Xing, L., Lockley, M. G., PERSONS IV, W. S., Klein, H., Romilio, A., Wang, D., & Wang, M. (2021). The bony plates on Stegosaurus's back were set . [103], Early skeletal mounts and plate interpretation. A 9 meter long dinosaur called Yutyrannus (meaning feathered tyrant) is the largest known dinosaur fossil discovered to show having feathers. Now!" Jason shouted, and our Dinozords appeared. The presence of a beak extended along much of the jaws may have precluded the presence of cheeks in these species. They found other fossils in Europe, China, Africa, and India. Some decorative bristles could work with Stegosaurus. [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. In some specimens of S. stenops, a caudal is also incorporated, as a caudosacral. (2006). New Mexico Museum of Natural History and Science Bulletin, 36. Indiana University Press. Did not have to worry about predation based on their size as long as they were adults and healthy. pp. Martin, A.J. "Appendix." [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. [100], One of the most recognizable of all dinosaurs,[40] Stegosaurus has been depicted on film, in cartoons and comics and as children's toys. They were not directly attached to the animal's skeleton, instead arising from the skin. Stegosaurus measured around 9m from nose to tail, making it something of a middleweight creature in the grand age of the dinosaurs. The first cervical vertebra is the axis bone, which is connected and often fused to the atlas bone. Stegosaurus may have preferred drier settings than these other dinosaurs. The remains of over 80 individual animals of this genus have been found. Here's a Stegosaurus skin: No feathers, but armour only. [9][11] This first reconstruction, of S. ungulatus with missing parts filled in from S. stenops, was published by Marsh in 1891. [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. 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. "Powered up . He delves into the latest discoveries in China, the US, Fossils of the genus have been found in the western United States and in Portugal, where they are found in Kimmeridgian- to Tithonian-aged strata, dating to between 155 and 145million years ago. Stegosaurus, or Triceratops, are still alive. Stegosaurus walked on its toes, which were supported by thick, wedge-shaped pads.. Throat guard. Stegosaurus had a relatively low brain-to-body mass ratio. Although they're sometimes called "flying dinosaurs," they are technically distinct from dinosaurs. Flexible, armorlike scales protected the throat of Stegosaurus.. Bony plates. They are powerful animals, and would need strongly reinforced fencing for their enclosures. 2. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. According to paleontologist and National Geographic grantee Jack Horner, it stands to reason that dinosaurs had similar courting behaviors as today's birds. Which dinosaurs did not have feathers? In fact, Tyrannosaurus rex was closely related to birds and didn't have feathers. Stegosaurus skeleton. Many dinosaurs may have been covered in elaborate feathers similar to those of modern-day birds, according to a study of new fossils. C. 2. The presacrals are divided into cervical (neck) and dorsal (back) vertebrae, with around 10 cervicals and 17 dorsals, the total number being one greater than in Hesperosaurus, two greater than Huayangosaurus, although Miragaia preserves 17 cervicals and an unknown number of dorsals. 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. [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. 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. "The fauna and flora of the Morrison Formation: 2006". Cool story have fun. Second Edition. Did stegosaurus have feathers? Its head was held low and its stiff tail was poised high in the air. 1. Barrett, P.M. (2001). While every effort has been made to follow citation style rules, there may be some discrepancies. [12] The type specimen of S. ungulatus (YPM 1853) was incorporated into the first ever mounted skeleton of a stegosaur at the Peabody Museum of Natural History in 1910 by Richard Swann Lull. Debate is raging about whether pterosaurs, flying reptiles that lived alongside the dinosaurs, had feathers or not. rex had feathers as well, Norell said. [85], S. stenops had four dermal spikes, each about 6090cm (2.03.0ft) long. These may have been some kind of proto-feathers, perhaps brightly colored to attract a mate or intimidate a rival, or . 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. Even though the larger adult tyrannosaurs probably didn't have any feathers, the babies, which were much smaller and . However, this mount was dismantled in 1917 when the old Peabody Museum building was demolished. Stegosaurus, (genus Stegosaurus ), one of the various plated dinosaurs ( Stegosauria) of the Late Jurassic Period (159 million to 144 million years ago) recognizable by its spiked tail and series of large triangular bony plates along the back. If its filaments are related to the proto-feathers of the theropods (which is possible but not. Stegosaur track assemblage from Xinjiang, China, featuring the smallest known stegosaur record. Two years ago a study claimed to have found fossil evidence of "protofeathers . [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". 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. [25] Initially, Marsh described S.ungulatus as having eight spikes in its tail, unlike S.stenops. The Stegosaurus had a large gut that was responsible for its digestion and breakdown of nutrients aided by gastroliths. Stegosaurus, one of the many dinosaurs described in the Bone Wars, was first collected by Arthur Lakes and consisted of several caudal vertebrae, a dermal plate, and several additional postcranial elements that were collected north of Morrison, Colorado at Lakes YPM Quarry 5. [45] Histological surveys of plate microstructure attributed the vascularization to the need to transport nutrients for rapid plate growth. This is why you remain in the best website to look the incredible ebook to have. He led the construction of the first ever Stegosaurus skeletal mount at the Peabody Museum of Natural History, which was depicted with paired plates. 10 besttroodon 5 yr. ago [90], A 2022 study by Wiemann and colleagues of various dinosaur genera including Stegosaurus suggests that it had an ectothermic (cold blooded) or gigantothermic metabolism, on par with that of modern reptiles. This dinosaur has a tyrannosauroid dinosaur classification, the same as T. Rex. So did dinosaurs have big outer ears? Jurassic West: The Dinosaurs of the Morrison Formation and Their World. 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. Did T. rex have fur or feathers? Robert Bakker noted the tail was likely to have been much more flexible than that of other dinosaurs, as it lacked ossified tendons, thus lending credence to the idea of the tail as a weapon. [12] The aging mount was dismantled in 2003 and replaced with a cast in an updated pose in 2004. Stegosaurus (/stsrs/;[1] lit. [28] 2007 saw the description of a Stegosaurus specimen from the Upper Jurassic Lourinha Formation of Portugal, the specimen was placed as cf. Though adult T. rexes were mostly covered in scales, scientists think . The spinal cord in the region of the sacrum was enlarged and was actually larger than the brain, a fact that gave rise to the misconception that Stegosaurus possessed two brains. Colorful and scientifically accurate illustrations paired with intriguing facts will be sure to captivate your kids in grades 4-8. 3. . Various hypotheses have attempted to explain the arrangement and use of the plates. Stegosaurus is one of the better-known dinosaurs, and has been featured in film, postal stamps, and many other types of media. Though it is not always perfectly preserved, the acromion ridge is slightly larger than in Kentrosaurus. All photos used are royalty-free, and credits are included in the Alt tag of each image. [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. Did the T. rex live in the Mesozoic era? Bakker also observed that Stegosaurus could have maneuvered its rear easily, by keeping its large hind limbs stationary and pushing off with its very powerfully muscled but short forelimbs, allowing it to swivel deftly to deal with attack. The T. rex actually existed closer in history to humans than to the Stegosaurus. Stegosaurus (/ s t s r s /; lit. Down feathers were found on a pterosaur, so the fibers most of them have are indeed true proto-feathers. 2.5 - 3 meters. [75] Mobility of the plates, however, has been disputed by other paleontologists. 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. Additional support for this idea was a punctured tail vertebra of an Allosaurus into which a tail spike fits perfectly. As to the number of eggs, incubation time, and parental care, we simply dont know yet. This was supported by elongated vertebrae (bones that make up the spinal column). Stegosaurs lost the armour from the flanks of the body that these early relatives had. Score: 4.3/5 (1 votes) . Annotated catalogue of the dinosaurs (Reptilia, Archosauria) in the collections of Carnegie Museum of Natural History. The dinosaurs with hips that . besttroodon 5 yr. ago No they do not have feathers. [75] Christiansen and Tschopp (2010), having studied a well-preserved specimen of Hesperosaurus with skin impressions, concluded that the plates were covered in a keratin sheath which would have strengthened the plate as a whole and provided it with sharp cutting edges. 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. Did all dinosaurs have feather? These are presumed to have served as defensive weapons, but they may have been ornamental. But T. rex didn't live until about 80 million years ago, up until about 65 million years ago in the great extinction event. Though they were large by our standards, the other dinosaurs that roamed while Stegosaurus was alive dwarfed it. They write new content and verify and edit content received from contributors. [94] One hypothesized feeding behavior strategy considers them to be low-level browsers, eating low-growing fruit of various nonflowering plants, as well as foliage. 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. University of Chicago Press. Spinosaurus had a huge sail on its back. Though it had not yet been completely prepared, the nearly complete and articulated type specimen of Stegosaurus stenops allowed Marsh to complete the first attempt at a reconstructed Stegosaurus skeleton. [88] One 2009 study of Stegosaurus specimens of various sizes found that the plates and spikes had delayed histological growth in comparison to the skeleton and when the dinosaur reached maturity, growth in the osteoderms may have increased. Did all dinosaurs have feather? [40], Despite the animal's overall size, the braincase of Stegosaurus was small, being no larger than that of a dog. [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. Unlike the sturdy jaws and grinding teeth common to its fellow ornithischians, Stegosaurus (and all stegosaurians) had small, peg-shaped teeth that have been observed with horizontal wear facets associated with tooth-food contact[92] and their unusual jaws were probably capable of only orthal (up-down) movements. Today, it is generally agreed that their spiked tails were most likely used for defense against predators, while their plates may have been used primarily for display, and secondarily for thermoregulatory functions. [6] Many later researchers have considered Hypsirhophus to be a synonym of Stegosaurus,[7] though Peter Galton (2010) suggested that it is distinct based on differences in the vertebrae. [9][2] In 1881, he named a third species Stegosaurus "affinis", based only on a hip bone, though the fossil has since been lost and the species declared a nomen nudum. [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. [39] Palaeontologists believe it would have eaten plants such as mosses, ferns, horsetails, cycads, and conifers or fruits. This study showed that 9.8% of Stegosaurus specimens examined had injuries to their tail spikes. B. While a human's. See full answer below. 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. [12] This historically significant specimen was re-mounted ahead of the opening of the new Peabody Museum building in 1925. The tail appears to have been held well clear of the ground, while the head of Stegosaurus was positioned relatively low down, probably no higher than 1m (3.3ft) above the ground. (eds.). not only the fused up-down motion to which stegosaur jaws were likely limited). Ankylosaurus And Feathers The dinosaurs' closest relatives that had the ability to fly, like the Ptesaurus, were reptiles and were not real dinosaurs. One of the major subjects of books and articles about Stegosaurus is the plate arrangement. [11] Foster, J. 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. 71-69 mya. [96] However, a 2016 study indicates that Stegosaurus's bite strength was stronger than previously believed. [77] Buffrnil, et al. Score: 4.3/5 (1 votes) . [7] The skeleton was shipped to Marsh in 1887, who named it Stegosaurus stenops ( "narrow-faced roof lizard") that year. Display and species recognition remain likely functions for the plates, although such hypotheses are difficult to investigate. [31] Some large individuals may have reached 7.5m (25ft) in length and 5.05.3 metric tons (5.55.8 short tons) in body mass. This suggests it could not walk very fast, as the stride of the back legs at speed would have overtaken the front legs, giving a maximum speed of 15.317.9km/h (9.511.1mph). [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. 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. It had a short neck and a small head, meaning it most likely ate low-lying bushes and shrubs. [26][25][24] The Stegosaurus skeletons have been mounted alongside an Allosaurus skeleton collected in Moffat County, Colorado originally in 1979. The skull and brain were very small for such a large animal. Dinosaurs did have feathers ancestrally but most groups lost them. [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. History and evolution of stegosaurus in China. The Stegosaurus had an arched back and short forelimbs. Long, the American Museum mount was a composite consisting of partial remains filled in with replicas based on other specimens. Fossils of the genus have been found in the western United States and in Portugal, where they are found in Kimmeridgian- to Tithonian-aged . Knight would go on to paint a stegosaur with a staggered double plate row in 1927 for the Field Museum of Natural History, and was followed by Rudolph F. Zallinger, who painted Stegosaurus this way in his "Age of Reptiles" mural at the Peabody Museum in 1947. A cranium (CM 12000) was also found by Carnegie crews, one of the few known. Comparisons were made between it (represented by a specimen known as "Sophie" from the United Kingdom's Natural History Museum) and two other herbivorous dinosaurs; Erlikosaurus and Plateosaurus to determine if all three had similar bite forces and similar niches. 03 of 10 The Name Coelophysis Means "Hollow Form" Nobu Tamura Read on to learn about the stegosaurus. Archaeologists found the most specimens in the Morrison Formation, which we have decent information about the ecosystem of during that time. Dong, Z. M. (1973). Paleontologists think feathers may have first evolved to keep dinosaurs warm. a. a keel bone (wishbone) c. a long tail b. teeth d. claw-bearing fingers . 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. Stegosaurus is a genus of armored dinosaur, with large bone plates along its neck, back and tail. In it, the researchers claimed that Tyrannosaurus and its relatives, collectively known as Tyrannosaurids, did not have feathers. 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. "In the groove and ready to move!" Zack shouted. 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. Stegosaurus was up to 30 feet (9.1 meters) long. The skull's low position suggests that Stegosaurus may have been a browser of low-growing vegetation. Become a member and. [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. Discoveries of articulated stegosaur armor show, at least in some species, these spikes protruded horizontally from the tail, not vertically as is often depicted. HAO, B., PENG, G., QIN, G., YE, Y., & JIANG, S. (2018). They suggested that such metabolisms may have been common for ornithischian dinosaurs in general, with the group evolving towards ectothermy from an ancestor with an endothermic (warm blooded) metabolism. Fewer S. ungulatus plates have been found, and none articulated, making the arrangement in this species more difficult to determine. [36] Such an extensive beak was probably unique to Stegosaurus and some other advanced stegosaurids among ornithischians, which usually had beaks restricted to the jaw tips. [81] The use of exaggerated structures in dinosaurs as species identification has been questioned, as no such function exists in modern species. Furthermore, within the hind limbs, the lower section (comprising the tibia and fibula) was short compared with the femur. "Ready to roll!" I shouted. McIntosh, J. S. (1981). This was uncovered using the spectroscopy of lipoxidation signals, which are byproducts of oxidative phosphorylation and correlate with metabolic rates. [25], The most recognizable features of Stegosaurus are its dermal plates, which consisted of between 17 and 22 separate plates and flat spines. But the paleontologist who first discovered a Stegosaurus fossil thought the plates laid flat on its back like a turtle's shell. The feet were short and broad. 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. [41] Actual brain anatomy in Stegosaurus is poorly known, but the brain itself was small even for a dinosaur. The stegosaurus is an immense yet stupid herbivore often found in the plains and jungles, where it feasts on grasses, plants, and leaves. Due to the fragmentary nature of most early Stegosaurus fossil finds, it took many years before reasonably accurate restorations of this dinosaur could be produced. [2] Many of the plates are manifestly chiral[19][20] and no two plates of the same size and shape have been found for an individual; however plates have been correlated between individuals. 233248. Let us know if you have suggestions to improve this article (requires login). [2][56] In 2015, Maidment et al. 3-4.500 lbs. The bony plates along its back were embedded in the skin of the animal, not attached to its skeleton, which is why in most . the favored book National Geographic Kids Ultimate Dinopedia Second Edition collections that we have. . [5], At one time, stegosaurs were described as having a "second brain" in their hips. [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. [76], Another possible function of the plates is they may have helped to control the body temperature of the animal,[76] in a similar way to the sails of the pelycosaurs Dimetrodon and Edaphosaurus (and modern elephant and rabbit ears). For example, though it states that scales came from the neck of a tyrannosaur, it does not state whether those scales were from the top, bottom, or sides of the neck. However, as Carpenter[25] has noted, the plates overlap so many tail vertebrae, movement would be limited. One skeleton collected at the site known as "Victoria" is very well preserved including many of the vertebrae preserved in semi-articulation and next to an Allosaurus skeleton found nicknamed "Big Al II". Dinosaurs from Wuerho. [26] It is a young adult of undetermined sex, 5.8m (19ft) long and 2.9m (9.5ft) tall. 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". 1,350 2,000 kg. 327-329. International Code of Zoological Nomenclature, "Principal characters of American Jurassic dinosaurs, part IX. We know Stegosaurus didn't live in herds, but was probably solitary or lived in small groups. The skeleton remained mounted until 1989 when the museum curator of the DMNS began a revision of the museum's fossil hall and dispatched an expedition to find additional Stegosaurus remains. If anything has feathers, it's connected to the bone and forms quill knobs. Furthermore, it is puzzling why other stegosaurs and other dinosaurs lacked elaborate thermoregulatory structures. Introduction to the Study of Dinosaurs. [3] Though several more complete specimens have been attributed to Stegosaurus armatus, preparation of the bones and analysis has discovered that this type specimen is actually dubious, which is not an ideal situation for the type species of a well-known genus like Stegosaurus. [24] Phillip Reinheimer, a steel worker, mounted the Stegosaurus skeleton at the DMNS in 1938. Description of the Stegosaurus. [44] The fore limbs were much shorter than the stocky hind limbs, which resulted in an unusual posture. While the idea of cloning . stegosaurus introducing dinosaurs english edition below. The resultant bite forces calculated for Stegosaurus were 140.1 newtons (N), 183.7N, and 275N (for anterior, middle and posterior teeth, respectively), which means its bite force was less than half that of a Labrador retriever. [43] All four limbs were supported by pads behind the toes. Around the middle of the tail, the neural spines become bifurcated, meaning they are divided near the top. Scant evidence in the fossil record has never been definitive - until now, scientists say. They also used hind legs to feed on trees or detect danger. (Tyrannosaurus Rex) How many fingers did Tyrannosaurus have? . In their case, it contains what is called the glycogen body, a structure whose function is not definitely known, but which is postulated to facilitate the supply of glycogen to the animal's nervous system. [29][26], Sophie the Stegosaurus is the best preserved Stegosaurus specimen, being 85% intact and containing 360 bones. This suggests that the different Stegosaurus species were relatively widespread. A well-preserved Stegosaurus braincase allowed Othniel Charles Marsh to obtain, in the 1880s, a cast of the brain cavity or endocast of the animal, which gave an indication of the brain size. Tooth wear and possible jaw action of. 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. He contends that they had insufficient width for them to stand erect easily in such a manner as to be useful in display without continuous muscular effort. Stegosaurus usually grew to a length of about 6.5 metres (21 feet), but some reached 9 metres (30 feet). [89] A 2013 study concluded, based on the rapid deposition of highly vascularised fibrolamellar bone, that Kentrosaurus had a quicker growth rate than Stegosaurus, contradicting the general rule that larger dinosaurs grew faster than smaller ones.