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However, new discoveries and reexamination of existing Stegosaurus specimens since the 1970s suggest that the plates alternated along the backbone, as no two plates from the same animal have exactly the same shape or size. [97], The Morrison Formation is interpreted as a semiarid environment with distinct wet and dry seasons, and flat floodplains. Stegosaurus remains were first identified during the "Bone Wars" by Othniel Charles Marsh at Dinosaur Ridge National Landmark. Despite its popularity in books and film, mounted skeletons of Stegosaurus did not become a staple of major natural history museums until the mid-20th century, and many museums have had to assemble composite displays from several different specimens due to a lack of complete skeletons. The Stegosaurus, an armored dinosaur with bony plates running along its backbone and ending in a giant spiked tail, had large space at the end of the spinal cord. He led the construction of the first ever Stegosaurus skeletal mount at the Peabody Museum of Natural History, which was depicted with paired plates. Carnotaurus. There were flat floodplains, savannas dominated by ferns and the occasional tree, and forests. [28] Christiansen and Tschopp (2010) proposed that the display function would have been reinforced by the horny sheath which would have increased the visible surface and such horn structures are often brightly colored. Also, the pelvic region of the specimens are similar to Kentrosaurus juveniles. [35], The long and narrow skull was small in proportion to the body. Updates? Some theories suggest that the large plates on their back could change color as a mating display or to attract a female. They advocated synonymizing S.stenops and S.ungulatus with S.armatus, and sinking Hesperosaurus and Wuerhosaurus into Stegosaurus, with their type species becoming Stegosaurus mjosi and Stegosaurus homheni, respectively. Introduction to the Study of Dinosaurs. Brinkman, P. D. (2010). [102], Stegosaurus made its major public debut as a paper mache model commissioned by the U.S. National Museum of Natural History for the 1904 Louisiana Purchase Exposition. Feathers are what distinguishes birds from other existing lifeforms; but they're also what connects them to the creatures of yore. In it, the researchers claimed that Tyrannosaurus and its relatives, collectively known as Tyrannosaurids, did not have feathers. The phalangeal formula is 2-2-2-2-1, meaning the innermost finger of the fore limb has two bones, the next has two, etc. [74] A 2015 study of the shapes and sizes of Hesperosaurus plates suggested that they were sexually dimorphic, with wide plates belonging to males and taller plates belonging to females. [45], Like the spikes and shields of ankylosaurs, the bony plates and spines of stegosaurians evolved from the low-keeled osteoderms characteristic of basal thyreophorans. S. stenops reached 6.5m (21.3ft) in length and 3.5 metric tons (3.9 short tons) in body mass, while S. ungulatus reached 7m (23.0ft) in length and 3.8 metric tons (4.2 short tons) in body mass. When it lived: Late Jurassic, 155-145 million years ago. [2], The next species of Stegosaurus to be named was S. marshi by Frederick Lucas in 1901. . Due to their distinctive combination of broad, upright plates and tail tipped with spikes, Stegosaurus is one of the most recognizable kinds of dinosaurs. The bony plates on Stegosaurus's back were set . This covering of spikes might have been based on a misinterpretation of the teeth, which Marsh had noted were oddly shaped, cylindrical, and found scattered, such that he thought they might turn out to be small dermal spines. If anything has feathers, it's connected to the bone and forms quill knobs. [72], As the plates would have been obstacles during copulation, it is possible the female stegosaur laid on her side as the male entered her from above and behind. 233248. Furthermore, within the hind limbs, the lower section (comprising the tibia and fibula) was short compared with the femur. [22] However, this classification scheme was not followed by other researchers, and a 2017 cladistic analysis co-authored by Maidment with Thomas Raven rejects the synonymy of Hesperosaurus with Stegosaurus. 2. What might the plates of Stegosaurus have been used for. 7-8 meters. [2] Because of this, the International Code of Zoological Nomenclature decided to replace the type species with the more well known species Stegosaurus stenops. Many dinosaurs may have been covered in elaborate feathers similar to those of modern-day birds, according to a study of new fossils. [39] Their teeth were "not tightly pressed together in a block for efficient grinding",[93] and no evidence in the fossil record of stegosaurians indicates use of gastrolithsthe stone(s) some dinosaurs (and some present-day bird species) ingestedto aid the grinding process, so how exactly Stegosaurus obtained and processed the amount of plant material required to sustain its size remains "poorly understood". . The Stegosaurus is another famous dinosaur species that has captivated our imagination. Scant evidence in the fossil record has never been definitive - until now, scientists say. Paleontology and Geology of the Upper Jurassic Morrison Formation. Two pairs of pointed bony spikes were present on the end of the tail. There were three different species of Stegosaurus, but all were relatively similar looking. "Appendix." These variations cast doubt on the hypothesis of a strong thermoregulatory function for the plates of Stegosaurus, because such structures were not optimized in all stegosaurs for collecting or releasing heat. So there's about just as much time between us and T. rex as there is between T. rex and Stegosaurus, so they never would have met each other. [7][2] Stegosaurus sulcatus most notably preserves a large spike that has been speculated to have been a shoulder spike that is used to diagnose the species. [51] in 2017, Raven and Maidment published a new phylogenetic analysis, including almost every known stegosaurian genus:[52][53].mw-parser-output table.clade{border-spacing:0;margin:0;font-size:100%;line-height:100%;border-collapse:separate;width:auto}.mw-parser-output table.clade table.clade{width:100%;line-height:inherit}.mw-parser-output table.clade td.clade-label{min-width:0.2em;width:0.1em;padding:0 0.15em;vertical-align:bottom;text-align:center;border-left:1px solid;border-bottom:1px solid;white-space:nowrap}.mw-parser-output table.clade td.clade-label::before,.mw-parser-output table.clade td.clade-slabel::before{content:"\2060 "}.mw-parser-output table.clade td.clade-fixed-width{overflow:hidden;text-overflow:ellipsis}.mw-parser-output table.clade td.clade-fixed-width:hover{overflow:visible}.mw-parser-output table.clade td.clade-label.first{border-left:none;border-right:none}.mw-parser-output table.clade td.clade-label.reverse{border-left:none;border-right:1px solid}.mw-parser-output table.clade td.clade-slabel{padding:0 0.15em;vertical-align:top;text-align:center;border-left:1px solid;white-space:nowrap}.mw-parser-output table.clade td.clade-slabel:hover{overflow:visible}.mw-parser-output table.clade td.clade-slabel.last{border-left:none;border-right:none}.mw-parser-output table.clade td.clade-slabel.reverse{border-left:none;border-right:1px solid}.mw-parser-output table.clade td.clade-bar{vertical-align:middle;text-align:left;padding:0 0.5em;position:relative}.mw-parser-output table.clade td.clade-bar.reverse{text-align:right;position:relative}.mw-parser-output table.clade td.clade-leaf{border:0;padding:0;text-align:left}.mw-parser-output table.clade td.clade-leafR{border:0;padding:0;text-align:right}.mw-parser-output table.clade td.clade-leaf.reverse{text-align:right}.mw-parser-output table.clade:hover span.linkA{background-color:yellow}.mw-parser-output table.clade:hover span.linkB{background-color:green}, Many of the species initially described have since been considered to be invalid or synonymous with earlier named species,[5] leaving two well-known and one poorly known species. Of the species that have been classified in the upper Morrison Formation of the western US, only three are universally recognized: S. stenops, S. ungulatus and S. sulcatus. . Oxford, Blackwell Publishing. So there is now more evidence that perhaps, yes, Tyrannosaurus Rex did have feathers! [24][25] The "Small Quarry" Stegosaurus' articulation and completeness clarified the position of plates and spikes on the back of Stegosaurus and the position and size of the throat ossicles found earlier first by Felch with the Stegosaurus stenops holotype, though like the S. stenops type, the fossils were flattened in a "roadkill" condition. besttroodon 5 yr. ago No they do not have feathers. [58] More recently, a study of the tail spikes by McWhinney et al.,[84] which showed a high incidence of trauma-related damage, lends more weight to the position that the spikes were indeed used in combat. [42], In Stegosaurus stenops there are 27 bones in the vertebral column anterior to the sacrum, a varying number of vertebrae in the sacrum, with four in most subadults, and around 46 caudal (tail) vertebrae. Plating among different stegosaurs varied: some forms apparently had parallel rather than alternating plates, and some, such as Kentrurosaurus, had plates along the front half of the back and spikes along the back half and tail. Galton noted that the plates in S. stenops have been found articulated in two staggered rows, rather than paired. 03 of 10 The Name Coelophysis Means "Hollow Form" Nobu Tamura During the Mesozoic Era (a period of more than 180 million years that included the Triassic, Jurassic, and Cretaceous periods), a species of non-avian dinosaur evolved into a species of avian dinosaur. [27] At Jensen-Jensen Quarry, an articulated torso including several dorsal plates from a small individual were collected and briefly described in 2014, though the specimen was collected years before and is still in preparation at Brigham Young University. Maidment, S. C. (2010). Much of their notoriety comes from their odd, and intriguing, appearance. This hypothesis proposes that the plates acted as radiators, releasing body heat to a cooler ambient environment; conversely, the plates could also have collected heat by being faced toward the sun like living solar panels. Confirmed Stegosaurus remains have been found in the Morrison Formation's stratigraphic zones 26, with additional remains possibly referrable to Stegosaurus recovered from stratigraphic zone 1. It is more likely, however, that much of the sacral cavity was used for storing glycogen, as is the case in many present-day animals. Now!" Jason shouted, and our Dinozords appeared. Stegosauria: a historical review of the body fossil record and phylogenetic relationships. Researchers have determined that some dinosaurs had large forebrains, which would lead to heightened senses of both hearing and smell. The feet were short and broad. By the early 1960s, this had become (and remains) the prevalent idea, mainly because some, This page was last edited on 4 March 2023, at 02:57. The T. rex actually existed closer in history to humans than to the Stegosaurus. Because the plates contained many blood vessels, the alternating placement appears consistent with a hypothesis of thermoregulation. It has a pubis and ischium that both point towards the posterior of the animal. Stegosaurus is one of the most recognisable dinosaurs, for one main reason: the big, triangle-shaped plates lining its neck, back and tail. Articulated with the scapula, the coracoid is sub-circular. Browsing on a wide variety of plants would be essential. [7] The other, Stegosaurus sulcatus, was named based on a left forelimb, scapula, left femur, several vertebrae, and several plates and dermal armor elements (USNM V 4937) collected in 1883. 10 besttroodon 5 yr. ago The fact is that evolution has a way of adapting specific anatomical features to multiple functions, so it may well be that the plates of Stegosaurus were literally all of the above: a sexually selected characteristic, a means to intimidate or defend against predators, and a temperature-regulation device. Tooth wear and possible jaw action of. not only the fused up-down motion to which stegosaur jaws were likely limited). However, this mount was dismantled in 1917 when the old Peabody Museum building was demolished. 327-329. International Code of Zoological Nomenclature, "Principal characters of American Jurassic dinosaurs, part IX. Scales that grew larger and began to diverge. We jumped onto our Dinozords. [2], The greatest Stegosaurus discovery came in 1885 with the discovery of a nearly complete, articulated skeleton of a subadult that included previously undiscovered elements like a complete skull, throat ossicles, and articulated plates. [78] Likewise, 2010 structural comparisons of Stegosaurus plates to Alligator osteoderms seem to support the conclusion that the potential for a thermoregulatory role in the plates of Stegosaurus definitely exists. 560 pp. [32][33], Most of the information known about Stegosaurus comes from the remains of mature animals; more recently, though, juvenile remains of Stegosaurus have been found. [2] F. F. Hubbell, a collector for Cope, also found a partial Stegosaurus skeleton while digging at Como Bluff in 1877 or 78 that are now part of the Stegosaurus mount (AMNH 5752) at the American Museum of Natural History. The discovery of these branched integumentary structures outside theropods suggests that featherlike structures coexisted with scales and were potentially widespread among the entire dinosaur clade; feathers may thus have been present in the earliest dinosaurs. This illustration would later go on to form the basis of the stop-motion puppet used in the 1933 film King Kong. Around the middle of the tail, the neural spines become bifurcated, meaning they are divided near the top. According to paleontologist and National Geographic grantee Jack Horner, it stands to reason that dinosaurs had similar courting behaviors as today's birds. C. 2. Did the T. rex live in the Mesozoic era? The Stegosaurus had a large gut that was responsible for its digestion and breakdown of nutrients aided by gastroliths. This was supported by elongated vertebrae (bones that make up the spinal column). . [13] 1918 saw the completion of the second Stegosaurus mount, and the first depicting S. stenops. However, their reproductive organs still could not touch as there is no evidence of muscle attachments for a mobile penis nor a baculum in male dinosaurs. The scapula (shoulder blade) is sub-rectangular, with a robust blade. No feathers c. Feather shafts were too thin d. Feather shafts were too heavy e. No wings. Based on the results of the study, it was revealed that the subadult Stegosaurus specimen had a bite similar in strength to that of modern herbivorous mammals, in particular, cattle and sheep. 71-69 mya. They do estimate that they fed on a number of different plant types, including ferns, moss, fruits, cycads, conifers, and horsetails. Feathers evolved before flight and may have functioned as . [24] Landberg excavated the skeleton with the DMNS crews, recovering a 70% complete Stegosaurus skeleton along with turtles, crocodiles, and isolated dinosaur fossils at the quarry that would be nicknamed "The Kessler Site". 8 -10 feet. This study showed that 9.8% of Stegosaurus specimens examined had injuries to their tail spikes. Thus, their conception of Stegosaurus would include three valid species (S.armatus, S.homheni, and S.mjosi) and would range from the Late Jurassic of North America and Europe to the Early Cretaceous of Asia. It was initially mounted with paired plates set wide, above the base of the ribs, but was remounted in 1924 with two staggered rows of plates along the midline of the back. This was uncovered using the spectroscopy of lipoxidation signals, which are byproducts of oxidative phosphorylation and correlate with metabolic rates. Did T. rex have fur or feathers? Score: 4.3/5 (1 votes) . The sacro-lumbar expansion is not unique to stegosaurs, nor even ornithischians. They found other fossils in Europe, China, Africa, and India. if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[336,280],'animals_net-large-leaderboard-2','ezslot_13',117,'0','0'])};__ez_fad_position('div-gpt-ad-animals_net-large-leaderboard-2-0');Unfortunately, fossils do not provide much insight into the behavior of an animal. 'roof-lizard') is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Palaeontologists have known for about two decades that theropods, the dinosaur group that contained the likes of Tyrannosaurus and Velociraptor and from which modern birds evolved, were covered. Fossils of the genus have been found in the western United States and in Portugal, where they are found in Kimmeridgian- to Tithonian-aged . [80] Christiansen and Tschopp (2010) state that the presence of a smooth, insulating keratin covering would have hampered thermoregulation, but such a function cannot be entirely ruled out as extant cattle and ducks use horns and beaks to dump excess heat despite the keratin covering. These are presumed to have served as defensive weapons, but they may have been ornamental. [26] The Sauriermuseum found several partial Stegosaurid skeletons throughout their excavations at Howe Quarry, Wyoming in the 1990s, though only Sophie has been described in detail. B. [101], Marsh published his more accurate skeletal reconstruction of Stegosaurus in 1891, and within a decade Stegosaurus had become among the most-illustrated types of dinosaur. This mount was created under the direction of Charles Gilmore at the U.S. National Museum of Natural History. [101] Artist Charles R. Knight published his first illustration of Stegosaurus ungulatus based on Marsh's skeletal reconstruction in a November 1897 issue of The Century Magazine. History and evolution of stegosaurus in China. [41] Actual brain anatomy in Stegosaurus is poorly known, but the brain itself was small even for a dinosaur. Ceratosaurus and Stegosaurus dinosaurs: Warm-blooded. [9][11] This first reconstruction, of S. ungulatus with missing parts filled in from S. stenops, was published by Marsh in 1891. Evolutionary scientists have recently claimed that pterosaurs had feathers. stegosaurus introducing dinosaurs english edition below. In Hesperosaurus there are two dorsosacrals, and only four fused sacrals, but in Kentrosaurus there may be as many as seven vertebrae in the sacrum, with both dorsosacrals and caudosacrals. Tail spikes. [25] A study by Mallison (2010) found support for a rearing up posture in Kentrosaurus, though not for ability for the tail to act as a tripod. The dinosaurs with hips that . Its head was held low and its stiff tail was poised high in the air. They had. The presence of feathers in raptorial dinosaurs cannot be denied. revised their suggestion due to the recognition by Galton of S. armatus as a nomen dubium and its replacement by S. stenops as type species. 3-4.500 lbs. Flexible, armorlike scales protected the throat of Stegosaurus.. Bony plates. In a zoological setting, these creatures would probably require care similar to rhinos or elephants. That's when Stegosaurus was a species of dinosaur that walked around the Earth. "Body mass estimates of an exceptionally complete Stegosaurus (Ornithischia: Thyreophora): Comparing volumetric and linear bivariate mass estimation methods", "The phylogenetic nomenclature of ornithischian dinosaurs", "A new long-necked 'sauropod-mimic' stegosaur and the evolution of the plated dinosaurs", "A new phylogeny of Stegosauria (Dinosauria, Ornithischia)", "Evidence for a Sauropod-Like Metacarpal Configuration in Stegosaurian Dinosaurs", "Dacentrurine stegosaurs (Dinosauria): A new specimen of Miragaia longicollum from the Late Jurassic of Portugal resolves taxonomical validity and shows the occurrence of the clade in North America", "A new specimen of the ornithischian dinosaur Hesperosaurus mjosi from the Upper Jurassic Morrison Formation of Montana, U.S.A., and implications for growth and size in Morrison stegosaurs", "Principal characters of American Jurassic dinosaurs, part III", "CAD assessment of the posture and range of motion of, "The socio-sexual behaviour of extant archosaurs: Implications for understanding dinosaur behaviour", "Internal vascularity of the dermal plates of Stegosaurus (Ornithischia, Thyreophora)", 10.1666/0094-8373(2005)031[0291:teafot]2.0.co;2, "The 'species recognition hypothesis' does not explain the presence and evolution of exaggerated structures in non-avialan dinosaurs", "Lies, damned lies, and Clash of the Dinosaurs", "Decoupled form and function in disparate herbivorous dinosaur clades", https://en.wikipedia.org/w/index.php?title=Stegosaurus&oldid=1142738597, By 1891, Marsh published a more familiar view of, The plates were paired in a double row along the back, such as in Knight's 1901 reconstruction and the 1933 film, Two rows of alternating plates. Stegosaurus defended itself by attacking its enemies with its spiked tail.Allosaurus bones have been found with holes made by Stegosaurus tail spikes.. Martin, A.J. [40], Despite the animal's overall size, the braincase of Stegosaurus was small, being no larger than that of a dog. In terms of its, sometimes unique, physical characteristics, Carnotaurus was known for its unique features, including its flat snout, horns above its eyes, teeny tiny arms and long, muscular legs. [39] Palaeontologists believe it would have eaten plants such as mosses, ferns, horsetails, cycads, and conifers or fruits. [24] The expedition was successful in finding a nearly complete Stegosaurus near the Kessler site by Bryan Small, whose name would become the namesake of the new site. [13] These were highly modified osteoderms (bony-cored scales), similar to those seen in crocodiles and many lizards today. 'roof-lizard') is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Our editors will review what youve submitted and determine whether to revise the article. Spinosaurus - Grace Hansen 2017-09-01 This title will help readers discover Spinosaurus dinosaurs that lived in the Cretaceous period around 95 million years ago. [5], At one time, stegosaurs were described as having a "second brain" in their hips. The only interactions between Stegosaurus and humans are in movies and television. [46] Galton (2019) interpreted plates of an armored dinosaur from the Lower Jurassic (Sinemurian-Pliensbachian) Lower Kota Formation of India as fossils of a member of Ankylosauria; the author argued that this finding indicates a probable early Early Jurassic origin for both Ankylosauria and its sister group Stegosauria. Stegosaurus is one of the better-known dinosaurs, and has been featured in film, postal stamps, and many other types of media. Did stegosaurus have feathers? It was a composite of several skeletons, primarily USNM 6531, with proportions designed to closely follow the S. stenops type specimen, which had been on display in relief nearby since 1918. It had passive defensive strategies like swinging its Stegosaurus tail for protection. [12] This historically significant specimen was re-mounted ahead of the opening of the new Peabody Museum building in 1925. Paleontologists initially suggested that this space could be for a second brain. Stegosaurus would have lived alongside dinosaurs such as Apatosaurus, Diplodocus, Camarasaurus and Allosaurus, the latter of which may have preyed on it. The fossils included only a couple postcranial remains, though in the 1900s-1920s Carnegie crews at Dinosaur National Monument discovered dozens of Stegosaurus specimens in one of the greatest single sites for the taxon. If not feathered, some dinosaurs are believed to have feather-like structures such as . This interpretation is supported by the absence of front teeth and their likely replacement by a horny beak or rhamphotheca. These middle Triassic reptiles, dating from about 230 million years ago, included such important genera as Eoraptor, Herrerasaurus, and Staurikosaurus; as far as paleontologists can tell, these were the first true dinosaurs, only recently evolved from their archosaur predecessors. This art shows a relative of Triceratops (Pachyrhinosaurus) with a thick fur-like feathery covering, which some people have suggested is feasible given its northerly range.. Its great to see that people are warming up to the idea of feathered dinosaurs though, because I have a . (Tyrannosaurus Rex) How many fingers did Tyrannosaurus have? [45] Bakker stated that Stegosaurus could flip its osteoderms from one side to another to present a predator with an array of spikes and blades that would impede it from closing sufficiently to attack the Stegosaurus effectively. It had a small antorbital fenestra, the hole between the nose and eye common to most archosaurs, including modern birds, though lost in extant crocodylians. [7] Gilmore and Lucas' interpretation became the generally accepted standard, and Lull's mount at the Peabody Museum was changed to reflect this in 1924. . Based on this data, it is likely Stegosaurus also ate woodier, tougher plants such as cycads, perhaps even acting as a means of spreading cycad seeds. [26] The hind feet each had three short toes, while each fore foot had five toes; only the inner two toes had a blunt hoof. Foster, J. [8][22] The AMNH mount is cast and on display at the Field Museum, which didn't collect any Stegosaurus skeletons during the Second Dinosaur Rush. [85], S. stenops had four dermal spikes, each about 6090cm (2.03.0ft) long. In fact, Tyrannosaurus rex was closely related to birds and didn't have feathers. Scientists arent exactly sure how they chewed and foraged for food, because their mouth is simply, weird. )[7], The skeleton of S. stenops has since been deposited at the National Museum of Natural History in Washington D. C., where it has been on display since 1915. Science correspondent, BBC News All dinosaurs were covered with feathers or had the potential to grow feathers, a study suggests. While this includes all species of birds, there is a hypothesis that many, if not all non-avian dinosaur species also possessed feathers in some shape or form. Preserved on slabs of ancient limestone in north-eastern Brazil, a newly discovered fossil of Tupandactylus imperator reveals the existence of pterosaur feathers about 113 million years ago. (Compsognathus) Compsognathus was a myth started by a man named Carl Strauss. Farther posteriorly, the proportionately larger the cervicals become, although they do not change greatly in anything other than size. Meet fierce, birdlike, armored, and giant dinosaurs from hundreds of millions of years ago! A. Fossils of this dinosaur are actually relatively rare, and because of this we can only speculate the other habitats this creature lived in. HAO, B., PENG, G., QIN, G., YE, Y., & JIANG, S. (2018). These, and all other non-avian dinosaurs became extinct at least 65 million years ago at the end of the Cretaceous Period. Its position in the dinosaur family tree raises big questions about the origins of feathers. [103], Early skeletal mounts and plate interpretation. One group of tracks is interpreted as showing four or five baby stegosaurs moving in the same direction, while another has a juvenile stegosaur track with an adult track overprinting it. Stegosaurus skeleton. The skull and dermal armour of, "A newly mounted skeleton of the armored dinosaur, Stegosaurus stenops, in the United States National Museum", Reconstructing an Icon: Historical Significance of the Peabodys Mounted Skeleton of, "Extinct Monsters: The Marsh Dinosaurs, Part II", "The Postcranial Skeleton of an Exceptionally Complete Individual of the Plated Dinosaur Stegosaurus stenops (Dinosauria: Thyreophora) from the Upper Jurassic Morrison Formation of Wyoming, U.S.A.", "Evidence for Sexual Dimorphism in the Plated Dinosaur Stegosaurus mjosi (Ornithischia, Stegosauria) from the Morrison Formation (Upper Jurassic) of Western USA". The model was based on Knight's latest miniature with the double row of staggered plates,[12] and was exhibited in the United States Government Building at the exposition in St. Louis before being relocated to Portland, Oregon for the Lewis and Clark Centennial Exposition in 1905. B. The skull and brain were very small for such a large animal. Like Marsh's reconstruction, Knight's first restoration had a single row of large plates, though he next used a double row for his more well-known 1901 painting, produced under the direction of Frederic Lucas. . So did dinosaurs have big outer ears? [5][2] Later in 1887, Marsh described two more species of Stegosaurus from Como Bluff, Stegosaurus duplex, based on a partial vertebral column, partial pelvis, and partial left hindlimb (YPM 1858) from Reed's Quarry 11, though the species is now seen as synonymous with Stegosaurus ungulatus. According to a recent study, they may have evolved in another group. Toes. Bite force was also calculated using these models and the known skull proportions of the animal, as well as simulated tree branches of different size and hardness.