations in associated genetic factors begin to affect specific muscular regions. Because of its large responsibility in the movement of dorsal muscles into the limb following delamination, mutation or deletion of Lbx1 results in defects in extensor and hindlimb muscles. As stated in the Proliferation section, Mox2 deletion or mutation causes abnormal patterning of limb muscles. The consequences of this abnormal patterning include severe reduction in size of hindlimbs and complete absence of forelimb muscles.
|
|
W.P. Coombs. 1978. "Forelimb muscles of the Ankylosauria (Reptilia, Ornithischia)". Journal of Paleontology 52(3): 642-657 Cladistic analysis of Struthiosaurus indicates that the taxon is a basal member of the Nodosauridae and suggested it may be one of the most basal ankylosaurs in the clade Ankylosauria. An analysis by Ösi in 2005, describing the taxon Hungarosaurus, found that while being younger in age than other nodosaurids, Struthiosaurus was one of the more basal taxa, although many features could not be coded for it.
|
|
Some tan or brown individuals bear light brown triangular patterns between the eyes and sacrum, an irregular dark brown line running from the canthus rostralis through the eye and over the tympanum and to the forelimb, dark brown spots on the flanks, and dark brown crossbars on the upper side of the limbs. A white or cream spot under the eye may be present, albeit being indistinct. Males have a white gular vocal sac. The male advertisement call is a pulsed, single clack repeated in rapid succession.
|
|
The forelimb bones of azhdarchids and ornithocheirids were unusually long compared to other pterosaurs, and, in azhdarchids, the bones of the arm and hand (metacarpals) were particularly elongated. Furthermore, as a whole, azhdarchid front limbs were proportioned similarly to fast-running ungulate mammals. Their hind limbs, on the other hand, were not built for speed, but they were long compared with most pterosaurs, and allowed for a long stride length. While azhdarchid pterosaurs probably could not run, they would have been relatively fast and energy efficient.
|
|
Three other specimens were referred to this species but remain undescribed. Like P. neimongoliensis, this species was discovered in the Eijnhoro Formation. Sereno (2010) found the species as described to be indistinguishable from P. sinensis, another small species, but suggested that additional study of P. ordosensis might reveal diagnostic features. He provisionally designated P. ordosensis a nomen dubium. ;P. mazongshanensis? Xu Xing, another Chinese paleontologist, named a new species of Psittacosaurus in 1997, based on a complete skull with associated vertebrae and a forelimb.
|
|
Gobiconodon is an extinct genus of carnivorous mammal from the early Cretaceous. It weighed and measured . It was one of the largest mammals known from the Mesozoic. Like other gobiconodontids, it possesses several speciations towards carnivory, such as shearing molar teeth, large canine-like incisors and powerful jaw and forelimb musculature, indicating that it probably fed on vertebrate prey; rather uniquely among predatory mammals and other eutriconodonts, the lower canines were vestigial, with the first lower incisor pair having become massive and canine-like.
|
|
Carpenter pointed out that even the lowest length estimates for A. fragillimus were higher than those for other giant sauropods, such as the diplodocid Supersaurus (), the brachiosaurid Sauroposeidon (), and the titanosaur Argentinosaurus (). Carpenter presented more speculative, specific proportions for M. fragillimus (again, based on a scaled-up Diplodocus), including a neck length of , a body length of , and a tail length of . He estimated the total forelimb height at and hind limb height at , and the overall height (at the highest point on the back) at .
|
|
Movement at the wrist was also limited in many species, forcing the entire forearm and hand to move as a single unit with little flexibility. In theropods and prosauropods, the only way for the palm to face the ground would have been by lateral splaying of the entire forelimb, as in a bird raising its wing. In carnosaurs like Acrocanthosaurus, the hand itself retained a relatively high degree of flexibility, with mobile fingers. This was also true of more basal theropods, such as herrerasaurs and dilophosaurs.
|
|
The most common sites of preserved injury and disease in theropod dinosaurs are the ribs and tail vertebrae. Despite being abundant in ribs and vertebrae, injuries seem to be "absent... or very rare" on the bodies' primary weight supporting bones like the sacrum, femur, and tibia. The lack of preserved injuries in these bones suggests that they were selected by evolution for resistance to breakage. The least common sites of preserved injury are the cranium and forelimb, with injuries occurring in about equal frequency at each site.
|
|
Remes, however, concluded that merely a second partial skeleton, "Skeleton k", including also some skull elements, could be reliably referred, and a series of caudal vertebrae. The remains are from the later strata of the Tendaguru, the obere Dinosauriermergel or "Upper Dinosaur Marl", dating from the Tithonian. Tornieria was a large sauropod, with a maximum known femur length of suggesting an animal around the same size as Barosaurus; and 23 metric tons. It shared elongated neck vertebrae and a rather long forelimb with Barosaurus.
|
|
The scapulae were robust and the bones of the forelimb were short in relation to the animal's size, but broad and sturdy. The humerus was short and stout, with its ends broadly expanded and flattened—the upper side for the and muscle attachment and the lower for articulation with the radius and ulna. The radius was short, stout and straight, and less than half the length of the humerus, while the ulna was a little longer. The ulna had a powerful and an expanded lower end.
|
|
Aenigmaspina was a small (<1 m long) archosaur with a slender skeleton and build. It is mostly known from the front half of its body, including its vertebral column, ribs, shoulder and parts of the forelimb, as well as possibly pieces of skull and pelvis that may belong to it. The vertebrae of Aenigmaspina are its most distinctive feature. These are characterised by their spine tables, where the tops of the neural spines split into a broad 'V' shape with a deep groove between them.
|
|
Trucchio was born in Ocean Hill, Brooklyn and raised in Ozone Park, Queens. As a child, Trucchio was hit by an automobile and sustained severe damage to the scapula and ulna in the humerus from a severe fracture in the forelimb, leaving his arm partially paralyzed. This injury led to his nickname of "Ronnie One Arm"."Queens Father and Son Accused In Illegal Gambling Operation" By WILLIAM K. RASHBAUM New York Times December 10, 2002 Trucchio is the father of reputed Gambino Capo Alphonse Trucchio.
|
|
The shoulder girdle and forelimb of D. schrani also exhibit unique features. An oblique ridge crosses the interior face of the scapular blade, extending from the top side near the far end of the blade to the bottom side near the base of the scapular blade. Finally, each end of the radius exhibits a unique form: the top, or proximal end, has a distinct concave embayment on its posterior face while the bottom, or distal end, is nearly square in shape instead of broadly expanded.
|
|
47762a+b at the Geology Museum, Trinity College Dublin, and BGS GSM 118410 at British Geological Survey, Keyworth, Nottingham. Each of the casts is a replica of parts of the original specimen, and comprises a representation of the skull, nine front neck vertebrae including the atlas-axis, and the right forelimb. In June 2014, three-dimensional digital models of BGS GSM 118410 were produced. Cruickshank (1994a) described LEICS G221.1851 as a neotype specimen for "P." megacephalus due to the destruction of BRSMG Cb 2335\.
|
|
Location and fauna of the Marchezan site The holotype specimen, CAPPA/UFSM 0009, is an almost complete and partially articulated skeleton, lacking only portions of the left shoulder girdle and left forelimb. It was found in 2014 at the Marchezan site, in the municipality of São João do Polêsine, Rio Grande do Sul, Brazil. This locality preserved rocks from Santa Maria Formation in the Candelária Sequence of the Paraná Basin. The skeleton was fossilized within a mudstone layer, along with small articulated skeletons of prozostrodont cynodonts.
|
|
The duration of amplexus has been found to vary across species. In some species it may last for many days, while in others it may last a few hours. Despite the variation in the duration of amplexus across species, typically all species that exhibit this behaviour have to use their forelimb muscles for the duration of amplexus. Studies have found that this reproductive behaviour of amplexus can come with different fitness costs, due to the fact that amplexus can occur for prolonged periods of time.
|
|
The holotype specimen (MGUWR WR 3871s) of D. gracilis was only a partial skeleton, consisting of the anterior end alone. Because it differed slightly from the fossils of D. gracilis, it was first thought to belong to the species D. schroederi, which is now considered a junior synonym for juvenile D. gracilis. Once this was established, the juvenile fossil, which was found before the adult fossils, became the holotype. The one limb that was found (a left forelimb), was noted to have a slimmer radius and ulna than Neusticosaurus, a similar nothosaur from Europe.
|
|
In a Ficus racemosa, in Polo Forest, Sabarkantha, Gujarat, India This is a large species, with a head and body length of about 43 cm and a tail of 50–52 cm. It has black to gray-brown fur, long and soft on the upper parts and somewhat shorter underneath the body, with a grizzled appearance. A wing membrane between the forelimb and hindlimb, paler coloured underneath, allows gliding between trees. The tail is hairy and blackish to gray-brown, the feet are black, and the nose is pale pink with black vibrissae.
|
|
Illustration of the proximal phalanges of the holotype from Knight's description (leftmost drawing depicts a cross-section) All known specimens of Tatenectes come from the Redwater Shale Member in the upper part of the Sundance Formation . This formation is located in Wyoming, in the Eastern Rocky Mountains. An incomplete plesiosaur skeleton preserving multitudinous vertebrae and a nearly complete forelimb from the Sundance Formation was described by Wilbur C. Knight in 1900. With this specimen as a holotype, which was never assigned a specimen number, he named a new species of Cimoliosaurus, C. laramiensis.
|
|
Restoration of three Tropeognathus in flight, notice their high aspect ratio The forelimbs of ornithocheirids were proportionally enormous, around five times longer than their legs. Substantial anchorage on the body is required given the mighty arms, and accordingly, ornithocheirids have robust scapulocoracoids, and stout, deeply keeled sterna, which served the purpose of housing their substantial forelimb muscles. The shoulder or pectoral girdle in ornithocheirids is set at a perpendicular angle to the spine, with the coracoids being much longer than the scapulae. The shoulder girdle is also of typical construction for ornithocheiroids.
|
|
On the fibula and tibia, Akidolestes and Ornithorhynchus have hypertrophied parafibular processes, proximolateral tuberosity of the tibia, and a distal tibial malleolus, all of which are absent in Zhangheotherium. Except the pelvic girdle and hindlimbs, Akidolestes shares several forelimb features with living monotremes as well. Similar to its hindlimbs, Zhangheotherium has asymmetrical condyles on the humerus, but the condyles of the humerus on Akidolestes and Ornithorhynchus are asymmetrical. Additionally, Zhangheotherium and other Mesozoic mammals have a straight tibia, but the tibia on Akidolestes and Ornithorhynchus are more curved.
|
|
Differences in the post-cranial skeleton between Akidolestes cifellii and related taxa allow insights into ecological differentiation within early therian mammal evolution. Correlation between limb posture and locomotor function in Akidolestes cifellii indicates that the hypertrophied parafibular process on the fibula helped the flexed function of the knee joint. A short neck on the femur and asymmetrical condyles on the humerus indicate a horizontal orientation of the femur. Akidolestes probably had a parasagittal forelimb posture and most likely a semi-erect or sprawling posture for both forelimbs and hindlimbs.
|
|
The encoded proteins of Tbx5 and Tbx4 play a role in limb development, and play a major role in limb bud initiation specifically. For instance, in chickens Tbx4 specifies hindlimb status while Tbx5 specifies forelimb status. The activation of these proteins by Hox genes initiates signaling cascades that involve the Wnt signaling pathway and FGF signals in limb buds. Ultimately, Tbx4 and Tbx5 lead to the development of apical ectodermal ridge (AER) and zone of polarizing activity (ZPA) signaling centers in the developing limb bud, which specify the orientation growth of the developing limb.
|
|
Because many tetrapods have less than five digits on the forelimb, even greater degrees of fusion are common, and a huge array of different possible combinations are found. The wing of a modern bird, for example, has only two remaining carpals; the radiale (the scaphoid of mammals) and a bone formed from the fusion of four of the distal carpals. The carpus and tarsus are both described as podial elements or (clusters of) podial bones. In some macropods, the scaphoid and lunar bones are fused into the scapholunar bone.
|
|
Kembawacela shares various features with other cistecephalids associated with a fossorial (burrowing) lifestyle. The ulna, the only known bone from the forelimb, has the typically large olecranon process associated with scratch-digging found in other cistecephalids. The skull has various features associated with burrowing, being broad and wedge-shaped. The large, forward facing eyes may be related to seeing in low-light environments, with binocular vision providing greater light sensitivity, although this is not typical of modern fossil mammals which have small eyes (as in Cistecephaloides and Kawingasaurus).
|
|
Eoabelisaurus () is a genus of abelisaurid theropod dinosaur from the Middle Jurassic Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Argentina, South America. The generic name combines a Greek ἠώς, (eos), "dawn", with the name Abelisaurus, in reference to the fact it represents an early relative of the latter. Only one species is currently recognized, E. mefi, from which the specific name honours the MEF, the Museo Paleontológico "Egidio Feruglio", where discoverer Diego Pol is active. It is characterized by reduced forelimb proportions that show primitive characteristics of the Abelisauridae family.
|
|
They however, disagreed with Therizinosaurus as a segnosaurian taxon since it was known from forelimb material; they corroborated the referred hindlimb material as segnosaurian though. Lastly, Barsbold and Maryańska noted the striking similarities between the pelvises of Nanshiungosaurus and Segnosaurus, such as the opisthopubic condition and large iliac blade. They concluded that the former was part of the Segnosauridae. Skeletal composite of two specimens of Alxasaurus With the description of the therizinosauroids Alxasaurus in 1993 by Dale A. Russell and Dong Zhiming, the affinities of the group were fairly more clear.
|
|
During embryonic development, the gene controlling Bmp signalling, Bmp2, is subjected to increased expression in bat forelimbsresulting in the extension of the manual digits. This crucial genetic alteration helps create the specialised limbs required for powered flight. The relative proportion of extant bat forelimb digits compared with those of Eocene fossil bats have no significant differences, suggesting that bat wing morphology has been conserved for over fifty million years. During flight, the bones undergo bending and shearing stress; the bending stresses felt are smaller than in terrestrial mammals, but the shearing stress is larger.
|
|
A giant panda has a 3D canine teeth bite force of 2603.47 newtons and bite force quotient of 292. Another study had a giant panda bite of 1298.9 newtons (BFQ 151.4) at canine teeth and 1815.9 newtons (BFQ 141.8) at carnassial teeth. Bones of the left forelimb The giant panda's paw has a "thumb" and five fingers; the "thumb" – actually a modified sesamoid bone – helps it to hold bamboo while eating. Stephen Jay Gould discusses this feature in his book of essays on evolution and biology, The Panda's Thumb.
|
|
In Lascaux, a red and black rock painting of a hyena is present in the part of the cave known as the Diverticule axial, and is depicted in profile, with four limbs, showing an animal with a steep back. The body and the long neck have spots, including the flanks. An image on a cave in Ariège shows an incompletely outlined and deeply engraved figure, representing a part of an elongated neck, smoothly passing into part of the animal's forelimb on the proximal side. Its head is in profile, with a possibly re-engraved muzzle.
|
|
Besides the articular processes, the hyposphene-hypantrum articulation formed an additional articulation between vertebrae, making the vertebral column more rigid; in Brachiosaurus, the hyposphene was much more pronounced than in Giraffatitan. Femur (left) and humerus of the holotype The coracoid was semicircular and taller than broad. Differences from Giraffatitan are related to its shape in side view, including the straighter suture with the scapula. Moreover, the articular surface that forms part of the shoulder joint was thicker and directed more sideward than in Giraffatitan and other sauropods, possibly indicating a more sprawled forelimb.
|
|
Similarly, digit II of the foot in Sinusonasus is not as specialized as those of derived troodontids, despite the hindlimb being overall derived. Conversely, the forelimb of Jianianhualong is short overall as in derived troodontids, despite the presence of basal traits. An ancestral state reconstruction conducted along with the phylogenetic analysis (results labelled in the above phylogenetic tree) suggests that wing feather asymmetry evolved only once, at the last common ancestor of the Paraves. Asymmetrical tail feathers would then also have evolved once, at the common ancestor of all paravians excluding scansoriopterygids and avialans.
|
|
Although not as specialized as Mesosaurus for living in the water, Piveteau noted its short neck, short manus, well developed haemal spines and slight pachyostosis of the ribs. Haughton (1930) restudied Piveteau's specimens from Madagascar, concluding that Tangasaurus (then included the Malagasy specimens) and Hovasaurus were allied and that both were diapsids. Tangasaurus was considered to be morphologically intermediate between Youngina and Hovasaurus which was recognized as an aquatic reptile due to its short forelimb and coracoid, small ossification and elongated body. Piveteau (1926) included Broomia, Saurosternon and Tangasaurus in the Tangasaurinae.
|
|
The left forelimb of the holotype shows fractures in the distal phalanges of the second and fourth digits and kinks in the distal phalanges of the first and third. Because the fractures and kinks run along a single line but do not extend into the matrix, and there are neither known fossils of scavengers from the assemblage where the specimen was found nor taphonomic evidence of scavenging in any other part of the carcass, the discoverers of Eohupehsuchus conclude that this pathology represents a bite wound from a predator.
|
|
The lower front of the radius is lightly concave between outer and inner ridges. A unique combination is present of a robust ulna, its upper surface having a width equalling more than 40% of the shaft length, with a slender radius having an upper width of less than 30% of total length. A rock associated with the forelimb, NHMUK R1868, was the first specimen known preserving parts of the sauropod skin. These probably are not impressions as the visible surface of the scales is convex, but natural casts.
|
|
Left radius The holotype, NHMUK R1870, was found in a layer of the Hastings Beds dating from the Berriasian- Valanginian, roughly 140 million years old. It consists of a left forelimb containing the associated humerus, ulna and radius. Specimen NHMUK R1868 was part of the original block and consists of a natural cast of a part of the skin, near the elbow. When the Beckles Collection was acquired, a metacarpal was referred to P. becklesii, specimen NHMUK R1869, but its large size precludes its belonging to the holotype.
|
|
He characterized elasmosaurids by their long necks and small heads, as well as by their rigid and well- developed scapulae (but atrophied or absent clavicles and interclavicles) for forelimb-driven locomotion. Meanwhile, pliosaurids had short necks but large heads, and used hindlimb-driven locomotion. Although the placement of Elasmosaurus in the Elasmosauridae remained uncontroversial, opinions on the relationships of the family became variable over subsequent decades. Williston created a revised taxonomy of plesiosaurs in 1925. In 1940 Theodore White published a hypothesis on the interrelationships between different plesiosaurian families.
|
|
As the name suggests, it is best known for the high neural spines on many of its vertebrae, which most likely supported a ridge of muscle over the animal's neck, back, and hips. Acrocanthosaurus was one of the largest theropods, reaching in length, and weighing up to . Large theropod footprints discovered in Texas may have been made by Acrocanthosaurus, although there is no direct association with skeletal remains. Recent discoveries have elucidated many details of its anatomy, allowing for specialized studies focusing on its brain structure and forelimb function.
|
|
The holotype specimen HGM41-HIII0421 consists of an incomplete skull, a lower jaw, eight cervical vertebrae, three dorsal vertebrae, nine caudal vertebrae, a nearly complete pectoral girdle, two chevrons, the left forelimb, both sternal plates, four sternal ribs, nine dorsal ribs, and a partially preserved pelvic girdle. The skull is 150mm long and appears to be a sub-adult. The mandible of Jiangxisaurus is toothless and has a height-to-length ratio of about 20%. The radius is 96mm in length and is 30% shorter than the length of the humerus (136mm).
|
|
This specimen is the largest and includes the only known complete skull and forelimb. Skeletal elements of OMNH 10147 are almost the same size as comparable bones in NCSM 14345, indicating an animal of roughly the same size, while the holotype and SMU 74646 are significantly smaller. The presence of Acrocanthosaurus in the Cloverly Formation was established in 2012 with the description of another partial skeleton, UM 20796\. This specimen, consisting of parts of two vertebrae, partial pubic bones, a femur, a partial fibula, and fragments, represents a juvenile animal.
|
|
Likewise, the middle claw may have been permanently flexed, while the third claw, also the smallest, was able to both flex and extend.Mounted skeleton seen from aboveAfter determining the ranges of motion in the joints of the forelimb, the study went on to hypothesize about the predatory habits of Acrocanthosaurus. The forelimbs could not swing forward very far, unable even to scratch the animal's own neck. Therefore, they were not likely to have been used in the initial capture of prey and Acrocanthosaurus probably led with its mouth when hunting.
|
|
Once the prey was trapped against the body, Acrocanthosaurus may have dispatched it with its jaws. Another possibility is that Acrocanthosaurus held its prey in its jaws, while repeatedly retracting its forelimbs, tearing large gashes with its claws. Other less probable theories have suggested the forelimb range of motion being able to grasp onto the side of a sauropod and clinging on to topple the sauropods of smaller stature, though this is unlikely due to Acrocanthosaurus having a rather robust leg structure compared to other similarly structured theropods.
|
|
There are several key differences between it and related species, though most of these are shared with ZPAL MgD-I/65. The claws on the hand are long, low at the back and rather straight, only slightly curved, with the lower surface nearly flat. The forelimb is long and also built more powerfully than that of other ornithomimids, with large crests on the scapulocoracoid of the shoulder and humerus (upper arm bone), which provided attachment points for large arm muscles like the biceps. The metacarpus of the hand is fused, adding to the strength.
|
|
The holotype specimen, UMNH VP 21400, hails from the Hayden- Corbett site of the Cedar Mountain Formation of Utah, approximately eight miles southeast from the city of Green River. The specimen was unearthed from a higher stratigraphic level (upper Yellow Cat Member) than Falcarius. The generic name, Martharaptor, is in honor to the paleontologist assistant Martha C. Hayden who helped in the discovery of the site, and the specific name, greenriverensis, is a reference to the Green River. The specimen includes fragments of vertebrae, a scapula, forelimb and hindlimb bones, and an ischium.
|
|
There are two main methods of upper forelimb flexion. The first method involves pulling the limb forward, so that the elbow flexes and the shoulder extends. This method tends to place more strain on the structures of the caudal elbow and cranial shoulder, and is best at localizing lameness to the bicipital bursa or the supraglenoid tubercle of the scapula, but also places strain on the biceps and triceps muscles and tendons, and the olecranon. The alternative method involves pulling the limb caudally, which flexes the shoulder and extends the elbow.
|
|
Its forearm was as long as the upper arm, unlike most other sauropods, resulting in a forelimb equalling the hindlimb in length. Its thigh bone was approximately six feet long. Skeletal drawing of C. oxoniensis In his original descriptions, Owen was unable to indicate any differences between Cetiosaurus and other sauropods for the simple reason these latter were not yet discovered. Now that such relatives have been found, the uniqueness of Cetiosaurus oxoniensis and its status as a valid taxon must be proven by indicating its new derived traits or autapomorphies.
|
|
Before limb development begins, T-box proteins initiate FGF10 expression in the proliferating mesenchymal cells of the lateral plate mesoderm, which form the limb bud mesoderm. WNT2B and WNT8C stabilize this FGF10 expression in the forelimb and hindlimb, respectively. This FGF10 expression stimulates WNT3 expression in the above ectodermal cells – resulting in formation of the apical ectodermal ridge as well as inducing FGF8 expression. The FGF8 secreted by the AER acts to keep the cells of the limb mesenchyme in a mitotically active state and sustains their production of FGF10.
|
|
The hand is located at the distal end of each arm. Apes and monkeys are sometimes described as having four hands, because the toes are long and the hallux is opposable and looks more like a thumb, thus enabling the feet to be used as hands. The word "hand" is sometimes used by evolutionary anatomists to refer to the appendage of digits on the forelimb such as when researching the homology between the three digits of the bird hand and the dinosaur hand. An adult human male's hand weighs about a pound.
|
|
Holotype material of O. velox The history of Ornithomimus classification, and the classification of ornithomimids in general, has been complicated. The type species, Ornithomimus velox, was first named by O.C. Marsh in 1890, based on syntypes YPM 542 and YPM 548, a partial hindlimb and forelimb found on 30 June 1889 by George Lyman Cannon in the Denver Formation of Colorado. The generic name means "bird mimic", derived from Greek ὄρνις, ornis, "bird", and μῖμος, mimos, "mimic", in reference to the bird-like foot. The specific name means "swift" in Latin.
|
|
Xixiasaurus () is a genus of troodontid dinosaur that lived during the Late Cretaceous Period in what is now China. The only known specimen was discovered in Xixia County, Henan Province, in central China, and became the holotype of the new genus and species Xixiasaurus henanensis in 2010. The names refer to the areas of discovery, and can be translated as "Henan Xixia lizard". The specimen consists of an almost complete skull (except for the hindmost portion), part of the lower jaw, and teeth, as well as a partial right forelimb.
|
|
Reconstruction Patagonykus (meaning "Patagonian claw") is a genus of theropod dinosaur from the Upper Cretaceous of Argentina. This alvarezsaur was discovered in exposures of the Portezuelo Formation (Turonian-Coniacian) of the Rio Neuquén Subgroup in the Neuquén Basin, Neuquen Province of Patagonia, Argentina. The holotype consists of an incomplete but well-preserved skeleton, lacking a skull, but including many vertebrae, the coracoids, a partial forelimb, pelvic girdle, and hindlimbs. Patagonykus has been classed with the Alvarezsauridae, a family which includes such taxa as the Mongolian Mononykus and the Argentinian Alvarezsaurus.
|
|
Its remains have been uncovered in six fossil localities: Limestone quarries at Rielingshausen, Zwingelhausen, and Vellberg (which has two quarries: Schumann and Ummenhofen), as well as roadcuts at Kupferzell and Wolpertshausen. The holotype specimen, SMNS 91352, is a mostly complete skeleton missing the head and neck, which was found at the Schumann quarry of Eschenau (part of Vellberg). Another specimen from the same quarry, SMNS 91083, preserves an incomplete skull and neck. A third specimen from the quarry, SMNS 90500, preserves a forelimb, osteoderms, and a femur (thigh bone).
|
|
The specific name honours Kenneth Carpenter for his work on dinosaurs in general and iguandonts in particular. David Norman, in 2013, considered Paul's description of Mantellodon to be inadequate, identical to that given by Paul of Darwinsaurus and entirely incorrect, noting that no dentary is preserved in the holotype specimen, and that the preserved forelimb elements "are gracile, carpals are not preserved, the metacarpals are elongate and slender, and a thumb spike is not preserved". Norman considered the holotype specimen of Mantellodon carpenteri to be referable to the species Mantellisaurus atherfieldensis.
|
|
Borealonectes is a genus of rhomaleosaurid pliosauroid, a type of plesiosaur. Its fossils were found in the Callovian-age (Middle Jurassic, about 165-161 million years ago) Hiccles Cove Formation of Melville Island, Canada, one of the islands in the Canadian Arctic Archipelago. It is based on a skull, neck vertebrae, and the right forelimb of one individual. Named in 2008 by Sato and Wu, Borealonectes is one of the few plesiosaurs known from the Jurassic of North America, and the first marine reptile from the Canadian Arctic with a well-preserved skull.
|
|
Retinal dehydrogenase plays a key role in the biosynthesis of retinoic acid, which in turn acts in cell signaling pathways. Retinoic acid is distinct from other cell signaling molecules in that it diffuses into the nucleus and binds directly to gene targets via retinoic acid receptors. This retinoic acid signaling pathway also appears to be unique to chordates, as suggested by the presence of retinal dehydrogenases exclusively in chordates. Retinoic acid signaling appears to control developmental processes like neurogenesis, cardiogenesis, forelimb bud development, foregut development, and eye development.
|
|
The Manning team also compared the curvature of the dromaeosaurid "sickle claw" on the foot with curvature in modern birds and mammals. Previous studies had shown that the amount of curvature in a claw corresponded to what lifestyle the animal has: animals with strongly curved claws of a certain shape tend to be climbers, while straighter claws indicate ground-dwelling lifestyles. The sickle claws of the dromaeosaurid Deinonychus have a curvature of 160 degrees, well within the range of climbing animals. The forelimb claws they studied also fell within the climbing range of curvature.
|
|
Juvenile and adolescent Smilodon specimens are extremely rare at Rancho La Brea, where the study was performed, indicating that they remained hidden or at denning sites during hunts, and depended on parental care while their canines were developing. A 2017 study indicates that juveniles were born with a robust build similar to the adults. Comparison of the bones of juvenile S. fatalis specimens from La Brea with those of the contemporaneous American lion revealed that the two cats shared a similar growth curve. Felid forelimb development during ontogeny (changes during growth) has remained tightly constrained.
|
|
Scientists have created a DKK1 knockout model in mice that revealed the effects of this gene. All mice that were homozygous for the DKK1 knockout were dead at birth due to defects in the cranium and structures formed by the neural crest, such as failed development of eyes, olfactory placodes, frontonasal mass and mandibular processes, as well as incomplete development of the forebrain and midbrain and fusion of the digits of the forelimb. This evidence supports the idea that inhibition of the Wnt signaling pathway by DKK1 is crucial to proper cranial development.
|
|
At least one individual of Aenigmaspina is definitively known. This individual, 'Edgar', consists of a pair of split blocks (the holotype NHMUK P9/3a) that together contain osteoderms, vertebrae, ribs and a scapula clustered tightly together, as well as more pieces from the forelimb and additional vertebrae that likely belong to this individual. The specimen was found tightly curled up, possibly because the animal died in a burrow before being preserved. This specimen was CT scanned to examine details of the bones more closely without risking further damage to the fossil.
|
|
Other isolated pieces, including pieces of skull and a pelvis, may belong to Aenigmaspina, however, because they are labelled similarly to fossils of other species from Pant-y-ffynnon their identity cannot be confirmed in isolation. Nonetheless, they do show similarities in both size and form (i.e. slender limbed), although some must come from at least one other individual based on duplicated bones from the forelimb. A single vertebra from a quarry in Cromhall in South Gloucestershire, England closely matches the cervicals of Aenigmaspina, including what appears to be the 'Y'-shaped spine table.
|
|
In 2001, another M. hochuanensis specimen was described. It had skull, pectoral girdle and forelimb material preserved, all of which were missing from the holotype. It was also found with four fused tail vertebra, which have expanded neural arches and taller neural spines, that belong at the tip of the tail. It's thought that these could be a weapon, such as a tail club, or a sensory organ. Other Chinese sauropods, Shunosaurus and Omeisaurus, are also known to have had ’tail clubs’ but they differ in shape to that of M. hochuanensis.
|
|
Venaticosuchus is a genus of pseudosuchian archosaurs from the family Ornithosuchidae. Known from a single species, Venaticosuchus rusconii, this genus is described based on an incomplete skull and jaw (as well as a lost partial forelimb and osteoderms) collected from the Late Triassic (Carnian) Ischigualasto Formation in the Ischigualasto-Villa Unión Basin in northwestern Argentina, which was deposited around 230 million years ago. This fossil material has been termed the holotype specimen PVL 2578. Venaticosuchus incorporated a myriad of features present in the other two genera of ornithosuchids, Ornithosuchus and Riojasuchus.
|
|
It indicated that the fossil also included a partial forelimb and osteoderms (bony scutes),Bonaparte, JF (1971), Annotated list of the South American Triassic tetrapods, in SH Haughton (ed.), Second Gondwana Symposium, Proceedings and Papers [1970]. Council of Scientific and Industrial Research [Praetoria] 2: 665-682. but these remains have not been located by modern paleontologists and are thus considered missing. Bones from the right side of the skull were also considered missing until 2015, when quadratojugal, quadrate, surangular, articular, and angular bones from the right side of the skull were rediscovered.
|
|
Evidence for periostitis found in the fossil record is studied by paleopathologists, specialists in ancient disease and injury. Periostitis has been seen in the late Cretaceous-Eocene crocodile Borealosuchus formidabilis, once known as Leidyosuchus. In one study, periostitis was the most common pathology in this species, with 134 instances of the condition out of 7,154 bones the scientists examined showing evidence for the condition. Periostitis has also been documented in dinosaurs, including a forelimb referred to the long-necked Camarasaurus grandis, as well as the shoulder blade of a horned dinosaur.
|
|
A tendon that runs through cartilaginous rings attached to the phalange allow an automatic locking system. The weigh tof the bat keeps the tendon taught, and hence the toes gripping when hanging, so the bat may sleep without falling from its roost. The uropatagium, the flap of skin that extends between the back legs and tail is supported by the calcaneum bone, which is located near the ankle. The forelimb bones are all elongated, with the degree of elongation increasing the farther the bones are from the body.
|
|
"Eugongbusaurus" skull IVPP 14559 "Eugongbusaurus" is the informal name (nomen nudum) proposed for a neornithischian found in the Oxfordian-age Shishugou Formation of Xinjiang, China. The intended type species, "Gongbusaurus" wucaiwanensis, was described by Dong Zhiming in 1989 for two partial skeletons as a second species of the poorly known tooth taxon Gongbusaurus. Fragmentary skeleton IVPP 8302, the type specimen for the new species, included a partial lower jaw, three tail vertebrae, and a partial forelimb. Second specimen IVPP 8303 consisted of two hip vertebrae, eight tail vertebrae, and two complete hind limbs.
|
|
Shoulder blade and coracoid of specimen AMNH 5895 Reconstructions of ankylosaur forelimb musculature made by Coombs in 1978 suggest that the forelimbs bore the majority of the animal's weight, and were adapted for high force delivery on the front feet, possibly for food gathering. In addition, Coombs suggested that ankylosaurs may have been capable diggers, though the hoof-like structure of the manus would have limited fossorial activity. Ankylosaurs were likely to have been slow-moving and sluggish animals, though they may have been capable of quick movements when necessary.
|
|
Left (top) and right (bottom) humeri in multiple views Almost all the right forelimb is known from Diamantinasaurus, although the left humerus is known in addition to the right, and the left first metacarpal is known while the right is unpreserved. Diagnostic of Diamantinasaurus, the glenoid (humerus) articulation of the scapula is rotated to the outside, differing from all other somphospondylans. Similar to Alamosaurus and taxa around the base of Titanosauria, at least a single ventral process is known, although it is poorly preserved. The scapula of Diamantinasaurus is robust, having a more round cross-section than other somphospondylans.
|
|
The ulna is long, while the radius is . Articulated manus of Diamantinasaurus displaying all preserved phalanges Because of the completeness of the forelimb material, the absence of carpal bones among the preserved material was presumed by Poropat et al. (2014) to be related to their genuine absence in life, as in Opisthocoelicaudia and Alamosaurus. The manus of Diamantinasaurus comparatively displays some plesiomorphic features, including: the middle metacarpal being the longest ( Mc III compared to next longest Mc II); the presence of a thumb claw; and the presence of multiple phalanges, having the phalangeal formula 2-1-1-1-1\.
|
|
The specific name tenerensis is after the Ténéré Desert where the animal was found. alt= The holotype, MNN GDF500, was found in the Tegama Beds of the Elrhaz Formation. It consists of a partial skeleton lacking the skull. It contains three neck ribs, parts of fourteen dorsal (back) vertebrae, ten dorsal ribs, gastralia (or "belly ribs"), pieces of three sacral vertebrae, parts of twelve caudal (tail) vertebrae, chevrons (bones that form the underside of the tail), a scapula (shoulder blade), a coracoid, a partial forelimb, most of the pelvis (hip bone), and parts of a hindlimb.
|
|
Like many other non-therian mammals, eutriconodonts retained classical mammalian synapomorphies like epipubic bones (and likely the associated reproductive constrictions), venomous spurs and sprawling limbs. However, the forelimb and shoulder anatomy of at least some species like Jeholodens are similar to those of therian mammals, though the hindlimbs remain more conservative. Eutriconodonts had a modern ear anatomy, the main difference from therians being that the ear ossicles were still somewhat connected to the jaw via the Meckel's cartilage. Uniquely among crown-group mammals, gobiconodontids replaced their molariform teeth by successors of similar complexity, while in other mammals less complex replacements are the norm.
|
|
If the angle was on the lower end (i.e., angled slightly headwards), this would have been a rather firm joint, allowing the deltoids to exert great force through the forelimb, such as when pinning down struggling prey, or holding down a carcass while ripping off flesh. If the humerus was positioned at a higher angle (angled downwards), this could have permitted enhanced extension forwards and backwards (along the long axis) and thus greater stride length, useful in an attack or short chase. The shoulder blade expands off to the sides of the animal (protrudes laterally), also providing a large attachment for the deltoids.
|
|
Vadasaurus is believed to have been at least partially aquatic, perhaps similar in lifestyle to the Galapagos marine iguana, Amblyrhynchus cristatus. It possessed thicker and heavier ribs and gastralia which may have functioned as ballast. Although a large amount of skeletal evidence provides evidence for the idea that the holotype specimen of Vadasaurus died in adulthood, the epiphyses of its forelimb bones were not completely fused. This is further evidence for a semiaquatic lifestyle, as animals which spend a large portion of their time in the water do not experience the forces of terrestrial locomotion to the same extent as fully terrestrial animals.
|
|
ZPA mouse, right forelimb In 1968, Saunders and Gasseling did transplantation studies using tissue from chick limb bud. Removing cells from the posterior region of the limb, they transplanted them to the anterior region and noticed that extra digits formed in the anterior area and these digits were mirror images to the normal ones. This posterior mesenchyme was the ZPA, which is now known to express the protein sonic hedgehog (Shh). One hypothesis is that at high concentrations, this unknown morphogen causes mesenchyme to form on the posterior side, while low concentrations induces meshenchyme to form on the anterior end.
|
|
The brachyury mutation was first described in mice by Nadezhda Alexandrovna Dobrovolskaya-Zavadskaya in 1927 as a mutation that affected tail length and sacral vertebrae in heterozygous animals. In homozygous animals the brachyury mutation is lethal at around embryonic day 10 due to defects in mesoderm formation, notochord differentiation and the absence of structures posterior to the forelimb bud (Dobrovolskaïa-Zavadskaïa, 1927). The name brachyury comes from the Greek brakhus meaning short and oura meaning tail. In 2018 HGNC updated the human gene name from T to TBXT, presumably to overcome difficulties associated with searching for a single letter gene symbol.
|
|
Despite this traditional naming, all sloths actually have three toes on each rear limb, although two-toed sloths have only two digits on each forelimb. The two groups of sloths are from different, distantly related families, and are thought to have evolved their morphology via parallel evolution from terrestrial ancestors. Besides the extant species, many species of ground sloths ranging up to the size of elephants (like Megatherium) inhabited both North and South America during the Pleistocene Epoch. However, they became extinct during the Quaternary extinction event around 12,000 years ago, together with most large bodied animals in the New World.
|
|
Haldanodon may have been a fossorial (burrowing) and/or semi- aquatic insectivore, similar in lifestyle to the modern desmans and Ornithorhynchus (the duck-billed platypus). This is indicated by some skeletal features, such as a wide scapula and stout limb bones with specialized joints. It likely had a sprawling gait based on the configuration of its limb joints, but this is probably a result of its specialized lifestyle instead of a primitive trait. The fingers and claws of the forelimb seem to correspond closely to scratch-digging modern mammals like armadillos and pangolins, rather than shovel-diggers like moles.
|
|
On the other hand, the relatively long forelimb and well-developed chest and shoulder keel on the humerus may indicate that the bird was able to provide enough strength to rise into the air. The presence of gastroliths indicates the prevalence of herbivorous in early birds. Depending on the point of view, C. zhengi represents a previously unknown sister taxa to the Ornithothoraces clade, belonging to Avialae, or a sister taxon to a clade made up of all other Avialae except Archaeopteryx. The creators of the genus proposed two possible cladograms depicting kinship between C. zhengi and related taxa.
|
|
Indeed, some humans even still develop vestigial vibrissal muscles in the upper lip. Thus, it is possible that the development of the whisker sensory system played an important role in mammalian development, more generally. Like monotremes today, the legs of early mammaliaforms were somewhat sprawling, giving a rather "reptilian" type of gait. However, there was a general tendency to have more erect forelimbs, forms like eutriconodonts even having a fundamentally modern forelimb anatomy while the hindlimbs remained "primitive"; this tendency is in some effect still seen in modern therian mammals, which often have more sprawling hindlimbs.
|
|
Life reconstruction of Zby atlanticus and size comparasion. Zby was first described and named by Octávio Mateus, Philip D. Mannion and Paul Upchurch in 2014 and the type species is Zby atlanticus, although it was initially thought to be Turiasaurus riodevensis. It is known solely from its holotype, a closely associated partial skeleton including a complete tooth with root, a fragment of cervical neural arch, an anterior chevron, and an almost complete right pectoral girdle and forelimb. Zby is differentiated from other sauropods based on four autapomorphies, including a prominent posteriorly projecting ridge on the humerus at the level of the deltopectoral crest.
|
|
Cardiocorax is known from the holotype MGUAN PA103 which consists of a complete pectoral and pelvic girdle, five neck and one back vertebrae, a partial forelimb including the humerus, radius bone, ulna and isolated phalanges, and several dorsal ribs. A second specimen was also referred to the species, MGAUN PA270, a more complete articulated pelvic girdle and a single hind limb. Both specimens are housed at the Museu de Geologia da Universidade Agostinho Neto in Luanda. The specimens were discovered at Bench 19 locality, about 7 meters from each other, in Bentiaba of the Namibe Province.
|
|
Lyson hypothesizes that this morphology in Eunotosaurus africanus suggests that turtles may have fossorial origin. The wide torso gave rise to the turtle shell but during the Permian period, the broadened ribs may have provided great stability in burrowing. The skeletal structure of E. africanus in comparison to the extant fossorial gopher tortoise share similar features adapted to withstand the impact and force needed in digging. For example, E. africanus exhibits shoulders and forelimb adapted to burrowing, showing increased muscle indicated in structures such as their tubercle on the posterior coracoid and their large and wide terminal phalanges.
|
|
Sinornithosaurus millenii, the first evidence of feathers in dromaeosaurids Cast of a Caudipteryx fossil with feather impressions and stomach content Sinornithosaurus millenii Jinfengopteryx elegans fossil Several non-avian dinosaurs are now known to have been feathered. Direct evidence of feathers exists for several species. In all examples, the evidence described consists of feather impressions, except those genera inferred to have had feathers based on skeletal or chemical evidence, such as the presence of quill knobs (the anchor points for wing feathers on the forelimb) or a pygostyle (the fused vertebrae at the tail tip which often supports large feathers).
|
|
Chalicotherioidea is an extinct superfamily of clawed perissodactyls (odd-toed ungulates) that lived from the early Eocene to the early Pleistocene subepochs.PaleoBiology Database: Chalicotherioidea, basic info Based on the fossil record they emerged and thrived largely in Eurasia, although specimens have been found in both Africa and North America. They were likely browsers that fed mainly on leaves, twigs, and other nonresistant vegetation. Many of the contained genera had derived specializations of the forelimb and manus that allowed the claws to be used as hooks for browsing and to be kept off of the ground while walking.
|
|
Gorillas are the most numerous of the animatronics, and there are usually four or five gorillas in each restaurant. Each group usually has a silverback, a baby hanging from a tree, and one or two other gorillas which are sometimes beating its chest and leaning on palm trees which they shake during their motion sequences. Leopards may be found at every location, but they are generally perched on a high ledge or tree with their tail and one forelimb hanging down. In the San Antonio Riverwalk location, there are panda bears resembling the adult and young in the upper level in the restaurant.
|
|
Plotopteridae is the name of an extinct family of flightless seabirds from the order Suliformes. Related to the gannets and boobies, they exhibited remarkable convergent evolution with the penguins, particularly with the now extinct giant penguins. That they lived in the North Pacific, the other side of the world from the penguins, has led to them being described at times as the Northern Hemisphere's penguins, though they were not closely related. More recent studies have shown, however, that the shoulder-girdle, forelimb and sternum of plotopterids differ significantly from those of penguins, so comparisons in terms of function may not be entirely accurate.
|
|
Drepanosaurus is known to have a huge claw on the index finger of each hand along with the tail claw. The skull of Drepanosaurus has never been found and is still unknown, however, the skulls of other drepanosaurs like Megalancosaurus give us an idea of what the skull of Drepanosaurus might look like. Looking at Megalancosaurus's skull shows that the claws of each index finger were probably the size of the entire head of Drepanosaurus and a bird like jaw and head shape. The forelimb of Drepanosaurus is highly modified compared to other vertebrates and very robust.
|
|
Life reconstruction by Dmitry Bogdanov Solenodonsaurus was likely best adapted to life on land, as opposed to living in an aquatic environment like many other early tetrapods. The limbs and pelvis are incomplete in all known specimens of Solenodonsaurus, making it difficult to infer how the animal may have moved. One feature that suggests a terrestrial lifestyle is the 90° rotation of the ends of the humerus, which orients the forelimb forward rather than out to the side. Several presumably terrestrial groups of Paleozoic tetrapods, including amphibamid temnospondyls, microsaurs, and the first amniotes, have a similar degree of rotation in their humeri.
|
|
Diagram showing the forelimb of Dilophosaurus in hypothesized resting posture Dilophosaurus had 10 cervical (neck), 14 dorsal (back), and 45 caudal (tail) vertebrae. It had a long neck, which was probably flexed nearly 90° by the skull and by the shoulder, holding the skull in a horizontal posture. The cervical vertebrae were unusually light; their centra (the "bodies" of the vertebrae) were hollowed out by pleurocoels (depressions on the sides) and centrocoels (cavities on the inside). The arches of the cervical vertebrae also had chonoses, conical recesses so large that the bones separating them were sometimes paper-thin.
|
|
Mesopropithecus and its closest sloth lemur relative, Babakotia, did share a few ancestral traits with indriids, unlike the largest sloth lemurs, Palaeopropithecus and Archaeoindris. These include the aforementioned four- toothed toothcomb, an inflated auditory bulla (bony structure that encloses part of the middle and inner ear), and an intrabullar ectotympanic ring (bony ring that holds the eardrum). While the skull of Mesopropithecus most closely resembles that of modern sifakas, the postcranial skeleton is quite different. Rather than having elongated hindlimbs for leaping, Mesopropithecus had elongated forelimbs, suggesting they predominantly used quadrupedal locomotion, slow climbing, with some forelimb and hindlimb suspension.
|
|
The digits also have a quasi-periodic arrangement along the proximodistal axis, consisting of tandem chains of skeletal elements. The generation of the basic limb plan during development results from the patterning of the mesenchyme by an interplay of factors that promote precartilage condensation and factors that inhibit it. The development of the basic limb plan is accompanied by the generation of local differences between the elements. For example, the radius and ulna of the forelimb, and the tibia and fibula of the hindlimb of the zeugopod are distinct from one another, as are the different fingers or toes in the autopod.
|
|
When beads were placed in the middle of the flank tissue, the anterior portion expressed Tbx5 and forelimb features, while the posterior portion of the limb expressed Tbx4 and hindlimb features. #When chick embryos were engineered to constitutively express Tbx4 (via viral- transfection) throughout their flank tissue, every limb they grew was a leg, even those that formed in the anterior region, which would normally become wings. This confirms the role of T-box proteins in the type of limb that develops. #Knocking out Tbx4 or Tbx5 knockout prevents FGF10 expression in the lateral plate mesoderm in mice.
|
|
Web site, accessed March 23, 2007 Horses are able to sleep standing up because a "stay apparatus" in their legs allows them to relax their muscles and doze without collapsing. In the front legs, their equine forelimb anatomy automatically engages the stay apparatus when their muscles relax. The horse engages the stay apparatus in the hind legs by shifting its hip position to lock the patella in place. At the stifle joint, a "hook" structure on the inside bottom end of the femur cups the patella and the medial patella ligament, preventing the leg from bending.
|
|
The full name can be translated as "Henan Xixia lizard". Remains of troodontids are very rare compared to those of other small theropod dinosaurs (only thirteen troodontid taxa were known at the time Xixiasaurus was named), and have mainly been found in Asia. The holotype specimen is the only known Xixiasaurus fossil, and consists of an almost complete skull except for the hindmost portion, as well as a partial right forelimb. The connection between the (forehead bone) and (bone running at the upper length of the snout) bones is displaced, and part of the is missing.
|
|
Most of the snout is preserved, with the of the right side being well- preserved. Only the front part of the left (tooth-bearing bone of the mandible) and some of its broken teeth are preserved. Though several teeth are missing from both jaws, their original number can be determined in the upper jaw, since their sockets there are preserved. The forelimb (of which all preserved parts are ) consists of the middle part of the and (bones of the lower arm), the extremity of the second and third (hand bones), the complete first finger, and the first of the second finger.
|
|
Several animals' remains were included in this package, but one of the most interesting was that of a small mammal, about the size of a small deer or sheep. In addition to a partial skull, a portion of a forelimb was found. The portions that Leidy was able to examine helped him determine it was likely related to modern llamas, even though there was a paucity of new material available after his 1848 diagnosis. This package spawned Leidy's interest in the White River badlands and its fauna, and he eventually sent collectors from the American Museum west to expand his collection.
|
|
The skull of MPC-D 100/86 is mostly undistorted and well preserved, lacking only the tip of the snout, while the rest of the skeleton is missing only middle cervical vertebrae, forelimb bones located lower than the elbow joints, some hindlimb bones, and most gastralia. It was discovered by a Japanese-Mongolian expedition, and represents the most complete specimen of a Late Cretaceous troodontid presently known. It was collected from the Dzamin Khond locality of the Djadokhta Formation in the central Gobi Desert, dating to the late Campanian stage of the Late Cretaceous, approximately 72 million years ago.
|
|
"Sexual Dimorphism in the Early Jurassic Theropod Dinosaur Dilophosaurus and a Comparison with Other Related Forms": In: Raath agreed that dimorphism in Coelophysis is evidenced by the size and structure of the forelimb. Rinehart et al. studied 15 individuals, and agreed that two morphs were present, even in juvenile specimens, and suggested that sexual dimorphism was present early in life, prior to sexual maturity. Rinehart concluded that the gracile form was female and the robust form was male based on differences in the sacral vertebrae of the gracile form, which allowed for greater flexibility for egg laying.
|
|
They analyzed the bio-mechanics of how stresses and strains would be distributed along the claws and into the limbs, using X-ray imaging to create a three-dimensional contour map of a forelimb claw from Velociraptor. For comparison, they analyzed the construction of a claw from a modern predatory bird, the eagle owl. They found that, based on the way that stress was conducted along the claw, they were ideal for climbing. The scientists found that the sharpened tip of the claw was a puncturing and gripping instrument, while the curved and expanded claw base helped transfer stress loads evenly.
|
|
The lesser coverts have dark bases, which gives the leading edge of the wing a streaky appearance. The uppertail coverts (feathers above the tail) are silvery white at the center, forming pale streaks. The median (between the greater and the lesser coverts), primary (connected to the distal forelimb), secondary (connected to the ulna), and greater coverts (feathers of the outermost, largest, row of upperwing coverts) are blackish, with the primaries having white shafts and the secondaries having variable silver-gray fringes. The tertials (feathers arising in the brachial region) are silver-gray with a brownish tinge.
|
|
Woodward, Keeper of Geology at the NHMUK, had "great pleasure" to recommend to the Trustees of the NHMUK the fossil be purchased. The purchase was sanctioned on 25 February 1899, along with the purchase of assorted other remains for just over £357 (~£43,596 now), where the Leeds sauropod gained the accession number BMNH R3078 (now NHMUK R3078). Known elements of Cetiosauriscus The amount of material made NHMUK R3078 the most complete sauropod specimen from the United Kingdom, comparable only later to the "Rutland Dinosaur" (referred to Cetiosaurus) discovered in 1967. Known regions of the specimen include the forelimb, hindlimb and vertebral column.
|
|
T. rex forelimb bones exhibit extremely thick cortical bone, which has been interpreted as evidence that they were developed to withstand heavy loads. The biceps brachii muscle of an adult T. rex was capable of lifting by itself; other muscles such as the brachialis would work along with the biceps to make elbow flexion even more powerful. The M. biceps muscle of T. rex was 3.5 times as powerful as the human equivalent. A T. rex forearm had a limited range of motion, with the shoulder and elbow joints allowing only 40 and 45 degrees of motion, respectively.
|
|
An avulsion injury left a divot on the humerus of Sue the T. rex, apparently located at the origin of the deltoid or teres major muscles. The presence of avulsion injuries being limited to the forelimb and shoulder in both Tyrannosaurus and Allosaurus suggests that theropods may have had a musculature more complex than and functionally different from those of birds. The researchers concluded that Sue's tendon avulsion was probably obtained from struggling prey. The presence of stress fractures and tendon avulsions in general provides evidence for a "very active" predation-based diet rather than obligate scavenging.
|
|
During embryonic development, the 21-kD protein FGF4 functions as a signaling molecule that is involved in many important processes. Studies using Fgf4 gene knockout mice showed developmental defects in embryos both in vivo and in vitro, revealing that FGF4 facilitates the survival and growth of the inner cell mass during the postimplantation phase of development by acting as an autocrine or paracrine ligand. FGFs produced in the apical ectodermal ridge (AER) are critical for the proper forelimb and hindlimb outgrowth. FGF signaling in the AER is involved in regulating limb digit number and cell death in the interdigital mesenchyme.
|
|
Anatomical terms used to describe a human hand Several anatomical terms are particular to the hands and feet. For improved clarity, the directional term palmar () is usually used to describe the front of the hand, and dorsal is the back of the hand. For example, the top of a dog's paw is its dorsal surface; the underside, either the palmar (on the forelimb) or the plantar (on the hindlimb) surface. The palmar fascia is palmar to the tendons of muscles which flex the fingers, and the dorsal venous arch is so named because it is on the dorsal side of the foot.
|
|
The most common injuries in the forelimb occur to the interosseous ligaments and the superficial digital flexor tendons and less commonly, the accessory ligament of the deep digital flexor tendon. Strain on the superficial digital flexors is greater when jumping higher fences, so horses may no longer be suitable for competitive jumping after damaging that apparatus. The effects of jumping on the hind legs can include injuries to the proximal, medial, or lateral branches of the suspensory ligaments. Jumping horses can also be at a higher risk of developing osteochondritis dissecans (OCD) or other arthritic conditions, even at a young age.
|
|
Lapillopsis was differentiated from the closely related Rotaurisaurus from Australia by several features: (1) a deep, semi-elliptical otic notch; (2) an abbreviated posterior skull table; (3) a broad shallow sulcus extending from the posterolateral corner of the quadratojugal to the posterior orbital margin; (4) a broadly flared anterior end of the cultriform process; (5) pterygoid-palatine separation, resulting in an ectopterygoid framing the interpterygoid vacuity; (6) jugal terminating at anterior orbital margin. The skull and mandible are particularly well-known, permitting a more or less complete reconstruction. Postcranial material consists largely of the pectoral and forelimb regions and a few vertebrae.
|
|
Ahshislepelta is known from the holotype SMP VP-1930, a closely associated and incomplete postcranial skeleton of an adult individual consisting of the shoulder girdle, a partial left forelimb, vertebrae and osteoderms. It was discovered in 2005 and collected between 2005 and 2009 from the Hunter Wash Member from the Kirtland Formation at the Ahshislepah Wash locality. Ahshislepelta was first named by Michael E. Burns and Robert M. Sullivan in 2011 and the type species is Ahshislepelta minor. The generic name comes from the Ahshislepah Wash locality, where the fossils were found, and pelta, "shield" in Greek.
|
|
Restoration of a rearing Diplodocus by Charles R. Knight, 1911. Since early in the history of their study, scientists, such as Osborn, have speculated that sauropods could rear up on their hind legs, using the tail as the third 'leg' of a tripod. A skeletal mount depicting the diplodocid Barosaurus lentus rearing up on its hind legs at the American Museum of Natural History is one illustration of this hypothesis. In a 2005 paper, Rothschild and Molnar reasoned that if sauropods had adopted a bipedal posture at times, there would be evidence of stress fractures in the forelimb 'hands'.
|
|
In humans, the only true anatomical joints between the shoulder girdle and the axial skeleton are the sternoclavicular joints on each side. No anatomical joint exists between each scapula and the rib cage; instead the muscular connection or physiological joint between the two permits great mobility of the shoulder girdle compared to the compact pelvic girdle; because the upper limb is not usually involved in weight bearing, its stability has been sacrificed in exchange for greater mobility. In those species having only the scapula, no joint exists between the forelimb and the thorax, the only attachment being muscular.
|
|
Many other fossil animals have been found, such as freshwater bivalves, gastropods, turtles, lizards such as Magnuviator, and champsosaurs. The multituberculate mammal Cimexomys has been found on Egg Mountain. The species Piksi barbarulna was described based on forelimb bones from the Two Medicine Formation; it was initially thought to be a bird, but subsequently it was reinterpreted as a pterosaur, likely a member of Ornithocheiroidea. Azhdarchoid pterosaurs are also known from the Two Medicine Formation, including a very large, yet- unnamed azhdarchid, the estimated wingspan of which was , and smaller Montanazhdarcho minor, a non-azhdarchid azhdarchoid.
|
|
The earliest form of eyewear for which any archaeological record exists comes from the middle of the 15th century. It is a primitive pince-nez whose frames were made from pieces of either metacarpal bone from the forelimb of a bull or from large pieces of antler. The two pieces were each paddle-shaped and were joined by an iron rivet which provided the tension over the nose and allowed the lenses to be folded together. The purpose of the three holes at the place where the handle connects to the hinge is uncertain, though they may have been used for pinhole vision, a principle which was known from ancient times.
|
|
This specimen, listed under the specimen numbers UW 15943 and UW 24801, consists of vertebrae, ribs, a shoulder girdle, a partial forelimb, and a fragmentary skull and was assigned as a neotype. Additionally, O'Keefe and Wahl noted that the shoulder girdle of this species was quite different from that of Tricleidus, so they named a new genus, Tatenectes, to include T. laramiensis. The name Tatenectes is derived from that of the Tate Museum and the Greek word Nectes, meaning "diver." O'Keefe and Hallie P. Street assigned more material to Tatenectes laramiensis in 2009, including UW 24215, a partial skeleton including further cranial, vertebral, pectoral, and phalangeal elements.
|
|
Tetrapod limb development involves many signaling molecules such as FGF, BMP, SHH and WNT. The apical ectodermal ridge is a structure found at the distal most tip which becomes a key signaling center for the developing limb. Surprisingly many of the same signaling pathways known to play a role in tetrapod limb development have been found to play a role in bat forelimb development but the timing, intensity, and spatial gene expression of some orthologous genes have changed. Since mice are also mammals, it is convenient to compare morphology and development of forelimbs between mice and bats; these comparisons may elucidate the genetic basis of adaptive bat wing development.
|
|
In amphibians and reptiles (birds included), these two bones are distinct, but together form a single structure bearing many of the muscle attachments for the forelimb. In such animals, the scapula is usually a relatively simple plate, lacking the projections and spine that it possesses in mammals. However, the detailed structure of these bones varies considerably in living groups. For example, in frogs, the procoracoid bones may be braced together at the animal's underside to absorb the shock of landing, while in turtles, the combined structure forms a Y-shape in order to allow the scapula to retain a connection to the clavicle (which is part of the shell).
|
|
Peking: Academia Sinica. pp.17–27. Noting the presence of pachypleurosaurs and the absence of fish among the Nanzhang- Yuan'an fauna, the authors who named Parahupehsuchus suggested that as apex predators, the pachypleurosaurs were likely to have preyed on smaller marine reptiles, including hupehsuchians. According to the discoverers of Eohupehsuchus, the jaws of Hanosaurus hupehensis are sufficiently large to have caused the bite wound seen in the left forelimb of WGSC V26003, corroborating this picture of the assemblage's paleoecology. On this basis, they suggest that the trophic structure of modern marine ecosystems, in which the diet of apex predators includes secondarily aquatic tetrapods, was already present in the Early Triassic.
|
|
The recovering peri-infarct regions that have bad circuits are competing with healthy tissue for cortical map space. An in vivo study by Murphy was done using mice to help identify the sequence and kinetics of the peri-infarct cortical remapping after stroke. The study showed that eight weeks after a stroke had occurred in the forelimb sensory cortex of a mouse, the 'surviving' portion was able to promptly relay enhanced sensory signals to the motor cortex, which resulted in the remapping of sensory function. The mouse that experienced a stroke had remapped responses that lasted longer and spread farther from the motor cortex than those of the control.
|
|
Cast of the hand of C. nasicornis (AMNH 27631): Most phalanges of the fingers are missing. The strongly shortened metacarpals and phalanges of Ceratosaurus raise the question whether the manus retained the grasping function assumed for other basal theropods. Within the Ceratosauria, an even more extreme manus reduction can be observed in abelisaurids, where the forelimb lost its original function, and in Limusaurus. In a 2016 paper on the anatomy of the Ceratosaurus manus, Carrano and Jonah Choiniere stressed the great morphological similarity of the manus with those of other basal theropods, suggesting that it still fulfilled its original grasping function, despite its shortening.
|
|
The Hox genes, which define features along the anterior-posterior axis of a developing organism, determine at which points along the axis that limb buds will form. Though limbs emerge at different locations in different species, their positions always correlate with the level of Hox gene expression along the anterior-posterior axis. All limb buds must also rely on other signaling factors to obtain their forelimb or hindlimb identity; Hox gene expression influences expression of T-box proteins that, in turn, determine limb identity for certain organisms. In turn, the activation of T-box protein activates signaling cascades that involve the Wnt signaling pathway and FGF signals.
|
|
Reconstruction of the pectoral girdle and forelimb of Saltriovenator zanellai On 4 August 1996, the first remains of Saltriovenator were discovered by amateur paleontologist Angelo Zanella, searching for ammonites in the Salnova marble quarry in Saltrio, northern Italy. Zanella had already been working for the Museo Civico di Storia Naturale di Milano and this institution after being informed sent out a team to investigate the find. Cristiano Dal Sasso and Alberto Lualdi, under the direction of Giorgio Teruzzi managed to salvage a number of chalk blocks visibly containing bones. The skeleton had shortly before its discovery been blown to pieces by explosives used in the quarry to break the marble layers.
|
|
The generic name combines the philosopher Confucius with a Greek ὄρνις, (ornis), "bird". The specific name means "holy one" in Latin and is a translation of Chinese 圣贤, shèngxián, "sage", again in reference to Confucius. The first discovered specimen was designated the holotype and catalogued under the specimen number IVPP V10918; it comprises a partial skeleton with skull and parts of the forelimb. Of the other two skeletons, one (paratype, IVPP V10895) comprises a complete pelvis and hind limb, and the other (paratype, IVPP V10919–10925) a fragmentary hind limb together with six feather impressions attached to both sides of the tibia (shin bone).
|
|
Evidence of webbing between the three free fingers of the pterosaur forelimb suggests that this forward membrane may have been more extensive than the simple pteroid-to-shoulder connection traditionally depicted in life restorations. The position of the pteroid bone itself has been controversial. Some scientists, notably Matthew Wilkinson, have argued that the pteroid pointed forward, extending the forward membrane and allowing it to function as an adjustable flap. This view was contradicted in a 2007 paper by Chris Bennett, who showed that the pteroid did not articulate as previously thought and could not have pointed forward, but rather was directed inward toward the body as traditionally interpreted.
|
|
Restless flycatcher in the downstroke of flapping flight Most birds can fly, which distinguishes them from almost all other vertebrate classes. Flight is the primary means of locomotion for most bird species and is used for searching for food and for escaping from predators. Birds have various adaptations for flight, including a lightweight skeleton, two large flight muscles, the pectoralis (which accounts for 15% of the total mass of the bird) and the supracoracoideus, as well as a modified forelimb (wing) that serves as an aerofoil. Wing shape and size generally determine a bird's flight style and performance; many birds combine powered, flapping flight with less energy-intensive soaring flight.
|
|
Bufo bufo The common toad responds to a moving insect or worm with a series of prey-catching reactions: (1) orienting towards prey, (2) stalking up to prey, (3) binocular fixation, (4) snapping, (5) swallowing and (6) mouth-wiping with forelimb (Ewert 1974). This series of movement constitutes a stimulus-response chain, where each reaction of the toad provides the stimulus constellation for the next response. First, if an object is recognized as prey and thus catches the toad's attention, the toad will orient towards the stimulus by turning its body to face it. Then it approaches the prey, binocularly focusing intently on it.
|
|
Different isoforms of retinal dehydrogenase exist and play a key role in development, as the types are differentially expressed inside a developing embryo. The enzyme retinal dehydrogenase type-2 (RALDH2) catalyzes much of the retinoic acid formation during development, but not all. RALDH2 is crucial for development midgestation and helps drive neural, heart, lung, and forelimb development; it is also responsible for all retinoic acid development during certain periods of midgestation. Later in development, retinal dehydrogenase type-1 (RALDH1) begins activity in the dorsal pit of the retina and retinal dehydrogenase type-3 (RALDH3) becomes active in the olfactory pit, ventral retina, and urinary tract.
|
|
Diagrams showing hand and foot bones of specimen SAM-PK-K1332 Although most researchers now consider Heterodontosaurus a bipedal runner, some earlier studies proposed a partial or fully quadrupedal locomotion. In 1980, Santa Luca described several features of the forelimb that are also present in recent quadrupedal animals and imply a strong arm musculature: These include a large olecranon (a bony eminence forming the uppermost part of the ulna), enlarging the lever arm of the forearm. The medial epicondyle of the humerus was enlarged, providing attachment sites for strong flexor muscles of the forearm. Furthermore, projections on the claws might have increased the forward thrust of the hand during walking.
|
|
Gerhart and Kirschner give the example of the evolution of a bird or bat wing from a tetrapod forelimb. They explain how, if bones undergo regulatory change in length and thickness as a result of genetic mutation, the muscles, nerves and vasculature will accommodate to those changes without themselves requiring independent regulatory change. Studies of limb development show that muscle, nerve, and vascular founder cells originate in the embryonic trunk and migrate into the developing limb bud, which initially contains only bone and dermis precursors. Muscle precursors are adaptable; they receive signals from developing dermis and bone and take positions relative to them, wherever they are.
|
|
The rest of the skeleton of this genus is poorly presented, with for example the vertebrae showing no evidence of the proportional changes in the height of the neural arches and spines seen on stegosaurs. The animal was covered on Osteoderms, altrougth the few found give no indication of how extensively they were distributed across the torso. Emausaurus, based on the proportions of the preserved metacarpals that the forelimb shows adaptations for weight support, rather than grasping, having ungulal phalanges that are conical and only slightly decurved. The partial known proximal pedal phalanges are short and block-like, with near the same proportions seen in the pes of Scelidosaurus.
|
|
Rocks in the Doelling's Bowl bonebed mainly consist of green-grey sandy mudstone, but also contain silcrete, casts of silificied plant roots, and chert pebbles. It belongs to the Cretaceous-aged Yellow Cat Member of the Cedar Mountain Formation. Mierasaurus was named after Bernardo de Miera y Pacheco of the 1776 Dominguez- Escalante expedition (pictured here) In 2010, a skeleton of a subadult sauropod dinosaur was discovered in an arroyo within Gary's Island, a region at the western end of the bonebed named after its discoverer Gary Hunt. Only part of the specimen - a partial left forelimb (scapula, sternal plates, ulna, radius, and hand), a complete left hindlimb, and ten caudal (tail) vertebrae - was articulated.
|
|
A timeline depicting observed evidence of post-canine megadontia The shift towards post-canine megadontia dates back to about 4-5 million years ago with the discovery of Ardipithecus ramidus in the Middle Awash region of Ethiopia. Distinctive features in A. ramidus such as dentition with reduced canines, the skull, hindlimb and forelimb suggest it to be near the split between the chimpanzee and hominin lineages. It was the origin of Australopithecus africanus, found in several regions of South Africa (Taung, Sterkfontein, Makapansgat) 2-3 million years ago that first demonstrated the enlargement of the pre-molars and molars. In terms of morphology, A. africanus shares many similar characteristics with A. afarensis as well as other genera in Paranthropus.
|
|
Study into Suminia post cranial anatomy reveal many autapomorphies for the single specimen. Significant post cranial autapomorphies of Suminia are the reduced number of presacral and dorsal vertebrae (exclusively amphicoelous) with lack of fusion in the sacral region between vertebrae (suggests high flexibility), wide pre- and postzygapophyses, longer proportions of cervical pleurocentra, distinct proportionally longer limbs, a manus that forms ~ 40% of the length of the forelimb with particularly long, curved terminal phalanges, a pes that makes up ~38% of the hindlimb, and enlarged carpal 1 and tarsal 1 (suggests divergent first digit). These different morphological features indicate a significantly deviated post cranial anatomy from other anomodonts, suggesting that Suminia adopted an arboreal lifestyle (see below).
|
|
The foot of the elephant possesses what is perhaps one of the most unusual distal cushions found in vertebrates. The forefoot (manus) and hindfoot (pes) contain huge pads of fat that are scaled to cope with the massive loadings imposed by the largest terrestrial vertebrate. In addition, a cartilage-like projection (prepollex in the forelimb and prehallux in the hind limb) appears to anchor the distal cushion to the bones of the elephant's foot. The distal cushions of all these organisms (dog, horse, human and elephant) are dynamic structures during locomotion, alternating between phases of compression and expansion; it has been suggested that these structures thereby reduce the loads experienced by the skeletal system.
|
|
Afterwards, the AER progressively decreases in height and eventually regresses. In mouse embryos, the ventral ectoderm of the emerging forelimb at E9.5 (embryonic day 9.5) already appears thicker in comparison to the dorsal ectoderm and it corresponds to the early AER. By E10, this thickening is more noticeable since the epithelium now consists of two layers and becomes confined to the ventral- distal margin of the bud although it is not detectable in living specimens using light microscope or by scanning electron microscopy (SEM). Between E10.5-11, a linear and compact AER with a polystratified epithelial structure (3-4 layers) has formed and positioned itself at the distal dorso-ventral boundary of the bud.
|
|
Vertebrae from the pectoral region of the holotype specimen The vertebrae that transitioned between the neck and back (or dorsal) vertebrae in the pectoral region of plesiosaurs, close to the front margin of the forelimb girdle, are often termed pectoral vertebrae. Elasmosaurus had three pectoral vertebrae, which is a common number for elasmosaurids. The rib facets of the pectoral vertebrae were triangular in shape and situated on transverse processes, and the centra bore pairs of nutritive foramina in the middle of the lower sides. The back vertebrae had rib facets level with the neural canal, and the front and back part of the transverse processes here had distinct ridges on their margins.
|
|
Anhuilong is known from the holotype AGB 5822, a forelimb consisting of a left humerus, ulna, and radius. It is distinguished by the following combination of features: low ratios of the average of the greatest widths of the proximal end, mid-shaft and distal end of the humerus/length of the humerus, total length of ulna to humerus and total length of radius to humerus; the lateral edge of the deltopectoral crest directs caudolaterally, the lateral accessory condyle on the craniodistal edge of humerus is more robust than the medial one, and the cross-sectional shape of the ulna at mid-shaft is elliptical with highest ratio of transverse to craniocaudal diameter among mamenchisaurids.
|
|
However, according to Renesto and Binelli it is feasible that this might be a result of poor knowledge of Longisquama rather than a reflection of its true phylogenetic position. The authors did note that there are similarities in the structure of forelimb and shoulder region of Longisquama and all or some drepanosaurids (e.g. both Longisquama and Vallesaurus have the fourth digit of manus as long as humerus); they stressed that they could not rule out that at least some of the similarities are convergent due to similar mode of life, and that they did not examine Longisquama firsthand, but stated that further studies of drepanosaurids should take the hypothesis that Longisquama might be a drepanosaurid into consideration.
|
|
Although the postcranial skeleton of Thalassodromeus is unknown, relatives had unusually short and blocky neck vertebrae, with well-developed front and hind-limbs that were almost equal in length (excluding the long wing-finger). The hindlimbs were 80 percent that of the forelimb length, a unique ratio among pterodactyloids (short-tailed pterosaurs). As a pterosaur, Thalassodromeus was covered with hair-like pycnofibres and had extensive wing membranes (which were extended by the wing finger). The skull of T. sethi had a streamlined profile, especially from the tip of the snout to the front edge of the nasoantorbital fenestra (opening which combined the antorbital fenestra in front of the eye with the bony nostril).
|
|
As shi yi also can mean "register of lost objects" the specific name is at the same time a pun on the fact that the teeth were later separately found among the assorted bones collected during the dig. Dong added a second species, "G." wucaiwanensis, in 1989 for a fragmentary skeleton (holotype IVPP 8302) including a partial lower jaw, three tail vertebrae, and a partial forelimb, and added another specimen (paratype IVPP 8303) consisting of two hip vertebrae, eight tail vertebrae, and two complete hind limbs. A partial foot (IVPP 8304) and four separate dorsal vertebrae and a caudal vertebra were referred. These remains came from the roughly contemporaneous Shishugou Formation of Wucaiwan, Xinjiang.
|
|
Within the "early stage" Bothrosauropodoidea, Zhao considered Klamelisaurus to be part of the Brachiosauridae, which by his definition included the modern Brachiosauridae alongside Cetiosauridae (as "Cetiosaurinae"), Camarasaurinae, and Euhelopodidae (as "Euhelopodinae"). Among these groups, he considered Klamelisaurus to be closest to Camarasaurinae due to the cervicals being longer than the dorsals; the bifid cervical and dorsal neural spines; the "well-developed" pleurocoels; the relatively short forelimb; and the fibula- femur length ratio. However, he noted that the combination of more than twelve cervicals, thirteen dorsals, five sacrals with four fused, and other characteristics in Klamelisaurus was distinct from these other groups, warranting the creation of a new subfamily. Subsequent literature has not used Zhao's taxonomy for Klamelisaurus.
|
|
Kenyasaurus is known only from the holotype specimen, KNM-MA1, a well preserved and partially complete postcranial skeleton, lacking much of the neck, pectoral girdle and forelimb, which is hosted at the Kenya National Museum. It was found at the Mariakani locality which is located 25 miles from Mombasa, southeastern Kenya. It was collected from the upper part of the Maji ya Chumvi Beds (Maji-Ya-Chumvi Formation). These beds form the lower part of the Middle Duruma Sandstone Series (Duruma Group) and on the basis of lithological similarities with beds in Tanzania and Madagascar were dated to the Induan and Olenekian stages of the Early Triassic period, about 251.0-245 million years ago.
|
|
Enaliarctos has been heralded as the ancestor of all known pinnipeds, including the families Otariidae (fur seals and sea lions), Desmatophocidae (extinct seal convergent pinnipeds), Phocidae (true seals), and Odobenidae (walruses). Investigations of the biomechanics of Enaliarctos indicate that it used both its forelimbs and hindlimbs during swimming. Modern fur seals and sea lions only use their forelimbs, while true seals primarily use their hindlimbs for aquatic propulsion; lastly, the extant walrus uses both fore- and hindlimbs for swimming. It has been postulated that the condition in Enaliarctos is ancestral for all pinnipeds, and that forelimb swimming was lost in true seals, while hindlimb swimming was lost in fur seals and sea lions.
|
|
The D. torosus holotype specimen mounted at the Canadian Museum of Nature. The type specimen of Daspletosaurus torosus (CMN 8506) is a partial skeleton including the skull, the shoulder, a forelimb, the pelvis, a femur and all of the vertebrae from the neck, torso and hip, as well as the first eleven tail vertebrae. It was discovered in 1921 near Steveville, Alberta, by Charles Mortram Sternberg, who thought it was a new species of Gorgosaurus. It was not until 1970 that the specimen was fully described by Dale Russell, who made it the type of a new genus, Daspletosaurus, from the Greek δασπλής (', stem and connective vowel resulting in '-) ("frightful") and σαυρος () ("lizard").
|
|
In 2007, the Chengdu University of Technology Museum based on the clues provided by the masses, searched for dinosaurs in Tongan Town, Huili County, Sichuan Province. The fossils come from the middle of the lower part of the Yimen Formation, whose age is estimated on 184.5 m.a. They were inspected and excavated, and a few new Sauropoda dinosaur fossil materials were obtained, including about 20 vertebrae, complete Right shoulder strap and right forelimb, distal left humerus, intact left and right ischia, left femur, and complete right hind limb, and More than 10 scattered spinous nerves, ribs, tibia and claw bones. Where the fossil materials were collected in the same location, and were proportional.
|
|
Fossil of Tianyulong, muzzle, hand, feet and tail framed in red The postcranial anatomy of Heterodontosaurus tucki has been well-described, although H. tucki is generally considered the most derived of the Early Jurassic heterodontosaurids, so it is impossible to know how many of its features were shared with other species. The forelimbs were long for a dinosaur, over 70% of the length of the hindlimbs. The well-developed deltopectoral crest (a ridge for the attachment of chest and shoulder muscles) of the humerus and prominent olecranon process (where muscles that extend the forearm were attached) of the ulna indicate that the forelimb was powerful as well. There were five digits on the manus ('hand').
|
|
These evolved into the sauropods which became gigantic quadrupedal herbivores, some of which reached lengths of at least 26 m (85 ft). Features defining this clade include a ratio of forelimb length to hindlimb length greater than 0.6. Most sauropods still had hindlimbs larger than forelimbs; one notable exception is Brachiosaurus whose long forelimbs suggest that it had evolved to feed from tall trees like a modern-day giraffe. Sauropod fossils are found from the times of the earliest dinosaurs right up to the Cretaceous–Paleogene extinction event, from 227 to Ma. Most sauropods are known from the Jurassic, to be more precise between 227 and 121 Ma. The Cretaceous sauropods form two groups.
|
|
Forelimbs of Therizinosaurus, specimen IGM 100/15 displayed at Nagoya City Science Museum Therizinosaurs were long considered an enigmatic group, whose mosaic of features resembling those of various different dinosaur groups, and scarcity of their fossils, led to controversy over their evolutionary relationships for decades after their initial discovery. The first genus, Therizinosaurus, was originally identified as a turtle when described from forelimb elements in 1954. Translated paper Perle noted in 1979 that the Segnosaurus fossils were possibly representative of a new family of dinosaurs, which he tentatively classified as theropods (traditionally thought of as the "meat-eating" dinosaurs). He named the family Segnosauridae, with Segnosaurus as type genus and sole member.
|
|
Subsequently, in 1993, Carole Jones and her husband Ramal Jones discovered fragmentary bones in a fossil site located in the northwestern region of the Swell. They brought the site to the attention of Donald Burge, director of the institution then called the College of Eastern Utah Prehistoric Museum (CEUM). The site, which is formally known as CEUM Locality 42em366v, would subsequently be named Carol's Site (sic) in her honour. The fossils, stored under the specimen number CEUM 9758, represent the partial remains of an adult hadrosauroid, including parts of the skull, vertebrae, ischium, and leg. CEUM 5212, a partial skull and forelimb from an adult, was found nearby in CEUM Locality 42em369v.
|
|
Albertonykus (meaning "Alberta claw") is an alvarezsaurid dinosaur from the Maastrichtian-age (Upper Cretaceous) rocks of the Horseshoe Canyon Formation of Alberta, Canada. It is known from forelimb and hindlimb remains from multiple individuals. All but two of the specimens come from a bonebed dominated by Albertosaurus, located located at the top of Unit 4 of the Horseshoe Canyon Formation,Larson, D. W., Brinkman, D. B., & Bell, P. R. (2010). Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebed This article is one of a series of papers published in this Special Issue on the theme Albertosaurus.
|
|
Restoration Model reconstruction at the State Museum of Natural History in Stuttgart, Germany Skull The Acanthostega had eight digits on each hand (the number of digits on the feet is unclear) linked by webbing, it lacked wrists, and was generally poorly adapted for walking on land. It also had a remarkably fish-like shoulder and forelimb. The front foot of Acanthostega could not bend forward at the elbow, and therefore could not be brought into a weight bearing position, appearing to be more suitable for paddling or for holding on to aquatic plants. Acanthostega is the earliest stem-tetrapod to show the shift in locomotory dominance from the pectoral girdle to the pelvic girdle.
|
|
The clavicle bones are thick and rounded at their base but taper as they extend outwards (and upwards in the case of a living animal). No conclusive evidence of a pelvic girdle or hindlimbs have been found, although Carroll (1969) considered that a few bone fragments around the 26th to 31st vertebrae may have been leg bones. As a whole, the lack of known limb and endochondral material yet the retention of a dermal shoulder girdle is a condition similar to that of the other family of adelospondyls, the adelogyrinids. Although forelimbs were supposedly found in various adelogyrinids in the late 1960s, Andrews & Carroll (1991) found that all cases of forelimb bones in adelogyrinids were actually misinterpretations.
|
|
The Sauriurae are a putative clade of primitive birds that includes Archaeopteryx, Confuciusornis, and Enantiornithes. It is thought by Feduccia and Martin to be phylogenetically separate from the Ornithurae and, thus, from modern birds. Apsaravis has features of both Sauriurae and Ornithurae. Apsaravis has several characters that place it near Aves (sensu Gauthier), including the presence of at least ten sacral vertebrae, a pubis and ischium that are closely appressed, distal pubes that do not touch, an 'obturator flange' on the ischium, loss of the cuppedicus muscle fossa on the ilium, a patellar groove on the distal femur, an anterior sternal keel, completely heterocoelus vertebrae, curved scapular shaft, and several features of the forelimb, ankle, and foot.
|
|
The "Barnes High sauropod" is the informal name given to MIWG-BP001, an undescribed sauropod dinosaur specimen from the Wessex Formation on the Isle of Wight. It was discovered in the cliffs around Barnes High in 1992 and is currently owned by the privately run unaccredited Dinosaur Farm Museum near Brighstone, the ownership situation was described as "complex" and the specimen is currently inaccessible to researchers. It is roughly 40% complete and consists of a "Partial postcranial skeleton, including presacral vertebrae, anterior caudal vertebrae, girdle and limb elements" including a largely complete forelimb. It has been suggested to be a Brachiosaur and is possibly synonymous with the earlier named Eucamerotus due to similarities with the vertebrae.
|
|
"Biscoveosaurus" is the informal name of an ornithopod dinosaur specimen from the Early Maastrichtian age Snow Hill Island Formation of James Ross Island, Antarctica. It comes from the Cape Lamb Member of the formation, the same member as Morrosaurus, another basal ornithopod. As such, it's been suggested it may be a secondary specimen of that species, but as the holotype of Morrosaurus is fragmentary and doesn't overlap with the material of "Biscoveosaurus", this can't as yet be tested. The specimen consists of dentaries, teeth, a braincase, parts of the maxillae, forelimb elements, assorted vertebrae, and the pectoral girdle; this makes it unique compared to the other James Ross Island ornithopods, which don't presever both cranial and postcranial remains.
|
|
The black tree monitor is primarily insectivorous, consuming mostly insects but also smaller lizards, small mammals such as shrews, scorpions, eggs, and the nestlings of birds. Like other members of the V. prasinus species complex, they are occasionally seen eating plants in captivity, although the gut contents of wild monitors were not reported to contain plant matter. In captivity, newly hatched members of the V. prasinus species complex often refuse food for more than two weeks, although force feeding may be recommended before then and until they begin feeding by themselves. Like other monitor lizards, this species is highly intelligent amongst reptiles, and like others of the V. prasinus species complex, demonstrates complex problem solving abilities, fine motor coordination, and skilled forelimb movements when hunting prey.
|
|
When Aulacephalodon peavoti was first described, the cranium of one specimen was compared to Aulacephalodon bainii to determine if A. peavoti can accurately be described as Aulacephalodon. The most distinct difference between A. bainii and A. peavoti is that specimens of A. peavoti are not found to possess tusks, which is a notable feature of A. bainii and Aulacephalodon. A. peavoti is also found to have a wider and more upright scapula blade compared to A. bainii, with deeper fossa on the proximal end of the scapula. While both species share some similar post-cranial features, there are numerous differences in the shapes of various girdle and forelimb elements prevents paleontologists from definitively recognizing A. peavoti as a member of Aulacephalodon.
|
|
It is an articulated skeleton missing the skull, part of the tail, and the right forelimb. The name Anchiornis huxleyi was chosen by Xu and colleagues in honor of Thomas Henry Huxley, an early proponent of biological evolution, and one of the first to propose a close evolutionary relationship between birds and dinosaurs. The generic name Anchiornis comes from combining the Ancient Greek words for "nearby" and "bird", because it was interpreted as important in filling a gap in the transition between the body plans of birds and dinosaurs. A second specimen came to light around the same time, and was given to a team of scientists from Shenyang Normal University by a local farmer when they were excavating at the Yaolugou dig site.
|
|
The overall robustness of the skeleton of Xingxiulong, especially in the hip, femur, and foot, are convergent upon sauropods, and collectively suggest that it had a relatively large gut and overall high body mass. However, unlike sauropods, Xingxiulong would have been bipedal; it lacks sauropodan adaptations to quadrupedalism including relatively longer forelimbs, the ulna bearing a prominent process on the front of its side, and the femur having a relatively straight shaft. Instead, its ulna and femur are overall more reminiscent of the typical basal sauropodomorph. The large and robust scapulae of Xingxiulong, Jingshanosaurus, and Yunnanosaurus may have increased the mobility of the forelimb during bipedal browsing, but this trait was later adopted as an adaptation to quadrupedality in sauropods.
|
|
Reconstructed forelimb and hand of Suchomimus, Museum of Ancient Life, Utah The use of the robust forelimbs and giant recurved claws of spinosaurs remains a debated topic. Charig and Milner speculated in 1986 that Baryonyx may have crouched by the riverbank and used its claws to gaff fish out of the water, similarly to grizzly bears. In 1987, British biologist Andrew Kitchener argued that with both its crocodile-like snout and enlarged claws, Baryonyx seemed to have too many adaptations for piscivory when one would have been enough. Kitchener instead postulated that Baryonyx more likely used its arms to scavenge the corpses of large dinosaurs, such as Iguanodon, by breaking into the carcass with the large claws, and subsequently probing for viscera with its long snout.
|
|
A double-sided retinoic acid gradient, that is high in the trunk and low at the junction with the head and tail, represses FGF8 in the developing trunk to allow normal somitogenesis, forelimb bud initiation, and formation of the atria in the heart. During exposure to excess ATRA, the hindbrain becomes enlarged, hindering the growth of other parts of the brain; other developmental abnormalities that can occur during excess ATRA are missing or fused somites, and problems with the aorta and large vessels within the heart. With an accumulation of these malformations, an individual can be diagnosed with DiGeorge syndrome. However, since ATRA partakes in various developmental processes, abnormalities associated with loss of ATRA are not just limited to sites associated with DiGeorge syndrome.
|
|
Restored cast of the holotype, Museu de Ciências Naturais da PUC Minas Forelimb bones Carnotaurus is one of the best-understood genera of the Abelisauridae, a family of large theropods restricted to the ancient southern supercontinent Gondwana. Abelisaurids were the dominant predators in the Late Cretaceous of Gondwana, replacing the carcharodontosaurids and occupying the ecological niche filled by the tyrannosaurids in the northern continents. Several notable traits that evolved within this family, including shortening of the skull and arms as well as peculiarities in the cervical and caudal vertebrae, were more pronounced in Carnotaurus than in any other abelisaurid. Though relationships within the Abelisauridae are debated, Carnotaurus is consistently shown to be one of the most derived members of the family by cladistical analyses.
|
|
Bronze cast of MOR 555 outside the Museum of the RockiesIn 1988, local rancher Kathy Wankel discovered another Tyrannosaurus rex in Hell Creek sediments on an island in the Charles M. Russell National Wildlife Refuge of Montana. This specimen was excavated by a team from the Museum of the Rockies led by paleontologist Jack Horner, with assistance from the U.S. Army Corps of Engineers. The specimen, given the number MOR 555 but informally called the "Wankel rex," includes approximately 46 percent of the skeleton, including the skull, as well as what at the time was the first complete T. rex forelimb. It has a recently estimated length of around and a weight between and in newer figures, being the average estimate.
|
|
Leptoptilos falconeri was similar in adaptations to a somewhat better-known cousin from a younger insular fossil species from Flores, Leptoptilos robustus, that also grew to very large dimensions, although current estimated sizes for that species are slightly smaller than L. falconeri. It can be inferred from the recorded dimensions of the bones that L. falconeri was substantially taller and heavier than other species of Leptoptilos. Much like L. robustus, L. falconeri showed reduced forelimb size relative to its otherwise oversized, robust skeletal structure, suggesting limited flying abilities (though, perhaps unlike L. robustus, it is not currently opined to have been completely flightlessness) and a strongly terrestrial lifestyle. The most striking feature of L. falconeri fossils are its very large size.
|
|
The number of traumatic events that led to these features is not certain, and it is possible that they were all caused by a single encounter, for example by crashing into a tree or rock during a fight with another animal, which may have caused puncture wounds with its claws. Since all the injuries had healed, it is certain that the Dilophosaurus survived for a long time after these events, for months, perhaps years. The use of the forelimbs for prey capture must have been compromised during the healing process. The dinosaur may therefore have endured a long period of fasting or subsisted on prey that was small enough for it to dispatch with the mouth and feet, or with one forelimb.
|
|
It contains both praemaxilla (frontmost upper jaw bones), both maxillae (main upper jaw bone), teeth, a lacrimal, a jugal, a postorbital, a squamosal, a supraoccipital, parts of the lower jaws, a possible hyoid, two cervical (neck) vertebrae (backbones), cervical ribs, rear dorsal (back) vertebrae, at least five front caudal (tail) vertebrae, chevrons, ribs, gastralia (or "belly ribs"), the lower parts of a left forelimb, a furcula (wishbone), both pubic bones, a left ischium (lower and rearmost hip bone), a right femur, a tibia (shin bone), the upper part of a fibula (calf bone), a left astragalus (ankle bone), three tarsals, and three metatarsals. About 40% of the skeleton is presented. Dracoraptor is thus the most complete Mesozoic non-bird theropod dinosaur known from Wales.
|
|
A study describing the fossils in 2012 concluded that O. edmontonicus was covered in plumaceous feathers at all growth stages, and that only adults had pennaceous wing-like structures, suggesting that wings may have evolved for mating displays. In 2014, Christian Foth and others argued that the evidence was insufficient to conclude that the forelimb feathers of Ornithomimus were necessarily pennaceous, citing the fact that the monofilamentous wing feathers in cassowaries would likely leave similar traces. A fourth feathered specimen of Ornithomimus, this time from the lower portion of the Dinosaur Park Formation, was described in October, 2015 by Aaron van der Reest, Alex Wolfe, and Phil Currie. It was the first Ornithomimus specimen to preserve the feathers along the tail.
|
|
Skilled motor tasks have been divided into two distinct phases: a fast-learning phase, in which an optimal plan for performance is established, and a slow-learning phase, in which longer-term structural modifications are made on specific motor modules. Even a small amount of training may be enough to induce neural processes that continue to evolve even after the training has stopped, which provides a potential basis for consolidation of the task. In addition, studying mice while they are learning a new complex reaching task, has found that "motor learning leads to rapid formation of dendritic spines (spinogenesis) in the motor cortex contralateral to the reaching forelimb". However, motor cortex reorganization itself does not occur at a uniform rate across training periods.
|
|
They suggested that the D-shaped cross-section of the premaxillary teeth could be one possible feature uniting Xixiasaurus, Byronosaurus, and Urbacodon. Forelimb bones of the holotype The following cladogram shows the position of Xixiasaurus within Troodontidae according to a 2017 analysis by the palaeontologist Caizhi Shen and colleagues: In 2019, the palaeontologist Scott Hartman and colleagues recovered Xixiasaurus as the sister taxon of Sinusonasus, in a clade with Daliansaurus and Hesperornithoides (sharing features such as a straight ulna and having an upwards projected curve on the claw of the first finger). Troodontids have mainly been discovered in the northern hemisphere, largely restricted to Asia and North America. They appear to have reached their greatest diversity during the Campanian stage of the Late Cretaceous in Asia.
|
|
Titanosaurinae included Titanosaurus and the new genus Aeolosaurus, united by multiple features of the caudal vertebrae; the new clade Saltasaurinae was created to include Saltasaurus and the new genus Neuquensaurus, united by very distinct dorsals, caudals, and ilia; the new clade Antarctosaurinae was created to include Antarctosaurus, distinguished by large size, a different form of braincase, more elongate girdle bones, and more robust limb bones; and Argyrosaurinae was created for Argyrosaurus, bearing a more robust forelimb and hand and more primitive dorsals. The new genus Epachthosaurus was named for a more basal titanosaurid classified as Titanosauridae indet. along with unnamed specimens, Clasmodosaurus and Campylodoniscus. John Stanton McIntosh provided a synopsis of sauropod relationships in 1990, using Titanosauridae as the group to contain all taxa like previous authors.
|
|
S. cutleri holotype specimen NHMUK R5161 at Natural History Museum, London Scolosaurus was named by Franz Nopcsa von Felső-Szilvás in 1928, based on holotype NHMUK R.5161, a nearly complete specimen that preserves the entire skeleton except for the distal end of the tail, the right forelimb, the right hindlimb, and the skull. The rare preservation of osteoderms and skin impression are also present. The fossil skeleton was discovered by William Edmund Cutler, an independent fossil collector in 1914 at Quarry 80 of the Deadlodge Canyon locality. It was collected from the bottom of the Dinosaur Park Formation in fine-grained sandstone and fine-grained claystone sediments that were deposited during the Campanian stage of the Late Cretaceous period, approximately 76.5 million years ago.
|
|
In those two groups, the forelimbs of quadrupedal species were usually rotated so that the hands faced forward with palms backward ("pronated") as the animals walked. Triceratops, like other ceratopsians and the related quadrupedal ornithopods, together forming the Cerapoda, walked with most of their fingers pointing out and away from the body, the original condition for dinosaurs, also retained by bipedal forms like the theropods. In Triceratops, the weight of the body was carried by only the first three fingers of the hand, while digits 4 and 5 were vestigial and lacked claws or hooves. The phalangeal formula of the hand is 2-3-4-3-1, meaning that the first or innermost finger of the forelimb has two bones, the next has three, etc.
|
|
Skull and foot bones of Erlikosaurus, which together with Segnosaurus (both from Mongolia) became the basis of the new infraorder Segnosauria; this group is now a junior synonym of Therizinosauria. Segnosaurus and its relatives, which are now recognized as therizinosaurs ("scythe reptiles"), were long considered an enigmatic group. Their mosaic of features resembling those of different dinosaur groups and the scarcity of their fossils led to controversy over their evolutionary relationships for decades after their initial discovery (the forelimb elements of Therizinosaurus itself were originally identified as belonging to a giant turtle when described in 1954). In 1979, Perle noted the Segnosaurus fossils were possibly representative of a new family of dinosaurs, which he named Segnosauridae, Segnosaurus being the type genus and sole member.
|
|
Because the Erlikosaurus specimen lacked a pelvis, the authors were unsure that the undetermined segnosaurian could belong to the same genus, in which case they would consider it part of a separate family. Though Erlikosaurus was difficult to compare directly to Segnosaurus because its remains were incomplete, Perle stated in 1981 there was no justification for separating it into another family. Therizinosaurus, the first known therizinosaur, was originally known only from forelimb bones from Mongolia (cast shown here, in Aathal Dinosaur Museum), which created confusion about its affinities with other theropods. In 1982, Perle reported the discovery of hindlimb fragments similar to those of Segnosaurus and assigned them to Therizinosaurus, whose forelimbs had been found in almost the same location.
|
|
Partial forelimb of the basal therizinosaur Beipiaosaurus with impressions of feather-like structures, Paleozoological Museum of China Perle and his co-authors of a 1994 redescription of Erlikosauruss skull accepted the synonymy of Segnosauridae with Therizinosauridae and they considered therizinosaurs to have been maniraptoran theropods, the group that also includes modern birds (because they did find Maniraptora to be valid through their analysis). They also discussed the alternative previous hypotheses for therizinosaur affinities and demonstrated faults with them. In 1995, Lev A. Nessov rejected the idea therizinosaurs were theropods; he considered them a distinct group within Saurischia. In 1996, Thomas R. Holtz Jr. found therizinosaurs to group with oviraptorosaurs in a phylogenetic analysis of coelurosaurian theropods. Russell coined the name Therizinosauria for the wider group in 1997.
|
|
The maniraptor model loading is typical for ducks, though these have a relatively larger wingspan and a lower aspect ratio. The bat model has a loading typical for shore birds, though again their wingspan is (much) larger while their aspect ratio to the contrary is higher. A problem for the hypothesis that Yi was specialised for gliding flight, resides in the fact that because of it having a forelimb wing, instead of a gliding skin along its torso as with most gliders, its center of mass seems to be behind its control and main lift surfaces, causing flight instability. This problem might have been lessened by a short fleshy tail and long tail feathers, as known from its relative Epidexipteryx.
|
|
Material from this specimen was originally spread across three institutions. Most of the back vertebrae, ribs, pelvis, hindlimb and most of the tail stayed at the University of Utah, while the neck vertebrae, some back vertebrae, the shoulder girdle and forelimb were shipped to the National Museum of Natural History in Washington D.C., and a small section of tail vertebrae ended up in the Carnegie Museum in Pittsburgh. However, in 1929 Barnum Brown arranged for all of the material to be shipped to the American Museum of Natural History in New York City, where it remains today. A cast of this specimen (AMNH 6341) was controversially mounted in the lobby of the American Museum, rearing up to defend its young (AMNH 7530, now classified as Kaatedocus siberi) from an attacking Allosaurus fragilis.
|
|
Mammals of Australia Few naturalist had the opportunity to observe and document the behaviour of the two species, one of the few existing accounts suggesting that it moved "like a broken-down hack in a canter, apparently dragging the hind quarters after it". This is contradicted by the Aboriginal people of central Australia, who knew it well and reported that if disturbed, it was capable of running with considerable speed by breaking into a smooth, galloping sprint. Chaeropus moved with a distinctive gait, exaggerated by their proportionally long and slender limbs that resemble a large grazing mammal like the African antelope. Each forelimb had two functional toes and the rear limb ending in a hoof like toe, with an apparent advantage when used to quickly evade a perceived threat.
|
|
To achieve this posture, the forelimbs of Lisowicia had to undergo several prominent anatomical changes compared to the normal condition in dicynodonts. On the humerus, the shoulder joint and the elbow are parallel to each other, unlike the rotated humerus of sprawling dicynodonts, and so the humerus is held upright beneath the shoulder and directly above the radius and the ulna. The forearm itself is also unusually short compared to other dicynodonts since the elbow is now positioned further down directly below the body and closer to the ground. The musculature of the forelimb has also been rearranged to facilitate its upright posture and gait, now functioning to draw the limb forwards and backwards and losing the ability to rotate the upper arm as it would in a sprawling stride.
|
|
Restoration of the right hand of the holotype in flexion, with the deformed third finger (below) unable to flex In 2016 Senter and Sara L. Juengst examined the paleopathologies of the holotype specimen and found that it bore the greatest and most varied number of such maladies on the pectoral girdle and forelimb of any theropod dinosaur so far described, some of which are not known from any other dinosaur. Only six other theropods are known with more than one paleopathology on the pectoral girdle and forelimbs. The holotype specimen had eight afflicted bones, whereas no other theropod specimen is known with more than four. On its left side it had a fractured scapula and radius, and fibriscesses (like abscesses) in the ulna and the outer phalanx bone of the thumb.
|
|
According to Senter and Juengst, the high degree of pain the dinosaur might have experienced in multiple locations for long durations also shows that it was a hardy animal. They noted that paleopathologies in dinosaurs are underreported, and that even though Welles had thoroughly described the holotype, he had mentioned only one of the pathologies found by them. They suggested that such features may sometimes be omitted because descriptions of species are concerned with their characteristics rather than abnormalities, or because such features are difficult to recognize. Senter and Sullivan found that the pathologies significantly altered the range of motion in the right shoulder and right third finger of the holotype, and that estimates for range of motion may therefore not match those made for a healthy forelimb.
|
|
In terms of limb proportions, Zhao indicated that the forelimb of Klamelisaurus was three-quarters the length of the hindlimb, and the ulna and tibia were respectively two-thirds the lengths of the humerus and femur. He considered these proportions to be distinguishing characteristics of Klamelisaurus. According to Zhao, Klamelisaurus had a thin, elongated scapula and a slender, small coracoid (the former being 4.3 to 4.5 times the length of the latter), but Moore and colleagues did not consider his measurements of the scapula to be reliable as most of the bone was covered by plaster and paint. The , located at the outer bottom end of the scapula, was broader than in Cetiosaurus, Shunosaurus, and many early-diverging sauropodomorphs, and the top edge of the acromion was straight, not concave like Tienshanosaurus.
|
|
In an invited reply in 2010, Peters and Peters stated that Chiappe and colleagues did not comment on their main argument, the gap in body size between the smaller size class and inferred hatchlings, which accounts for one order of magnitude and would be most consistent with a sexual size dimorphism. Marugán-Lobón and colleagues studied the relationships between the presence and absence of long tail feathers and the lengths of various long bones of the arms and limbs, using a once more enlarged sample of 130 specimens. While confirming that the tail feathers are unrelated to body size, their presence corresponds to different proportions of the forelimb compared to the hind limb. The authors concluded that the meaning of the observed distributions of both the tail feathers and the body size remains contentious.
|
|
At least two lines of arrested growth (growth lines that form annually) could be identified, demonstrating an extended growth over several years; the studied female would have been in its third year. Long tail feathers were confirmed to occur in small individuals, the smallest of which was only around 23% the mass of the largest specimens. Assuming that the occurrence of tail feathers indicates sexual maturity, the authors concluded that the latter must have occurred well before the animals reached their final size, unlike in birds but similar to non-avian dinosaurs. In a 2018 study, Jingmai O'Connor and colleagues questioned the identification of medullary bone, arguing that the purported medullary bone was only found in the forelimb, while in modern birds it is mostly present in the hind limb.
|
|
The holotype, MPCN PV 0001, consists of a partial skeleton lacking the skull. It contains four vertebrae of the back, three vertebrae of the middle tail, ribs, a basket of belly-ribs, the left shoulder girdle, the left forelimb, the right lower arm, the lower ends of both pubic bones, the right thighbone, the lower end of the left thighbone, the upper ends of the right shinbone and calf bone, elements of both metatarsi and three toes of the right foot. Most bones were uncovered in their original anatomical position but much of the skeleton had been destroyed by erosion. Gualicho has been suggested to be synonymous with the megaraptoran Aoniraptor, also known from Huincul Formation and uncovered at the Violante site in view of similarities in their caudal vertebrae.
|
|
Diagram of Deinonychus (left) and Archaeopteryx (right) forelimbs illustrating wing-like posture Contrary to the way theropods have often been reconstructed in art and the popular media, the range of motion of theropod forelimbs was severely limited, especially compared with the forelimb dexterity of humans and other primates. Most notably, theropods and other bipedal saurischian dinosaurs (including the bipedal prosauropods) could not pronate their hands—that is, they could not rotate the forearm so that the palms faced the ground or backwards towards the legs. In humans, pronation is achieved by motion of the radius relative to the ulna (the two bones of the forearm). In saurischian dinosaurs, however, the end of the radius near the elbow was actually locked into a groove of the ulna, preventing any movement.
|
|
Restoration Although numerous artists' reconstructions of Rahonavis show it in flight, it is not clear that it could fly; there has even been some doubt that the forearm material, which includes the quill knobs, belongs with the rest of the skeleton. Some researchers have suggested that Rahonavis represents a chimera consisting of the forelimb of a bird conflated with the skeleton of a dromaeosaurid, and consider Rahona as described a nomen dubium. The nearby discovery of the primitive bird Vorona berivotrensis at least shows that the possibility of a mix-up cannot be fully excluded. However, many other scientists, including the original describers of Rahonavis, maintain that its remains belong to a single animal, citing the close proximity of the wing bones to the rest of the skeleton.
|
|
As only the tarsometatarsus is known from Yungavolucris, it might be the same species as one of the other El Brete enantiornitheans described based on forelimb bones. The size of Yungavolucris is hard to tell; the comparatively huge Enantiornis might be a match if Yungavolucris had short legs of normal width, but Enantiornis seems to be a fairly conventionally- built taxon. If Yungavolucris had both unusually short and wide legs, it might have been the size of the small species of Martinavis or maybe the slightly larger Elbretornis. However, these genera have tibiotarsus material tentatively referred to them, and while this material may not actually belong to Martinavis or Elbretornis, it does not match the shape of a tibiotarsus that would form a working ankle with the Yungavolucris tarsometatarsus.
|
|
Model carcass based on the position of the holotype bones, NHM Charig and Milner presented a possible scenario explaining the taphonomy (changes during decay and fossilisation) of the B. walkeri holotype specimen. The fine-grained sediments around the skeleton, and the fact that the bones were found close together (skull and forelimb elements at one end of the excavation area and the pelvis and hind-limb elements at the other), indicates that the environment was quiet at the time of deposition, and water currents did not carry the carcass far—possibly because the water was shallow. The area where the specimen died seems to have been suitable for a piscivorous animal. It may have caught fish and scavenged on the mud plain, becoming mired before it died and was buried.
|
|
Parts of the Protoceratops are missing, which has been seen as evidence of scavenging by other animals. Comparisons between the scleral rings of Velociraptor, Protoceratops, and modern birds and reptiles indicates that Velociraptor may have been nocturnal, while Protoceratops may have been cathemeral, active throughout the day during short intervals, suggesting that the fight may have occurred at twilight or during low-light conditions. The distinctive claw, on the second digit of dromaeosaurids, has traditionally been depicted as a slashing weapon; its assumed use being to cut and disembowel prey. In the "Fighting Dinosaurs" specimen, the Velociraptor lies underneath, with one of its sickle claws apparently embedded in the throat of its prey, while the beak of Protoceratops is clamped down upon the right forelimb of its attacker.
|
|
Zoneait (pronounced "zone-eight" and meaning "large tooth" in the Kiowa language) is an extinct genus of thalattosuchian crocodylomorph known from a single species, Zoneait nargorum, from the Middle Jurassic of Oregon. Z. nargorum was named in 2015 by paleontologist Eric Wilberg on the basis of several partial skulls, vertebrae, and forelimb bones that were found in an outcrop of the Snowshoe Formation near the town of Izee. It is a member of Metriorhynchoidea, a clade of marine-adapted thalattosuchians that existed until the Early Cretaceous. The skeleton of Zoneait possesses several adaptations for offshore marine life but retains features characteristic of its land-living ancestors, indicating that it is a transitional form between the fully marine metriorhynchids of the late Middle Jurassic to Early Cretaceous, and earlier non-marine crocodylomorphs.
|
|
In genera where both neck and forelimb elements are preserved, however, the necks were equal in length or longer than the forelimbs, so pulling vegetation would only be likely if lower parts of long branches were pulled down to access out-of-reach vegetation. Lautenschlager also found that therizinosaurid claws would not have been used for digging, which would have been done with the foot claws because, since as in other maniraptorans, feathers on the forelimbs would have interfered with this function. Additionally, this action leads to a higher stress tension on the dorsal area of the claw−this is more evident in Therizinosaurus. However, he could neither confirm nor disregard that the hand claws could have been fully used for sexual display, self-defense, intraspecific competition, mate- gripping during mating or grasping stabilization when foraging.
|
|
The holotype specimen of Teleocrater, NHMUK PV R6795, was found by Francis Rex Parrington in 1933. It consists of a partial, disarticulated skeleton that includes four vertebrae from the neck, seven from the trunk, and seventeen from the tail; parts of one neck and one trunk rib; part of a scapula and coracoid; the radius and ulna from the right forelimb; part of the left ilium; both femora and tibiae, as well as the left fibula; and isolated fragments from metatarsals and phalanges. Parts of the trunk vertebrae and humerus, likely originating from another individual, were referred to the same animal under the specimen number NHMUK PV R6796. Although the exact locality is unknown, Parrington recorded the specimen as originating from near the village of Mkongoleko, "south of river Mkongoleko", in the Ruhuhu Basin of southern Tanzania.
|
|
The specimen was given the accession number AMNH 5764, then including two dorsals, a pubis, a femur, a tooth, a scapula, coracoid and an ulna. While the forelimb material was not originally assigned to Amphicoelias, paleontologists Henry Fairfield Osborn and Charles Mook in 1921 added them to the holotype specimen on the basis that they were found in the same strata not far away, and bore differences from the Camarasaurus they were found alongside. Because of the uncertainty about the referral of these remains, in 2015 Emanuel Tschopp and colleagues hesitantly rejected the referral of the tooth, scapula and coracoid, but accepted the ulna referral. Based on collection data, the specimen was determined to have come from the Late Jurassic Morrison Formation, in the youngest layers, separate from those that held the Camarasaurus fossils also described by Cope.
|
|
The Ichthyosauromorpha are an extinct clade of marine reptiles consisting of the Ichthyosauriformes and the Hupehsuchia, living during the Mesozoic. The node clade Ichthyosauromorpha was first defined by Ryosuke Motani et. al. in 2014 as the group consisting of the last common ancestor of Ichthyosaurus communis and Hupehsuchus nanchangensis, and all its descendants. Their synapomorphies, unique derived traits, include: the presence of an anterior flange on the humerus and radius; the lower end of the ulna being as wide as or wider than the upper end, the forelimb being as long as or longer than the hindlimb, the hand having at least three quarters of the length of the upper arm and lower arm combined, the fibula extending behind the level of the thighbone, and the transverse process of the vertebral neural arch being reduced or absent.
|
|
WGSC V26003 was discovered in Yangping, a town in Yuan’an County in Hubei Province, Central China, and excavated by Chinese paleontologists Xiao-hong Chen and Long Cheng in 2011. Despite being exposed at the surface when discovered, the specimen is largely articulated and moderately complete, preserving much of the head, trunk, left pectoral girdle, and left forelimb, and parts of the left hindlimb and the anterior part of the tail. However, several of the preserved elements have been extensively damaged by erosion, including the left pelvic girdle, and other elements were completely destroyed by erosion before discovery, including the tips of the jaws. The genus was named and formally diagnosed in a 2014 paper published in the open access journal PLOS One by paleontologists Xiao-hong Chen, Ryosuke Motani, Long Cheng, Da-yong Jiang, and Olivier Rieppel.
|
|
In Lily Park, Moffat County, James Leroy Kay and Albert C. Lloyd in 1955 recovered CM 21786, a skeleton lacking skull and neck. From 'Scheetz’ Quarry 1, at Uravan, Montrose County, in 1973 Peter Malcolm Galton and James Alvin Jensen described specimen BYU ESM-171R found by Rodney Dwayne Scheetz and consisting of some vertebrae, a left lower jaw, a left forelimb and two hindlimbs.Galton, P.M. & Jensen, J.A., 1973, "Small bones of the hypsilophodontid dinosaur Dryoraurus altus from the Upper Jurassic of Colorado", Great Basin Nature, 33: 129-132 Cast of the D. elderae holotype skull Rodney D. Scheetz and his family discovered a fossil locality around five miles from Uravan, Colorado in the spring of 1972. This site, unintentionally exposed by a bulldozer, was found to contain fossil fragments, said to be in such condition they looked like unfossilized bone.
|
|
SAM 5882, the holotype for Mesosuchus, consists of a partial rostrum, palate, braincase, lower jaws, sections of articulated presacral vertebral column, nine articulated caudal vertebrae, portions of scapula and pelvic girdle, and partial forelimb and hindlimbs. SAM 6046, one of the paratypes of Mesosuchus, consists of an incomplete right maxilla, an articulated series of the last ten presacrals, both sacrals, and first six caudals, partial forelimbs, left and right pelvic girdles, right hind limb, as well as element of left tarsus. SAM 6536, another paratype, consists of a virtually complete skull with lower jaws, articulated cervical vertebrae and ribs, dorsal vertebrae and ribs, complete left scapulocoracoid and partial right scapula, interclavicle, clavicles, distal end of left humerus, and gastralia. 50px This article contains quotations from this source, which is available under the Creative Commons Attribution 4.0 International (CC BY 4.0) license.
|
|
In bats, the skin forming the surface of the wing is an extension of the skin of the abdomen that runs to the tip of each digit, uniting the forelimb with the body. The patagium of a bat has four distinct parts: # Propatagium: the patagium present from the neck to the first digit # Dactylopatagium: the portion found within the digits # Plagiopatagium: the portion found between the last digit and the hindlimbs # Uropatagium: the posterior portion of the body between the two hindlimbs Other mammals such as gliding possums and flying squirrels also glide using a patagium, but with much poorer efficiency than bats. They cannot gain height. The animal launches itself from a tree, spreading its limbs to expose the gliding membranes, usually to get from tree to tree in rainforests as an efficient means of both locating food and evading predators.
|
|
Unlike limb development in tetrapods, where the forelimb and hindlimb buds emerge at roughly the same timepoint, the pelvic fin bud emerges much later than the pectoral fin. While the pectoral fin bud is apparent at 36 hours post fertilization (hpf) in zebrafish, the pelvic fin bud is only clear at around 21 days post fertilization (dpf), roughly when the animal is 8 mm in length. The pelvic fin appears at roughly 21 days post fertilization in zebrafish In zebrafish, the pelvic fin bud starts as a mesenchymal condensation that forms an apical ectodermal thickening. A fin fold forms from this thickening, which is then invaded by migratory mesenchyme, separating the fin bud into the proximal mesenchyme (which will give rise to the endoskeletal girdle and radials) and the distal mesenchyme (which will give rise to dermal fin rays).
|
|
Faulting in either setting is reliant on the lock-up and strain accumulation of a fold typically at its critical angle. Asymmetric folding develops in the forelimb (the limb furthest from the source of thrust) of the fold and may either absorb strain into or transmit strain through the stratigraphic units composing the fold. A system that absorbs strain is recognized as a trishear zoneZehnder, A. T. and Allmendinger, R. W. (2000) Velocity field for the trishear model, Journal of structural Geology, 22, 1009-1014 being triangular in shape; while a parallel deformation zone transmits shear across the units of the fold and typically takes on the form of a parallelogram or is rectangular in geometry. These two deformation patterns may exist in a single fold and at some time during continued deformation may reconnect with the detachment.
|
|
In addition, they are many palatal teeth, and the teeth of the upper jaws are numerous (four premaxillary and eleven maxillary teeth) and spatulate with many cuspids. The front teeth, fairly long and slightly recurved, were probably suited to aid in gathering vegetation into the mouth, whereas it is presumed that palatal teeth had to worked in conjunction with a tough and massive muscular tongue as indicated by the presence of a very well- developed hyoid apparatus. Characteristically, Euromycter shows an unusually broad skull, large temporal fenestra, and lack of expansion of the axial neural spine. It can be distinguished from other caseids by the presence of a supernumerary blade-like intranarial bone located posteromedially to the septomaxilla, proportional differences in forelimb and manus, presence of an accessory proximal articulation between metacarpals 3 and 4, medial recurvature of metacarpal, and its manual phalangeal formula of 2-3-4-4-3.
|
|
In a 2009 response to Xu and colleague's description of Limusaurus, biologist Alexander Vargas, Wagner and Gauthier stated in 2009 that it is plausible that ceratosaurians underwent BDR independent of the tetanurans, and therefore have no bearing on the issue of avian digit homology. Xu and colleagues replied in 2011 that they still found a step-wise shift more plausible than a hidden frameshift. As demonstrated by a teratological analysis by biologist Geoffrey Guinard in 2016, the abbreviation (mesomelia) and loss of digits (hypophalangia) in the forelimb of Limusaurus is likely the result of a developmental anomaly that appeared exclusively in and persisted throughout the evolutionary lineage of ceratosaurians, and is unconnected to the pattern of digital reduction and frameshift that occurred in tetanurans. Carrano and paleontologist Jonah Choiniere suggested in 2016 that this is supported by the hands of the ceratosaurians Ceratosaurus, Berberosaurus, and Eoabelisaurus having plesiomorphic (i.e.
|
|
Saurosphargis is known from several individuals, all of which were collected from Member II of the Guanling Formation, dating to the Pelsonian substage of the latest Anisian stage of the early Middle Triassic, about 243 million years ago. The holotype IVPP V 17040 and paratype IVPP V 16076 are housed at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, and represent a nearly complete articulated skeleton and skull, and a partial disarticulated postcranial skeleton including dorsal vertebra, ribs, with osteoderms and gastral rib fragments, respectively. ZMNH M 8797, an incomplete postcranial skeleton showing a very well preserved right forelimb housed at the Zhejiang Museum of Nature History of Hangzhou, was also referred to Saurosphargis in its original description. The holotype and ZMNH M 8797 were collected at Yangmazhai of Luoping County, Yunnan Province, while the paratype came from Yangjian of Pan County, Guizhou Province.
|
|
The skeletons were discovered during eight seasons of fieldwork (2004–2012 field seasons) in the Slottsmøya Member, that have yielded other skeletal remains of marine reptiles, including the plesiosauroids Colymbosaurus svalbardensis, Djupedalia and Spitrasaurus, and the ichthyosaurs Cryopterygius and Palvennia. P. funkei was first described and named by Espen M. Knutsen, Patrick S. Druckenmiller and Jørn H. Hurum in 2012. The specific name honors Bjørn Funke, the discoverer of the holotype, and his wife May-Liss Knudsen Funke for volunteering in the paleontological collections at the Museum. Low resolution pdf The holotype of P. funkei is represented by the anterior portions of the upper and lower jaws (including premaxillary and dentary teeth), one nearly complete cervical centrum and two partial cervical centra, three pectoral centra with neural arches, fifteen dorsal centra and eight neural arches, a complete right coracoid, numerous rib fragments and gastralia, and a complete right forelimb.
|
|
Later on, thorough scrutiny of this Svalbard specimen revealed that it was not as massive as originally claimed; total length estimates have been revised to and was named Pliosaurus funkei in Knutsen et al. 2012, with estimated skull lengths of 160–200 cm and a forelimb length of 300 cm for the holotype (PMO 214.135), and an estimated skull length of 200–250 cm for the referred specimen (PMO 214.136), suggesting that the animal had proportionally bigger flippers than other pliosaurs compared to the skull size and dimensions of the vertebrae. This estimate has since been questioned due to the smaller size of P. funkei vertebrae in comparison to Kronosaurus, which was used to obtain the estimate. Analysis of bones from the four flippers suggest that the animal cruised using just two fore-flippers, using the back pair for extra speed when pursuing and capturing prey.
|
|
The only specimen consists of a partial forelimb discovered in 2002 during the construction of the Huihang highway. It can be distinguished from other mamenchisaurids in having the following unique combination of features: such as transverse length of the proximal end of the humerus is 36% of the total length of the humerus, accessory processes are located near the middle of the cranial edge of the distal end of the humerus, length of the radius is 58% of that of the humerus, length of the ulna is two thirds of that of the humerus, craniomedial process on the proximal end of the ulna is longer than the craniolateral one, and ridges develop on the cranial, caudomedial, and caudolateral faces of the distal portion of the ulna. Ren et al. (2018) recover Huangshanlong as sister to Anhuilong and Omeisaurus in a clade within Mamenchisauridae exclusive of other mamenchisaurids.
|
|
Artist's impression of an individual in brooding position The identification, in 2000, of a probable Deinonychus egg associated with one of the original specimens allowed comparison with other theropod dinosaurs in terms of egg structure, nesting, and reproduction. In their 2006 examination of the specimen, Grellet-Tinner and Makovicky examined the possibility that the dromaeosaurid had been feeding on the egg, or that the egg fragments had been associated with the Deinonychus skeleton by coincidence. They dismissed the idea that the egg had been a meal for the theropod, noting that the fragments were sandwiched between the belly ribs and forelimb bones, making it impossible that they represented contents of the animal's stomach. In addition, the manner in which the egg had been crushed and fragmented indicated that it had been intact at the time of burial, and was broken by the fossilization process.
|
|
The forelimb lacks the manus (hand) and part of the radius and ulna, although the hindlimb lacks only a few bones in the pes (foot) and fragments of the tibia, fibula and ilium. The vertebrae known are four parts of dorsal vertebrae, the neural spines of the sacrum, multiple anterior caudal vertebrae (tail bones), and a series of 27 nearly complete vertebrae from the middle of the tail with associated or articulated chevrons (ribs along the underside of the tail), although the vertebral series is not continuous. A tail tip (NHMUK R1967) from the same locality, but a different individual was thought by palaeontologist Alan Charig in 1980 to belong to Cetiosauriscus. The assignment of NHMUK R1967 to Cetiosauriscus was considered unlikely in alternate studies by palaeontologists Friedrich von Huene, Paul Upchurch and Darren Naish because of the lack of overlap and uncertain phylogenetic positions.
|
|
There is debate as to the placement of Lesothosaurus as a sister group to Genasauria as or as a basal member of Genasauria. Sereno (1986) argues that Lesothosaurus does not contain the defining Genasaurian synapomorphies of a medial offset of the maxillary dentition, a sprout-shaped mandibular symphysis, moderately sized coronoid process, and an edentulous (without teeth) anterior portion of the premaxilla, and a pubic peduncle of the ilium that is less robust than the ischial peduncle. Butler (2011) argues that the synapomorphies that should exclude Lesothosaurus from Genasauria have been described in Lesothosaurus specimens. Butler writes “The position of Lesothosaurus within Neornithischia is supported by three unequivocal characters: reduction of the forelimb to less than 40% of the hind-limb length, presence of a dorsal groove on the ischium, and a strongly reduced, splint-like metatarsal one.” The following two cladograms illustrate the two opinions.
|
|
M. crassus and M. sphenocerus holotypes Monoclonius was Edward Drinker Cope's third named ceratopsian, after Agathaumas and Polyonax. Several fossils were found by Cope, assisted by a young Charles Hazelius Sternberg, in the summer of 1876 near the Judith River in Chouteau County, Montana, only about a hundred miles (some 150 km) from the site of the Battle of the Little Bighorn, fought that June. The finds did not represent a single, let alone articulated, skeleton, but came from different locations. Together they included elements of most parts of the animal (only the feet were entirely missing), including the base part of a long nasal horn, part of the skull frill, brow horns, three fused cervical vertebrae, a sacrum, a shoulder girdle, an ilium, an ischium, two thighbones, a shinbone, a fibula and parts of a forelimb. Just two weeks after leaving Montana, Cope hastily described and named these finds on 30 October 1876 as the type species Monoclonius crassus.
|
|
The fossil of Linhenykus was collected by Jonah N. Choiniere and Michael Pittman from the Late Cretaceous Wulansuhai Formation of Nei Mongol (Inner Mongolia), China. Biostratigraphic and lithographic correlations suggest that the formation dates to the Campanian stage, 84-75 Ma. Linhenykus is currently known from a partial skeleton, holotype IVPP V17608, including cervical, dorsal, sacral and caudal vertebrae, forelimb, hindlimbs, and pelvis, and a referred complete pes (anatomy). The genus was first described and named in the Proceedings of the National Academy of Sciences by Xu Xing, Corwin Sullivan, Pittman, Choiniere, David Hone, Paul Upchurch, Tan Qingwei, Xiao Dong, Lin Tan and Han Fenglu in 2011. In 2013, an osteological monograph of the genus was published which included a quantitative analysis of alvarezsauroid biogeography. The latter found statistically significant biogeographic reconstructions suggesting a dominant role for sympatric (or ‘within area’) events, combined with a mix of vicariance, dispersal and regional extinction.
|
|
The WAIR hypothesis for the origin of flight is a version of the "cursorial model" of the evolution of avian flight, in which birds' wings originated from forelimb modifications that provided downforce, enabling the proto-birds to run up extremely steep slopes such as the trunks of trees. The hypothesis was prompted by the observation of living young chukar chicks using WAIR, and proposes that dinosaur wings developed their aerodynamic functions as a result of the need to run quickly up very steep slopes such as tree trunks, possibly to escape from predators. Originally, it was thought that birds need downforce to give their feet increased grip in this scenario. However, a study found lift generated from wings to be the primary factor for successfully accelerating, indicating the onset of flight ability was constrained by neuromuscular control or power rather than by the shape of the wing itself, and that partially developed wings not yet capable of flight could indeed provide useful lift during WAIR.
|
|
Proximal end of the right ulna Fossils of Aenigmastropheus were first described by the British paleontologist Dr. Francis Rex Parrington in 1956, in an article titled as "A problematic reptile from the Upper Permian". Parrington reported collecting these remains in the Ruhuhu Valley in the Songea District of southern Tanzania in 1933, and considered them to come from a single individual. This specimen, UMZC T836, in currently housed at the University Museum of Zoology, in Cambridge, UK. UMZC T836 consists of a partial postcranial skeleton including five posterior cervical and anterior dorsal vertebrae, the distal half of the right humerus, a fragment of probable left humeral shaft, the proximal end of the right ulna, and three indeterminate fragments of bone, one of which may represent a partial radius. In his article, Parrington (1956) highlighted the apparent contrast between the primitive appearance of the forelimb bones and the more derived appearance of the vertebrae, resembling those of archosaurs.
|
|
Several studies of the skeleton, including a comparison with Hemicyon ursinus, a fossil bear widely accepted as a predator, show that Agriotherium did not have the limb strength or speed needed for active hunting, either by ambush or by chasing down prey. It also did not show the long claws and increased forelimb strength typical of mammals that dig for food. These very large bears may have specialized on a combination of grazing, eating fruit and invertebrate food in season, and intimidating predators away from carcasses in order to scavenge meat and bone marrow. Very large size would have been necessary to steal and defend kills in environments dominated by some of the most powerful carnivorous mammals that have ever lived, such as the sabertooth cat Amphimachairodus, with whom it shared territory in both Afro-Eurasia and North America, and the bone-cracking canid Epicyon and the massive feliform sabertooth Barbourofelis, which it lived alongside in Texas, as evidenced by fossil deposits at Coffee Ranch.
|
|
Ji and Ji (1996) identified many features that set Sinosauropteryx apart from other birds and dinosaurs. They found that it was a small primitive bird with a relatively high skull, blunt rostrum and a slightly high premaxilla; that the antorbital fenestra was elliptical but not enlarged, the dentary was robust, the surangular was narrow and elongated, and the dentition is extremely well developed and acute; that there are over 50 extremely elongated caudals, constituting 60% of the body length, and the forelimb is extremely short with a short and thick humerus; the pubis was elongated and extremely inflated at its distal end and the ischium is broad; the hind limb was long and robust, the tibia is only slightly longer than the femur, the tarsals are separated, and the metatarsals are relatively robust with unfused proximal ends; the feathers are short, small, and uniform; many ornament the top of the skull, cervical, and dorsal regions, in addition to the dorsal and ventral caudal region.
|
|
Recent stratiographic information from the Lago Colhue Huapi Formation has the area that the holotype was collected from being a more probable early late Maastrichtian age instead of early Coniacian.Lucio M. Ibiricu, Gabrieal A. Casal, Ruben D. Martinez, Bruno A. Alvarez, Stephen F. Poropat, (2019). New Materials and an overview of Cretaceous vertebrates from the Chubut Group of the Golfo San Jorge Basin, Central Patagonia, Argentina. Journal of South American Earth Sciences. Vol. 98 When discovered, the forelimb was apparently a part of a complete skeleton, however, during excavation the rest of the remains were completely destroyed. In the same publication, Lydekker assigned a partial left femur from Chubut Province, MLP 21, to Argyrosaurus but he did not explain his reasoning why he thought the femur was referable to the genus. He also assigned two caudal vertebra centra, MLP 22, from the Santa Cruz Province.alt=After these specimens, other remains were found, including other limb bones, a clavicle, a pubic bone and some tail vertebrae that were referred to the same genus.Upchurch, Barrett, Dodson; Sauropoda, in The Dinosauria, 2 vol, Weishampel, Dodson, Osmólska, University of California Press, (2004), pag. 259–322, .
|
|
Skeletal diagram showing the known remains of all three of the known specimens of Guaibasaurus candelariensis Guaibasaurus was originally named on the basis of the holotype, MCN PV2355, a well-preserved partial postcranial skeleton and the paratype, MCN PV2356, an articulated and nearly complete left hindlimb, which were discovered in the "Sesmaria do Pinhal 2" locality near Candelária, Rio Grande do Sul, in Brazil, in the upper portion of the Candelária Sequence or the Caturrita Formation. Later, two additional specimens were referred to G. candelariensis: UFRGS PV0725T (an articulated and nearly complete postcranial skeleton missing one forelimb, both feet and the neck), and MCN PV 10112 (a not-fully-prepared block containing articulated parts and some isolated elements, including a partial hand). The referred materials were collected from the "Linha São Luiz" locality near the town of Faxinal do Soturno, Rio Grande do Sul, also in the upper portion of the Candelária Sequence or the Caturrita Formation. All specimen were collected in these two localities from the lower portion of the Caturrita Formation (Rosário do Sul Group, Paraná Basin) or alternatively the uppermost Santa Maria 2 Sequence, dating to the early Norian faunal stage of the Late Triassic.
|
|
Life restoration of Europasaurus in its habitat Aside from being a very small neosauropod, Europasaurus was thought to have multiple unique morphological features to distinguish it from close relatives by its original describers, Sander et al. (2006). The nasal process of the premaxilla was thought to curve anteriorly while projecting upwards (now known to be preservational), there is a notch on the upper surface of the centra of cervical vertebrae, the scapula has a prominent process on the posterior surface of its body, and the astragalus (an ankle bone) is twice as wide as tall. When compared to Camarasaurus, Europasaurus has a different morphology of the postorbital where the posterior flange is not as short, a short contact between the nasal and frontal bones of the skull, the shape of its parietal (rectangular in Europasaurus), and the neural spines of its vertebrae in front of the pelvis are unsplit. Comparisons with Brachiosaurus (now named Giraffatitan) were also mentioned, and it was identified that Europasaurus has a shorter snout, a contact between the quadratojugal and squamosal, and a humerus (upper forelimb bone) that has flattened and aligned proximal and distal surfaces.
|
|
The high fidelity of these scans allowed Lacovara et al. (2014) to study the heavy fossils of Dreadnoughtus schrani in a way that was safe for the fossils and enhanced virtual and long-distance collaboration. Lacovara with fibula and humerus of Dreadnoughtus The holotype specimen, MPM- PV 1156, consists of a partial skeleton, somewhat preserved in its original layout, that comprises: a maxilla (jaw) fragment; a tooth; a posterior cervical vertebra; cervical ribs; multiple dorsal vertebrae and dorsal ribs; the sacrum; 32 caudal vertebrae and 18 haemal arches (bones from the tail) that include a sequence of 17 anterior and middle caudal vertebrae and their corresponding haemal arches found in their original layout; the left pectoral girdle and forelimb minus the front foot; both sternal plates; all pelvic elements; the left hind limb lacking a hind foot and right tibia; metatarsals I and II; and one claw from digit I. The paratype, MPM-PV 3546, consists of a partially articulated postcranial skeleton of a slightly smaller individual whose remains were discovered in the same location as the holotype. It includes a partial anterior cervical vertebra, multiple dorsal vertebrae and ribs, the sacrum, seven caudal vertebrae and five haemal arches, a nearly complete pelvis, and the left femur.
|
|