167-688: Stegosaurus ( / ˌ s t ɛ ɡ ə ˈ s ɔːr ə s / ; lit. ' 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. 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 145 million years ago . Of
334-404: A coachwhip ) or, as more recently suggested, tactile function. The tail may have served as a counterbalance for the neck. The middle part of the tail had "double beams" (oddly shaped chevron bones on the underside, which gave Diplodocus its name). They may have provided support for the vertebrae, or perhaps prevented the blood vessels from being crushed if the animal's heavy tail pressed against
501-401: A 29 m (95 ft) long D. hallorum was estimated to weigh 23 metric tons (25 short tons) in body mass. A study in 2024 later found the mass of a 33 m (108 ft) D. hallorum to be only 21 metric tons (23 short tons), though the study suggested this only represents the average adult size and not the above average or maximum body size. The nearly complete D. carnegii skeleton at
668-649: A brain of no more than 80 g (2.8 oz) contributed to the popular old idea that all dinosaurs were unintelligent, an idea now largely rejected. Actual brain anatomy in Stegosaurus is poorly known, but the brain itself was small even for a dinosaur. 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. The presacrals are divided into cervical (neck) and dorsal (back) vertebrae, with around 10 cervicals and 17 dorsals,
835-483: A canyon west of San Ysidro , New Mexico . The find was reported to the New Mexican Museum of Natural History , who dispatched an expedition led by David D. Gillette in 1985, that collected the specimen after several visits from 1985 to 1990. The specimen was preserved in semi-articulation, including 230 gastroliths , with several vertebrae, partial pelvis, and right femur and was prepared and deposited at
1002-561: A cervical plate, and several assorted postcranial elements. Sophie the Stegosaurus is the best preserved Stegosaurus specimen, being 85% intact and containing 360 bones. Sophie was first discovered by Bob Simon in 2003 at a quarry on the Red Canyon Ranch near Shell, Wyoming , and was excavated by crews from the Swiss Sauriermuseum in 2004 and later prepared by museum staff, who gave it the nickname Sarah after
1169-399: 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. 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. A cranium (CM 12000)
1336-523: A decrease in abundance of leaf-chewing larvae in the fall when hardwood leaf palatability decreases due to increased tannin levels which results in a decline of arthropod species richness , and increased palatability of plant communities at higher elevations where grasshoppers abundances are lower. Climatic stressors such as ocean acidification can lead to responses in plant-herbivore interactions in relation to palatability as well. The myriad defenses displayed by plants means that their herbivores need
1503-429: A dermal plate, and several additional postcranial elements that were collected north of Morrison, Colorado at Lakes’ YPM Quarry 5. These first, fragmented bones (YPM 1850) became the holotype of Stegosaurus armatus when Yale paleontologist Othniel Charles Marsh described them in 1877. Marsh initially believed the remains were from an aquatic turtle-like animal, and the basis for its scientific name , 'roof(ed) lizard'
1670-423: A funiculus cord that runs from the external occipital crest of the skull to elongate vertebral neural spines or “withers” in the shoulder region plus sheet-like extensions called laminae run from the cord to the neural spines on some or all of the cervical vertebrae. However, most sauropods do not have withers in the shoulders, so if they possessed a similar ligament, it would differ substantially, perhaps anchoring in
1837-623: A greater and more diverse set of resources. Coevolution and phylogenetic correlation between herbivores and plants are important aspects of the influence of herbivore and plant interactions on communities and ecosystem functioning, especially in regard to herbivorous insects. This is apparent in the adaptations plants develop to tolerate and/or defend from insect herbivory and the responses of herbivores to overcome these adaptations. The evolution of antagonistic and mutualistic plant-herbivore interactions are not mutually exclusive and may co-occur. Plant phylogeny has been found to facilitate
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#17327825446512004-465: A herbivore in a dense forest would spend more time handling (eating) the vegetation because there was so much vegetation around than a herbivore in a sparse forest, who could easily browse through the forest vegetation. According to the Holling's disk equation, a herbivore in the sparse forest would be more efficient at eating than the herbivore in the dense forest. The marginal value theorem describes
2171-524: A horizontal posture, with forelimbs shorter than hind limbs. Diplodocids flourished in the Late Jurassic of North America and possibly Africa. A subfamily, the Diplodocinae , was erected to include Diplodocus and its closest relatives, including Barosaurus . More distantly related is the contemporaneous Apatosaurus , which is still considered a diplodocid, although not a diplodocine, as it
2338-493: A largely horizontal posture. The skeletal structure of these long-necked, long-tailed animals supported by four sturdy legs have been compared with cantilever bridges . In fact, D. carnegii is currently one of the longest dinosaurs known from a complete skeleton, with a total length of 24–26 meters (79–85 ft). Modern mass estimates for D. carnegii have tended to be in the 12–14.8-metric-ton (13.2–16.3-short-ton) range. Diplodocus hallorum , known from partial remains,
2505-526: A limb on the Diplodocus . The skin fossil itself is small in size, reaching less than 70 cm in length. Due to the vast amount of scale diversity seen within such a small area, as well as the scales being smaller in comparison to other diplodocid scale fossils, and the presence of small and potentially “juvenile” material at the Mother’s Day Quarry, it is hypothesized that the skin originated from
2672-495: A mutual relationship with the plant species that they forage by digging and disturbing the sediment which removes competing plants and subsequently allows colonization of other plant species. When herbivores are affected by trophic cascades , plant communities can be indirectly affected. Often these effects are felt when predator populations decline and herbivore populations are no longer limited, which leads to intense herbivore foraging which can suppress plant communities. With
2839-525: A nature hike. Kessler contacted the Denver Museum of Nature and Science , who sent paleontologist Robert Landberg. 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". Phillip Reinheimer, a steel worker, mounted the Stegosaurus skeleton at
3006-535: A nearly complete skull of a juvenile Diplodocus , was found at the quarry and is one of few known and highlighted ontogenetic dietary changes in the genus. Diplodocus is both the type genus of, and gives its name to, the Diplodocidae, the family in which it belongs. Members of this family, while still massive, have a markedly more slender build than other sauropods, such as the titanosaurs and brachiosaurs . All are characterized by long necks and tails and
3173-557: A new patch of food when the patch they are currently feeding on requires more energy to obtain food than an average patch. Within this theory, two subsequent parameters emerge, the Giving Up Density (GUD) and the Giving Up Time (GUT). The Giving Up Density (GUD) quantifies the amount of food that remains in a patch when a forager moves to a new patch. The Giving Up Time (GUT) is used when an animal continuously assesses
3340-726: A phylogenetic analysis including almost every known stegosaurian genus. Their dataset was expanded upon in the following years with additional taxa. In their 2024 description of stegosaur fossil material from China's Hekou Group , Li et al . used a modified version of the dataset of Raven and Maidment to analyze the phylogenetic relations of the Stegosauria: Bashanosaurus Chungkingosaurus Huayangosaurus Isaberrysaura Gigantspinosaurus Alcovasaurus Herbivorous A herbivore
3507-413: A relatively low brain-to-body mass ratio . It had a short neck and a small head, meaning it most likely ate low-lying bushes and shrubs. One species, Stegosaurus ungulatus , is one of the largest known of all the stegosaurians , with the largest known specimens measuring about 7.5 metres (25 ft) long and weighing over 5 metric tons (5.5 short tons). Stegosaurus remains were first identified during
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#17327825446513674-715: A result of their plant-based diet, herbivorous animals typically have mouth structures ( jaws or mouthparts ) well adapted to mechanically break down plant materials, and their digestive systems have special enzymes (e.g. amylase and cellulase ) to digest polysaccharides . Grazing herbivores such as horses and cattles have wide flat- crowned teeth that are better adapted for grinding grass , tree bark and other tougher lignin -containing materials, and many of them evolved rumination or cecotropic behaviors to better extract nutrients from plants. A large percentage of herbivores also have mutualistic gut flora made up of bacteria and protozoans that help to degrade
3841-479: A semi articulated skull of a diplodocine with mandibles (CM 11161) in the Monument. Another skull (CM 3452) was found by Carnegie crews in 1915, bearing 6 articulated cervical vertebrae and mandibles, and another skull with mandibles (CM 1155) was found in 1923. All of the skulls found at Dinosaur National Monument were shipped back to Pittsburgh and described by William Jacob Holland in detail in 1924, who referred
4008-402: A single action. Also, the palinal (backwards) motion of the lower jaws could have contributed two significant roles to feeding behavior: (1) an increased gape, and (2) allowed fine adjustments of the relative positions of the tooth rows, creating a smooth stripping action. Young et al. (2012) used biomechanical modeling to examine the performance of the diplodocine skull. It was concluded that
4175-635: A single plant can have hundreds of different chemical defenses. Chemical defenses can be divided into two main groups, carbon-based defenses and nitrogen-based defenses. Plants have also changed features that enhance the probability of attracting natural enemies to herbivores. Some emit semiochemicals, odors that attract natural enemies, while others provide food and housing to maintain the natural enemies' presence, e.g. ants that reduce herbivory. A given plant species often has many types of defensive mechanisms, mechanical or chemical, constitutive or induced, which allow it to escape from herbivores. According to
4342-462: A skull molded based on USNM 2673, a skull assigned to Galeamopus pabsti . The Carnegie Museum mount became very popular, being nicknamed " Dippy " by the populace, eventually being cast and sent to museums in London , Berlin , Paris , Vienna , Bologna , St. Petersburg , Buenos Aires , Madrid , and Mexico City from 1905 to 1928. The London cast specifically became very popular; its casting
4509-486: A small or even “juvenile” Diplodocus . The first record of Diplodocus comes from Marshall P. Felch’s quarry at Garden Park near Cañon City , Colorado , when several fossils were collected by Benjamin Mudge and Samuel Wendell Williston in 1877. The first specimen (YPM VP 1920) was very incomplete, consisting only of two complete caudal vertebrae, a chevron, and several other fragmentary caudal vertebrae. The specimen
4676-574: A terrestrial mammal to be called a grazer, at least 90% of the forage has to be grass, and for a browser at least 90% tree leaves and twigs. An intermediate feeding strategy is called "mixed-feeding". In their daily need to take up energy from forage, herbivores of different body mass may be selective in choosing their food. "Selective" means that herbivores may choose their forage source depending on, e.g., season or food availability, but also that they may choose high quality (and consequently highly nutritious) forage before lower quality. The latter especially
4843-399: A tradeoff however, between foraging on many plant species to avoid toxins or specializing on one type of plant that can be detoxified. Herbivore modification is when various adaptations to body or digestive systems of the herbivore allow them to overcome plant defenses. This might include detoxifying secondary metabolites , sequestering toxins unaltered, or avoiding toxins, such as through
5010-438: A trophic cascade involved plant-herbivore interactions are coral reef ecosystems. Herbivorous fish and marine animals are important algae and seaweed grazers, and in the absence of plant-eating fish, corals are outcompeted and seaweeds deprive corals of sunlight. Agricultural crop damage by the same species totals approximately $ 100 million every year. Insect crop damages also contribute largely to annual crop losses in
5177-579: A variety of physical and metabolic alterations in the way the host plant interacts with itself and other surrounding biotic factors. Fungi, bacteria, and protists that feed on living plants are usually termed plant pathogens (plant diseases), while fungi and microbes that feed on dead plants are described as saprotrophs . Flowering plants that obtain nutrition from other living plants are usually termed parasitic plants . There is, however, no single exclusive and definitive ecological classification of consumption patterns; each textbook has its own variations on
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5344-527: A variety of skills to overcome these defenses and obtain food. These allow herbivores to increase their feeding and use of a host plant. Herbivores have three primary strategies for dealing with plant defenses: choice, herbivore modification, and plant modification. Feeding choice involves which plants a herbivore chooses to consume. It has been suggested that many herbivores feed on a variety of plants to balance their nutrient uptake and to avoid consuming too much of any one type of defensive chemical. This involves
5511-419: A wealth of skeletal remains, Diplodocus is one of the best-studied dinosaurs. Many aspects of its lifestyle have been subjects of various theories over the years. Comparisons between the scleral rings of diplodocines and modern birds and reptiles suggest that they may have been cathemeral , active throughout the day at short intervals. Marsh and then Hatcher assumed that the animal was aquatic, because of
5678-538: Is a Neo-Latin term derived from Greek διπλός ( diplos ) "double" and δοκός ( dokos ) "beam", in reference to the double-beamed chevron bones located in the underside of the tail, which were then considered unique. The genus of dinosaurs lived in what is now mid-western North America, at the end of the Jurassic period . It is one of the more common dinosaur fossils found in the middle to upper Morrison Formation , between about 154 and 152 million years ago, during
5845-470: Is a member of the sister subfamily Apatosaurinae . The Portuguese Dinheirosaurus and the African Tornieria have also been identified as close relatives of Diplodocus by some authors. Diplodocoidea comprises the diplodocids, as well as the dicraeosaurids , rebbachisaurids , Suuwassea , Amphicoelias possibly Haplocanthosaurus , and/or the nemegtosaurids . The clade
6012-460: Is a model for predicting animal behavior while looking for food or other resources, such as shelter or water. This model assesses both individual movement, such as animal behavior while looking for food, and distribution within a habitat, such as dynamics at the population and community level. For example, the model would be used to look at the browsing behavior of a deer while looking for food, as well as that deer's specific location and movement within
6179-530: Is actually dubious, which is not an ideal situation for the type species of a well-known genus like Diplodocus . A petition to the International Commission on Zoological Nomenclature was being considered which proposed making D. carnegii the new type species. This proposal was rejected by the ICZN and D. longus has been maintained as the type species, because Hatcher did not demonstrate why
6346-403: Is aided in reproduction. Plants can also be indirectly affected by herbivores through nutrient recycling , with plants benefiting from herbivores when nutrients are recycled very efficiently. Another form of plant-herbivore mutualism is physical changes to the environment and/or plant community structure by herbivores which serve as ecosystem engineers , such as wallowing by bison. Swans form
6513-439: Is an animal anatomically and physiologically evolved to feed on plants , especially upon vascular tissues such as foliage , fruits or seeds , as the main component of its diet . These more broadly also encompass animals that eat non-vascular autotrophs such as mosses , algae and lichens , but do not include those feeding on decomposed plant matters (i.e. detritivores ) or macrofungi (i.e. fungivores ). As
6680-406: Is debated but it should have been able to browse from low levels to about 4 m (13 ft) when on all fours. However, studies have shown that the center of mass of Diplodocus was very close to the hip socket ; this means that Diplodocus could rear up into a bipedal posture with relatively little effort. It also had the advantage of using its large tail as a 'prop' which would allow for
6847-431: Is derived from Latin herba 'small plant, herb' and vora , from vorare 'to eat, devour'. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants , algae and photosynthesizing bacteria . More generally, organisms that feed on autotrophs in general are known as primary consumers . Herbivory is usually limited to animals that eat plants. Insect herbivory can cause
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7014-563: Is determined by the body mass of the herbivore, with small herbivores selecting for high-quality forage, and with increasing body mass animals are less selective. Several theories attempt to explain and quantify the relationship between animals and their food, such as Kleiber's law , Holling's disk equation and the marginal value theorem (see below). Kleiber's law describes the relationship between an animal's size and its feeding strategy, saying that larger animals need to eat less food per unit weight than smaller animals. Kleiber's law states that
7181-783: Is irrelevant and derived to explain trends that do not exist in nature. Holling's disk equation models the efficiency at which predators consume prey. The model predicts that as the number of prey increases, the amount of time predators spend handling prey also increases, and therefore the efficiency of the predator decreases. In 1959, S. Holling proposed an equation to model the rate of return for an optimal diet: Rate (R )=Energy gained in foraging (Ef)/(time searching (Ts) + time handling (Th)) R = E f / ( T s + T h ) {\displaystyle R=Ef/(Ts+Th)} Where s=cost of search per unit time f=rate of encounter with items, h=handling time, e=energy gained per encounter. In effect, this would indicate that
7348-555: Is now Dinosaur National Monument on the border region between Colorado and Utah, with the sandstone dating to the Kimmeridgian of the Morrison Formation . From 1909 to 1922, with the Carnegie Museum excavating the quarry, eventually unearthing over 120 dinosaur individuals and 1,600+ bones, many of the associated skeletons being very complete and are on display in several American museums. In 1912, Douglass found
7515-488: Is the ability of a plant to withstand damage without a reduction in fitness. This can occur by diverting herbivory to non-essential plant parts, resource allocation, compensatory growth, or by rapid regrowth and recovery from herbivory. Resistance refers to the ability of a plant to reduce the amount of damage it receives from herbivores. This can occur via avoidance in space or time, physical defenses, or chemical defenses. Defenses can either be constitutive, always present in
7682-608: Is the first known from a Diplodocus . Another Diplodocus skeleton was collected at the Carnegie Quarry in Dinosaur National Monument, Utah, by the National Museum of Natural History in 1923. The skeleton (USNM V 10865) is one of the most complete known from Diplodocus , consisting of a semi-articulated partial postcranial skeleton, including a well preserved dorsal column. The skeleton
7849-415: Is the most likely feeding behavior of Diplodocus , as it explains the unusual wear patterns of the teeth (coming from tooth–food contact). In unilateral branch stripping, one tooth row would have been used to strip foliage from the stem, while the other would act as a guide and stabilizer. With the elongated preorbital (in front of the eyes) region of the skull, longer portions of stems could be stripped in
8016-465: Is the plate arrangement. The argument has been a major one in the history of dinosaur reconstruction. Four possible plate arrangements have been proposed over the years: After the end of the Bone Wars, many major institutions in the eastern United States were inspired by the depictions and finds by Marsh and Cope to assemble their own dinosaur fossil collections. The competition was foremost started by
8183-668: Is the sister group to Macronaria ( camarasaurids , brachiosaurids and titanosaurians). A cladogram of the Diplodocidae after Tschopp, Mateus, and Benson (2015) below: Amphicoelias altus Unnamed species Apatosaurus ajax Apatosaurus louisae Brontosaurus excelsus Brontosaurus yahnahpin Brontosaurus parvus Unnamed species Tornieria africana Supersaurus lourinhanensis Supersaurus vivianae Leinkupal laticauda Galeamopus hayi Diplodocus carnegii Diplodocus hallorum Kaatedocus siberi Barosaurus lentus Due to
8350-424: Is to study the ligaments and their attachments to bones in extant animals to see if they resemble any bony structures in sauropods or other dinosaur species like Parasaurolophus . If diplodocus relied on a mammal-like nuchal ligament, it would have been for passively sustaining the weight of its head and neck. This ligament is found in many hoofed mammals, such as bison and horses. In mammals, it typically consists of
8517-797: 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. The American Museum of Natural History was the first to launch an expedition in 1897, finding several assorted, but incomplete, Stegosaurus specimens at Bone Cabin Quarry in Como Bluff. These remains haven't been described and were mounted in 1932,
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#17327825446518684-586: The American Museum of Natural History . Arthur Lakes made another discovery later in 1879 at Como Bluff in Albany County, Wyoming , the site also dating to the Upper Jurassic of the Morrison Formation , when he found several large Stegosaurus fossils in August of that year. The majority of the fossils came from Quarry 13, including the type specimen of Stegosaurus ungulatus ( YPM 1853), which
8851-513: The Bighorn Basin Paleontological Institute in 2017. The quarry was very productive, having mostly isolated Diplodocus bones from juveniles to adults in pristine preservation. The quarry notably had a great disparity between the amount of juveniles and adults in the quarry, as well as the frequent preservation of skin impressions, pathologies , and some articulated specimens from Diplodocus. One specimen,
9018-479: The Carnegie Museum of Natural History in Pittsburgh, Pennsylvania , on which size estimates of D. hallorum are mainly based, also was found to have had its 13th tail vertebra come from another dinosaur, throwing off size estimates for D. hallorum even further. While dinosaurs such as Supersaurus were probably longer, fossil remains of these animals are only fragmentary and D. hallorum still remains among
9185-586: The International Code of Zoological Nomenclature decided to replace the type species with the more well known species Stegosaurus stenops . Marsh also incorrectly referred several fossils to S. armatus , including the dentary and teeth of the sauropod Diplodocus and putting sauropod limb bones and an Allosaurus tibia under YPM 1850. 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
9352-411: The Morrison Formation of Sheep Creek , Wyoming , with funding from Scottish-American steel tycoon Andrew Carnegie , they discovered a massive and well preserved skeleton of Diplodocus. The skeleton was collected that year by Jacob L. Wortman and several other crewmen under his direction along with several specimens of Stegosaurus , Brontosaurus parvus , and Camarasaurus preserved alongside
9519-454: The Mother's Day Quarry , exhibits several different types of scale shapes including rectangular, polygonal, pebble, ovoid, dome, and globular. These scales range in size and shape depending upon their location on the integument, the smallest of which reach about 1mm while the largest 10 mm. Some of these scales show orientations that may indicate where they belonged on the body. For instance,
9686-690: 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 . This group is widespread, with members across the Northern Hemisphere, Africa and possibly South America . Stegosaurus frequently is discovered in a clade within the Stegosauridae called Stegosaurinae, usually including
9853-595: The bony plates and spines of stegosaurians evolved from the low-keeled osteoderms characteristic of basal thyreophorans. 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. The vast majority of stegosaurian dinosaurs thus far recovered belong to
10020-491: The cellulose in plants, whose heavily cross-linking polymer structure makes it far more difficult to digest than the protein - and fat -rich animal tissues that carnivores eat. Herbivore is the anglicized form of a modern Latin coinage, herbivora , cited in Charles Lyell 's 1830 Principles of Geology . Richard Owen employed the anglicized term in an 1854 work on fossil teeth and skeletons. Herbivora
10187-459: The size of these animals. Diplodocus had small, 'peg'-like teeth that pointed forward and were only present in the anterior sections of the jaws. Its braincase was small, and the neck was composed of at least 15 vertebrae . The discovery of partial diplodocid skin impressions in 1990 showed that some species had narrow, pointed, keratinous spines, much like those on an iguana . The spines could be up to 18 centimeters (7.1 in) long, on
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#173278254465110354-432: The wetland ecosystem . Such differences in herbivore modalities can potentially lead to trade-offs that influence species traits and may lead to additive effects on community composition and ecosystem functioning. Seasonal changes and environmental gradients such as elevation and latitude often affect the palatability of plants which in turn influences herbivore community assemblages and vice versa. Examples include
10521-439: The " Bone Wars " by Othniel Charles Marsh at Dinosaur Ridge National Landmark. 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. Despite its popularity in books and film, mounted skeletons of Stegosaurus did not become a staple of major natural history museums until
10688-489: The "Cope's Nipple" site in Garden Park, Colorado in 1878. Many later researchers have considered Hypsirhophus to be a synonym of Stegosaurus , though Peter Galton (2010) suggested that it is distinct based on differences in the vertebrae. 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
10855-695: The "whiplash" portion of their tails, and possibly along the back and neck as well, similarly to hadrosaurids . The spines have been incorporated into many recent reconstructions of Diplodocus , notably Walking with Dinosaurs . The original description of the spines noted that the specimens in the Howe Quarry near Shell, Wyoming were associated with skeletal remains of an undescribed diplodocid "resembling Diplodocus and Barosaurus ." Specimens from this quarry have since been referred to Kaatedocus siberi and Barosaurus sp., rather than Diplodocus . Fossilized skin of Diplodocus sp., discovered at
11022-413: The 1970s, general consensus has the sauropods as firmly terrestrial animals, browsing on trees, ferns, and bushes. Scientists have debated as to how sauropods were able to breathe with their large body sizes and long necks, which would have increased the amount of dead space . They likely had an avian respiratory system , which is more efficient than a mammalian and reptilian system. Reconstructions of
11189-728: The Carnegie Museum that had been collected at Dinosaur National Monument. The specimen (DMNH 1494) was nearly as complete as the Smithsonian specimen. It consists of the vertebral column complete from cervical 8 to caudal 20, right scapula-coracoid, complete pelvis, and both hind limbs without feet. It was mounted in the museum during the late 1930s and remounted in the early 1990s. Although not described in detail, Tschopp and colleagues determined that this skeleton also belonged to D. hallorum . Few Diplodocus finds came for many years until 1979, when three hikers came across several vertebrae stuck in elevated stone next to several petroglyphs in
11356-495: The DMNS in 1938. 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. The expedition was successful in finding a nearly complete Stegosaurus near the Kessler site by Bryan Small, who would become the eponym of the new site. The "Small Quarry" Stegosaurus' articulation and completeness clarified
11523-545: The New Mexican Museum of Natural History under NMMNH P-3690. The specimen was not described until 1991 in the Journal of Paleontology , where Gillette named it Seismosaurus halli (Jim and Ruth Hall's seismic lizard) , though in 1994, Gillette published an amendment changing the name to S. hallorum. In 2004 and later 2006, Seismosaurus was synonymized with Diplodocus and even suggested to be synonymous with
11690-515: The U.S. Herbivores also affect economics through the revenue generated by hunting and ecotourism. For example, the hunting of herbivorous game species such as white-tailed deer, cottontail rabbits, antelope, and elk in the U.S. contributes greatly to the billion-dollar annually, hunting industry. Ecotourism is a major source of revenue, particularly in Africa, where many large mammalian herbivores such as elephants, zebras, and giraffes help to bring in
11857-508: The air. 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 function of this array of plates and spikes has been the subject of much speculation among scientists. 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. Stegosaurus had
12024-513: The animal's overall size, the braincase of Stegosaurus was small, being no larger than that of a dog. 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. The endocast showed the brain was indeed very small, the smallest proportionally of all dinosaur endocasts then known. The fact that an animal weighing over 4.5 metric tons (5 short tons ) could have
12191-450: The animal's skeleton, instead arising from the skin. The largest plates were found over the hips and could measure over 60 cm (24 in) wide and 60 cm (24 in) tall. 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. Galton noted that
12358-405: The apex forms a blunt, triangular point. The most prominent wear facet is on the apex, though unlike all other wear patterns observed within sauropods, diplodocine wear patterns are on the labial (cheek) side of both the upper and lower teeth. This implies that the feeding mechanism of Diplodocus and other diplodocids was radically different from that of other sauropods. Unilateral branch stripping
12525-416: The balance between eating all the food in a patch for immediate energy, or moving to a new patch and leaving the plants in the first patch to regenerate for future use. The theory predicts that absent complicating factors, an animal should leave a resource patch when the rate of payoff (amount of food) falls below the average rate of payoff for the entire area. According to this theory, an animal should move to
12692-431: The base of their necks at the maximum possible vertical extension when in a normal, alert posture, and argued that the same would hold true for sauropods barring any unknown, unique characteristics that set the soft tissue anatomy of their necks apart from other animals. The study found faults with Stevens' assumptions regarding the potential range of motion in sauropod necks, and based on comparing skeletons to living animals
12859-469: The body, including the limbs. The scapula (shoulder blade) is sub-rectangular, with a robust blade. Though it is not always perfectly preserved, the acromion ridge is slightly larger than in Kentrosaurus . The blade is relatively straight, although it curves towards the back. There is a small bump on the back of the blade, that would have served as the base of the triceps muscle. Articulated with
13026-824: The colonization and community assembly of herbivores, and there is evidence of phylogenetic linkage between plant beta diversity and phylogenetic beta diversity of insect clades such as butterflies . These types of eco-evolutionary feedbacks between plants and herbivores are likely the main driving force behind plant and herbivore diversity. Abiotic factors such as climate and biogeographical features also impact plant-herbivore communities and interactions. For example, in temperate freshwater wetlands herbivorous waterfowl communities change according to season, with species that eat above-ground vegetation being abundant during summer, and species that forage below-ground being present in winter months. These seasonal herbivore communities differ in both their assemblage and functions within
13193-439: The conclusion that the plates were arranged in pairs in two rows along the back, arranged above the bases of the ribs. Lucas commissioned Charles R. Knight to produce a life restoration of S. ungulatus based on his new interpretation. However, the following year, Lucas wrote that he now believed the plates were probably attached in staggered rows. In 1910, Richard Swann Lull wrote that the alternating pattern seen in S. stenops
13360-403: The depictions and finds by Marsh and Cope to assemble their own dinosaur fossil collections. The competition to mount the first sauropod skeleton specifically was the most intense, with the American Museum of Natural History , Carnegie Museum of Natural History , and Field Museum of Natural History all sending expeditions to the west to find the most complete sauropod specimen, bring it back to
13527-694: The discovery of a 40% complete Stegosaurus skeleton in Rabbit Valley in Mesa County, Colorado by Harold Bollan near the Dinosaur Journey Museum . The skeleton was nicknamed the "Bollan Stegosaurus" and is in the collections of the Dinosaur Journey Museum. At Jensen-Jensen Quarry , an articulated torso including several dorsal plates from a small individual were collected and briefly described in 2014, though
13694-470: 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. Marshall P. Felch collected the skeleton throughout 1885 and 1886 from Morrison Formation strata at his quarry in Garden Park, a town near Cañon City , Colorado . The skeleton was expertly unearthed by Felch, who first divided
13861-769: The dubious D. longus and later Tschopp et al. 's phylogenetic analysis in 2015 supported the idea that many specimens referred to D. longus actually belonged to D. hallorum . In 1994, the Museum of the Rockies discovered a very productive fossil site at Mother's Day Quarry in Carbon County, Montana from the Salt Wash member of the Morrison Formation that was later excavated by the Cincinnati Museum of Natural History and Science in 1996, and after that
14028-424: The effectiveness of plant defenses activated by sunlight. A plant defense is a trait that increases plant fitness when faced with herbivory. This is measured relative to another plant that lacks the defensive trait. Plant defenses increase survival and/or reproduction (fitness) of plants under pressure of predation from herbivores. Defense can be divided into two main categories, tolerance and resistance. Tolerance
14195-538: The end of that period. Herbivory among four-limbed terrestrial vertebrates, the tetrapods , developed in the Late Carboniferous (307–299 million years ago). The oldest known example being Desmatodon hesperis. Early tetrapods were large amphibious piscivores . While amphibians continued to feed on fish and insects, some reptiles began exploring two new food types, tetrapods (carnivory) and plants (herbivory). The entire dinosaur order ornithischia
14362-507: The equivalent of millions of US dollars to various nations annually. Diplodocus Diplodocus ( / d ɪ ˈ p l ɒ d ə k ə s / , / d aɪ ˈ p l ɒ d ə k ə s / , or / ˌ d ɪ p l oʊ ˈ d oʊ k ə s / ) is an extinct genus of diplodocid sauropod dinosaurs known from the Late Jurassic of North America. The first fossils of Diplodocus were discovered in 1877 by S. W. Williston . The generic name, coined by Othniel Charles Marsh in 1878,
14529-606: The finger and hand bones arranged into a vertical column, horseshoe-shaped in cross section. Diplodocus lacked claws on all but one digit of the front limb, and this claw was unusually large relative to other sauropods, flattened from side to side, and detached from the bones of the hand. The function of this unusually specialized claw is unknown. No skull has ever been found that can be confidently said to belong to Diplodocus , though skulls of other diplodocids closely related to Diplodocus (such as Galeamopus ) are well known. The skulls of diplodocids were very small compared with
14696-558: The first few dorsals, the centrum of the bones become more elongate front-to-back, and the transverse processes become more elevated dorsal . The sacrum of S. stenops includes four sacral vertebrae, but one of the dorsals is also incorporated into the structure. In some specimens of S. stenops , a caudal is also incorporated, as a caudosacral. In Hesperosaurus there are two dorsosacrals, and only four fused sacrals, but in Kentrosaurus there may be as many as seven vertebrae in
14863-496: The first half of the 20th century, due largely to the disarticulated nature of most fossil specimens. Until 1918, the only mounted skeleton of Stegosaurus in the world was O. C. Marsh's type specimen of S. ungulatus at the Peabody Museum of Natural History , which was put on display in 1910. However, this mount was dismantled in 1917 when the old Peabody Museum building was demolished. This historically significant specimen
15030-493: The first land plants evolved. Insects fed on the spores of early Devonian plants, and the Rhynie chert also provides evidence that organisms fed on plants using a "pierce and suck" technique. During the next 75 million years , plants evolved a range of more complex organs, such as roots and seeds. There is no evidence of any organism being fed upon until the middle-late Mississippian , 330.9 million years ago . There
15197-596: The food chain because they consume plants to digest the carbohydrates photosynthetically produced by a plant. Carnivores in turn consume herbivores for the same reason, while omnivores can obtain their nutrients from either plants or animals. Due to a herbivore's ability to survive solely on tough and fibrous plant matter, they are termed the primary consumers in the food cycle (chain). Herbivory, carnivory, and omnivory can be regarded as special cases of consumer–resource interactions . Two herbivore feeding strategies are grazing (e.g. cows) and browsing (e.g. moose). For
15364-565: The food source, in this case, the plant. Several factors play into these fluctuating populations and help stabilize predator-prey dynamics. For example, spatial heterogeneity is maintained, which means there will always be pockets of plants not found by herbivores. This stabilizing dynamic plays an especially important role for specialist herbivores that feed on one species of plant and prevents these specialists from wiping out their food source. Prey defenses also help stabilize predator-prey dynamics, and for more information on these relationships see
15531-426: The forested habitat and its interaction with other deer while in that habitat. This model has been criticized as circular and untestable. Critics have pointed out that its proponents use examples that fit the theory, but do not use the model when it does not fit the reality. Other critics point out that animals do not have the ability to assess and maximize their potential gains, therefore the optimal foraging theory
15698-832: The fossil record of their jaws near the Permio-Carboniferous boundary, approximately 300 million years ago. The earliest evidence of their herbivory has been attributed to dental occlusion , the process in which teeth from the upper jaw come in contact with teeth in the lower jaw is present. The evolution of dental occlusion led to a drastic increase in plant food processing and provides evidence about feeding strategies based on tooth wear patterns. Examination of phylogenetic frameworks of tooth and jaw morphologes has revealed that dental occlusion developed independently in several lineages tetrapod herbivores. This suggests that evolution and spread occurred simultaneously within various lineages. Herbivores form an important link in
15865-443: The ground, while the head of Stegosaurus was positioned relatively low down, probably no higher than 1 m (3.3 ft) above the ground. The most recognizable features of Stegosaurus are its dermal plates, which consisted of between 17 and 22 separate plates and flat spines. These were highly modified osteoderms (bony-cored scales), similar to those seen in crocodiles and many lizards today. They were not directly attached to
16032-407: The ground. These "double beams" are also seen in some related dinosaurs. Chevron bones of this particular form were initially believed to be unique to Diplodocus ; since then they have been discovered in other members of the diplodocid family as well as in non-diplodocid sauropods, such as Mamenchisaurus . Like other sauropods, the manus (front "feet") of Diplodocus were highly modified, with
16199-482: The hip region. Another hypothesized neck-supporting ligament is an avian-like elastic ligament, such as that seen in Struthio camelus . This ligament acts similarly to the mammal-like nuchal ligament but comprises short segments of ligament that connect the bases of the neural spines, and therefore does not need a robust attachment zone like those seen in mammals. A 2009 study found that all tetrapods appear to hold
16366-512: The home institution, and mount it in their fossil halls. The American Museum of Natural History was the first to launch an expedition, finding a semi-articulated partial postcranial skeleton containing many vertebrae of Diplodocus in at Como Bluff in 1897. The skeleton (AMNH FR 223) was collected by Barnum Brown and Henry Osborn , who shipped the specimen to the AMNH and it was briefly described in 1899 by Osborn, who referred it to D. longus . It
16533-430: The incorporation of silica into cell walls is analogous to that of the role of lignin in that it is a compression-resistant structural component of cell walls; so that plants with their cell walls impregnated with silica are thereby afforded a measure of protection against herbivory. Chemical defenses are secondary metabolites produced by the plant that deter herbivory. There are a wide variety of these in nature and
16700-583: The information known about Stegosaurus comes from the remains of mature animals; more recently, though, juvenile remains of Stegosaurus have been found. One subadult specimen, discovered in 1994 in Wyoming, is 4.6 m (15.1 ft) long and 2 m (6.6 ft) high, and is estimated to have weighed 1.5-2.2 metric tons (1.6-2.4 short tons) while alive. It is on display in the University of Wyoming Geological Museum. The long and narrow skull
16867-406: The interaction of herbivory and plant defense is negative, with one individual reducing the fitness of the other, some is beneficial. This beneficial herbivory takes the form of mutualisms in which both partners benefit in some way from the interaction. Seed dispersal by herbivores and pollination are two forms of mutualistic herbivory in which the herbivore receives a food resource and the plant
17034-524: The landowner's daughter. The skeleton had been excavated on private land and was available for purchase. The Natural History Museum, London worked with private donors, most notably Jeremy Herrmann, to find the funding and then arranged to purchase the specimen, which was given the new official museum collection specimen designation NHMUK PV R36730 and re-nicknamed Sophie after Jeremy Herrmann's daughter. The mounted skeleton went on display in December 2014 and
17201-462: The late Kimmeridgian Age , although it may have made it into the Tithonian. The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs, such as Apatosaurus , Barosaurus , Brachiosaurus , Brontosaurus , and Camarasaurus . Its great size may have been a deterrent to the predators Allosaurus and Ceratosaurus : their remains have been found in
17368-520: The longest known dinosaur (excluding those known from exceedingly poor remains, such as Amphicoelias or Maraapunisaurus ). The estimated length was later revised downward to 30.5–35 m (100–115 ft) and later on to 29–33.5 m (95–110 ft) based on findings that show that Gillette had originally misplaced vertebrae 12–19 as vertebrae 20–27. Weight estimates based on the revised length are as high as 38 metric tons (42 short tons) although more recently, and according to Gregory S. Paul,
17535-427: The longest known dinosaurs. Diplodocus had an extremely long tail, composed of about 80 caudal vertebrae , which are almost double the number some of the earlier sauropods had in their tails (such as Shunosaurus with 43), and far more than contemporaneous macronarians had (such as Camarasaurus with 53). Some speculation exists as to whether it may have had a defensive or noisemaking (by cracking it like
17702-563: The longest necks would have required a 1.6-ton heart – a tenth of the animal's body weight. The study proposed that animals like these would have had rudimentary auxiliary "hearts" in their necks, whose only purpose was to pump blood up to the next "heart". Some argue that the near-horizontal posture of the head and neck would have eliminated the problem of supplying blood to the brain, as it would not be elevated. Diplodocines have highly unusual teeth compared to other sauropods. The crowns are long and slender, and elliptical in cross-section, while
17869-407: The metabolic rate (q 0 ) of an animal is the mass of the animal (M) raised to the 3/4 power: q 0 =M Therefore, the mass of the animal increases at a faster rate than the metabolic rate. Herbivores employ numerous types of feeding strategies. Many herbivores do not fall into one specific feeding strategy, but employ several strategies and eat a variety of plant parts. Optimal foraging theory
18036-492: The mid-20th century, and many museums have had to assemble composite displays from several different specimens due to a lack of complete skeletons. Stegosaurus is one of the better-known dinosaurs and has been featured in film, on postal stamps, and in many other types of media. Stegosaurus , one of the many dinosaurs described in the Bone Wars , was first collected by Arthur Lakes and consisted of several caudal vertebrae,
18203-438: The morphology of sauropod necks have concluded that the neutral posture of Diplodocus neck was close to horizontal, rather than vertical, and scientists such as Kent Stevens have used this to argue that sauropods including Diplodocus did not raise their heads much above shoulder level. A nuchal ligament may have held the neck in this position. One approach to understanding the possible ligament structure in ancient sauropods
18370-435: The most complete being USNM 6531. 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 . 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. Additional specimens recovered from
18537-551: The mount being a composite primarily of specimens AMNH 650 & 470 from Bone Cabin Quarry. The AMNH mount is cast and on display at the Field Museum, which didn't collect any Stegosaurus skeletons during the Second Dinosaur Rush. The Carnegie Museum in Pittsburgh on the other hand collected many Stegosaurus specimens, first at Freezout Hills in Carbon County, Wyoming in 1902–03. The fossils included only
18704-447: The namesake of the species, meaning "hoofed roofed lizard". 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. 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
18871-449: The neck and thorax of Diplodocus show great pneumaticity , which could have played a role in respiration as it does in birds. The depiction of Diplodocus posture has changed considerably over the years. For instance, a classic 1910 reconstruction by Oliver P. Hay depicts two Diplodocus with splayed lizard-like limbs on the banks of a river. Hay argued that Diplodocus had a sprawling, lizard-like gait with widely splayed legs, and
19038-438: The new mount for the museum's journal, Barnum Brown described (and disputed) the popular misconception that the Stegosaurus had a "second brain" in its hips. 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. One of the major subjects of books and articles about Stegosaurus
19205-422: The ovoid scales are closely clustered together and look similar to scales in modern reptiles that are located dorsally. Another orientation on the fossil consists of arching rows of square scales that interrupts nearby polygonal scale patterning. It is noted that the arching scale rows look similar to the scale orientations seen around crocodilian limbs, suggesting that this area may have also originated from around
19372-416: The paratype. There were political reasons rather than scientific for naming the first dinosaur collected by the Carnegie Museum for their patron, Andrew Carnegie. It was not until 1907, that the Carnegie Museum of Natural History created a composite mount of Diplodocus carnegii that incorporated CM 84 and CM 94 along with several other specimens and even other taxa were used to complete the mount, including
19539-402: The patch quality. Interactions between plants and herbivores can play a prevalent role in ecosystem dynamics such community structure and functional processes. Plant diversity and distribution is often driven by herbivory, and it is likely that trade-offs between plant competitiveness and defensiveness , and between colonization and mortality allow for coexistence between species in
19706-475: The peak of the back, and that there was no evidence of the plates having shifted relative to the body during fossilization. Gilmore and Lucas' interpretation became the generally accepted standard, and Lull's mount at the Peabody Museum was changed to reflect this in 1924. Though considered one of the most distinctive types of dinosaur, Stegosaurus displays were missing from a majority of museums during
19873-570: The plant, or induced, produced or translocated by the plant following damage or stress. Physical, or mechanical, defenses are barriers or structures designed to deter herbivores or reduce intake rates, lowering overall herbivory. Thorns such as those found on roses or acacia trees are one example, as are the spines on a cactus. Smaller hairs known as trichomes may cover leaves or stems and are especially effective against invertebrate herbivores. In addition, some plants have waxes or resins that alter their texture, making them difficult to eat. Also
20040-425: The plates are manifestly chiral and no two plates of the same size and shape have been found for an individual; however plates have been correlated between individuals. Well preserved integumentary impressions of the plates of Hesperosaurus show a smooth surface with long and parallel, shallow grooves. This indicates that the plates were covered in keratinous sheaths. Like the spikes and shields of ankylosaurs ,
20207-478: The plates in S. stenops have been found articulated in two staggered rows, rather than paired. Fewer S. ungulatus plates have been found, and none articulated, making the arrangement in this species more difficult to determine. 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. Many of
20374-405: The position of its nasal openings at the apex of the cranium. Similar aquatic behavior was commonly depicted for other large sauropods, such as Brachiosaurus and Apatosaurus . A 1951 study by Kenneth A. Kermack indicates that sauropods probably could not have breathed through their nostrils when the rest of the body was submerged, as the water pressure on the chest wall would be too great. Since
20541-482: 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. The Stegosaurus skeletons have been mounted alongside an Allosaurus skeleton collected in Moffat County, Colorado originally in 1979. 1987 saw
20708-538: The presence of herbivores. However, the effects of herbivory on plant diversity and richness is variable. For example, increased abundance of herbivores such as deer decrease plant diversity and species richness , while other large mammalian herbivores like bison control dominant species which allows other species to flourish. Plant-herbivore interactions can also operate so that plant communities mediate herbivore communities. Plant communities that are more diverse typically sustain greater herbivore richness by providing
20875-403: The production of large amounts of saliva to reduce effectiveness of defenses. Herbivores may also utilize symbionts to evade plant defenses. For example, some aphids use bacteria in their gut to provide essential amino acids lacking in their sap diet. Plant modification occurs when herbivores manipulate their plant prey to increase feeding. For example, some caterpillars roll leaves to reduce
21042-414: The proposal that its dentition was used for bark-stripping was not supported by the data, which showed that under that scenario, the skull and teeth would undergo extreme stresses. The hypotheses of branch-stripping and/or precision biting were both shown to be biomechanically plausible feeding behaviors. Diplodocine teeth were also continually replaced throughout their lives, usually in less than 35 days, as
21209-426: The sacrum, with both dorsosacrals and caudosacrals. S. stenops preserves 46 caudal vertebrae, and up to 49, and along the series both the centrums and the neural spines become smaller, until the neural spines disappear at caudal 35. Around the middle of the tail, the neural spines become bifurcated , meaning they are divided near the top. With multiple well-preserved skeletons, S. stenops preserves all regions of
21376-464: The same strata , which suggests that they coexisted with Diplodocus . Diplodocus is among the most easily identifiable dinosaurs, with its typical sauropod shape, long neck and tail, and four sturdy legs. For many years, it was the longest dinosaur known. Among the best-known sauropods, Diplodocus were very large, long-necked, quadrupedal animals, with long, whip-like tails. Their forelimbs were slightly shorter than their hind limbs, resulting in
21543-529: The same quarry by the United States National Museum of Natural History , including tail vertebrae and an additional large plate (USNM 7414), belong to the same individual as YPM 1853. The next species of Stegosaurus to be named was S. marshi by Frederick Lucas in 1901. Lucas reclassified this species in the new genus Hoplitosaurus later that year. Lucas also re-examined the issue of the life appearance of Stegosaurus , coming to
21710-487: The scapula, the coracoid is sub-circular. The hind feet each had three short toes, while each fore foot had five toes; only the inner two toes had a blunt hoof. 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. All four limbs were supported by pads behind the toes. The fore limbs were much shorter than the stocky hind limbs, which resulted in an unusual posture. The tail appears to have been held well clear of
21877-490: The section on Plant Defenses. Eating a second prey type helps herbivores' populations stabilize. Alternating between two or more plant types provides population stability for the herbivore, while the populations of the plants oscillate. This plays an important role for generalist herbivores that eat a variety of plants. Keystone herbivores keep vegetation populations in check and allow for a greater diversity of both herbivores and plants. When an invasive herbivore or plant enters
22044-556: The size of herbivores having an effect on the amount of energy intake that is needed, larger herbivores need to forage on higher quality or more plants to gain the optimal amount of nutrients and energy compared to smaller herbivores. Environmental degradation from white-tailed deer ( Odocoileus virginianus ) in the US alone has the potential to both change vegetative communities through over-browsing and cost forest restoration projects upwards of $ 750 million annually. Another example of
22211-484: The skeleton into labeled blocks and prepared them separately. The skeleton was shipped to Marsh in 1887, who named it Stegosaurus stenops ( "narrow-faced roof lizard") that year. 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. This first reconstruction, of S. ungulatus with missing parts filled in from S. stenops ,
22378-484: The skeleton. The skeleton (CM 84) was preserved in semi articulation and was very complete, including 41 well preserved vertebrae from the mid caudals to the anterior cervicals , 18 ribs, 2 sternal ribs, a partial pelvis, right scapulocoracoid , and right femur. In 1900, Carnegie crews returned to Sheep Creek, this expedition led by John Bell Hatcher , William Jacob Holland , and Charles Gilmore , and discovered another well preserved skeleton of Diplodocus adjacent to
22545-466: The species is now seen as synonymous with Stegosaurus ungulatus . 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. 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. The greatest Stegosaurus discovery came in 1885 with
22712-565: 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 . The remains of over 80 individual animals of this genus have been found. Stegosaurus would have lived alongside dinosaurs such as Apatosaurus , Diplodocus , Camarasaurus and Allosaurus , the latter of which may have preyed on it. They were large, heavily built, herbivorous quadrupeds with rounded backs, short fore limbs, long hind limbs, and tails held high in
22879-453: The specimen collected in 1899. The second skeleton (CM 94) was from a smaller individual and had preserved fewer vertebrae, but preserved more caudal vertebrae and appendicular remains than CM 84. Both of the skeletons were named and described in great detail by John Bell Hatcher in 1901, with Hatcher making CM 84 the type specimen of a new species of Diplodocus , Diplodocus carnegii (" Andrew Carnegie 's double beam"), with CM 94 becoming
23046-404: The specimen he called Diplodocus carnegii was not actually just a more complete specimen of Diplodocus longus . Although the type specimen was very fragmentary, several additional diplodocid fossils were collected at Felch’s quarry from 1877 to 1884 and sent to Marsh, who then referred them to D. longus . One specimen ( USNM V 2672), an articulated complete skull, mandibles, and partial atlas
23213-511: The specimen was collected years before and is still in preparation at Brigham Young University . 2007 saw the description of a Stegosaurus specimen from the Upper Jurassic Lourinha Formation of Portugal , the specimen was placed as Stegosaurus cf. ungulatus by the describers. The specimen is one of the few associated Stegosaurus skeletons known, though it only contains a tooth, 13 vertebrae, partial limbs,
23380-420: The specimens to D. longus . This assignment was also questioned by Tschopp, who stated that all of the aforementioned skulls could not be referred to any specific diplodocine. Hundreds of assorted postcranial elements were found in the Monument that have been referred to Diplodocus , but few have been properly described. A nearly complete skull of a juvenile Diplodocus was collected by Douglass in 1921, and it
23547-452: The study also argued that soft tissues could have increased flexibility more than the bones alone suggest. For these reasons they argued that Diplodocus would have held its neck at a more elevated angle than previous studies have concluded. As with the related genus Barosaurus , the very long neck of Diplodocus is the source of much controversy among scientists. A 1992 Columbia University study of diplodocid neck structure indicated that
23714-453: The system, the balance is thrown off and the diversity can collapse to a monotaxon system. The back and forth relationship of plant defense and herbivore offense drives coevolution between plants and herbivores, resulting in a "coevolutionary arms race". The escape and radiation mechanisms for coevolution, presents the idea that adaptations in herbivores and their host plants, has been the driving force behind speciation . While much of
23881-746: The taxa Wuerhosaurus and Hesperosaurus . The cladogram below displays the results of the "preferred tree" phylogenetic analysis of Raven et al . (2023), showing the position of the Stegosaurinae within Stegosauria and Eurypoda . Ankylosauria Tuojiangosaurus Paranthodon Chungkingosaurus Gigantspinosaurus Isaberrysaura Huayangosaurus Jiangjunosaurus Dacentrurus Stegosaurus stenops Hesperosaurus Wuerhosaurus Loricatosaurus Alcovasaurus Kentrosaurus Adratiklit Miragaia In 2017, Raven and Maidment published
24048-667: The teeth when viewed from the side, and these probably supported a turtle-like beak in life. The presence of a beak extended along much of the jaws may have precluded the presence of cheeks in these species. 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. Other researchers have interpreted these ridges as modified versions of similar structures in other ornithischians which might have supported fleshy cheeks, rather than beaks. Stegosaurian teeth were small, triangular, and flat; wear facets show that they did grind their food. Despite
24215-485: The theme. The understanding of herbivory in geological time comes from three sources: fossilized plants, which may preserve evidence of defence (such as spines), or herbivory-related damage; the observation of plant debris in fossilised animal faeces ; and the construction of herbivore mouthparts. Although herbivory was long thought to be a Mesozoic phenomenon, fossils have shown that plants were being consumed by arthropods within less than 20 million years after
24382-421: The theory of predator –prey interactions, the relationship between herbivores and plants is cyclic. When prey (plants) are numerous their predators (herbivores) increase in numbers, reducing the prey population, which in turn causes predator number to decline. The prey population eventually recovers, starting a new cycle. This suggests that the population of the herbivore fluctuates around the carrying capacity of
24549-482: The total number being one greater than in Hesperosaurus , two greater than Huayangosaurus , although Miragaia preserves 17 cervicals and an unknown number of dorsals. The first cervical vertebra is the axis bone , which is connected and often fused to the atlas bone . Farther posteriorly, the proportionately larger the cervicals become, although they do not change greatly in anything other than size. Past
24716-744: The vertebrae preserved in semi-articulation and next to an Allosaurus skeleton found nicknamed "Big Al II". The quadrupedal Stegosaurus is one of the most easily identifiable dinosaur genera, due to the distinctive double row of kite-shaped plates rising vertically along the rounded back and the two pairs of long spikes extending horizontally near the end of the tail. S. stenops reached 6.5 m (21.3 ft) in length and 3.5 metric tons (3.9 short tons) in body mass, while S. ungulatus reached 7 m (23.0 ft) in length and 3.8 metric tons (4.2 short tons) in body mass. Some large individuals may have reached 7.5 m (25 ft) in length and 5.0–5.3 metric tons (5.5–5.8 short tons) in body mass. Most of
24883-429: Was a gap of 50 to 100 million years between the time each organ evolved and the time organisms evolved to feed upon them; this may be due to the low levels of oxygen during this period, which may have suppressed evolution. Further than their arthropod status, the identity of these early herbivores is uncertain. Hole feeding and skeletonization are recorded in the early Permian , with surface fluid feeding evolving by
25050-524: Was also found by Carnegie crews, one of the few known. Both the AMNH and CM material has been referred to Stegosaurus ungulatus . 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. An important discovery came in 1937 again at Garden Park by a high school teacher named Frank Kessler in while leading
25217-484: Was briefly described by Charles Gilmore in 1932, who also referred it to D. longus , and it was mounted in the fossil hall at the National Museum of Natural History the same year. In Emmanuel Tschopp et al .'s phylogenetic analysis of Diplodocidae, USNM V 10865 was also found to be an individual of D. hallorum . The Denver Museum of Nature and Science obtained a Diplodocus specimen through exchange from
25384-401: Was collected by Lakes and William Harlow Reed the same year and named by Marsh. 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. The type specimen also preserved the pes, which was
25551-407: Was collected in 1883, and was the first complete diplodocid skull to be reported. Tschopp et al. ’s analysis placed it as an indeterminate diplodocine in 2015 due to the lack of overlap with any diagnostic Diplodocus postcranial material, as was the fate with all skulls assigned to Diplodocus . After the end of the Bone Wars, many major institutions in the eastern United States were inspired by
25718-431: Was composed of herbivorous dinosaurs. Carnivory was a natural transition from insectivory for medium and large tetrapods, requiring minimal adaptation. In contrast, a complex set of adaptations was necessary for feeding on highly fibrous plant materials. Arthropods evolved herbivory in four phases, changing their approach to it in response to changing plant communities. Tetrapod herbivores made their first appearance in
25885-468: Was discovered by Michael D'Emic et al. Within each tooth socket, as many as five replacement teeth were developing to replace the next one. Studies of the teeth also reveal that it preferred different vegetation from the other sauropods of the Morrison, such as Camarasaurus . This may have better allowed the various species of sauropods to exist without competition. The flexibility of Diplodocus neck
26052-472: Was dismantled in 2003 and replaced with a cast in an updated pose in 2004. A third mounted skeleton of Stegosaurus , referred to S. stenops , was put on display at the American Museum of Natural History in 1932. Mounted under the direction of Charles J. Long, the American Museum mount was a composite consisting of partial remains filled in with replicas based on other specimens. In his article about
26219-425: Was due to his early belief that the plates lay flat over the animal's back, overlapping like the shingles ( tiles ) on a roof. 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 . Because of this,
26386-471: Was even larger, and is estimated to have been the size of four elephants . When first described in 1991, discoverer David Gillette calculated it to be 33 m (110 ft) long based on isometric scaling with D. carnegii . However, he later stated that this was unlikely and estimated it to be 39 – 45 meters (130 – 150 ft) long, suggesting that some individuals may have been up to 52 m (171 ft) long and weighed 80 to 100 metric tons, making it
26553-456: Was later mounted—the first Diplodocus mount made—and was the first well preserved individual skeleton of Diplodocus discovered. In Emmanuel Tschopp et al .'s phylogenetic analysis of Diplodocidae , AMNH FR 223 was found to be not a skeleton of D. longus , but the later named species D. hallorum . The most notable Diplodocus find also came in 1899, when crew members from the Carnegie Museum of Natural History were collecting fossils in
26720-415: Was probably due to shifting of the skeleton after death. He led the construction of the first ever Stegosaurus skeletal mount at the Peabody Museum of Natural History , which was depicted with paired plates. In 1914, Charles Gilmore argued against Lull's interpretation, noting that several specimens of S. stenops , including the now-completely prepared holotype, preserved the plates in alternating rows near
26887-599: Was published by Marsh in 1891. (In 1893, Richard Lydekker mistakenly re-published Marsh's drawing under the label Hypsirhophus .) 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. Another mount was made for the NMNH in the form of a mounted composite skeleton consisting of several specimens referred to S. stenops that were collected at Quarry 13 at Como Bluff in 1887,
27054-499: Was re-mounted ahead of the opening of the new Peabody Museum building in 1925. 1918 saw the completion of the second Stegosaurus mount, and the first depicting S. stenops . This mount was created under the direction of Charles Gilmore at the U.S. National Museum of Natural History . 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. The aging mount
27221-499: Was requested by King Edward VII and it was the first sauropod mount put on display outside of the United States. The goal of Carnegie in sending these casts overseas was apparently to bring international unity and mutual interest around the discovery of the dinosaur. The Carnegie Museum of Natural History made another landmark discovery in 1909 when Earl Douglass unearthed several caudal vertebrae from Apatosaurus in what
27388-416: Was scientifically described in 2015. It is a young adult of undetermined sex, 5.8 m (19 ft) long and 2.9 m (9.5 ft) tall. 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. One skeleton collected at the site known as "Victoria" is very well preserved including many of
27555-530: Was sent to the Yale Peabody Museum and was named Diplodocus longus ('long double-beam') by paleontologist Othniel Charles Marsh in 1878. Marsh named Diplodocus during the Bone Wars , his competition with Philadelphian paleontologist Edward Drinker Cope to collect and describe as many fossil taxa as possible. Though several more complete specimens have been attributed to D. longus , detailed analysis has discovered that this type specimen
27722-516: Was small in proportion to the body. 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. The skull's low position suggests that Stegosaurus may have been a browser of low-growing vegetation. This interpretation is supported by the absence of front teeth and their likely replacement by a horny beak or rhamphotheca . The lower jaw had flat downward and upward extensions that would have completely hidden
27889-423: Was supported by Gustav Tornier . This hypothesis was contested by William Jacob Holland , who demonstrated that a sprawling Diplodocus would have needed a trench through which to pull its belly. Finds of sauropod footprints in the 1930s eventually put Hay's theory to rest. Later, diplodocids were often portrayed with their necks held high up in the air, allowing them to graze from tall trees. Studies looking at
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