It belongs to a group of armoured dinosaurs called ankylosaurs that thrived during the Cretaceous period.
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It likely lived in a wet, swampy environment and feasted on hadrosaurs, ankylosaurs, and other prey, according to Nesbitt.
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The so-called bird-hipped Ornithischia includes the herbivorous spiky-tailed stegosaurs, tank-like ankylosaurs, horned dinosaurs, duckbills and dome-headed dinosaurs.
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That's because most Ankylosaurs found here are preserved in ancient river and stream deposits, and skeletons would have been picked apart by scavengers or strewn about by the water.
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Illustration: Andrey AtuchinThey're calling this newly discovered dinosaur "thorny head," and it's changing what we know of North American ankylosaurs, the heavily armored herbivores that had the misfortune of living alongside Tyrannosaurus rex during the Late Cretaceous.
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Triceratops pull wagons down cobblestone streets, iguanodons lift lamplighters to gas-powered lanterns, microdactyls deliver messages like toothier carrier pigeons, and, on a much less whimsical note, gun-toting gangs of hooded men spread terror from the saddled backs of raptors and ankylosaurs.
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Ankylosaurs are easily recognised by their extensive body armour. The skull is heavily ossified. Early in their evolution, ankylosaurs split into the Nodosauridae and Ankylosauridae, distinguished by features of the skull.
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Ligabueichnium is an ichnogenus of dinosaur footprint, probably made by ankylosaurs.
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Thyreophora is characterized by body armor and includes stegosaurs, ankylosaurs, Scelidosaurus, and Scutellosaurus.
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In 1978, W.P. Coombs, Jr. classified almost all valid species of Ankylosauria within either Nodosauridae or Ankylosauridae. This was a pivotal study and described many characters of ankylosaurs in the earliest phylogenetic analyses of the group. Later in 1998, Paul Sereno formally defined Ankylosauridae as all ankylosaurs more closely related to Ankylosaurus than to Panaplosaurus. Ankylosaurs not known to possess a tail club were included in Kenneth Carpenter's 2001 phylogeny of Ankylosauridae.
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In 1998 Kenneth Carpenter and James Kirkland, in a review of North American Lower Cretaceous ankylosaurs, considered it tentatively valid as an unusually large nodosaurid, larger than all those described before.Carpenter, K., and Kirkland, J.I. (1998). Review of Lower and middle Cretaceous ankylosaurs from North America.
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Ornithischians were more diverse than they were in the Jurassic Period. Tenontosaurus, Dakotadon, Protohadros, and Eolambia are some of the ornithopods that lived during this time period. Ankylosaurs replaced their stegosaur cousins in the Cretaceous. Ankylosaurs from the Early Cretaceous of North America include Sauropelta and Gastonia.
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Footprints discovered in the formation include those of theropods, hadrosaurs, ceratopsians, ankylosaurs, pterosaurs and birds, notably the Magnoavipes denaliensis.
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Acrocanthosaurus was the largest theropod in its ecosystem and likely an apex predator which preyed on sauropods, ornithopods, and ankylosaurs.
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The horns may have originally been osteoderms that fused to the skull. The scale-like cranial ornamentation on the surfaces of ankylosaurs skulls is called "", and were the result of remodeling of the skull itself. This obliterated the sutures between skull elements, which is common for adult ankylosaurs. The caputegulum pattern of the skull was variable between specimens, though some details are shared.
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Carpenter, K., and Kirkland, J.I. (1998). Review of Lower and middle Cretaceous ankylosaurs from North America. In: Lucas, S.G., Kirkland, J.I., and Estep, J.W. (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems.
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Other dinosaurs known from the Oldman Formation include the hadrosaur Brachylophosaurus, the ceratopsians Coronosaurus and Albertaceratops, ornithomimids, therizinosaurs and possibly ankylosaurs. Theropods included troodontids, oviraptorosaurs, the dromaeosaurid Saurornitholestes and possibly an albertosaurine tyrannosaur.
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Bloomington: Indiana University Press. Pp. 454–483.Hill, R.V., Witmer, L.M., Norell, M.A. 2003. A New specimen of Pinacosaurus grangeri (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia: ontogeny and phylogeny of ankylosaurs.
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All lacked the elaborate ornamentation of their predecessors, the lambeosaurs. The ankylosaurs had been reduced to down to a handful of species, with ankylosaurs like Anodontosaurus and Ankylosaurus, as well as nodosaurs like Denversaurus, Edmontonia and Glyptodontopelta being the only known survivors. In the south the transition to the Lancian is even more dramatic, which Lehman describes as "the abrupt reemergence of a fauna with a superficially "Jurassic" aspect." These faunas are dominated by Alamosaurus and feature abundant Quetzalcoatlus, Bravoceratops and Ojoceratops in Texas. Saurolophus.
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As in other ankylosaurs, thick triangular scutes projected from the postorbital bone, above and behind the eyes, as well as the jugal bone, below and behind the eyes. More typically for nodosaurids, leaf-shaped teeth lined both upper and lower jaws, used for cutting plant material. The front end of the skull is unknown, but there would have been a sharp bony ridge (tomium) at the end of both upper and lower jaws, as seen in other ankylosaurs. This ridge probably would have supported a keratinous beak.
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Skeletal diagram of MPC 700/17 Tsagantegia was a medium to large-sized ankyosaur, with an estimated length of Genus List for Holtz 2012 Weight Information and weighing about . The skull measures about in length, with a near width of , missing the lower jaws. Unlike other Asian ankylosaurs, in Tsagantegia the caputegulae (cranial ornamentation) are not subdivided into a mosaic of polygons but are amorphous and flattened; they show some degree of symmetry. The quadratojugal, squamosal and orbital horns are poorly preserved, in contrast with other ankylosaurs.
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Carpenter, K., Kirkland, J.I., Burge, D.L., & Bird, J. 1999. Ankylosaurs (Dinosauria: Ornithischia) of the Cedar Mountain Formation, Utah, and their stratigraphic distribution. In: Gillette, D. (Ed.) Vertebrate Paleontology in Utah. Utah Geological Survey Miscellaneous Publication 99-1.
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New Mexico Museum of Natural History and Science Bulletin 14:249-270. Ken Carpenter and James Kirkland noted that many of the resemblances between the two were more widely distributed among ankylosaurs than previously thought, or were based on damage to the bones, such as some femoral characters. However, its similarity to Polacanthus has been noted since Lucas renamed in 1902, the two being most similar in armor, although Hoplitosaurus lacks the sacral shield of armor found in Polacanthus. Today, both are considered to be polacanthine or polacanthid ankylosaurs,Carpenter, K. (2001).
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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.
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The Qiupa Formation has yielded numerous dinosaur fossils, particularly eggs. The remains of various theropods such as troodontids, dromaeosaurids and oviraptorosaurs have been found. In addition, indeterminate remains of sauropods, ornithopods, ankylosaurs, lizards, turtles and a possible avian bone are reported.
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Uncertainty over the precise age of the Xinminbao Group adds to the difficulty of determining the affinities. Usually it is given as Early Cretaceous when both stegosaurs and ankylosaurs were present, but sometimes as Late Cretaceous when stegosaurs were probably extinct.
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Conchoraptor shared its habitat with other oviraptorosaurs including Avimimus and Nomingia, other theropods include troodontids such as Tochisaurus and Zanabazar, the tyrannosaurids Alioramus and Tarbosaurus. Ornithischians include the pachycephalosaurs Homalocephale and Prenocephale, the hadrosaurid Saurolophus, the ankylosaurs Saichania and Tarchia.
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A juvenile specimen of Pinacosaurus preserves large paraglossalia (triangular bones or cartilages located in the tongue) which show signs of muscular stress, and it is thought this was a common feature of ankylosaurs. Pinacosaurus and other ankylosaurs likely relied heavily on muscular tongues and hyobranchia (tongue bones) when feeding, since their teeth were fairly small and were replaced at a relatively slow rate. Some modern salamanders have similar tongue bones, and use prehensile tongues to pick up food. Though Pinacosaurus may not have fed on fibrous and woody plants, they may have had a more varied diet, including tough leaves and pulpy fruits.
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Fellow theropods include the large Achillobator, and the deinocheirid Garudimimus. Other herbivorous dinosaurs are represented by the ankylosaurs Talarurus and Tsagantegia, small marginocephalians Amtocephale and Graciliceratops, the hadrosauroid Gobihadros, and the sauropod Erketu. Other fauna include semiaquatic reptiles like crocodylomorphs and nanhsiungchelyid turtles.
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Top view of the skull Cedarpelta is an extinct genus of herbivorous basal ankylosaurid ankylosaur, based on material recovered from the Lower Cretaceous of North America. The skull lacks extensive cranial ornamentation, a trait which has been interpreted as plesiomorphic for ankylosaurs.
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Apart from the tyrannosaurid material, specimens of Sinoceratops, hadrosaurids (probably Shantungosaurus) and ankylosaurs were recovered from it. Zhuchengtyrannus was found in an area that was a floodplain in the Cretaceous period and contains one of the highest concentrations of dinosaur bones in the world.
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Extrapolating from this, Haas suggested that ankylosaurs ate relatively soft non-abrasive vegetation. Later research on Euoplocephalus indicates that forward and sideways jaw movement was possible in these animals, the skull being able to withstand considerable forces. A 2016 study of the dental occlusion (contact between the teeth) of ankylosaur specimens found that the ability for backwards (palinal) jaw movement evolved independently in different ankylosaur lineages, including Late Cretaceous North American ankylosaurids like Ankylosaurus and Euoplocephalus. A specimen of the ankylosaur Pinacosaurus preserves large paraglossalia (triangular bones or cartilages located in the tongue) that show signs of muscular stress, and it is thought this was a common feature of ankylosaurs.
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Ji Q., Wu X., Cheng Y., Ten F., Wang X., and Ji Y. 2016. Fish-hunting ankylosaurs (Dinosauria, Ornithischia) from the Cretaceous of China. Journal of Geology, 40(2). The type species L. paradoxus was named by Xu Xing, Wang Xiaolin and You Hailu in 2001.
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The length of Hungarosaurus has been estimated at about 4 to 4.5 meters., 2013, "Sympatry of two ankylosaurs (Hungarosaurus and cf. Struthiosaurus) in the Santonian of Hungary", Cretaceous Research 44: 58-63 The skull of this dinosaur is estimated to have been 32–36 centimetres in length.
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In the Primeval spin- off novel The Lost Island the team run into a sleeping herd of Polacanthus when marooned in the Cretaceous. Cutter carefully manages to move the team around the group of Ankylosaurs, and later they observe a herd of them associating with Iguanodon.
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Although fragmentary, its position can be established. In 2012, Thompson et al. conducted an analysis of almost all known valid ankylosaurs and outgroup taxa at the time. They based their resulting phylogeny on characters representing cranial, post-cranial, and osteodermal anatomy, and details of synapomorphies for each recovered clade.
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Ankylosaurs were built low to the ground, typically one foot off the ground surface. They had small, triangular teeth that were loosely packed, similar to stegosaurs. The large hyoid bones left in skeletons indicates that they had long, flexible tongues. They also had a large, side secondary palate.
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This family included Ankylosaurus, Euoplocephalus, and Pinacosaurus. The clubs were made of several plates of bone that were permeated by soft tissue, allowing them to absorb thousands of pounds of force. Their beaks were larger and broader than the nodosaurids, indicating that these ankylosaurs were generalists in their diet.
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This posture is also seen in ankylosaurs, ceratopsians, and the early cynodont Procynosuchus. Several aspects of the forelimbs have been interpreted as adaptations to digging. Like many digging tetrapods, the radius is significantly shorter than the humerus. Like other aetosaurs, there is a prominent deltopectoral crest on the humerus.
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Emausaurus has been put on an outgroup to Ankylosauria, with Scelidosaurus and the basal stegosaur Huayangosaurus.Hill RV, Witmer LM, Norell MA. 2003. A new specimen of Pinacosaurus grangeri (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia: ontogeny and phylogeny of ankylosaurs. American Museum Novitates 3395: 1–29 7\.
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The researchers who examined the specimen suggested that ankylosaurs relied heavily on muscular tongues and hyobranchia (tongue bones) when feeding since their teeth were fairly small and were replaced at a relatively slow rate. Some modern salamanders have similar tongue bones, and use prehensile tongues to pick up food. The retracted position of the nostrils of Ankylosaurus have been compared to those of fossorial (digging) worm lizards and blind snakes, and though it was probably not a burrowing animal, the snout of Ankylosaurus may indicate earth-moving behavior. These factors, as well as the low rate of tooth formation in ankylosaurs compared to other ornithischians, indicate that Ankylosaurus may have been omnivorous (eating both plant and animal matter).
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Further, other lineages have produced tough outer coatings analogous to an exoskeleton, such as some mammals. This coating is constructed from bone in the armadillo, and hair in the pangolin. The armor of reptiles like turtles and dinosaurs like Ankylosaurs is constructed of bone; crocodiles have bony scutes and horny scales.
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Holotype skull of A. inceptus, TMP 1997.132.1 Anodontosaurus was a medium-sized ankylosaurid that was quadrupedal, ground-dwelling and herbivorous. Like other ankylosaurs, Anodontosaurus has armor on a majority of the dorsal surfaces of its body. It has a wide, pointed tail club at the end of its armored tail.
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The high- resolution mapping of the site from 1998 to 2015 revealed a total of 12,092 individual dinosaur tracks in 465 trackways. Nine different morphotypes of dinosaur tracks have been documented. Amongst them are several trackways of theropods, ornithopods, ankylosaurs and sauropods, with the latter group accounting for 26% of the trackways.
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In a study done in 2004 by Vickaryous et al., Gargoyleosaurus, Gastonia, and Minmi were recorded as basal ankylosaurids, with the rest of the ankylosaurids filled out with Gobisaurus, Shamosaurus, and ankylosaurines from China, Mongolia, and North America. In 2012, Thompson et al. undertook an analysis of almost all known valid ankylosaurs and outgroup taxa at the time.
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The drive sits on the top of Skyline Ridge, a hogback composed of upturned Dakota sandstone. Outcrops of the Morrison and the Fountain formations can also be seen. Along the drive is the "Dinosasur trackway," a fenced-off area along the road adjacent to some exposed strata, which showcases the fossilized footprints of ankylosaurs walking towards the west.
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Polacanthinae is a grouping of ankylosaurs, possibly primitive nodosaurids. Polacanthines are late Jurassic to early Cretaceous in age, and appear to have become extinct about the same time a land bridge opened between Asia and North America.Kirkland, J. I. (1996). Biogeography of western North America's mid- Cretaceous faunas - losing European ties and the first great Asian-North American interchange.
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Amtosaurus (; Amtgai lizard) is a genus of ornithischian dinosaur based on a fragmentary skull collected from the Upper Cretaceous Bayan Shireh Formation (Cenomanian to Santonian) of Mongolia and originally believed to represent an ankylosaurid.Kurzanov, S. M., & Tumanova, T. A. 1978. [On the structure on the endocranium in some ankylosaurs from Mongolia]. Paleontol. Zh. 1978:90-96.
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The armour of Loricosaurus has caused some controversy. When Huene first described it, he considered it to be from an ankylosaur. Later, it was discovered to not belong to ankylosaurs, but to belong to titanosaurs.Holtz, Thomas R Jr. (2011) Dinosaurs: The Most Complete,Up-to-date Encyclopedia for Dinosaur Lovers Of All Ages, Winter 2010 Appendix.
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In the later twentieth century, the term was used for an assembly of "primitive" ornithischians close to the ancestry of ankylosaurs and stegosaurs, such as Scutellosaurus, Emausaurus, Lusitanosaurus and Tatisaurus. Today, paleontologists usually consider the Scelidosauridae paraphyletic, thus not forming a separate branch or clade; however, Benton (2004) lists the group as monophyletic.Benton, M.J. (2004). Vertebrate Palaeontology (Third ed.).
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Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are known to have first appeared in the early Jurassic Period, and persisted until the end of the Cretaceous Period.
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In the Late Cretaceous, the hadrosaurs, ankylosaurs, and ceratopsians experienced success in Asiamerica (Western North America and eastern Asia). Tyrannosaurs dominated the large predator niche in North America. They were also present in Asia, although were usually smaller and more primitive than the North American varieties. Pachycephalosaurs were also present in both North America and Asia.
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Vickaryous et al. (2004), did the default phylogenetic analysis for ingroup ankylosaurs, due to including cranial and postcranial characters, a wide range of taxa and made no ingroup relationships, altrougth this analysis used the holotype Lesothosaurus and Huayangosaurus as outgroups, ignoring Scelidosaurus and Emausaurus.Vickaryous MK, Maryańska T, Weishampel DB. 2004. Ankylosauria. In: Weishampel DB, Dodson P, Osmólska H, eds.
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In 1990, Sue Ann Bilbey and Evan Hall discovered a quarry with the remains of ankylosaurs near the Price River in Carbon County, Utah. In 1998, the discovery was reported in the scientific literature.Carpenter K., Kirkland J.I., 1998, "Review of Lower and middle Cretaceous ankylosaurs from North America", New Mexico Museum of Natural History and Science Bulletin 14: 249-270 In 2001, the type species Cedarpelta bilbeyhallorum was named and described by Kenneth Carpenter, James Kirkland, Donald Burge and John Bird. The scientific name means "Bilbey and Hall's Cedar (Mountain) shield," with the genus named for the Cedar Mountain Formation and the animal's armored plates — from the Greek pelte, "small shield" — and the specific name honouring Sue Ann Bilbey and Evan Hall as the discoverers of the type locality.
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These represent the oldest known ankylosaurines from Asia, although they are not very closely related to each other. It appears that the closest relative of Talarurus was Nodocephalosaurus, an ankylosaurin with similar facial osteoderms. Most of the skeletal mounts of Talarurus are outdated by numerous issues, such as the ribs pointing to the bottom instead of stick to the sides, as in most ankylosaurs; an inaccurate skull cast which is mainly based on related species and not on the available skull material; very displayed arms and legs; four digits on the feet, which in reality only had three as indicated by related ankylosaurines. All of these mistakes were made by anatomical misunderstandings since ankylosaurs were not fully known at that time, also, Talarurus is not known from a complete skeleton.
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Gargoyleosaurus (meaning "gargoyle lizard") is one of the earliest ankylosaurs known from reasonably complete fossil remains. Its skull measures in length, and its total body length is an estimated . It may have weighed as much as . The holotype was discovered at the Bone Cabin Quarry West locality, in Albany County, Wyoming in exposures of the Upper Jurassic (Kimmeridgian to Tithonian stages) Morrison Formation.
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The combined upper side of the nasal bones is pierced by two paired oval openings. The antorbital fossa, with ankylosaurs the remnant of the antorbital fenestra, extends over the contact point of the maxilla, lacrimal bone and jugal bone. The prefrontal bone extends to below, touching the maxilla. At least some dorsal vertebrae have an elongated centrum, 30% longer than wide.
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The ankylosaur would win, although Velociraptor could easily kill young ankylosaurs, which have easily penetrable armor. Outcome 1: (Winner, ankylosaur) The ankylosaur is being harassed by two Velociraptors. They try to attack it multiple times, but its armor proves too thick. The ankylosaur eventually drives them away by swinging its tail (one blow would have killed one of the Velociraptors).
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The tail of Sauropelta was characteristically long and made up nearly half of the body length. One skeleton preserved forty caudal (tail) vertebrae, although some were missing, suggesting that the true number of caudal vertebrae may have exceeded fifty. Ossified tendons stiffened the tail along its length. Like other ankylosaurs, Sauropelta had a wide body, with a very broad pelvis and ribcage.
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The incomplete mandible of the largest specimen (CMN 8880) is the same length. AMNH 5214 has 35 dental alveoli in the left dentary and 36 in the right, for a total of 71. The predentary bone of the tip of the mandibles has not yet been found. Like other ankylosaurs, Ankylosaurus had small, phylliform (leaf-shaped) teeth, which were compressed sideways.
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Velaux-La Bastide Neuve represents a continental deposit. However, it was probably close to the shoreline, judging by the presence of claws from decapods, gastropods, and unionid mussels at the site. Fossils from the locality are well-preserved and were likely slowly transported. Other dinosaurs discovered at the site include the titanosaur Atsinganosaurus, in addition to teeth from nodosaurid ankylosaurs as well as neoceratosaurian and dromaeosaurid theropods.
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Local dinosaurs include ankylosaurs, Coelosaurus, Dryptosaurus, and Hadrosaurus. Other local reptile fossils include crocodilians and Tylosaurus. This legend likely predates European contact and may have originated prior to 1500. The bones being burnt in the "clay spoon" is a reference to a primitive kind of clay pipe that the local people had abandoned in favor of a design with a deeper bowl by the 17th century.
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Conifers were apparently the dominant canopy plants, with an understory of ferns, tree ferns, and angiosperms. Dinosaur Park is known for its diverse community of herbivores. As well as Stegoceras, the formation has also yielded fossils of the ceratopsians Centrosaurus, Styracosaurus and Chasmosaurus, the hadrosaurids Prosaurolophus, Lambeosaurus, Gryposaurus, Corythosaurus, and Parasaurolophus, and the ankylosaurs Edmontonia and Euoplocephalus. Theropods present include the tyrannosaurids Gorgosaurus and Daspletosaurus.
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The specific name honours Birger Bohlin, a Swedish paleontologist who during the 1930s took part in several paleontological expeditions to China. He described numerous Chinese ankylosaurs. As well as his work on dinosaurs and prehistoric mammals, Bohlin was part of the group that established the existence of Peking Man. The holotype, IVPP V12745, was found in a layer of the Sunjiawan Formation dating from the Cenomanian-Turonian.
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Stenonychosaurus inequalis is known from the Dinosaur Park Formation of southern Alberta, Canada, which at the time was a warm coastal floodplain covered by temperate forests. Apex predators included tyrannosaurids such as Daspletosaurus and Gorgosaurus. Herbivores included hadrosaurids such as Lambeosaurus, Corythosaurus, and Prosaurolophus; ceratopsids such as Styracosaurus, Centrosaurus, and Chasmosaurus; ankylosaurs such as Scolosaurus, Euoplocephalus, and Edmontonia; and pachycephalosaurs such as Stegoceras and Foraminacephale.
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Theropod dinosaurs are very diverse in the Nemegt and include the abundant tyrannosaur Tarbosaurus, which might have preyed upon Opisthocoelicaudia. The only other known sauropod is Nemegtosaurus, which is known from a single skull. Ornithischians are represented by the "duck-billed" hadrosaurids (including the very common Saurolophus), the thick-skulled pachycephalosaurs, and the heavily armored ankylosaurs. Neoceratopsians are absent, despite being present in the older Barun Goyot and Djadochta formations.
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Majungasaurus was the largest predator in its environment, while the only known contemporaneous large herbivores were sauropods like Rapetosaurus. Scientists have suggested that Majungasaurus specialized in hunting sauropods. Majungasaurus tooth marks on Rapetosaurus bones indicate that it at least fed on these sauropods, whether or not it actually killed them. Typically, titanosaurs were unusual among sauropods in that they coexisted with large ornithischian dinosaurs such as ceratopsids, hadrosaurs, and ankylosaurs.
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At the time that glyptodonts evolved, the apex predators in the island continent of South America were phorusrhacids, a family of giant flightless carnivorous birds. In physical appearance, glyptodonts superficially resembled the much earlier dinosaurian ankylosaurs and, to a lesser degree, the recently extinct giant meiolaniid turtles of Australia. These are examples of the convergent evolution of unrelated lineages into similar forms. The largest glyptodonts could weigh up to 2,000 kilograms.
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Macroolithus rugustus is abundant in the Nemegt Formation, which dates to the late Campanian to early Maastrichtian. This formation represents depositions of a meandering river. Well-preserved dinosaur remains are common in the Nemegt Formation, including oviraptorosaurs, titanosaurs, troodontids, tyrannosaurs, ankylosaurs, pachycephalosaurs, hadrosaurs, ornithomimosaurs, alvarezsaurs, and therizinosaurs. Remains of small animals are relatively rare, but several types of birds are known from Nemegt, as well as several types of multituberculate mammals.
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It lived alongside other reptiles from the upper part, most notably the large dromaeosaurid Achillobator, the tyrannosauroid Alectrosaurus, therizinosaurs Erlikosaurus and Segnosaurus, the pachycephalosaur Amtocephale; ankylosaurs Talarurus and Tsagantegia, the large sauropod Erketu and the basal hadrosauroid Gobihadros. Additional paleofauna has been recovered, expanding the aquatic biodiversity: Paralligator, Lindholmemys and the shark Hybodus. The discoveries of azhdarchids pterosaurs have been reported from at least two locations, compromising mainly cervical vertebrae.
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The caputegulae are named according to their position on the skull, and those of Ankylosaurus include a relatively large, hexagonal (or diamond-shaped) nasal caputegulum at the front of the snout between the nostrils, which had a loreal caputegulum on each side, an anterior and posterior supraorbital caputegulum above each orbit, and a ridge of nuchal caputegulae at the back of the skull. Tooth of AMNH 5895 in inner and outer view The snout region of Ankylosaurus was unique among ankylosaurs, and had undergone an "extreme" transformation compared to its relatives. The snout was arched and truncated at the front, and the nostrils were elliptical and were directed downward and outward, unlike in all other known ankylosaurids where they faced obliquely forward or upward. Additionally, the nostrils were not visible from the front because the sinuses were expanded to the sides of the premaxilla bones, to a larger extent than seen in other ankylosaurs.
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Cambridge University Press, Cambridge: 617-622\. It was the first dinosaur found in Antarctica. It may be a possible nodosaur but there has been no formal phylogenic analysis to prove its relationship with other ankylosaurs. Although the formation is made up of only marine deposits, the bodies of these animals along with other debris may have frequently been washed out to sea to later sink to the bottom and be buried by sediment.
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This list of thyreophoran type specimens is a list of fossils that serve as official standard-bearers for inclusion in the species and genera of the dinosaur clade Thyreophora, which includes the armored ankylosaurs and the plate-backed spike-tailed stegosaurs. Type specimens are those that are definitionally members of biological taxa, and additional specimens can only be "referred" to these taxa if an expert deems them sufficiently similar to the type.
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Another type of osteoderm was oval-shaped with a keel running down the middle. A few examples of this fifth type were found ossified to the ribs, suggesting that they ran in rows along the flanks of the animal, a very typical pattern among ankylosaurs. The final group consisted mainly of small bony nodules which are often called ossicles, and were probably scattered throughout the body. Several ribs were also found with these ossicles attached.
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Triceratops), armored dinosaurs (Thyreophora) such as stegosaurs and ankylosaurs, pachycephalosaurs and the ornithopods. There is strong evidence that certain groups of ornithischians lived in herds, often segregated by age group, with juveniles forming their own flocks separate from adults. Some were at least partially covered in filamentous (hair- or feather- like) pelts, and there is much debate over whether these filaments found in specimens of Tianyulong, Psittacosaurus, and Kulindadromeus may have been primitive feathers.
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Tsagantegia (; meaning Tsagan Teg) is a genus of medium-sized ankylosaur thyreophoran dinosaur that lived in Asia during the Late Cretaceous period. The genus is monotypic, including only the type species, T. longicranialis. The specimen consists of a very partial individual, compromising the skull and lacking postcranial remains. Since it only preserves the skull, Tsagantegia is mainly characterized by its elongated snout and the flattened facial osteoderms, greatly differing from other ankylosaurs.
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Almost all oviraptorids come from desert deposits of the Gobi Desert. Even in the late Cretaceous period, much of this area was desert, or at least very dry, habitat. In many of the localities where they are found, oviraptorids are among the most abundant dinosaurs present, second only to ankylosaurs and protoceratopsids. This is consistent with the idea that they were primarily herbivores, which tend to far outnumber carnivores in a given environment.
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Skull from above and below With a length of about , the skull of Zuul is of considerable size, being only surpassed among the ankylosaurs of Laramidia (western North America) by the three known skulls of Ankylosaurus, specimens AMNH 5214, AMNH 5895 and CMN 8880. The skull is also rather flat but this is partly caused by compression. The snout is wide and truncated at the front. The bony nostrils are pointing to the front.
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The tooth rows in the maxillae of this specimen are about long. Each alveolus had a foramen (opening) near its side where a replacement tooth could be seen. Compared to other ankylosaurs, the mandible of Ankylosaurus was low in proportion to its length, and, when seen from the side, the tooth row was almost straight instead of arched. The mandibles are completely preserved only in the smallest specimen (AMNH 5214) and are about long.
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In 2011, Currie published a study on the hand and foot, body parts often incompletely known with other ankylosaurs. The same year Michael Burns dedicated an article to four juveniles from the Bayan Mandahu. Also in 2011, the postcranial skeleton MPC 100/1305 was described in detail, though at the time referred to Saichania. Most recently, Michael Burns and colleagues described and illustrated the original Alag Teeg material from the Soviet- Mongolian expeditions in 1969 and 1970.
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The fossils of Ajkaceratops were discovered in the Csehbánya Formation, which is interpreted as "a floodplain and channel deposit formed by variegated clay, silt with interbedded grey and brown sand, and sandstone beds". This strata dates to the Santonian stage, around 86 to 84 mya (million years ago). Ajkaceratops shared its environment with other dinosaurs such as Rhabdodon, nodosaurid ankylosaurs, Non-Avian theropods and enantiornithine birds, as well as eusuchian crocodiles, azhdarchid pterosaurs, bothremydid turtles and teiid lizards.
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It shared its paleoenvironment with other dinosaurs, such as the hadrosaurs Acristavus and Adelolophus, the ceratopsian Diabloceratops, and unnamed ankylosaurs and pachycephalosaurs. Vertebrates present in the Wahweap Formation at the time included freshwater fish, bowfins, abundant rays and sharks, turtles such as Compsemys, crocodilians, and lungfish. Numerous mammals lived in this region, which included several genera of multituberculates, cladotherians, marsupials, and placental insectivores. The mammals were more primitive than those that lived in the younger Kaiparowits Formation.
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Glyptodonts, on the other hand, had rigid, turtle-like shells of fused osteoderms. Both groups have or had a cap of armor atop their heads. Glyptodonts also had heavily armored tails; some, such as Doedicurus, had mace-like clubs at the ends of their tails, similar to those of ankylosaurs, evidently used for defensive or agonistic purposes. Most armadillos eat insects and other invertebrates; some are more omnivorous and may also eat small vertebrates and vegetable matter.
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The family Nodosauridae was erected by Othniel Charles Marsh in 1890, and anchored on the genus Nodosaurus. The clade Nodosauridae was first defined by Paul Sereno in 1998 as "all ankylosaurs closer to Panoplosaurus than to Ankylosaurus," a definition followed by Vickaryous, Teresa Maryańska, and Weishampel in 2004. Vickaryous et al. considered two genera of nodosaurids to be of uncertain placement (incertae sedis): Struthiosaurus and Animantarx, and considered the most primitive member of the Nodosauridae to be Cedarpelta.
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One skull measured 35 centimeters (13.75 in) in width at its widest point, behind the eyes. Unlike some other nodosaurids, the roof of the skull was characteristically flat, not domed. The roof of the skull was very thick and covered in flat, bony plates that are so tightly fused that there appear to be no sutures (boundaries) like the ones seen in Panoplosaurus, Pawpawsaurus, Silvisaurus, and many other ankylosaurs. This could also be an artifact of preservation or preparation.
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In 1932, Charles Mortram Sternberg reported the presence of the footprints of a large, four-footed dinosaur from Lower Cretaceous rocks in British Columbia, Canada. He described a new ichnogenus and species for these tracks, Tetrapodosaurus borealis, and attributed them to ceratopsians. However, in 1984 paleontologist Kenneth Carpenter re-examined the British Columbian Tetrapodosaurus prints and argued that they were made by ankylosaurs rather than ceratopsians. Specifically, Carpenter concluded that these were probably the footprints of Sauropelta.
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Since the comments were written by Boyle himself, and since they cite information he received specifically from Purnell, they are as legitimate a source of information as the article itself. Edmontosaurus dentary with teeth, typical of hadrosauridae Mallon et al. (2013) examined herbivore coexistence on the island continent of Laramidia, during the Late Cretaceous. It was concluded that hadrosaurids could reach low-growing trees and shrubs that were out of the reach of ceratopsids, ankylosaurs, and other small herbivores.
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Thorax of the neotype. The vertebral column of Scelidosaurus contained at least six neck vertebrae, seventeen dorsal vertebrae, four sacral vertebrae and at least thirty-five tail vertebrae. Though perhaps the actual total of cervical vertebrae was as high as seven or eight, the neck was only moderately long. The torso was relatively flat in side view, however, despite the belly being broad, it was not extremely vertically compressed as with ankylosaurs but taller than wide.
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Paleontologist David Evans, of the Royal Ontario Museum calls Sloboda "basically a legend in Alberta. She's probably one of the best dinosaurs in the world." Her discoveries include the first pterosaur bonebed in North America,, reprinted in and a pterosaur leg showing evidence of predation by a small dinosaur that inspired author Daniel Loxton's 2013 book Pterosaur Trouble. Sloboda has made numerous discoveries in Alberta's Dinosaur Provincial Park, including fossil skulls of Corythosaurus, ankylosaurs (including Euoplocephalus) and crocodilians.
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This definition is essentially followed by most paleontologists today. This "stem- based" definition means that the primitive armored dinosaur Scelidosaurus, which is slightly closer to ankylosaurids than to stegosaurids, is technically a member of Ankylosauria. Upon the discovery of Bienosaurus, Dong Zhiming (2001) erected the family Scelidosauridae for both of these primitive ankylosaurs. In 2001, Carpenter proposed a new group uniting Scelidosaurus, Ankylosauridae, Nodosauridae, and Polacanthidae, with Minmi (thought to be a primitive ankylosaurian), to the exclusion of Stegosaurus.
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The largest osteoderms were probably arranged in transverse and longitudinal rows across most of the body, with four or five transverse rows separated by creases in the skin. The osteoderms on the flanks would probably have had a more square outline than those on the back. There may have been four longitudinal rows of osteoderms on the flanks. Unlike some basal ankylosaurs and many nodosaurs, ankylosaurids do not appear to have had co- ossified pelvic shields above their hips.
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The specific name honors Walter P. Coombs Jr., who pioneered the study of ankylosaurs in the late twentieth century. The holotype, AMNH 5337, was found in a layer of the Dinosaur Park Formation at an altitude of 667 metres, which indicates an age of about 76,8 million years. It consists of a skeleton with skull, lacking the tail and hindlimbs. It represents a mature and aged individual, in view of fused ribs, a fused shoulder girdle, rough articulation surfaces and rough armour.
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Most subsequent researchers placed polacanthines as primitive ankylosaurids, though mostly without any rigorous study to demonstrate this idea. The first comprehensive study of 'polacanthid' relationships, published in 2011, found that they are either an unnatural grouping of primitive nodosaurids, or a valid subfamily at the base of Nodosauridae. The clade Nodosauridae was first defined by Paul Sereno in 1998 as "all ankylosaurs closer to Panoplosaurus than to Ankylosaurus," a definition followed by Vickaryous, Teresa Maryańska, and Weishampel in 2004. Vickaryous et al.
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Like other ankylosaurs, Antarctopelta oliveroi was a stocky, herbivorous quadruped protected by armor plates embedded in the skin. Although a complete skeleton has not been found, the species is estimated to have reached a maximum length of 4 meters (13 ft) from snout to tail tip. In 2010 Gregory Paul gave a higher estimation of 6 meters (20 ft) and 350 kg (772 lbs). Very little of the skull is known, but all of the known skull fragments were heavily ossified for protection.
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The osteoderms were certainly far more sparse than those of ankylosaurs, and did not completely cover the back in scutes. Because of their sparse arrangement, it was unlikely that they served a significant role in defense. However, they may have played an important role in nutrient storage for titanosaurs living in highly seasonal climates and for female titanosaurs laying eggs. Osteoderms were present on both large and small species, so they were not solely used by smaller species as protection against predators.
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Detail of skull and neck. Reconstructed skeleton at the USU Eastern Prehistoric Museum, Price, Utah Other angle of skeleton Size of Animantarx, compared to a human. The generic name is composed of the Latin words animatus ("living" or "animated") and arx ("fortress" or "citadel"), referring to its armored nature. In particular, the name is a reference to a comment made by paleontologist R. S. Lull about ankylosaurs, that as "an animated citadel, these animals must have been practically unassailable..."Lull, R.S. 1914.
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This morphotype has been compared to the armor of ankylosaurs. The upper side of the tail also possesses very characteristic and unusual osteoderms, designated as "morphotype D". These are elongated plates that stick up from the tail, with one plate per vertebra. They are wide at their base but flattened (from the side) elsewhere, and also acquire a swept-back orientation. In life, they would probably have been connected by soft tissue to form a tail fin to assist swimming.
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Artist's restoration of some megafaunal dinosaurs of the Dinosaur Park Formation. The Dinosaur Park Formation is time-equivalent to the Oldman Formation, and both formations are part of the Belly River Group. It represents the deposits of a perennial, sinuous river system and paralic environments. It is widely known for its incredible diversity of dinosaurian fauna, representing over 50 valid taxa including theropods such as dromaeosaurs, caenagnathids, troodontids, ornithomimids, and tyrannosaurids, as well as ornithischians such as pachycephalosaurs, hadrosaurs, ceratopsians, ankylosaurs, and thescelosaurs.
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Though the latter is the smallest specimen of Ankylosaurus, its skull is still larger than those of any other ankylosaurins. A few other ankylosaurs reached about in length. Because the vertebrae of AMNH 5214 are not significantly larger than those of other ankylosaurines, Arbour and Mallon considered their upper range estimate of nearly for large Ankylosaurus too long, and suggested a length of instead. Arbour and Mallon estimated a weight of for AMNH 5214, and tentatively estimated the weight of CMN 8880 at .
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Skull of specimen CMN 8880, the largest-known ankylosaurid, including lower jaw (E–F) and tooth (G) Like other ornithischians, Ankylosaurus was herbivorous. Its wide muzzle was adapted for non-selective low-browse cropping, although not to the extent seen in some related genera, especially Euoplocephalus. Though ankylosaurs may not have fed on fibrous and woody plants, they may have had a varied diet, including tough leaves and pulpy fruits. Ankylosaurus probably fed on abundant ferns and low-growing shrubs.
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Usually in ankylosaurs these have the form of "halfrings" leaving the underside unprotected, but with Gastonia only two segments seem present, one at each side of the midline, causing Kirkland to refer to them as "quarter rings". Each segment had a pointed keel and a hollow underside. Kirkland stressed that the rump armour was hard to reconstruct because it had not been found in articulation. The sides of the thorax seem to have been covered by about five pairs of large flat triangular spikes.
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Restoration of the skull Europelta is a medium-sized nodosaurid, approximately four and a half meters in length.Matthew Piper, "Utah paleos: Euro dinosaur find hints at continental history", The Salt Lake Tribune, 2 December 2013 Europelta is distinguished from other ankylosaurs by the following diagnostic traits: Its quadrate bone is shorter and mediolaterally wider than in any other ankylosaur. The rear margin of the skull is concave in dorsal view. In lateral view, the sacrum of Europelta is arched dorsally, describing an arc of about 55°.
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During the Early Jurassic Period, dinosaurs such as Dilophosaurus, Anchisaurus, Coelophysis (formerly known as Megapnosaurus), and the early thyreophoran Scutellosaurus lived in North America. The latter is believed to have been the ancestor of all stegosaurs and ankylosaurs. The Middle Jurassic is the only poorly represented time period in North America, although several Middle Jurassic localities are known from Mexico. Footprints, eggshells, teeth, and fragments of bone representing theropods, sauropods, and ornithopods have been found, but none of them are diagnostic to the genus level.
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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.
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The genus name refers to its location on the continent of Antarctica and its armored nature. Antarctica is derived from the Greek words αντ/ant- ('opposite of') and αρκτος/arktos ('bear' referring to the constellation Ursa Major, which points north). The Greek πελτη/pelte ('shield') is commonly used to name genera of ankylosaurs (Cedarpelta and Sauropelta, for example). The single known species, A. oliveroi, is named after Eduardo Olivero, who discovered the holotype, first mentioned it in print, and has worked in Antarctica for decades.
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Other ankylosaurs have also been found in marine sediments, likely as a result of carcasses washing out to sea. Although Antarctica in the Cretaceous was in the southern polar region, the Earth had a much warmer climate during this time period, and the continent would have been ice-free. Animals like Antarctopelta oliveroi would have lived in forests of conifers and even deciduous trees. Despite the higher temperatures, darkness would still have descended for the winter, just as it does today at high latitudes.
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"A new species of the centrosaurine ceratopsid Pachyrhinosaurus from the North Slope (Prince Creek Formation: Maastrichtian) of Alaska." Acta Palaeontologica Polonica, available online 26 Aug 2011. Dinosaurs that lived alongside Einiosaurus include the basal ornithopod Orodromeus, hadrosaurids (such as Hypacrosaurus, Maiasaura, and Prosaurolophus), the ankylosaurs Edmontonia and Euoplocephalus, the tyrannosaurid Daspletosaurus (which appears to have been a specialist of preying on ceratopsians), as well as the smaller theropods Bambiraptor, Chirostenotes, Troodon, and Avisaurus. Einiosaurus lived in a climate that was seasonal, warm, and semi-arid.
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Tyrannosaurus and other animals of the Hell Creek Formation Several notable Tyrannosaurus remains have been found in the Hell Creek Formation. During the Maastrichtian this area was subtropical, with a warm and humid climate. The flora consisted mostly of angiosperms, but also included trees like dawn redwood (Metasequoia) and Araucaria. Tyrannosaurus shared this ecosystem with ceratopsians Leptoceratops, Torosaurus, and Triceratops, the hadrosaurid Edmontosaurus annectens, the parksosaurid Thescelosaurus, the ankylosaurs Ankylosaurus and Denversaurus, the pachycephalosaurs Pachycephalosaurus and Sphaerotholus, and the theropods Ornithomimus, Struthiomimus, Acheroraptor, Dakotaraptor, Pectinodon and Anzu.
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In the Otis Chalk assemblage, Triopticus lived alongside a number of other archosauriforms including the allokotosaurs Trilophosaurus and Malerisaurus; the doswelliid Doswellia; the phytosaurs Parasuchus and Angistorhinus; the aetosaurs Longosuchus, Lucasuchus, and Coahomasuchus; the shuvosaurid Effigia; the silesaurid Silesaurus; the lagerpetid dinosauromorph Dromomeron, and the coelophysoid theropod dinosaur Lepidus. Some of these also exhibit evolutionary convergence upon archosaurs living after the Triassic–Jurassic extinction event - the phytosaurs resemble the thalattosuchians, gavialoids, and spinosaurids, the aetosaurs resemble the ankylosaurs, and the shuvosaurids resemble the ornithomimosaurs.
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It was a medium-sized, heavily built, ground-dwelling, quadrupedal herbivore, that could grow up to long and weighed about , nearly a ton. Like other ankylosaurs it had heavy armour and a club on its tail, making much of its mobility slow. Talarurus is classified as a member of the Ankylosauria, in the Ankylosaurinae, a group of derived ankyosaurs. Talarurus is known from the Bayan Shireh Formation, being likely niche partitioned with Tsagantegia, as indicated by its muzzle, which has a rectangular shape specialized for grazing.
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It had a wide, low skull, with two horns pointing backward from the back of the head, and two horns below these that pointed backward and down. Unlike other ankylosaurs, its nostrils faced sideways rather than towards the front. The front part of the jaws was covered in a beak, with rows of small, leaf-shaped teeth farther behind it. It was covered in armor plates, or osteoderms, with bony half-rings covering the neck, and had a large club on the end of its tail.
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Gallagher W.B., Tumanova T.A., Dodson P., Axel L., 1998, "CT scanning Asian ankylosaurs: paleopathology in a Tarchia skull", Journal of Vertebrate Paleontology 18: 44A-45A Arbour pointed out that Saichania, Tarchia and Zaraapelta shared the same habitat. She assumed that this relative ankylosaurian abundance in species had been caused by them being the main herbivores in the area, enough crop thus being available to feed three populations, although their relative niches were unclear. The differences in head ornamentation would then have served species recognition. She saw no indications of sexual dimorphism.
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The vertical spikes could have intimidated rivals and animals could have determined who was the strongest by ramming their heads together. Kirkland proposed that the typical ankylosaurid down-turned head, made possible by a more ventrally directed occipital condyle compared to nodosaurids, and an increased loosening of the rear skull elements to absorb shocks, were adaptations to this kind of behaviour. Ankylosaurs are often assumed to have been solitary living animals because their short legs seem poorly adapted to the trekking behaviour of herds, but the concentration of Gastonia fossils seems to contradict this.
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One bone in particular, identified as a supraorbital, included a short spike which would have projected outwards over the eye. The leaf-shaped teeth are asymmetrical, with the majority of the denticles on the edge closest to the tip of the snout. These teeth are also proportionately large compared to those of other ankylosaurs, with the largest measuring 10 millimeters (0.4 in) across. This compares to the much larger North American Euoplocephalus, 6–7 m (20–23 ft) in body length, which had teeth averaging only 7.5 mm (0.3 in) across.
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The holotype skeleton was collected about 90 m (300 ft) from the base of the Gamma Member of the Snow Hill Island Formation in Antarctica. This member was deposited in a shallow marine environment and also preserves marine fossils such as shark teeth, remains of the mosasaur Lakumasaurus antarcticus, ammonites, bivalves, and gastropods. Index fossils like ammonites suggest the rocks were deposited in the late Campanian stage of the Late Cretaceous Period, or about 74 to 70 Ma (million years ago). Despite being found in marine sediment, Antarctopelta, like all ankylosaurs, lived on land.
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Armor plates and teeth In 1905, Samuel Wendell Williston described FMNH UR88, a partial armored dinosaur skeleton consisting of a maxilla fragment, seven cervical and two dorsal vertebrae, part of a sacrum and both ilia, caudal vertebrae, parts of the scapulae, both humeral heads, portions of an ulna and both radii, a metacarpal, partial tibia, metatarsal, and armor including a shoulder spine and neck ring.Carpenter, K., and Kirkland, J.I. (1998). Review of Lower and middle Cretaceous ankylosaurs from North America. In: Lucas, S.G., Kirkland, J.I., and Estep, J.W. (eds.).
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Possible back osteoderm (AMNH 5895), in outer and inner view The osteoderms of ankylosaurids were thin in comparison to those of other ankylosaurs, and appear to have been strengthened by randomly distributed cushions of collagen fibers. Structurally similar to Sharpey's fibres, they were embedded directly into the bone tissue, a feature unique to ankylosaurids. This would have provided the ankylosaurids with an armor covering that was both lightweight and highly durable, being resistant to breakage and penetration by the teeth of predators. The palpebral bones over the eyes may have provided additional protection for them.
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These "relict" species include the compsognathid dinosaur Sinosauropteryx and the anurognathid pterosaur Dendrorhynchoides. It also has the earliest and most primitive known members of groups that spread all around the world by the Late Cretaceous, including neoceratopsians, therizinosaurs, tyrannosaurs, and oviraptorids. Northeastern Asia may have been the center of diversification of these dinosaur groups. The Jehol Biota was not entirely isolated, however, because it also includes animals which were known from all around the world at the same time, including discoglossid frogs, paramacellodid lizards, multituberculate mammals, enantiornithine birds, ctenochasmatid pterosaurs, iguanodontian ornithopods, titanosauriform sauropods, nodosaurid ankylosaurs, and dromaeosaurid theropods.
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The former building of the Baumwollspinnerei Streiff & Cie weaving mill in Aathal was built in 1903 and houses the museum on about 4,500 square meters, including the outside park on the surrounding property. The focus is on the museum's own excavations and original dinosaur bones, 19 special exhibitions and subsequently integrated new finds. A shop, a cafeteria and a park for children (Dino-Gardino) are sections of the museum. Among around 645 exhibits, there are skeletons, reproductions and originals finds of Stegosaurus, Ankylosaurs, Pterosaurs, 'featured' Dinosaurs, Archaeopteryx, eggs and embryos and footprints, as well as meteorites and minerals of Siber + Siber.
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Specimen UMNH VP 28350 consists of three dorsal vertebrae, the distal end of a left ulna, proximal ends of left and right radii, an incomplete metatarsal, and additional osteoderms. Specimen UMNH VP 28351, the first found, contains dorsal vertebrae and osteoderms. The name Invictarx means "invincible/unconquerable fortress", in reference to the fact that Invictarx, like all other ankylosaurs, was protected from predators by armor. The specific name, zephyri, is the genitive form of the Latin noun zephyrus, meaning (of the) western wind, referring to the "blustery conditions that prevail among the outcrops where the specimens were discovered".
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Likewise, ankylosaur remains are among the dinosaur bones found along the Red Deer River of Alberta, Canada where the Piegan people believe that the Grandfather of the Buffalo once lived. The first scientifically documented ankylosaur remains were recovered from Early Cretaceous rocks in England and named Hylaeosaurus armatus by Gideon Mantell in 1833. However, the Ankylosauria itself would not be named until Henry Fairfield Osborn did so in 1923 nearly a hundred years later. Prior to this, the ankylosaurs had been considered members of the Stegosauria, which included all armored dinosaurs when Othniel Charles Marsh named the group in 1877.
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It was not until 1927 that Alfred Sherwood Romer implemented the modern use of the name Stegosauria as specifically pertaining to the plate-backed and spike- tailed dinosaurs of the Jurassic that form the ankylosaurs' nearest relatives. The next major revision to ankylosaur taxonomy would not come until Walter Coombs divided the group into the two main families paleontologists still recognize today; the nodosaurids and ankylosaurids. Since then, many new ankylosaur genera and species have been discovered from all over the world and continue to come to light. Many fossil ankylosaur trackways have also been recognized.
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The findings also include the remains of a 20-meter (66 ft) hadrosaurid, a record size for the duck-billed dinosaur. A fossilized skull of a large ceratopsian was also found along with bones which belong to club-tailed ankylosaurs. According to Professor Zhao Xijin, a palaeontologist in charge of the excavations from the Institute of Vertebrate Paleontology and Paleoanthropology, "This group of fossilised dinosaurs is currently the largest ever discovered in the world... in terms of area." Such a high concentration of fossil bones in such a small area is significant for the theories of extinction of dinosaurs.
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They suggest it may be a fragmentary tail spine instead. The genuine absence of parascapular spines in other stegosaurids is considered a secondary loss since many basal stegosaurs like Gigantspinosaurus and Huayangosaurus have been discovered with them. Stegosaurids also lack lateral scute rows that run longitudinally on either side of the trunk in huayangosaurids and ankylosaurs, indicating yet another secondary loss of a plesiomorphic characters. However, the absence of lateral scutes as well as pre-maxillary teeth mentioned above are not specifically diagnostic of stegosaurids, since these features are also present in other non- huayangosaurid stegosaurs, whose phylogenetic relations within Stegosauria are unclear.
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The formation has a diverse assemblage of dinosaurs including theropods such as Troodon, Albertosaurus, ornithomimids and dromaeosaurs, as well as several types of hadrosaurs, ceratopsians, ankylosaurs, and smaller ornithischians such as Orodromeus. It also includes pterodactyloid pterosaurs, Champsosaurus, turtles, lizards, and mammals. Other types of eggs from Two Medicine include Montanoolithus, Prismatoolithus levis (the eggs of Troodon formosus), some small unidentified theropod eggs, P. hirschi, Triprismatoolithus, Tubercuoolithus, Spheroolithus albertensis (eggs of Maiasaura), S. choteauensis, eggs of Hypacrosaurus, and Krokolithes. The Oldman Formation was formed by ephemeral rivers in a semi- arid environment characterized by seasonal precipitation.
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Assuming it was endothermic, Ankylosaurus would have eaten of ferns per day, similar to the amount of dry vegetation a large elephant would consume. The requirements for nutrition could have been more effectively met if Ankylosaurus ate fruit, which its small, cusp-like teeth and the shape of its beak seem well adapted for, compared to for example Euoplocephalus. Certain invertebrates, which the small teeth may have been adapted for handling, could also have provided supplemental nutrition. Fossils of Ankylosaurus teeth exhibit wear on the face of the crown rather than on the tip of the crown, as in nodosaurid ankylosaurs.
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With its low center of gravity, Ankylosaurus would have been unable to knock down trees like modern elephants do. It was also incapable of chewing bark and thus unlikely to have practiced bark stripping. As an adult, Ankylosaurus does not appear to have congregated in groups (though some ankylosaurs appear to have congregated when young). So, although it was a large herbivore with similar energetic requirements, it is therefore improbable that Ankylosaurus was able to modify the landscape of its ecosystem in the way elephants do; hadrosaurids may instead have had such an "ecosystem engineer" role.
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Modern reconstructions show the animal with a more upright limb posture and with the tail held off the ground. Likewise, large spines projecting sideways from the body (similar to those of nodosaurid ankylosaurs) are present in many traditional depictions, but are not known from Ankylosaurus itself. The armor of Ankylosaurus has often been conflated with that of Edmontonia (earlier referred to as Palaeoscincus); in addition to Ankylosaurus being depicted with spikes, Edmontonia has also been depicted with an Ankylosaurus-like tail club (a feature nodosaurids did not have), including in a mural by the American artist Charles R. Knight from 1930.
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The formation has produced impressive assemblages of invertebrates (including ammonites), plants, mammals, fish, reptiles (including the lizard Obamadon), marine reptiles (including the marine reptiles like mosasaurs, plesiosaurs and sea turtles), and amphibians. Notable dinosaur finds include Tyrannosaurus and Triceratops, ornithomimids as well, caenagnathids like Anzu, a variety of small theropods, pachycephalosaurs, ankylosaurs, crocodylomorphs and squamates, including various animal fossils unearthed in the Hell Creek Formation. The most complete hadrosaurid dinosaur ever found, an Edmontosaurus, was retrieved in 2000 from the Hell Creek Formation and widely publicized in a National Geographic documentary aired in December 2007. A few bird, mammal, and pterosaur fossils have also been found.
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The family Polacanthidae was named by Wieland in 1911 to refer to a group of ankylosaurs which seemed to him intermediate between the ankylosaurids and nodosaurids. This grouping was ignored by most researchers until the late 1990s, when it was used as a subfamily (Polacanthinae) by Kirkland for a natural group recovered by his 1998 analysis suggesting that Polacanthus, Gastonia, and Mymoorapelta were closely related within the family Ankylosauridae. Kenneth Carpenter resurrected the name Polacanthidae for a similar group which he also found to be closer to ankylosaurids than to nodosaurids. Carpenter became the first to define Polacanthidae as all dinosaurs closer to Gastonia than to either Edmontonia or Euoplocephalus.
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The Judith River Group preserves the remains of many aquatic amphibians and reptiles, including frogs, salamanders, turtles, Champsosaurus and crocodilians. Terrestrial lizards, including whiptails, skinks, monitors and alligator lizards have also been discovered. Azhdarchid pterosaurs, and birds like Apatornis and Avisaurus flew overhead, while several varieties of mammals coexisted with Daspletosaurus and other types of dinosaurs in the various formations that make up the Judith River wedge. Skull of a juvenile D. horneri In the Oldman Formation (the geological equivalent of the Judith River formation), Daspletosaurus torosus could have preyed upon the hadrosaur species Brachylophosaurus canadensis, the ceratopsians Coronosaurus brinkmani and Albertaceratops nesmoi, pachycephalosaurs, ornithomimids, therizinosaurs and possibly ankylosaurs.
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In any case, it lacks stegosaurian synapomorphies.Wilson, J. A., P. C. Sereno, S. Srivastava, D. K. Bhatt, A. Khosla, and A. Sahni. 2003. "A new abelisaurid (Dinosauria, Theropoda) from the Lameta Formation (Cretaceous, Maastrichtian) of India", Contributions from the Museum of Paleontology of the University of Michigan, 31:1–42 On the assumption it might at least be some member of the Thyreophora, it has been considered a possible ankylosaurian, the ankylosaurs being a sister group of the Stegosauria that survived into the Late Cretaceous. Even then, however, it was considered a nomen dubium as so few remains of the animal have been found.
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This shield is also found in ankylosaurs like Polacanthus and Antarctopelta. Large, pointed spines lined the sides of the neck, increasing in size towards the shoulders, and then decreasing in size again along the side of the body until they stopped just before the hips. Behind the hips, flat triangular plates lined the tail on both sides, pointing laterally (outwards) and decreasing in size towards the end of the tail. Carpenter originally described the cervical (neck) spines and caudal plates as belonging to a single row on each side, although more recently he and Jim Kirkland reconstructed them in two parallel rows on each side, one above the other.
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The numerous small vascular canals around the skull roof, the lateral wall of the brain case and cranial vessels form a complex network around the brain which allowed the redistribution of the blood flow and physiological mechanisms for heat exchange in order to cool-down the brain and maintain optimal temperatures. In addition, the length of the cochlear ducts in the inner ear suggests that Bissektipelta, and many other ankylosaurs, were adapted for low frequency-hearing within 100 Hz and 3000 Hz. The elongated cochlear ducts in the more advanced ankylosaurines seem to indicate that these traits were adapted for enhanced hearing at lower frequencies.
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The rest of the tail would have been more capable of bending downward, but lacked many adaptations for lateral movement. This means that, if Doswellia was an aquatic predator, it probably would not have used its tail for swimming as in modern crocodilians. Although limb material is not well known in Doswellia, material that is preserved suggests that both the front and rear legs were strongly built. Although the bizarre downward pointing hip could have given Doswellia an upright posture as in dinosaurs (including the armored ankylosaurs), various other primitive features suggest that it was more likely to have been sprawling or semi-sprawling most of the time.
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The most complete specimen measures up to in length though T. rex could grow to lengths of over , up to tall at the hips, and according to most modern estimates to in weight. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it is still among the largest known land predators and is estimated to have exerted the strongest bite force among all terrestrial animals. By far the largest carnivore in its environment, Tyrannosaurus rex was most likely an apex predator, preying upon hadrosaurs, armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. Some experts have suggested the dinosaur was primarily a scavenger.
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The squamosal horns of the largest Ankylosaurus specimen are blunter than those of the smallest specimen, which is also the case in Euoplocephalus, and this may represent ontogenetic variation (related to growth development). Studies of specimens of Pinacosaurus of different ages found that during ontogenetic development, the ribs of juvenile ankylosaurs fused with their vertebrae. The forelimbs strongly increased in robustness while the hindlimbs did not become larger relative to the rest of the skeleton, further evidence that the arms bore most of the weight. In the cervical half-rings, the underlying bone band developed outgrowths connecting it with the underlying osteoderms, which simultaneously fused to each other.
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Ankylosaurus magniventris is the armored herbivore of Hell Creek, largely living a solitary life. Ankylosaurus is a very territorial animal in-game, and tolerates other members of its species only during the breeding season. Ankylosaurus also gains significant benefits from eating specific plants, and therefore must range widely and defend choice plots of foliage, not only from each other, but from other herbivores as well. While adults are rarely bothered by predators other than Tyrannosaurus, young ankylosaurs will be vulnerable to many Hell Creek predators due to their still forming armour, and must either hide from predators or seek shelter in the company of more intimidating targets.
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This genus already possessed many advanced turtle traits, and thus probably indicates many millions of years of preceding turtle evolution; this is further supported by evidence from fossil tracks from the Early Triassic of the United States (Wyoming and Utah) and from the Middle Triassic of Germany, indicating that proto-turtles already existed as early as the Early Triassic. Proganochelys lacked the ability to pull its head into its shell, had a long neck, and had a long, spiked tail ending in a club. While this body form is similar to that of ankylosaurs, it resulted from convergent evolution. Turtles are divided into two extant suborders: Cryptodira and Pleurodira.
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Size comparison Much of the skull and skeleton has been recovered, and the taxon displays cranial sculpturing, including pronounced deltoid quadratojugal and squamosal bosses. The taxon is further characterized by a narrow rostrum (in dorsal view), the presence of seven conical teeth in each premaxilla, an incomplete osseous nasal septum, a linearly arranged nasal cavity, the absence of an osseus secondary palate, and, as regards osteoderms, two sets of co-ossified cervical plates and a number of elongate conical spines. A very unusual feature is the sagittal (midline) osteoderm on the first set of cervical plates; in most other ankylosaurs, these osteoderms are bilateral, i.e. paired with one on each side of the midline.
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Ossified tendons from the tail of UALVP 2 Gilmore's classification was supported by the American palaeontologists Barnum Brown and Erich Maren Schlaikjer in their 1943 review of the dome-headed dinosaurs, by then known from 46 skulls. From these specimens, Brown and Schlaikjer named the new species T. sternbergi and T. edmontonensis (both from Alberta), as well as moving the large species T. wyomingensis (which was named in 1931) to the new genus Pachycephalosaurus, along with two other species. They found T. validus distinct from T. formosus, but considered S. brevis the female form of T. validus, and therefore a junior synonym. By this time, the dome-headed dinosaurs were either considered relatives of ornithopods or of ankylosaurs.
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On the maxillary bone of a new dinosaur (Priodontognathus phillipsii), contained in the Woodwardian Museum of the University of Cambridge. Quarterly Journal of the Geological Society of London 31:439-443. Because the replacement teeth had not yet erupted, their serrations had not been worn down and many sharp denticula could be seen, shaped as the points of a saw. Because armored dinosaurs were very poorly known at the time, he had little to compare it to, and in light of this it is not too surprising that he later, in 1893, had it mixed up with the stegosaurian Omosaurus (now Dacentrurus); stegosaurs are most closely related to the ankylosaurs within the Thyreophora.
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N. rumosus was most likely laid by some kind of non-avian maniraptor because of its similarities in microstructure and ornamentation to oviraptorosaur eggs and the eggs of Deinonychus. Other very small theropod eggs (ranging in size from to ), including Elongatoolithus, Prismatoolithus (and other indeterminate prismatoolithids), as well as ornithopod eggs assigned to Spheroolithus, are also known from the Kamitaki site. These eggs, along with skeletal remains, show that the parents of Nipponoolithus coexisted with numerous other small theropods, as well as an assemblage of ankylosaurs, titanosaurs, hadrosauroids, tyrannosaurs, and therizinosaurs. The parent of Nipponoolithus probably weighed roughly , comparable to the size of some contemporary small theropods from the Jehol biota in China.
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Ankylosaurid phylogenetic relations are hard to determine because many taxa are only partially known, the exact armour configuration has rarely been preserved, fused osteoderms obscure many details of the skull and the Ankylosauridae are conservative in their postcranial skeleton, showing little variation in their vertebrae, pelves and limbs. Previously it was assumed that as one of the oldest known ankylosaurids, Talarurus possessed some basal characters that are shared with nodosaurids but were later lost in more advanced ankylosaurs, such as the presence of four toes. However, the presumed "primitive" traits proved to be largely artefacts of the initial skeletal restoration. Recent phylogenetic analysis provides evidence for an assignment of Talarurus to the Ankylosaurinae, a derived ankylosaurid group.
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In spite of its familiarity, it is known from far fewer remains than its closest relatives. In 2017 the Canadian paleontologists Victoria M. Arbour and Jordan Mallon redescribed the genus in light of newer ankylosaur discoveries, including elements of the holotype that had not been previously mentioned in the literature (such as parts of the skull and the cervical half-rings). They concluded that though Ankylosaurus is iconic and the best-known member of its group, it was bizarre in comparison to related ankylosaurs, and therefore not representative of the group. Many traditional popular depictions show Ankylosaurus in a squatting posture and with a huge tail club being dragged over the ground.
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From the fifth came the stars, planets and moons, and from the sixth came all the plants. Finally, from the seventh came all the herbivores (Ceratopsians, Ankylosaurs, Sauropods and Hadrosaurs, among others), and from the eighth and final egg came the carnivores which preyed upon them, (Tyrannosaurs, Ornithomimids and Dromaeosaurids, among others.) God created the five original female hunters by biting off her left arm, each of her fingers becoming a Quintaglio. They wished to create as God did, so she bit off her right arm and these became the first males, the mates of the original hunters. Quintaglio tradition states that a Quintaglio must go on at least one proper hunt in their life in order to go through the rites of passage.
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Ankylosaurus (rear left) and other animals of the Hell Creek Formation The formations where Ankylosaurus fossils have been found represent different sections of the western shore of the Western Interior Seaway dividing western and eastern North America during the Cretaceous, a broad coastal plain extending westward from the seaway to the newly formed Rocky Mountains. These formations are composed largely of sandstone and mudstone, which have been attributed to floodplain environments. The regions where Ankylosaurus and other Late Cretaceous ankylosaurs have been found had a warm subtropical/temperate climate, which was monsoonal, had occasional rainfall, tropical storms, and forest fires. In the Hell Creek Formation, many types of plants were supported, primarily angiosperms, with less common conifers, ferns and cycads.
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In 2000, Robert Gabbard, member of a team headed by Philip John Currie, found an ankylosaur skull in the Gobi Desert near Hermiin Tsav at the Baruungoyot. In 2014, Victoria Megan Arbour named and described the find as the species Zaraapelta nomadis, but at first it remained an invalid nomen ex dissertatione.Arbour, Victoria Megan, 2014, Systematics, evolution, and biogeography of the ankylosaurid dinosaurs Ph.D thesis, University of Alberta Later that year, however, it was validly named as the type species Zaraapelta nomadis by Arbour, Currie and, posthumously, the female Mongolian paleontologist Demchig Badamgarav. The generic name is derived from Mongolian zaraa, "hedgehog", in reference to the prickly appearance of ankylosaurs, and the Greek πέλτη, peltè, "small shield", a common component of ankylosaurian names in view of their body armour.
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The family Polacanthidae was named by George Reber Wieland in 1911 to refer to a group of ankylosaurs that seemed to him to be intermediate between the ankylosaurids and nodosaurids.G.R. Wieland, 1911, "Notes on the armored Dinosauria", The American Journal of Science, series 4 31: 112-124 This grouping was ignored by most researchers until the late 1990s, when it was used as a subfamily (Polacanthinae) by Kirkland for a natural group recovered by his 1998 analysis suggesting that Polacanthus, Gastonia, and Mymoorapelta were closely related within the family Ankylosauridae. Kenneth Carpenter resurrected the name Polacanthidae for a similar group that he also found to be closer to ankylosaurids than to nodosaurids. Carpenter became the first to define Polacanthidae as all dinosaurs closer to Gastonia than to either Edmontonia or Euoplocephalus.
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Diagram showing nasal chambers inside the snout (AMNH 5895) In 1977 the Polish paleontologist Teresa Maryańska proposed that the complex sinuses and nasal cavities of ankylosaurs may have lightened the weight of the skull, housed a nasal gland, or acted as a chamber for vocal resonance. Carpenter rejected these hypotheses, arguing that tetrapod animals make sounds through the larynx, not the nostrils, and that reduction in weight was minimal, as the spaces only accounted for a small percent of the skull volume. He also considered a gland unlikely and noted that the sinuses may not have had any specific function. It has also been suggested that the respiratory passages were used to perform a mammal-like treatment of inhaled air, based on the presence and arrangement of specialized bones.
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All ankylosaurs that possess these characteristics - a narrow predentary; a nearly horizontal quadrate that is not fused and is oriented 30 degrees from the skull roof; the presence of mandibular condyles that are three times wider than long; premaxillary and dentary teeth that are near a symphysis with the front of the lower jaw (the predentary); a sacrum arched on top; an acromion process above the midpoint of the scapula to coracoid attachment; a straight ischium with a straight dorsal margin; relatively long, slender limbs; sacral shield armour; and the presence of erect pelvic osteoderms with flat bases - form a clade of basal nodosaurids, the Struthiosaurinae. That set of cranial and postcranial features are only present on genera considered to be in the clade. The features above distinguish Struthiosaurinae from other clades and genera found by other analysis'.
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Skeletal mounts of the ankylosaur Scolosaurus This timeline of ankylosaur research is a chronological listing of events in the history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spikes and sometimes by a clubbed tail. Although formally trained scientists did not begin documenting ankylosaur fossils until the early 19th century, Native Americans had a long history of contact with these remains, which were generally interpreted through a mythological lens. The Delaware people have stories about smoking the bones of ancient monsters in a magic ritual to have wishes granted and ankylosaur fossils are among the local fossils that may have been used like this. The Native Americans of the modern southwestern United States tell stories about an armored monster named Yeitso that may have been influenced by local ankylosaur fossils.
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The lack of growth lines also means that the individual ages of the Kosmoceratops and Utahceratops specimens cannot be estimated, but Levitt determined that the examined Kosmoceratops specimens were subadult to adult, ruling out Fowler and colleagues' 2011 claim that they represented immature Vagaceratops. She also determined that the largest Kosmoceratops and Utahceratops were adults, and therefore ruled out that one was the juvenile of the other. In a 2017 Master's thesis, paleontologist Nicole Marie Ridgwell described two coprolites (fossilized dung) from the Kaiparowits Formation which, due to their size, may have been produced by a member of one of three herbivorous dinosaur groups known from the formation: ceratopsians (including Kosmoceratops), hadrosaurs, or ankylosaurs (rarest of the three groups). The coprolites contained fragments of angiosperm wood (which indicates a diet of woody browse); though there was previously little evidence of dinosaurs consuming angiosperms, these coprolites showed that dinosaurs adapted to feeding on them (they only became common in the Early Cretaceous, diversifying in the Late Cretaceous).
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The American paleontologist Kenneth Carpenter accepted the teeth as belonging to A. magniventris in 2004, and that all the specimens belonged to the same species, noting that the teeth of other ankylosaurs are highly variable. Replica of the 1964 World's Fair Ankylosaurus (note spikes and dragging tail), Royal Alberta Museum Most of the known Ankylosaurus specimens were not scientifically described at length, though several paleontologists planned to do so until Carpenter redescribed the genus in 2004. Carpenter noted that Ankylosaurus has become the archetypal member of its group, and the best-known ankylosaur in popular culture, perhaps due to a life-sized reconstruction of the animal being featured at the 1964 World's Fair in New York City. That sculpture, as well as the American artist Rudolph Zallinger's 1947 mural The Age of Reptiles and other later popular depictions, showed Ankylosaurus with a tail club, following the first discovery of this feature in 1910.
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Williston also stated that a skeletal reconstruction of the related Polacanthus by Hungarian paleontologist Franz Nopcsa was a better example of how ankylosaurs would have appeared in life. The claim of synonymy was not accepted by other researchers, and the two genera are now considered distinct. Brown had collected 77 osteoderms while excavating a Tyrannosaurus specimen in the Lance Formation of Wyoming in 1900. He mentioned these osteoderms (specimen AMNH 5866) in his description of Ankylosaurus but thought they belonged to the Tyrannosaurus instead. Paleontologist Henry Fairfield Osborn also expressed this view when he described the Tyrannosaurus specimen as the now synonymous genus Dynamosaurus in 1905. More recent examination has shown them to be similar to those of Ankylosaurus; it seems that Brown had compared them with some Euoplocephalus osteoderms, which had been erroneously cataloged as belonging to Ankylosaurus at the AMNH. Excavation of AMNH 5214 (center, above the pick), 1910 In 1910 another AMNH expedition led by Brown discovered an Ankylosaurus specimen (AMNH 5214) in the Scollard Formation by the Red Deer River in Alberta, Canada.
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