Stegosaurs were known for sporting diamond-shaped plates, which marched across their backs.
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Dinosaur fans can also check out the Tyrannosaurus rex and stegosaurs when they come to visit.
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The research team analyzed the fossils in order to determine how it compares with other stegosaurs.
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The tracks also represent the only evidence that a type of armored dinosaur called stegosaurs lived in Australia.
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For the first time, researchers traced dinosaur footprints along the island's northeastern coast and discovered that stegosaurs were part of this community.
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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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And finding stegosaurs in Scotland from this time period places these footprints among the oldest in the known fossil record for the dinosaur group.
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"Most stegosaurs we know of, including the Natural History Museum's Sophie, the most complete stegosaur discovered, have been found in Laurasian rock formations," Maidment said.
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In addition to finding a freakishly large footprint, the team discovered five different types of predatory dinosaur tracks, six types of tracks from armored dinosaurs, and the first evidence of stegosaurs ever found in Australia.
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The lives of great artists and thinkers and statesmen are like the lives of the great extinct species, the tyrannosaurs and stegosaurs, while the lives of the obscure can be likened to extinct species of beetles.
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The most intriguing tracks appear to have been made by an early member of a group of heavily built, four-legged plant-eaters called stegosaurs that boasted large bony plates along the neck and back, and wielded a menacing spiked tail.
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"Despite being from the African continent our phylogenetic analysis indicated that, surprisingly, Adratiklit is more closely related to European stegosaurs than it is to the two genera known from southern Africa," said Tom Raven, study co-author and PhD student at the museum.
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This is a shame, because the Middle Jurassic was a critical time in dinosaur evolution, an era that witnessed the emergence of the earliest meat-eating tyrannosaurs, the spread and diversification of plate-backed stegosaurs, the introduction of the first birds, and the rise of the long-necked, four-legged sauropods.
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Unlike in all other stegosaurs except Stegosaurus, the prezygapophysis faces dorsally.
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Thyreophora is characterized by body armor and includes stegosaurs, ankylosaurs, Scelidosaurus, and Scutellosaurus.
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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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Stegosaurs are easily recognised by the prominent row of plates above the spine and long spines on the tail. Most stegosaurs, but not Stegosaurus, also have a spine over each shoulder. These spines and plates have evolved from the earlier surface scutes. Huayangosaurus is the oldest and most primitive known stegosaur.
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Stegosaurs were apparently rare (e.g. Regnosaurus northamptoni). Theropods like Concavenator and Baryonyx may have existed alongside it as well.
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The suborder Stegosauria comprises Stegosauridae and Huayangosauridae. These dinosaurs lived mostly from the Middle to Late Jurassic, although some fossils have been found in the Cretaceous. Stegosaurs had very small heads with simple, leaf-like teeth. Stegosaurs possessed rows of plates and/or spikes running down the dorsal midline and elongated dorsal vertebra.
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Like all stegosaurs, Chungkingosaurus was a herbivore. Chungkingosaurus is thought to have coexisted with large plant-eaters and stegosaurids such as Chialingosaurus, Tuojiangosaurus, Mamenchisaurus, and Omeisaurus. It may have also been preyed upon by theropods such as Yangchuanosaurus.
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Dong, Z., 1990, "Stegosaurs of Asia", In: Carpenter, K. and Currie J. (eds.). Dinosaur Systematics. Cambridge: Cambridge University Press. pp 255-268 The holotype, IVPP V 6975, was found in a layer of the Lura Formation dating from the latest Jurassic.
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Maidment has published more than 30 scientific papers, primarily focused on the systematics, evolution and palaeobiology of ornithischian dinosaurs. She has worked extensively on stegosaurs, and is considered the world leader on this group. Her contributions have included overall revisions of the systematics of the group, the description of the Portuguese stegosaur Miragaia, the description of the oldest known stegosaur, Adratiklit, from the Middle Jurassic of Morocco, anatomical and systematic revisions of Chinese stegosaurs, and work on the postcranial skeleton and body mass of Stegosaurus. She has also published several papers on locomotion and the evolution of quadrupedality in ornithischian 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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Priodontognathus (meaning "saw tooth jaw") was a genus of ankylosaurian dinosaur possibly from the Oxfordian-age Upper Jurassic Lower Calcareous Grit of Yorkshire, England. It is a dubious genus based on a maxilla, and has been erroneously mixed up with iguanodonts and stegosaurs.
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It has been suggested that stegosaur plates functioned in control of body temperature (thermoregulation) and/or were used as a display to identify members of a species, as well as to attract mates and intimidate rivals. Well known stegosaurs are Stegosaurus and Kentrosaurus.
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According to Dong e.a. the Chungkingosaurus jiangbeiensis holotype was one of the smallest stegosaurs with a length of less than four metres, even though it was apparently an adult, judging by the ossification of the sacrum. Chungkingosaurus sp. 1 was estimated at five metres; Chungkingosaurus sp.
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Adratiklit is a basal stegosaurian. It is more closely related to the European stegosaurs Dacentrurus and Miragaia than it is to the southern African taxa Kentrosaurus and Paranthodon. This places it in the subfamily Dacentrurinae, which was previously thought to be confined only to the Late Jurassic of Europe.
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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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"Siamodracon" is an extinct genus of invalid stegosaurid dinosaur known from a single dorsal vertebra found in Thailand's Phu Kradung Formation. According to Galton and Carpenter (2016) it did not meet the requirements of the International Code of Zoological Nomenclature.Ulansky, R. E., 2014. Evolution of the stegosaurs (Dinosauria; Ornithischia).
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Lusotitan lived alongside species of the predatory theropods Allosaurus (A. europaeus), Ceratosaurus, Lourinhanosaurus, and Torvosaurus, the ankylosaurian Dracopelta, the sauropods Supersaurus, Lourinhasaurus, and Zby, and the stegosaurs Dacentrurus and Miragaia.Octávio Mateus. Late Jurassic dinosaurs from the Morrison Formation (USA) included the Lourinhã and Alcobaça Formations (Portugal), and the Tendaguru Beds (Tanzania).
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The posterior maxilla is incomplete so no information is known about the jugal or lacrimal contact. Paranthodon has an elongate, dorsally convex nasal, like in most other stegosaurs. There are thickened ridges along the sides of the nasals. The preserved portion of the nasal does not contact the premaxilla or maxilla.
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Stegosaurian tracks were first recognized in 1996 from a hindprint-only trackway discovered at the Cleveland-Lloyd quarry, which is located near Price, Utah."Walk and Don't Look Back: The Footprints; Stegosaurs" in Foster, J. (2007). Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. pg.
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"Two Lower Cretaceous dinosaurs of Mongolia." American Museum Novitates, 95: 1–10. In the Linnaean classification system, the group is usually considered either a suborder or an infraorder. It is contained within the group Thyreophora, which also includes the stegosaurs, armored dinosaurs known for their combination of plates and spikes.
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Z. Dong. (1990). "Stegosaurs of Asia". In: K. Carpenter and P. J. Currie (eds.), Dinosaur Systematics: Perspectives and Approaches, Cambridge University Press, Cambridge pp. 255-268 Later still, in 1996, Spencer Lucas reclassified Tatisaurus oehleri as a species of Scelidosaurus, S. oehleri, in order to use Scelidosaurus for a biochron.
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Stegopodus was a new ichnogenus erected in 1998 for the second set of stegosaur tracks from the Morrison Formation. The tracks were found near Arches National Park, also in Utah."Walk and Don't Look Back: The Footprints; Stegosaurs" Foster (2007) pg. 238 Unlike the first, this trackway preserved traces of the forefeet.
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Thyreophora includes various subgroups, including the suborders Ankylosauria and Stegosauria. In both the suborders, the forelimbs were much shorter than the hindlimbs, particularly in stegosaurs. The clade has been defined as the group consisting of all species more closely related to Ankylosaurus than to Triceratops. Thyreophora is the sister group of Cerapoda within Genasauria.
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The herbivorous ornithischian dinosaurs were diverse but not as common as sauropods in the Morrison. Fruitadens, previously known as the "Fruita Echinodon", was found to be a heterodontosaurid. Plate-backed stegosaurids included Hesperosaurus mjosi, Stegosaurus armatus, S. ungulatus, S. stenops, and Alcovasaurus longispinus. Armored dinosaurs that weren't stegosaurs were unknown in the formation until the 1990s.
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Tizi-n-Aït tracksite is a fossil trackway location in Morocco in the Azilal province. It is Jurassic (Pliensbachian, 189.6 - 183.0 Ma) in age, with tracks attributed to sauropods or stegosaurs, and an unidentified carnosaur. The tracksite is part of the Aganane Formation and the tracks are located at base of formation.J. Jenny and J.-A. Jossen. (1982).
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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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These new branches on the dinosaur family tree led to well-known dinosaur groups, such as the horned ceratopsians, armoured stegosaurs, and tyrannosaurs. Clark joined Xu, from Beijing’s Institute of Vertebrate Paleontology and Paleoanthropology, to explore the Junggar Basin, and in particular the Shishugou Formation, where the exposed rocks have been linked to the Middle Jurassic.
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Among the theropods, Allosaurus, Saurophaganax, Torvosaurus, Ceratosaurus, Coelurus, Ornitholestes, Tanycolagreus, Stokesosaurus, and Marshosaurus are found in the Morrison. An abundance of sauropods has been found there, including Apatosaurus, Diplodocus, Barosaurus, Brachiosaurus, Camarasaurus, Brontosaurus and Amphicoelias. Three genera of stegosaurs, Alcovasaurus, Stegosaurus and Hesperosaurus, have been found there. Finally, ornithopods found in the Morrison include Dryosaurus, Camptosaurus, Drinker, Othnielia, and Othnielosaurus.
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The skin of ceratopsians consisted of large polygonal scales, sometimes with scattered circular plates. See also image at "Mummified" remains and skin impressions of hadrosaurids reveal pebbly scales. It is unlikely that the ankylosaurids, such as Euoplocephalus, had insulation, as most of their surface area was covered in bony knobs and plates. Likewise there is no evidence of insulation in the stegosaurs.
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Cambridge, Cambridge University Press, 1999; p. 95. (At the time in question, c. 116–117 Ma, India was located in the southern Indian Ocean; plate tectonics had not yet moved the Indian landmass into its present position.) Note that the stegosaur group of dinosaurs went extinct around this time. Wuerhosaurus, probably the last of the stegosaurs, lived during this time.
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Dacentrurus and Miragaia were both stegosaurs, while Dracopelta was an ankylosaurian. Draconyx was an iguanodontid related to Camptosaurus. Due to the marine nature of the Lourinhã Formation, sharks, plesiochelyid turtles, and teleosaurid crocodyliforms are also present.OCTÁVIO MATEUS LATE JURASSIC DINOSAURS FROM THE MORRISON FORMATION (USA), THE LOURINHÃ AND ALCOBAÇA FORMATIONS (PORTUGAL), AND THE TENDAGURU BEDS (TANZANIA): A COMPARISON Foster, J.R. and Lucas, S. G. R.M., eds.
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Paleontologists now regard dinosaurs as being very intelligent for reptiles, but generally not as smart as their avian descendants. Some have speculated that if the Cretaceous–Paleogene extinction event had not occurred, the more intelligent forms of small theropods might have eventually evolved human-like levels of intelligence. Popular misconceptions of dinosaur neurology include the concept of a second brain in the pelvis of stegosaurs and sauropods.
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Stegosaurids exhibit the characteristic dorsal osteoderms, found in all stegosaurs, in the form of erect plates and spines. Stegosaurid plates have a thick base and central portion, but are transversely thin elsewhere. The plates become remarkably large and thin in Stegosaurus. They are found in varying sizes along the dorsum, with the central region of the back usually having the largest and tallest plates.
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This new taxon originally included all armored dinosaurs. 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. From the time of their earliest description, the chief mystery surrounding stegosaurs was the function of their distinctive back plates. Marsh originally interpreted them as being plates of armor that would protect against predators.
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Like in Huayangosaurus but not Stegosaurus or Hesperosaurus, the nasal fenestra faces anterolaterally, being visible from the front and sides. The naris is longer than wide like in other stegosaurs, and also has a smooth internal surface, so it was most likely a simple passage. The maxilla is roughly triangular, as in most other thyreophorans. The tooth row is horizontal in lateral view, and in ventral view it is sinuous.
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Chialingosaurus (meaning "Chialing Lizard") is a genus of herbivorous stegosaurian dinosaur similar to Kentrosaurus from the Upper Shaximiao Formation, Late Jurassic beds in Sichuan Province in China. Its age makes it one of the oldest species of stegosaurs, living about 160 million years ago. Since it was an herbivore, scientists think that Chialingosaurus probably ate ferns and cycads, which were plentiful during the period when Chialingosaurus was alive.
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Holotype mount from the front Paul (1988) noted that Elaphrosaurus bambergi was too small to prey on the sauropods and stegosaurs present in its paleoenvironment, and instead, it likely hunted the small and swift ornithopod herbivores. However, newer studies support the idea that Elaphrosaurus was a herbivore or omnivore, owing to its close relation with Limusaurus and a neck which is much less flexible than those characteristic of carnivorous theropods.
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"Saldamosaurus" is an informal genus of stegosaurid dinosaur known from a complete braincase discovered in the Early Cretaceous Saldam Formation of Siberia, Russia. The type species, "Saldamosaurus tuvensis", was named in 2014 but according to Galton and Carpenter (2016) it did not meet the requirements of the International Code of Zoological Nomenclature and is hence a nomen nudum,.Ulansky, R. E., 2014. Evolution of the stegosaurs (Dinosauria; Ornithischia).
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Stegosaur tracks were first recognized in 1996 from a hindprint-only trackway discovered at the Clevland-Lloyd quarry, which is located near Price, Utah."Walk and Don't Look Back: The Footprints; Stegosaurs" Foster (2007) pg. 238 Two years later, a new ichnogenus called Stegopodus was erected for another set of stegosaur tracks which were found near Arches National Park, also in Utah. Unlike the first, this trackway preserved traces of the forefeet.
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Fossil remains indicate that stegosaurs have five digits on the forefeet and three weight-bearing digits on the hind feet. From this, scientists were able to successfully predict the appearance of stegosaur tracks in 1990, six years in advance of the first actual discovery of Morrison stegosaur tracks. Since the erection of Stegopodus, more trackways have been found, however none have preserved traces of the front feet, and stegosaur traces remain rare.
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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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Fossil remains indicate that stegosaurs have five digits on the forefeet and three weight-bearing digits on the hind feet. From this, paleontologists were able to successfully predict the appearance of stegosaur tracks in 1990, six years in advance of the first actual discovery of Morrison stegosaur tracks. Since the erection of Stegopodus, more trackways have been found, however none have preserved traces of the front feet, and stegosaur traces remain rare.
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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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Hesperosaurus (meaning "western lizard", from Classical Greek ἕσπερος (') "western" and σαυρος (') "lizard") is an herbivorous stegosaurian dinosaur from the Kimmeridgian epoch of the Jurassic period, approximately 156 million years ago. Fossils of Hesperosaurus have since 1985 been found in the state of Wyoming and Montana in the United States of America. The type species Hesperosaurus mjosi was named in 2001. It is from an older part of the Morrison Formation, and so a little older than other Morrison stegosaurs.
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Known vertebra fragments, compared to a complete Stegosaurus dorsal vertebra (F) Thirteen teeth are preserved in Paranthodon, but as they extend to the back of the maxilla there were possibly more in life. The teeth are symmetrical as in stegosaurs except Chungkingosaurus. Along the base of the tooth crown there is a swelling (cingulum), which is seen in all other known stegosaurid teeth except Huayangosaurus. The teeth have a middle ridge, with five fewer prominent ridges on either side.
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The Mugher locality is approximately 151 million years old, about 14 million older than has previously been suggested for Paranthodon, as well as across both southern and eastern Africa. The fauna in the Mugher locality differ from elsewhere of the same time and place in Africa. While the Tendaguru has abundant stegosaurs, sauropods, ornithopods and theropods, the Mugher Mudstone preserves the stegosaur Paranthodon, a hypsilophodontid ornithopod, a probable sauropod, and theropods related to Allosauridae and Dromaeosauridae.
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Mamenchisaurus and Chialingosaurus in environment Yang in 1959 provided a diagnosis, emphasising the slender build of the animal. It might have been only four metres (thirteen feet) long. However, the gracile proportions may have been caused by the subadult age and the remainder of the diagnostic traits were in fact shared by other stegosaurs. In 1990, Peter Malcolm Galton identified just a single autapomorphy: the lesser trochanter of the thighbone is triangular with a broad base.
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Among stegosaurids, only Kentrosaurus has been found with parascapular spines, which project posteriorly out of the lower part of the shoulder plates. These spines are long, rounded and comma-shaped in lateral view and have an enlarged base. Loricatosaurus was also believed to have a parascapular spine, but Maidment et al. (2008) observed that the discovered specimen, from which the spine is described, has a completely different morphology than the parascapular spine specimens of other stegosaurs.
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The jugal is triradiate and the anterior process of the jugal forms the posteroventral corner of the antorbital fossa and surpasses anteriorly the base of the lacrimal, a feature seen in basal thyreophorans and stegosaurs. The dorsal process of the jugal is proportionally long. The quadratojugal is very broad and the premaxilla is incompletely preserved while the post-cranial material is as-yet-undescribed at present. The dentition is heterodont, with six premaxillary teeth and thirty maxillary teeth.
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Great quantities of rubble were excavated to uncover the bones, which lay about below the surface. These included the well-preserved skeletons of two stegosaurs, an armor-plated dinosaur. Ol Doinyo Lengai, which Reck climbed in 1913 Reck found an early Iron Age site at Engaruka, where a stream from the Ngorongoro hills plunges down the western wall of the Gregory Rift at a point between Lake Natron and Lake Manyara, and published a description in 1913.
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Yangchuanosaurus is an extinct genus of metriacanthosaurid theropod dinosaur that lived in China from the Middle to Late Jurassic periods (Bathonian to Oxfordian stages), and was similar in size and appearance to its North American and European relative, Allosaurus. Yangchuanosaurus hails from the Upper Shaximiao Formation and was the largest predator in a landscape that included the sauropods Mamenchisaurus and Omeisaurus and the stegosaurs Chialingosaurus, Tuojiangosaurus and Chungkingosaurus. This theropod was named after the area in which was discovered, Yongchuan, in China.
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Since the pattern of plates and spines vary between species, he suggested it could be important for intraspecific recognition and as a display for sexual selection. This is corroborated by Spassov's (1982) observations that the plates are arranged for maximum visible effect when viewed laterally during non-aggressive agonistic behaviour, as opposed to from a head-on aggressive stance.Spassov, N. B. (1982). The ‘‘bizarre’’ dorsal plates of stegosaurs: ethological approach. Comptes rendus de l’academie bulgare des Sciences, 35, 367–370.
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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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Adratiklit is an extinct genus of herbivorous stegosaurian dinosaur that lived in the supercontinent Gondwana during the Middle Jurassic Period. The type and only known species is Adratiklit boulahfa. Its remains were found in the El Mers Group, probably in the El Mers II Formation (Bathonian), near Boulahfa, south of Boulemane, Fès-Meknes, Morocco. Eurypodan dinosaurs, in particular stegosaurs, were during the Jurassic diverse and abundant in Laurasia (nowadays the northern continents), but their remains are extremely rare in deposits of Gondwana, nowadays the southern continents.
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Lower jaw A study by Maidment indicated that Gigantspinosaurus is the most basal known member of the Stegosauria. Peng and colleagues, however, placed it in the Huayangosaurinae. A 2018 redescription by Hao et al clarified aspects of the anatomy and found that it was an intermediate basal stegosaur, sharing basal traits with huayangosaurines as well as somewhat more advanced traits with other stegosaurs. Nevertheless, this analysis found that it was not the most basal stegosaur, as the huayangosaurids Chungkingosaurus and Huayangosaurus were considered more basal.
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The Cretaceous fauna of India is well attested in both Coniacian and Maastrichtian aged sites such as the Lameta Formation. Generally speaking, the local dinosaurian and crocodilian fauna is almost identical to that of Madagascar, with clades like abelisaurids, titanosaurs, noasaurids and notosuchians being well represented here. A possible deviation is the presence of stegosaurs, the last remaining members of this lineage;Peter M. Galton; Krishnan Ayyasami (2017). "Purported latest bone of a plated dinosaur (Ornithischia: Stegosauria), a "dermal plate" from the Maastrichtian (Upper Cretaceous) of southern India".
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Terrestrial environment of the Toarcian of Łęczna (Ciechocinek Formation, Lublin, Poland), based on the Bogdanka Coal Mine Flora. Dinosaurs are based on material found on various locations of the formation On land, a number of new types of dinosaurs—the heterodontosaurids, scelidosaurs, stegosaurs, and tetanurans—appeared, and joined those groups like the coelophysoids, prosauropods and the sauropods that had continued over from the Triassic. Accompanying them as small carnivores were the sphenosuchian and protosuchid crocodilians. In the air, new types of pterosaurs replaced those that had died out at the end of the Triassic.
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Kentrosaurus ( ) is a genus of stegosaurian dinosaur from the Late Jurassic of Tanzania. The type species is K. aethiopicus, named and described by German palaeontologist Edwin Hennig in 1915. Often thought to be a "primitive" member of the Stegosauria, several recent cladistic analyses find it as more derived than many other stegosaurs, and a close relative of Stegosaurus from the North American Morrison Formation within the Stegosauridae. Fossils of K. aethiopicus have been found only in the Tendaguru Formation, dated to the late Kimmeridgian and early Tithonian ages, about 152 million years ago.
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Skeletal mount of Stegosaurus. This timeline of stegosaur research is a chronological listing of events in the history of paleontology focused on the stegosaurs, the iconic plate-backed, spike-tailed herbivorous eurypod dinosaurs that predominated during the Jurassic period. The first scientifically documented stegosaur remains were recovered from Early Cretaceous strata in England during the mid-19th century. However, they would not be recognized as a distinct group of dinosaurs until Othniel Charles Marsh described the new genus and species Stegosaurus armatus in 1877, which he regarded as the founding member of the Stegosauria.
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Lungfish, triconodont mammals, and several species of turtles lived in the Cloverly, while crocodilians prowled the rivers, lakes, and swamps, providing evidence of a year-round warm climate. The Late Jurassic fauna dominated by allosauroids, stegosaurs, and many varieties of huge sauropods gave way by Cloverly times to an Early Cretaceous fauna in which dromaeosaurs, ornithopods, and nodosaurs like Sauropelta were predominant. After the Cloverly ended, a large wave of Asian animals, including tyrannosaurids, ceratopsians, and ankylosaurids would disperse into western North America, forming the mixed fauna seen throughout the Late Cretaceous.
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The flora during this time-period was dominated by seasonal small, fast-growing herbaceous plants, which stegosaurids could consume easily if Reichel's reconstruction is accurate. Mallison (2010) suggested that Kentrosaurus may have used a tripodal stance on their hindlimbs and tail to double the foraging height from the general low browsing height under one metre for stegosaurids. This challenged the view that stegosaurs are primarily low vegetation feeders because of their small heads, short necks and short forelimbs, since the tripodal stance would also give them access to young trees and high bushes.
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Compared to other Morrison theropods, Ceratosaurus showed taller neural spines on the foremost tail vertebrae, which were vertical rather than inclined towards the back. Together with the deep chevron bones on the underside of the tail, they indicate a deep, "crocodile-like" tail possibly adapted for swimming. On the contrary, allosaurids feature a shorter, taller, and stiffer body with longer legs. They would have been adapted for rapid running in open terrain and for preying upon large herbivorous dinosaurs such as sauropods and stegosaurs, but as speculated by Bakker and Bir, seasonally switched to aquatic prey items when the large herbivores were absent.
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Ribs and pelvic elements. The left rib fragment shows a healed fracture at the underside of the base of the capitulum. Work from the 1800s drawn by J. Erxleben Living in what is now Europe, during the Jurassic Period (~201 to ~145 million years ago), Megalosaurus may have hunted stegosaurs and sauropods. Repeated descriptions during the nineteenth and early twentieth century of Megalosaurus hunting Iguanodon (another of the earliest dinosaurs named) through the forests that then covered the continent are now known to be inaccurate, because Iguanodon skeletons are found in much younger Early Cretaceous formations.
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An entirely different suggestion was made by John Ostrom who surmised it might have been a sauropod. The first to state that it was a stegosaurian in the modern sense was George Olshevsky in 1993.Olshevsky, G., and Ford, T.L., 1993, "The origin and evolution of the stegosaurs", Gakken Mook, Dinosaur Frontline, 4: 65-103 This was confirmed by Paul Barrett and Paul Upchurch in 1995 who concluded that it is a stegosaur similar to Huayangosaurus, as the jaws are very similar. As the remains are so limited, many recent researchers have concluded Regnosaurus to be a nomen dubium.
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Whether or not this is the case, Sinraptor and Yangchuanosaurus were close relatives, and are classified together in the family Metriacanthosauridae. Holtz estimated it to be 8.8 meters (29 feet) in length. In 2016 other authors stated that the holotype (IVPP 10600) was a subadult and estimated the size of the probable adult specimen (IVPP 15310) at 11.5 meters (37.7 feet) and 3.9 tonnes (4.3 short tons). The dentition of Sinraptor was very similar to that of Allosaurus and indicated that it likely would have preyed upon medium-sized dinosaurs such as stegosaurs by using its blade-like teeth to inflict massive, fatal wounds.
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Lambe was sympathetic to this idea of a new type of "unicorn dinosaur" in a 1903 review of Nopscsa's paper. At this time, there was still uncertainty over which group of dinosaur Stegoceras belonged to, with both ceratopsians (horned dinosaurs) and stegosaurs (plated dinosaurs) as contenders. Hatcher doubted whether the Stegoceras specimens belonged to the same species and whether they were dinosaurs at all, and suggested the domes consisted of the frontal, occipital, and parietal bones of the skull. In 1918, Lambe referred another dome (CMN 138) to S. validus, and named a new species, S. brevis, based on specimen CMN 1423 (which he originally included in S. validus).
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Ampelosaurus, a titanosaur with osteoderms, depicted with the osteoderms arranged in a pair of rows Some titanosaurs had osteoderms. Osteoderms were first confirmed in the genus Saltasaurus but are now known to have been present in a variety of titanosaurs within the clade Lithostrotia. The exact arrangement of osteoderms on the body of a titanosaur is not known, but some paleontologists consider it likely that the osteoderms were arranged in two parallel rows on the animal's back, an arrangement similar to the plates of stegosaurs. Several other arrangements have been proposed, such as a single row along the midline, and it is possible that different species had different arrangements.
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Its diet would have consisted of ferns or conifers, as grasses did not evolve until late into the Cretaceous Period, after Scelidosaurus was long extinct. Another similarity with the stegosaurs is the narrow head, which might indicate a selective diet consisting of high- quality fodder. However, Barrett pointed out that for an animal the size of Scelidosaurus, with a large gut allowing efficient fermentation, the intake of easily digestible food of high energetic value was less important than with smaller animals, that are often critically dependent on it. Norman concluded that Scelidosaurus fed on low scrubby vegetation, with a height up to one metre.
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Dong is considered an instrumental part of the reason that China has such an array of known stegosaurid species. In the 2012 textbook The Complete Dinosaur (co- authored by researchers M. K. Brett-Surman, Thomas R. Holtz Jr., and James O. Farrow), Dong and his mentor Yang Zhongjian are praised for their efforts to advance palaeontology's understanding of stegosaurids: > Although the fossil record of stegosaurs for most of Asia is very > fragmentary (Averianov et al. 2007; Maidment 2010), that of the People's > Republic of China is the longest and most diverse (see Dong 1990, 1992; > Olshevsky and Ford 1993; Galton and Upchurch 2004; Maidment et al. 2008; > Maidment 2010).
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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.
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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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Public awareness of this animal was increased in early 2006 when Tracy Ford, considering it a validly established taxon, published a short article on reconstructing it. Ford suggested that earlier reconstructions of Gigantspinosaurus attached the shoulder spines upside-down, and his new reconstruction shows the spine extending somewhat upwards, ending higher than the top of the animal's back. Susannah Maidment and Wei Guangbiao in 2006 concluded that G. sichuanensis was a valid taxon in their review of Late Jurassic Chinese stegosaurs, but did not redescribe it because at that time it was under study by Zigong Dinosaur Museum staff. In fact, a Chinese redescription by Peng Guangzhao and colleagues in 2005 would predate Maidment's publication.
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The museum is open all year round and hosts a gallery with more than 50 mounted skeletons, including a full mount of Supersaurus vivianae excavated from a quarry near Douglas, Wyoming. The replica skeleton on display is 106 feet long and is the first mount based on data from the second and most complete Supersaurus ever found affectionately named "Jimbo" (WDC DMJ-001) which was donated to the museum in 2003. Other dinosaurs present include a T rex, Triceratops, Medusaceratops as well as various Hadrosaurs, Stegosaurs and Allosaurs. One of the newest members to the museum is the almost 90% complete, composite skeleton of a Camarasaurus found on the property by staff and visitors, excavated over the past 20 years.
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Because of the poor state of preservation of the Cetiosauriscus leedsi fossil, Charig sent a petition to the International Commission on Zoological Nomenclature to instead make C. stewarti the type species. Cetiosauriscus stewarti became the oldest confirmed diplodocid until a phylogenetic analysis published in 2003 instead found the species to belong to Mamenchisauridae, and followed by studies in 2005 and 2015 that found it outside Neosauropoda, while not a mamenchisaurid proper. Cetiosauriscus was found in the marine deposits of the Oxford Clay Formation alongside many different invertebrate groups, marine ichthyosaurs, plesiosaurs and crocodylians, a single pterosaur, and various dinosaurs: the ankylosaur Sarcolestes, the stegosaurs Lexovisaurus and Loricatosaurus, the ornithopod Callovosaurus, as well as some unnamed taxa. The theropods Eustreptospondylus and Metriacanthosaurus are known from the formation, although probably not from the same level as Cetiosauriscus.
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Hennig and Janensch, while grouping the dermal armour elements into four distinct types, recognised an apparently continuous change of shape among them, shorter and flatter plates at the front gradually merging into longer and more pointed spikes towards the rear, suggesting an uninterrupted distribution along the entire body, in fifteen pairs. Because each type of osteoderm was found in mirrored left and right versions, it seems probable that all types of osteoderms were distributed in two rows along the back of the animal, a marked contrast to the better-known North American Stegosaurus, which had one row of plates on the neck, trunk and tail, and two rows of spikes on the tail tip. There is one type of spike that differs from all others in being strongly, and not only slightly, asymmetrical, and having a very broad base. Because of bone morphology classic reconstructions placed it on the hips, at the iliac blade, while many recent reconstructions place it on the shoulder, because a similarly shaped spike is known to have existed on the shoulder in the Chinese stegosaurs Gigantspinosaurus and Huayangosaurus.
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