Stegosaurus Wikipedia

We know this group of herbivorous dinosaurs for their array of plates and spikes. This herbivorous, four-legged, armored dinosaur from the Late Jurassic period is characterized by its distinctive kite-shaped upright plates along its back and spikes on its tail. The bony plates along its back were embedded in the skin of the animal, not attached to its skeleton, which is why in most fossil finds the plates are separated from the body. This study showed that 9.8% of Stegosaurus specimens examined had injuries to their tail spikes. 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. The current owner has made “Apex” available for scientific research, but private vegas casino app ownership of important fossil specimens is controversial, with many researchers insisting that fossils be permanently curated at a formal institution for universal scientific access.

Plate function

The thermoregulation hypothesis has been seriously questioned, since other stegosaurs such as Kentrosaurus, had more low surface area spikes than plates, implying that cooling was not important enough to require specialized structural formations such as plates. Another possible function of the plates could have been helping to control the animal’s body temperature, in a similar way to the sails of the pelycosaurs Dimetrodon and Edaphosaurus (and modern elephant and rabbit ears). 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. Bakker suggested in 1986 that the plates were covered in horn comparing the surface of the fossilized plates to the bony cores of horns in other animals known or thought to bear horns. However, their reproductive organs still could not touch as there is no evidence of muscle attachments for a mobile penis nor a baculum in male dinosaurs. Like the spikes and shields of ankylosaurs, the bony plates and spines of stegosaurians evolved from the low-keeled osteoderms characteristic of basal thyreophorans.

• 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.
• This herbivorous, four-legged, armored dinosaur from the Late Jurassic period is characterized by its distinctive kite-shaped upright plates along its back and spikes on its tail.
• The function of this array of plates and spikes has been the subject of much speculation among scientists.
• The plates had blood vessels running through grooves and air flowing around the plates would have cooled the blood.

Sophie the Stegosaurus is the best preserved Stegosaurus specimen, being 85% intact and containing 360 bones. In 2007, Escaso and colleagues described a Stegosaurus specimen from the Upper Jurassic Alcobaça Formation of Portugal, which they classified as Stegosaurus cf. The skeleton was nicknamed the “Bollan Stegosaurus” and is in the collections of the Dinosaur Journey Museum.

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This holotype specimen, YPM 1850, is housed at the Yale Peabody Museum. This was after its fossils were discovered by 1876 by Marshall Parker Felch. This herbivore roamed the earth alongside other iconic dinosaurs, leaving behind a legacy that continues to fascinate us today. The genus Stegosaurus is further divided into several species, with the type species Stegosaurus stenops being the most well-known and well-preserved. In the taxonomy of dinosaurs, it is classified under the Order Ornithischia–known for their bird-like hip structure.

Until 1918, the only mounted skeleton of Stegosaurus in the world was O. Gilmore and Lucas’ interpretation became the generally accepted standard, and Lull’s mount at the Peabody Museum was changed to reflect this in 1924. Stenops was probably due to shifting of the skeleton after death. However, the following year, Lucas wrote that he now believed the plates were probably attached in staggered rows.

The Natural History Museum, London

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. F. Hubbell, a collector for Cope, also found a partial Stegosaurus skeleton while digging at Como Bluff in 1877 or ’78 that are now part of the Stegosaurus mount (AMNH 5752) at the American Museum of Natural History. 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. It had a short neck and a small head, meaning it most likely ate low-lying bushes and shrubs.

Find out how it has changed and what the new tree reveals about dinosaurs’ origins and evolution. Compared with the rest of its body, Stegosaurus had a small head and its brain was around the size of a plum! Another suggestion is that the plates were used to regulate body temperature. After finding a specimen that had been covered with mud, which had held the plates in place, Marsh realised that they stood vertically, alternately on either side of the spine. When O C Marsh described the first fossil of a Stegosaurus, he concluded that the plates would have lain flat on its back.

Like Marsh’s reconstruction, Knight’s first restoration had a single row of large plates, though he next used a double row for his more well-known 1901 painting, produced under the direction of Frederic Lucas. Marsh published his more accurate skeletal reconstruction of Stegosaurus in 1891, and within a decade Stegosaurus had become among the most-illustrated types of dinosaur. This covering of spikes might have been based on a misinterpretation of the teeth, which Marsh had noted were oddly shaped, cylindrical, and found scattered, such that he thought they might turn out to be small dermal spines. In their case, it contains what is called the glycogen body, a structure whose function is not definitely known, but which is postulated to facilitate the supply of glycogen to the animal’s nervous system. This “brain” was proposed to have given a Stegosaurus a temporary boost when it was under threat from predators.

In 1987, a 40% complete Stegosaurus skeleton was discovered in Rabbit Valley in Mesa County, Colorado, by Harold Bollan near the Dinosaur Journey Museum. Stegosaurus was made the official state fossil of Colorado in 1982, after a two-year campaign begun by a class of 4th graders and their teacher Ruth Sawdo at McElwain Elementary School in Thornton, Colorado. Phillip Reinheimer, a steel worker, mounted the Stegosaurus skeleton at the DMNS in 1938.

Early skeletal mounts and plate interpretation

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. Furthermore, within the hind limbs, the lower section (comprising the tibia and fibula) was short compared with the femur. 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. Soon after its discovery, Marsh considered Stegosaurus to have been bipedal, due to its short forelimbs.

Stegosaurus

Thus, their conception of Stegosaurus would include three valid species (S. armatus, S. homheni, and S. mjosi) and would range from the Late Jurassic of North America and Europe to the Early Cretaceous of Asia. Armatus, and sinking Hesperosaurus and Wuerhosaurus into Stegosaurus, with their type species becoming Stegosaurus mjosi and Stegosaurus homheni, respectively. Many of the species initially described have since been considered to be invalid or synonymous with earlier named species, leaving two well-known and one poorly known species. This indicates that the plates were covered in keratinous sheaths. Well preserved integumentary impressions of the plates of Hesperosaurus show a smooth surface with long and parallel, shallow grooves. Many of 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.

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The largest plates were found over the hips and could measure over 60 cm (24 in) wide and 60 cm (24 in) tall. They were not directly attached to the animal’s skeleton, instead arising from the skin. The most recognizable features of Stegosaurus are its dermal plates, which consisted of between 17 and 22 separate plates and flat spines. The tail appears to have been held well clear of the ground, while the head of Stegosaurus was positioned relatively low down, probably no higher than 1 m (3.3 ft) above the ground.

A Glance at Stegosaurus

• Tipping the scales at 20.8 ounces (80 grams) or so, the actual brain only made up about 0.001 percent of the creature’s total body weight.
• The thagomizer, with its four prominent spikes, almost certainly functioned as a defensive weapon, used to ward off predators like Allosaurus.
• 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.
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This predator-prey relationship would have influenced the behavior and evolution of both species. It is likely that it had to eat a large amount of vegetation to sustain its large body and this would have had an impact on the vegetation of the area. Ferns, horsetails, and gymnosperms such as conifers, ginkgoes, and cycads dominated this terrain. This specimen has allowed scientists to make more accurate reconstructions and to gain new insights into its biology and behavior.

The endocast showed the brain was indeed very small, the smallest proportionally of all dinosaur endocasts then known. On July 17, 2024, a nearly complete, 27-foot (8.2m) long Stegosaurus skeleton, nicknamed “Apex”, fetched $44.6m (£34m) at a Sotheby’s auction in New York City–the most ever paid for a fossil. At Jensen-Jensen Quarry, an articulated torso including several dorsal plates from a small individual were collected and briefly described in 2014, though the specimen was collected years before and is still in preparation at Brigham Young University. The Stegosaurus skeletons have been mounted alongside an Allosaurus skeleton collected in Moffat County, Colorado originally in 1979. Stenops type, the fossils were flattened in a “roadkill” condition.

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Even by stegosaur standards, it was a biggie; most of the dinosaurs in that group were only 13 to 23 feet (4 to 7 meters) long. Instead, later discoveries proved the objects stood upright, leaving the flanks on these dinosaurs exposed. Spikes were a stegosaur mainstay, adorning the tails of every known species. Stegosaurus belonged to a suborder of dinosaurs called — what else?

This was a slow-moving dinosaur, with an estimated top speed estimated at around 5 mph. This was an herbivore and likely are low-lying plants such as ferns, horsetails, and gymnosperms. Primarily, they may have used the plates for display, and secondarily for thermoregulatory functions. They might have been competitors for the same plant resources, yet their differing body sizes and feeding heights could have allowed for resource partitioning. In contrast, the Apatosaurus, Diplodocus, and Camarasaurus, all herbivores like the Stegosaurus, likely had a different kind of relationship with our main dinosaur.

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. Ungulatus plates have been found, and none articulated, making the arrangement in this species more difficult to determine. 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. 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. Actual brain anatomy in Stegosaurus is poorly known, but the brain itself was small even for a dinosaur.

Stegosaurus belongs to a group of dinosaurs called stegosaurs, which first appeared in the early Jurassic period. Fossil discoveries have primarily been made in North America, particularly in the Morrison Formation, a rich source of Jurassic period fossils. The thagomizer, formed by four prominent spikes at the end of the tail, served as a defensive weapon. Stegosaurus was a large, quadrupedal dinosaur, reaching lengths of up to 9 meters and weighing around 5 to 7 metric tons.

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. A 2015 study of the shapes and sizes of Hesperosaurus plates suggested that they were sexually dimorphic, with wide plates belonging to males and taller plates belonging to females. However, the stegosaur plates were covered in horn rather than skin. The vascular system of the plates have been theorized to have played a role in threat displaying as Stegosaurus could have pumped blood into them, causing them to “blush” and give a colorful, red warning.