Stegosaurus: Body Like a Bus, Tiny Little Brain HowStuffWorks

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. In his article about 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. 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. It was a composite of several skeletons, primarily USNM 6531, with proportions designed to closely follow the S. This historically significant specimen was re-mounted ahead of the opening of the new Peabody Museum building in 1925.

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 was the largest stegosaur, reaching up to 12 m (39.4 ft) in length and weighing up to 5,000 kg (5.5 short tons). Stegosaurus was originally named by Othniel Charles Marsh in 1877, from fossils found near Morrison, Colorado. It is possible that it lived in herds, as suggested by the discovery of several fossils found together.

Stegosaurus Origins, Taxonomy and Timeline

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. Landberg excavated the skeleton with the DMNS crews, recovering a 70% complete Stegosaurus skeleton along with turtles, crocodiles, and isolated dinosaur fossils at the quarry that would be nicknamed “The Kessler Site”. The fossils included only a couple postcranial remains, though in the 1900s-1920s Carnegie crews at Dinosaur National Monument discovered dozens of Stegosaurus specimens in one of the greatest single sites for the taxon. The bundle of nerves near the base of the tail that controlled reflexes in the back of the body was larger than the brain and is sometimes said to be a “second brain”. The dinosaur could have used the spikes on its tail, called thagomizers, as a formidable weapon against predators. Notable specimens, such as the “Sophie” specimen at the Natural History Museum in London, have contributed greatly to our understanding of this dinosaur.

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?

Stegosaurus: The Armored Giant of the Late Jurassic

One skeleton collected at the site known as “Victoria” is very well preserved including many of the vertebrae preserved in semi-articulation and next to an Allosaurus skeleton found nicknamed “Big Al II”. The mounted skeleton went on display in December 2014 and was scientifically described in 2015. The skeleton had been excavated on private land and was available for purchase. 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 the landowner’s daughter.

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The fore limbs were much shorter than the stocky hind limbs, which resulted in an unusual posture. The hind feet each had three short toes, while each fore foot had five toes; only the inner two toes had a blunt hoof. Around the middle of the tail, the neural spines become bifurcated, meaning they are divided near the top.

One 2009 study of Stegosaurus specimens of various sizes found that the plates and spikes had slower histological growth than the skeleton at least until the dinosaur reached its mature size. It is one of the most easily recognized dinosaurs, with its distinctive double row of kite-shaped plates on its back, and the long spikes on its tail. Their distinctive combination of broad, upright plates and tail tipped with spikes makes the Stegosaurus one of the most recognizable kinds of dinosaurs. This genus of herbivorous, four-legged, armored dinosaurs from the Late Jurassic is characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. With its unique combination of broad, upright plates and tail tipped with spikes, this is one of the most recognizable kinds of dinosaurs. This has led to the influential idea that dinosaurs like Stegosaurus had a “second brain” in the tail, which may have been responsible for controlling reflexes in the rear portion of the body.

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 argument has been a major one in the history of dinosaur reconstruction. Stenops type specimen, which had been on display in relief nearby since 1918. However, this mount was dismantled in 1917 when the old Peabody Museum building was demolished. Ungulatus at the Peabody Museum of Natural History, which was put on display in 1910.

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.

It has often been said that the Stegosaurus brain was the size of a walnut. Because of its short front legs, its head vegas casino app was close to the ground, probably no higher than 1 m (3.3 ft). Several different Stegosaurus species have been found. Stegosaurus (meaning “roof-lizard”) was a type of plant-eating dinosaur which lived in what is now western North America.

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.

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Additional specimens recovered from 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. Another mount was made for the NMNH in the form of a mounted composite skeleton consisting of several specimens referred to S. 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. The majority of the fossils came from Quarry 13, including the type specimen of Stegosaurus ungulatus (YPM 1853), which was collected by Lakes and William Harlow Reed the same year and named by Marsh. Stegosaurus was a member of the Thyreophora, or armored dinosaurs, a family of dinosaurs which includes the ankylosaurs. Unlike most dinosaurs, it did not have a lacuna (hole) in its skull between the nose and eye.

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. 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. Stenops, including the now-completely prepared holotype, preserved the plates in alternating rows near the peak of the back, and that there was no evidence of the plates having shifted relative to the body during fossilization.

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.

• This “brain” was proposed to have given a Stegosaurus a temporary boost when it was under threat from predators.
• Because the plates contained blood vessels, experts used to think they helped stegosaurs chill out.
• Called “gular armor,” it helped protect the dinosaur when Allosaurus and other carnivores went for the jugular.
• However, some fossil sites have yielded multiple Stegosaurus individuals found together, suggesting they may have lived in small herds.

The plates were highly vascularized, meaning they contained numerous blood vessels. A more widely accepted hypothesis is that the plates served as a thermoregulatory device, allowing Stegosaurus to absorb or dissipate heat. Early theories suggested they served as armor, but the plates were relatively thin and lacked strong muscular attachments. The purpose of the dorsal plates has been a topic of debate among paleontologists for decades. Its diet consisted primarily of low lying vegetation such as ferns, cycads, horsetails, and possibly even conifer needles. Its most striking features are, without a doubt, the dorsal plates and the thagomizer.

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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.

Second dinosaur rush

The greatest Stegosaurus discovery came in 1885 with the discovery of a nearly complete, articulated skeleton of a subadult that included previously undiscovered elements like a complete skull, throat ossicles, and articulated plates. 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. The type specimen also preserved the pes, which was the namesake of the species, meaning “hoofed roofed lizard”.

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.

Social Behavior and Reproduction

• However, recent research re-examined this and concluded this species also had four.
• One skeleton collected at the site known as “Victoria” is very well preserved including many of the vertebrae preserved in semi-articulation and next to an Allosaurus skeleton found nicknamed “Big Al II”.
• This dinosaur lived across millions of years and multiple continents and thus shared its world with an intriguing array of contemporaries.

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.