Ceratosaurus‭ (‬Horned lizard‭)

Short Info

Ceratosaurus‭ (‬Horned lizard‭)

Phonetic : See-rat-oh-sire-us.

Named By : Othniel Charles Marsh‭ ‬-‭ ‬1884

Diet : Carnivore

Size : Estimated 6 meters long

Type of Dinosaur : Large Theropod

Type Species : C.‭ ‬nasicornis‭ (‬type‭)‬,‭ ‬C.‭ ‬dentisulcatus,‭ ‬C.‭ ‬magnicornis,‭ ‬‬C.‭ ‬stechowi

Found in : USA,‭ ‬Morrison Formation.‭ ‬Portugal.‭ ‬Tanzania

When it Lived : Late Jurassic, 153-148 million years ago

Ceratosaurus /,ser@toU’so:r@s(also known as (from Greek keras/keratos, keras/keratos meaning “horn” and sauros sauros meaning “lizard”) was a carnivore theropod dinosaur during the Late Jurassic period (Kimmeridgian to Tithonian). The genus was first mentioned around 1884, by American paleontologist Othniel Charles Marsh based upon the discovery of a skeleton that was nearly complete within Garden Park, Colorado, within the rocks of the Morrison Formation. The species of interest is Ceratosaurus Nasicornis.


Ceratosaurus mount utah museum 1
Jens Lallensack, CC BY-SA 4.0, via Wikimedia Commons


The Garden Park specimen remains the most complete skeleton found in the Genus and only a few more specimens has been reported since. Two other species, Ceratosaurus dentisulcatus and Ceratosaurus magnicornis, were discovered in 2000, based on two fragmentary skeletons discovered in the Cleveland-Lloyd Quarry located in Utah as well as from near Fruita, Colorado. The authenticity of these two additional species has been challenged, however, and the three skeletons could represent different stages of growth for the identical species. In 1999 it was reported that an early juvenile specimen was announced. From 2000 onwards, a small specimen has been excavated as well as described in the Lourinha Formation of Portugal, which proved the existence of the genus beyond North America. Fragmentary remains were also identified in Tanzania, Uruguay, and Switzerland however, their connection to Ceratosaurus is not currently accepted by most paleontologists.

Ceratosaurus was a large theropod. The original specimen was estimated to be 5.3 meters (17 feet) (or 5.69 5 m (18.7 ft) long. The specimen identified in the literature as C. dentisulcatus appeared to be bigger in size, with 7 meters (23 feet) long. Ceratosaurus was distinguished by its deep jaws that had proportionally long, blade-like teeth. They also had the horn was prominent and ridge-like in the middle of the snout and two horns above the eyes. The forelimbs were narrow, yet functional. The hand was equipped with four fingers. The tail was long from top to the bottom. A small row of osteoderms (skin bones) were found in into the middle back, neck, and the tail. Additionally, osteoderms were found in unidentified places on the body of the animal.

Ceratosaurus is the name that it gives to the Ceratosauria which is a clade of theropod dinosaurs who separated earlier from evolutionary lines, leading into modern bird species. Within the Ceratosauria certain paleontologists have proposed that it is closest with Genyodectes from Argentina that share the strong elongated teeth. The genus that is older in geology Proceratosaurus of England was initially considered to be a probable predecessor to Ceratosaurus however, was later discovered to be not related. Ceratosaurus was in close proximity to other theropod genera of great size, including Torvosaurus and Allosaurus It is believed that these theropods shared various ecological niches to minimize competition. Ceratosaurus might have preyed on plants-eating dinosaurs, but certain paleontologists suggest that it hunted prey from the water like fish. The nasal horn probably was not employed as a weapon like the one thought by Marsh and Marsh, but it more likely was used for display purposes only.


CeratosaurusSkeletonO.C. Marsh (1831–1899), Public domain, via Wikimedia Commons


The first specimen, which was the USNM 4735 holotype, was found and excavated by farmer Marshall Parker Felch in 1883 and 1884. It was found in articulation, and where the bones were linked to one another, the specimen was almost complete, which included the skull. The most significant missing parts are an undetermined number of vertebrae and all, excluding the last spine ribs and the humeri (upper arm bones) and the distal finger bones of both hands majority of the right fore limb; the majority of the hind leg on left and the majority of feet. The specimen was found in a sandstone encasement. stone; the skull and spine were significantly distorted in the process of fossilization. 2114 location of the discovery, which is within The Garden Park area north of Canon City, Colorado, and referred to by the name Felch Quarry 1 is considered as being one of the largest fossil sites in the Morrison Formation. Numerous dinosaur fossils have been found in the quarry long prior to discovering Ceratosaurus and, in particular, an almost complete specimen from Allosaurus (USNM 4734) in 1883 and 1884. 7 114

After excavation, the specimen was shipped to the Peabody Museum of Natural History in New Haven, where it was studied by Marsh, who described it as the new genus and species Ceratosaurus nasicornis in 1884.: 114 The name Ceratosaurus may be translated as “horn lizard” (from Greek keras/keratos, keras/keratos–“horn” and sauros/sauros–“lizard”), and nasicornis with “nose horn” (from Latin nasus–“nose” and cornu–“horn”). Because of the fullness of this specimen, it is likely that the recently identified species was the most famous theropod to be discovered in America. Between 1898 and 1899 the specimen was moved into the National Museum of Natural History in Washington, DC, together with other fossils that were originally identified by Marsh. The specimen was completely prepared at the time it arrived in Washington The subsequent preparation took place between 1911 and the final day of 1918. The packaging and transportation of the material from New Haven to Washington caused some damage to the Ceratosaurus specimen. 2114 1920 Charles Gilmore published an exhaustive description of this specimen and other theropod specimens that were collected in New Haven, including the almost entire Allosaurus specimen that was found in the same quarry.


Ceratosaurus nasicornis reconstruction gilmore 1920
Gilmore, Charles W. (1874–1945)Gilmore, Charles W., Public domain, via Wikimedia Commons


In a paper published in 1892, Marsh published the first skeletal reconstruction of Ceratosaurus that depicts Ceratosaurus at 22 feet (6.7 meters) in length, and 12 feet (3.7 meters) at its highest. As was noted by Gilmore in 1920 the trunk was shown far too long in the reconstruction, and it included at minimum six dorsal vertebrae, which was too numerous. This mistake was repeated in publications following which included the first reconstruction, drawn with the help of Frank Bond under the guidance of Charles R. Knight, but was not published until 1920. A more accurate reconstruction of life was published in the year 1901. It was drawn in 1901 by Joseph M. Gleeson, again under Knight’s direction. The holotype was displayed by Gilmore between 1910 between 1911 and 1910, and it was displayed by the National Museum of Natural History. Early reconstructions of the holotype show Ceratosaurus in an upright position and the tail moving onto the ground. 115-116 Gilmore’s mounting of the holotype, by contrast, was way ahead of its time. It was 276 Inspiring to the upper bones of the thigh that were found to be with the lower leg angled to the left The mount was depicted by Gilmore as a jogger with a horizontal , not an upright posture , and a tail that didn’t meet the ground. Due to the strong reduction of the fossils Gilmore put the specimen up not as a skeleton that could stand on its own however, as a bas-relief inside a wall. The bones being partially embedded in a wall, scientific access was restricted. In the course restoration of the dinosaur exhibit between 2014 and 2019, the fossil was taken down and removed from the plaque that encased it. The new exhibit that is scheduled to be open next year, the exhibit is scheduled to be replaced with a free-standing cast, with the bones that were originally found to be kept in the museum’s collection in order so that it is accessible to all researchers.

Ceratosaurus adhered to the typical body structure of huge theropod dinosaurs. Bipedal, it moved on its powerful hind legs and its arms were smaller in dimensions. Its specimen USNM 4735 The first skeleton discovered and Holotype of Ceratosaurus nasicornis was a single specimen 5.3 meters (17 feet) or 5.69 meters (18.7 feet) in length as per distinct sources. The 115th figure indicates that whether the creature was grown fully isn’t evident. [20] (66) Othniel Charles Marsh, in 1884 claimed that the specimen was roughly half that of the modern Allosaurus. According to more recent reports the weight was recalculated at 418 kg (922 lbs) 524 kilograms (1,155 lb) or 670 kg (1,480 1 lb). Three additional skeletons that were discovered in the second part in the early 20th century, were considerably larger. The first one, UMNH VP 5278, was informally calculated by James Madsen to have been approximately 8.8 meters (29 feet) in length, however it was later found to be 7 meters (23 feet) of length. The weight was determined to be 980 kilograms (2,160 lbs) and 452 kilograms (996 lbs) 700 kilograms (1,540 lbs) in two separate work. MWC 1, the second one, MWC 1, was slightly smaller that UMNH VP 5278, and could be as much as 275 kg (606 lbs) by weight. The third, but undescribed piece BYUVP 12893 was said to be the most massive that has been discovered, though estimates are not yet published. Another instance (ML 352) was discovered within Portugal during 2000, is estimated to be 6 meters (20 feet) of length, and 600 kilograms (1,320 pounds) to weight.

Source: Wikipedia