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?

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.

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 brain”

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.

The Dinosaurs

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.

Its spiked tail was a natural deterrent that could have been a formidable weapon against the Allosaurus. This dinosaur lived across millions of years and multiple continents and thus shared its world with an intriguing array of contemporaries. Additionally, evidence of a complex social life emerges from the presence of plates it possibly used for display. This was a slow-moving dinosaur, with a top speed estimated at around 5 mph.

  • 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.
  • Stegosaurus had very short forelimbs in relation to its hind legs.
  • Some have suggested that plates in stegosaurs were used to allow individuals to identify members of their species.
  • The endocast showed the brain was indeed very small, the smallest proportionally of all dinosaur endocasts then known.
  • However, the stegosaur plates were covered in horn rather than skin.

The Function of Plates and Thagomizer

Stegosaurus’s presence also likely influenced the behavior of other dinosaurs, creating a complex web of interactions. This, in turn, influenced the distribution and abundance of other plant eating dinosaurs. Fossil discoveries have revealed several species of Stegosaurus, including Stegosaurus armatus and Stegosaurus stenops. Stegosaurus itself represents a peak in stegosaur evolution, showcasing the most developed plates and a powerful tail.

They suggested that such metabolisms may have been common for ornithischian dinosaurs in general, with the group evolving towards ectothermy from an ancestor with an endothermic (warm blooded) metabolism. A 2013 study concluded, based on the rapid deposition of highly vascularised fibrolamellar bone, that Kentrosaurus had a quicker growth rate than Stegosaurus, contradicting the general rule that larger dinosaurs grew faster than smaller ones. Also, the pelvic region of the specimens are similar to Kentrosaurus juveniles. The specimens can be identified as not mature because they lack the fusion of the scapula and coracoid, and the lower hind limbs. More recently, a study of the tail spikes by McWhinney et al., which showed a high incidence of trauma-related damage, lends more weight to the position that the spikes were indeed used in combat. However, as Carpenter has noted, the plates overlap so many tail vertebrae, movement would be limited.

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.

The thagomizer, with its four prominent spikes, almost certainly functioned as a defensive weapon, used to ward off predators like Allosaurus. Another possibility is that the plates played a role in display, possibly used for attracting mates or signaling to other Stegosaurus. By orienting themselves towards or away from the sun, Stegosaurus could control its body temperature.

In 1914, Charles Gilmore argued against Lull’s interpretation, noting that several specimens of S. He led the construction of the first ever Stegosaurus skeletal mount at the Peabody Museum of Natural History, which was depicted with paired plates. 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. The skeleton was shipped to Marsh in 1887, who named it Stegosaurus stenops ( “narrow-faced roof lizard”) that year.

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Scientists are not exactly sure what the plates were used for. A large, slow moving plant-eater, Stegosaurus would have defended itself from predators like Allosaurus and Ceratosaurus with its powerful spiked tail. Following renovations to the museum in the 2010s, the model was moved once again for display at the Museum of the Earth in Ithaca, New York. Knight would go on to paint a stegosaur with a staggered double plate row in 1927 for the Field Museum of Natural History, and was followed by Rudolph F. Zallinger, who painted Stegosaurus this way in his “Age of Reptiles” mural at the Peabody Museum in 1947. Again under Lucas, Knight revised his version of Stegosaurus again two years later, producing a model with a staggered double row of plates.

List of All Dinosaurs

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.

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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). Due to their distinctive combination of broad, upright plates and tail tipped with spikes, Stegosaurus is one of the most recognizable kinds of dinosaurs. Stegosaurus (/ˌstɛɡəˈsɔːrəs/; lit. ’roof-lizard’) is a genus of herbivorous four-legged armored dinosaurs from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Its broad, upright plates and tail tipped with spikes are not only distinctive but also reflect the dinosaur’s adaptability and survival instincts. One species, Stegosaurus ungulatus, is one of the largest known of all the stegosaurians, reaching 7 metres (23 ft) in length and 3.8 metric tons (4.2 short tons) in body mass. Interestingly, findings of Stegosaurus fossils have extended across the Atlantic to Portugal, suggesting a broader geographic distribution of these dinosaurs than initially assumed.

The initial discovery was made in Morrison, Colorado and the dinosaur was aptly named Stegosaurus armatus, or ‘armored roof lizard’. This dinosaur first stepped into the limelight in 1877 when it was finally described by renowned paleontologist O.C. Derived from the Greek words ‘stegos’ meaning ‘roof’ and ‘sauros’ meaning ‘lizard’, the name is a nod to the large, flat bony plates that adorned its back. The Stegosaurus has a name that carries a meaning as distinctive as the dinosaur itself. The Stegosaurus, a well-known dinosaur that resonates with a sense of awe and wonder, is one that has captured the imagination of many. However, some fossil sites have yielded multiple Stegosaurus individuals found together, suggesting they may have lived in small herds.

The observatory alleged that government forces had previously targeted Alawite communities in coastal regions and Druze residents in Sahnaya and Sweida, and were now directing similar actions against Kurds. The Damascus government factions framed its actions as a response to what it described as a major escalation by the SDF toward Aleppo neighborhoods and accused the group of committing “numerous massacres against civilians.” Schools and public institutions in Sheikh Maqsood and Ashrafiyeh remained closed for a second consecutive day due to ongoing clashes between Syrian government-affiliated forces and SDF security units.

Second dinosaur rush

  • In 1987, a 40% complete Stegosaurus skeleton was discovered in Rabbit Valley in Mesa County, Colorado, by Harold Bollan near the Dinosaur Journey Museum.
  • But the US sees Syria as a crucial partner in the fight against ISIL or ISIS, and wants a strong government in Damascus to avoid the return of Iranian influence in the country.
  • 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.
  • The Damascus government factions declared Sheikh Maqsood and Ashrafiyeh military zones, triggering heavy fighting, civilian casualties, mass displacement, and strong reactions from Kurdish leaders and rights groups.

Lucas also re-examined the issue of the life appearance of Stegosaurus, coming to the conclusion that the plates were arranged in pairs in two rows along the back, arranged above the bases of the ribs. Lucas reclassified this species in the new genus Hoplitosaurus later that year. 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. The skeleton was expertly unearthed by Felch, who first divided the skeleton into labeled blocks and prepared them vegas casino app separately. 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. 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 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.

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. Ungulatus reached 7 m (23.0 ft) in length and 3.8 metric tons (4.2 short tons) in body mass. Stenops reached 6.5 m (21.3 ft) in length and 3.5 metric tons (3.9 short tons) in body mass, while S. The “Small Quarry” Stegosaurus’ articulation and completeness clarified 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.

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Not only is the Jurassic herbivore Colorado’s official state fossil, but it was also the inspiration for Godzilla’s dorsal plates. Regardless, there’s no reason to think Stegosaurus — or any dinosaur — had multiple brains. 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. Good thing Stegosaurus had four tail spikes at its disposal. Sauropods — or “long-necked” dinosaurs — like the 60-foot (18-meter) Camarasaurus and the 80-foot (24-meter) Diplodocus were some of the creature’s neighbors.