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. Farther posteriorly, the proportionately larger the cervicals become, although they do not change greatly in anything other than size. The authors said the feathers belonged to a type of non-flying dinosaur. Spinosaurus had a huge sail on its back. This study showed that 9.8% of Stegosaurus specimens examined had injuries to their tail spikes. Long, the American Museum mount was a composite consisting of partial remains filled in with replicas based on other specimens. An important discovery came in 1937 again at Garden Park by a high school teacher named Frank Kessler in while leading a nature hike. 1. 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. 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. Galton noted that the plates in S. stenops have been found articulated in two staggered rows, rather than paired. [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. The sacro-lumbar expansion is not unique to stegosaurs, nor even ornithischians. "In the groove and ready to move!" Zack shouted. Grasses did not evolve until much later, so these dinosaurs would never have grazed on grasses. Flexible, armorlike scales protected the throat of Stegosaurus.. Bony plates. [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 findings debunk the theory that feathers evolved . 2. 71-69 mya. Giant sauropods like Diplodocus and Camarasaurus, smaller herbivores like Camptosaurus, and predators including Allosaurus and Ceratosaurus. So from being sluggish "terrible lizards" with scales, cold blood and pea-brains that went extinct, dinosaurs are now understood to . 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. (1986) found "extreme vascularization of the outer layer of bone",[78][76] which was seen as evidence that the plates "acted as thermoregulatory devices". Stegosaurs lost the armour from the flanks of the body that these early relatives had. [91], Stegosaurus and related genera were herbivores. Lucas also re-examined the issue of the life appearance of Stegosaurus, coming to the conclusion that the plates were arranged in pairs in two rows along the back, arranged above the bases of the ribs. [71][40] Tracks discovered by Matthew Mossbrucker (Morrison Natural History Museum, Colorado) suggest that Stegosaurus lived and traveled in multiple-age herds. [15] Another composite mount, using specimens referred to S. ungulatus collected from Dinosaur National Monument between 1920 and 1922, was put on display at the Carnegie Museum of Natural History in 1940.[16]. [75] Mobility of the plates, however, has been disputed by other paleontologists. Though it is not always perfectly preserved, the acromion ridge is slightly larger than in Kentrosaurus. [11] If anything has feathers, it's connected to the bone and forms quill knobs. 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. (In 1893, Richard Lydekker mistakenly re-published Marsh's drawing under the label Hypsirhophus. [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". [85], S. stenops had four dermal spikes, each about 6090cm (2.03.0ft) long. [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. While every effort has been made to follow citation style rules, there may be some discrepancies. . A. HAO, B., PENG, G., QIN, G., YE, Y., & JIANG, S. (2018). Aside from feathers, researchers. The presence of a beak extended along much of the jaws may have precluded the presence of cheeks in these species. Stegosaurus skeleton. (2007). Stegosaurus had much longer hind legs than forelegs, and very strong muscles around its hips. Score: 4.3/5 (1 votes) . [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. When did dinosaurs start getting feathers? besttroodon 5 yr. ago No they do not have feathers. 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. Also, the pelvic region of the specimens are similar to Kentrosaurus juveniles. [23][5], As part of the Dinosaur Renaissance and the resurgent interest in dinosaurs by museums and the public, fossils of Stegosaurus were once again being collected, though few have been fully described. [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. These are presumed to have served as defensive weapons, but they may have been ornamental. [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. Did stegosaurus have feathers? As the recently-described Yutyrannus shows, even 30-foot-long tyrannosaurs were fluffy. [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. Stegosaurus shared the land with a lot of other famous dinosaurs. They do estimate that they fed on a number of different plant types, including ferns, moss, fruits, cycads, conifers, and horsetails. [96] However, a 2016 study indicates that Stegosaurus's bite strength was stronger than previously believed. Ornithischians were plant-eaters and include famous dinosaurs such as Triceratops, Iguanodon and Stegosaurus. Over the last two decades, thousands of fossils unearthed in China's Liaoning Province have confirmed what paleontologists long suspected: Dinosaurs rocked feathers long before birds took to the sky. [47], The vast majority of stegosaurian dinosaurs thus far recovered belong to the Stegosauridae, which lived in the later part of the Jurassic and early Cretaceous, and which were defined by Paul Sereno as all stegosaurians more closely related to Stegosaurus than to Huayangosaurus. not only the fused up-down motion to which stegosaur jaws were likely limited). 24-26 feet. [29] The specimen is one of the few associated Stegosaurus skeletons known, though it only contains a tooth, 13 vertebrae, partial limbs, a cervical plate, and several assorted postcranial elements. The Stegosaurus had an arched back and short forelimbs. 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. Feathers evolved before flight and may have functioned as . Lucas commissioned Charles R. Knight to produce a life restoration of S. ungulatus based on his new interpretation. 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. [2] These first, fragmented bones (YPM 1850) became the holotype of Stegosaurus armatus when Yale paleontologist Othniel Charles Marsh described them in 1877. [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. Tobin restored the Stegosaurus as bipedal and long-necked, with the plates arranged along the tail and the back covered in spikes. [5], On the other side of the Bone Wars, Edward Drinker Cope named Hypsirhophus discurus as another stegosaurian based on fragmentary fossils from Cope's Quarry 3 near the "Cope's Nipple" site in Garden Park, Colorado in 1878. Since the dinosaurs, particularly the therapods were more birdlike, they should be covered with feathers. Stegosaurus, therefore, probably browsed primarily among smaller twigs and foliage, and would have been unable to handle larger plant parts unless the animal was capable of biting much more efficiently than predicted in this study. Stegosauria: a historical review of the body fossil record and phylogenetic relationships. Stegosaurus usually grew to a length of about 6.5 metres (21 feet), but some reached 9 metres (30 feet). Another suggestion is that the female would stand on all fours but squat down the fore limbs and raise the tail up and out of the male's way as he supports his fore limbs on her hips. Spinosaurus was a giant meat-eating dinosaur that grew to lengths of 18 m (60 ft.). [9][11] This first reconstruction, of S. ungulatus with missing parts filled in from S. stenops, was published by Marsh in 1891. However, it has also been suggested that the plates could have helped the animal increase heat absorption from the sun. The competition was foremost started by the American Museum of Natural History, the Carnegie Museum of Natural History, and the Field Museum of Natural History which all sent expeditions to the west to make their own dinosaur collections and mount skeletons in their fossil halls. 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. World Book's four-volume 'Dinosaurs!' series explains the origins and features of more than 100 types of dinosaurs. [39] This has been proposed by Bakker[58][69] and opposed by Carpenter. The saurischian dinosaurs are "lizard-hipped," while the ornithischian dinosaurs are "bird-hipped.". Although it was undoubtedly lacking in other respects, Stegosaurus did possess one relatively advanced anatomical feature: Extrapolating from the shape and arrangement of its teeth, experts believe this plant eater may have possessed primitive cheeks. The discovery of 150-million-year-old fossils in Siberia. [40], A detailed computer analysis of the biomechanics of Stegosaurus's feeding behavior was performed in 2010, using two different three-dimensional models of Stegosaurus teeth given realistic physics and properties. 3-4.500 lbs. 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. Read on to learn about the stegosaurus. Stegosaurus would have lived alongside dinosaurs such as Apatosaurus, Diplodocus, Camarasaurus and Allosaurus, the latter of which may have preyed on it. Lucas reclassified this species in the new genus Hoplitosaurus later that year. [12] This historically significant specimen was re-mounted ahead of the opening of the new Peabody Museum building in 1925. 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. This "brain" was proposed to have given a Stegosaurus a temporary boost when it was under threat from predators. . However, their teeth and jaws are very different from those of other herbivorous ornithischian dinosaurs, suggesting a different feeding strategy that is not yet well understood. The name Stegosaurus roughly translates to roof lizard, which only makes sense if you know what they look like! [99] Stegosaurus is commonly found at the same sites as Allosaurus, Apatosaurus, Camarasaurus, and Diplodocus. stegosaurus introducing dinosaurs english edition below. How aggressive were they? )[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. [26][25][24] The Stegosaurus skeletons have been mounted alongside an Allosaurus skeleton collected in Moffat County, Colorado originally in 1979. A. Stegosaurus may have preferred drier settings than these other dinosaurs. The remains of over 80 individual animals of this genus have been found. Articulated with the scapula, the coracoid is sub-circular. "Stegosaurus!" "Tyrannosaurus!" The six of us Morphed, and appeared where Hatchasaurus is. In its own period, the late Jurassic, Stegosaurus was a relative minnow, sharing the planet with giant sauropods like Diplodocus and large predators like Allosaurus.Weighing up to 7 metric tons, its mass was similar to that of a large elephant. According to a recent study, they may have evolved in another group. And just how closely related T. rex to a chicken Award-winning journalist John Pickrell reveals how dinosaurs developed flight and became the birds in our backyards. So there is now more evidence that perhaps, yes, Tyrannosaurus Rex did have feathers! [98], Dinosaurs that lived alongside Stegosaurus included theropods Allosaurus, Saurophaganax, Torvosaurus, Ceratosaurus, Marshosaurus, Stokesosaurus, Ornitholestes, Coelurus and Tanycolagreus. Like all non-bird Dinosaurs, T. rex lived in the Mesozoic era. That's why its name in Greek means "roof lizard.". a. a keel bone (wishbone) c. a long tail b. teeth d. claw-bearing fingers . [23] CM 11341, the most complete skeleton found at the quarry, was used for the basis of a composite Stegosaurus mount in 1940 along with several other specimens to finish the mount. The function of this array of plates and spikes has been the subject of much speculation among scientists. [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. It would be blatantly impossible to own one as a pet, even in theory. 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. 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. Corrections? Evolutionary scientists have recently claimed that pterosaurs had feathers. This dinosaur has a tyrannosauroid dinosaur classification, the same as T. Rex. Prefrontal bone Predentary bone Maxilla Perforate Acetabulum, Examine the hip structure in the image of the dinosaur Stegosaurus. "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. Did T. rex have fur or feathers? Many dinosaurs may have been covered in elaborate feathers similar to those of modern-day birds, according to a study of new fossils. "The fauna and flora of the Morrison Formation: 2006". One subadult specimen, discovered in 1994 in Wyoming, is 4.6m (15.1ft) long and 2m (6.6ft) high, and is estimated to have weighed 1.5-2.2metric tons (1.6-2.4short tons)[34] while alive. 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". Updates? If not feathered, some dinosaurs are believed to have feather-like structures such as . The skull's low position suggests that Stegosaurus may have been a browser of low-growing vegetation. No feathers c. Feather shafts were too thin d. Feather shafts were too heavy e. No wings. [68] He had changed his mind, however, by 1891, after considering the heavy build of the animal. Last Update: May 30, 2022. . When it comes to the Steg, it may have been slow-moving, but it wasn't easy prey! Martin, A.J. 10 besttroodon 5 yr. ago Furthermore, within the hind limbs, the lower section (comprising the tibia and fibula) was short compared with the femur. . Become a member and. 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. An average Stegosaurus was around 20 feet (6.1 meters) long, and weighed 2 tons. Cool story have fun. [40], Despite the animal's overall size, the braincase of Stegosaurus was small, being no larger than that of a dog. The earliest popular image of Stegosaurus was an engraving produced by A. Tobin for the November 1884 issue of Scientific American, which included the dinosaur amid a speculative Morrison age landscape. . 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. Overall, these creatures were short, stout, and powerfully built. [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. When it lived: Late Jurassic, 155-145 million years ago. [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. Vegetation varied from river-lining forests of conifers, tree ferns, and ferns (gallery forests), to fern savannas with occasional trees such as the Araucaria-like conifer Brachyphyllum. This was uncovered using the spectroscopy of lipoxidation signals, which are byproducts of oxidative phosphorylation and correlate with metabolic rates. [5], At one time, stegosaurs were described as having a "second brain" in their hips. There were three different species of Stegosaurus, but all were relatively similar looking. 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. Because they had very small brains, reliance on environmental enrichment would be much less pressing than in hyper-intelligent species like elephants. Paleontologists had long thought that Stegosaurus had two parallel rows of plates, either staggered or paired, and that these afforded protection to the animals backbone and spinal cord. These are, of course, digital or animatronic dinosaurs.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[336,280],'animals_net-banner-1','ezslot_9',116,'0','0'])};__ez_fad_position('div-gpt-ad-animals_net-banner-1-0'); Humans never domesticated Stegosaurus in any way, and never interacted with these extinct creatures. Ankylosaurus And Feathers The dinosaurs' closest relatives that had the ability to fly, like the Ptesaurus, were reptiles and were not real dinosaurs. all of these. Browsing on a wide variety of plants would be essential. . Tooth wear and possible jaw action of. Various hypotheses have attempted to explain the arrangement and use of the plates. Scientists have known for years that many dinosaurs had feathers. The concept of genetic engineering, which is at the heart of Jurassic Park 's dinosaur creation, is a real scientific principle that has been used in a variety of fields. [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. Stegosaurus measured around 9m from nose to tail, making it something of a middleweight creature in the grand age of the dinosaurs. 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. Found in: USA. Furthermore, it is puzzling why other stegosaurs and other dinosaurs lacked elaborate thermoregulatory structures. 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. "Ready to roll!" I shouted. A study of pterosaur fossils published . [21][8] These remains haven't been described and were mounted in 1932, the mount being a composite primarily of specimens AMNH 650 & 470 from Bone Cabin Quarry. Much of their notoriety comes from their odd, and intriguing, appearance. The presence of feathers in raptorial dinosaurs cannot be denied. Sereno, P.C., 1998, "A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria". There are quill knobs in the forearm bones, while smaller species like microraptors got preserved feathers in their fossils. [86] It also may function as a balance organ, or reservoir of compounds to support the nervous system. However, the type specimen of S. ungulatus preserves two flattened spine-like plates from the tail that are nearly identical in shape and size, but are mirror images of each other, suggesting that at least these were arranged in pairs. A feathered dinosaur is any species of dinosaur possessing feathers. The skull and brain were very small for such a large animal. Why were cheeks so important? [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. There is a small bump on the back of the blade, that would have served as the base of the triceps muscle. apatosaurus c. tyrannosaurus b. plateosaurus d. stegosaurus. [37][38] Other researchers have interpreted these ridges as modified versions of similar structures in other ornithischians which might have supported fleshy cheeks, rather than beaks. [13], In a 2010 review of Stegosaurus species, Peter Galton suggested that the arrangement of the plates on the back may have varied between species, and that the pattern of plates as viewed in profile may have been important for species recognition. Ears are made of cartilage and skin, and these are soft tissues which typically do not preserve well in the fossil record. This scenario has Stegosaurus foraging at most 1m above the ground. 2. Other ornithischians included Camptosaurus, Gargoyleosaurus, Dryosaurus, Othnielosaurus and Drinker. [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. [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. 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. [5] The specimen was one of many found at the quarry, the specimen consisting of a partial skull, several vertebrae, an ischium, partial limbs, several plates, and four thagomizers, though eight thagomizers were referred based on a specimen preserved alongside the type. A feathered dinosaur is any species of dinosaur possessing feathers. [14] A third mounted skeleton of Stegosaurus, referred to S. stenops, was put on display at the American Museum of Natural History in 1932. [103], Early skeletal mounts and plate interpretation. Dinosaurs did have feathers ancestrally but most groups lost them. The Stegosaurus had a large gut that was responsible for its digestion and breakdown of nutrients aided by gastroliths. Stegosaurus ungulatus by the describers. [3] Marsh initially believed the remains were from an aquatic turtle-like animal, and the basis for its scientific name, 'roof(ed) lizard' was due to his early belief that the plates lay flat over the animal's back, overlapping like the shingles (tiles) on a roof. 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. Stegosaurus was extinct for 66 million years before Tyrannosaurus walked on Earth. [44] The fore limbs were much shorter than the stocky hind limbs, which resulted in an unusual posture. Its skull looked like a parrot, especially the beak, but with no feathers. Up until a few years ago,. Fossils of this dinosaur are actually relatively rare, and because of this we can only speculate the other habitats this creature lived in. . However, as Carpenter[25] has noted, the plates overlap so many tail vertebrae, movement would be limited. "Appendix." The first known skeletons were fragmentary and the bones were scattered, and it would be many years before the true appearance of these animals, including their posture and plate arrangement, became well understood. About 67 million years ago, two iconic dinosaurs, a Triceratops horridus and a Tyrannosaurus rex, died and were quickly buried together side by side in a single grave. So did dinosaurs have big outer ears? They walked on four short legs, had small heads, and long tails capped with defensive spines. They were not directly attached to the animal's skeleton, instead arising from the skin. [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".