Styracosaurus ( ; meaning "spiked lizard" from the Ancient Greek / "spike at the butt-end of a spear-shaft" and / "lizard") is an extinct genus of herbivorous dinosaur from the Late Cretaceous (Campanian stage) of North America. It had four to six long parietal spikes extending from its neck frill, a smaller jugal horn on each of its cheeks, and a single horn protruding from its nose, which may have been up to long and wide. The function or functions of the horns and frills have been debated for many years.
Styracosaurus was a relatively large dinosaur, reaching lengths of and weighing about . It stood about tall. Styracosaurus possessed four short legs and a bulky body. Its tail was rather short. The skull had a beak and shearing cheek teeth arranged in continuous dental batteries, suggesting that the animal sliced up plants. Like other ceratopsians, this dinosaur may have been a herd animal, travelling in large groups, as suggested by bone beds.
Named by Lawrence Lambe in 1913, Styracosaurus is a member of the Centrosaurinae. One species, S. albertensis, is currently assigned to Styracosaurus. Another species, S. ovatus, named in 1930 by Charles Gilmore was reassigned to a new genus, Rubeosaurus, by Andrew McDonald and Jack Horner in 2010,Andrew T. McDonald & John R. Horner (2010). "New Material of "Styracosaurus" ovatus from the Two Medicine Formation of Montana". Pages 156–168 in: Michael J. Ryan, Brenda J. Chinnery-Allgeier, and David A. Eberth (eds), New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium, Indiana University Press, Bloomington and Indianapolis, IN. but it has been considered either its own genus or a species of Styracosaurus (or even a specimen of S. albertensis) again, since 2020.
Discoveries and species
The first fossil of Styracosaurus was discovered in the summer of 1913 by American palaeontologist Charles H. Sternberg as part of an expedition of the Geological Survey of Canada along the Red Deer River. At the time of discovery it was embedded horizontally with the right side of the skull exposed and weathered, but otherwise largely complete though neither the mandible nor remainder of the skeleton were found at the time. Sternberg discovered the skull on the southwest bank of the Red Deer River about below the mouth of Berry Creek in what was then called the Belly River Formation. This mostly complete skull was described in 1913 by Canadian palaeontologist Lawrence Lambe as the holotype of the new ceratopsian Styracosaurus albertensis. A second partial skull, including the bones surrounding the found upriver of the type, was also referred to Styracosaurus in a footnote by Lambe.
In 1935, the quarry was revisited by Levi Sternberg, son of Charles H., in part of a field crew of the Royal Ontario Museum, where the mandible and largely complete skeleton of the same individual were excavated. The quarry and sediments are now within the boundaries of Dinosaur Provincial Park and the Dinosaur Park Formation. Negotiations concluded in 1955 allowing the Canadian Museum of Nature to acquire this mandible and skeleton, reuniting the full type individual of Styracosaurus, now under the accession number CMN 344. The skull and skeleton were then mounted on a steel armature, supervised by Charles Mortram Sternberg, son of Charles H., where the were drilled out, elements were welded, and damage or missing bones were modelled with plaster. This mounted skeleton remained on display in the Victoria Memorial Museum Building in Ottawa until the gallery was dismantled in the early 2000's, when the skeleton was disassembled, repaired, and available to be studied.
American palaeontologist Barnum Brown collected another specimen of Styracosaurus in 1915 from the same horizon as the type, but from the middle fork of Sand Creek downstream of Steveville. Collected for the American Museum of Natural History as AMNH 5372, it was found above the Red Deer River and initially identified as a specimen of Monoclonius due to similarities in the skeleton. Once prepared in 1936, Brown and American palaeontologist Erich Maren Schlaikjer reidentified it as a nearly complete skeleton and partial skull of a new species of Styracosaurus, which they described and named S. parksi in 1937. The species name was in honour of the late Canadian palaeontologist William Parks, who helped Brown and Schlaijker compare their specimen with the skeleton of S. albertensis that was at the time at the University of Toronto. Another specimen in the American Museum, AMNH 5361, as well as Monoclonius and S. albertensis, were used to help restore the fragmentary skull and nearly complete skeleton for mounting and display. While the locality Brown found S. parksi in was lost for some time, in 2006 it was relocated by Darren Tanke of the Royal Tyrrell Museum of Palaeontology in the upper portion of the Dinosaur Park Formation.
Though Styracosaurus is a relatively rare component of the Dinosaur Park Formation, multiple other partial skulls, skeletons, and a bonebed have also been found. As well as the skeleton of the type, in 1935 Levi Sternberg collected a partial frill from Sand Creek around southwest of the mouth of the creek and above the river, now catalogued as ROM 1436. Other partial or complete skulls lacking skeletons have been found within the park at Sandhill (or Sand) Creek (TMP 1987.52.1), South Sandhill Coulee (TMP 2005.12.58), Wolf Coulee (TMP 2018.12.23), or along the main river valley in the east (TMP 1986.121.1, TMP 1988.36.20, TMP 2003.12.168). These additional specimens can be referred to Styracosaurus from their large spikes on the frill and have all been found within the upper of the formation just below the prairie level. A nearly complete skull and skeleton (TMP 1989.97.1) was found in 1989 at Sage Creek only below the prairie level in the coulee, but approximately southeast of the holotype and the only definitive specimen of Styracosaurus albertensis from outside Dinosaur Provincial Park. Another nearly complete skull and partial skeleton (TMP 2009.80.1) was discovered in August 2008 and collected in August 2009 by the crew of the Royal Tyrrell Museum in the central fork of Princess Coulee just south of Dinosaur Provincial Park. It is notable as the smallest and likely youngest known Styracosaurus with a nearly complete skull. In May 2015 a skeleton of a large Styracosaurus was found along Matzhiwin Creek near the town of Duchess, Alberta around west of Dinosaur Provincial Park by the University of Alberta and excavated over three years. The skull of the specimen (UALVP 55900) was described in 2020 but the skeleton remains under preparation and while the locality was lower in elevation than all other Styracosaurus this is from a regional dip in the formation. The University of Alberta also collected the partial skull and skeleton UALVP 52612, from the top of the formation in the eastern river valley of the park.
These fossils indicate that S. albertensis was around in length and stood about high at the hips. An unusual feature of this first skull is that the smallest frill spike on the left side is partially overlapped at its base by the next spike. It appears that the frill suffered a break at this point in life and was shortened by about . The normal shape of this area is unknown because the corresponding area of the right side of the frill was not recovered.
Barnum Brown and crew, working for the American Museum of Natural History in New York, collected a nearly complete articulated skeleton with a partial skull in 1915. These fossils were also found in the Dinosaur Park Formation, near Steveville, Alberta. Brown and Erich Maren Schlaikjer compared the finds, and, though they allowed that both specimens were from the same general locality and geological formation, they considered the specimen sufficiently distinct from the holotype to warrant erecting a new species, and described the fossils as Styracosaurus parksi, named in honor of William Parks. Among the differences between the specimens cited by Brown and Schlaikjer were a cheekbone quite different from that of S. albertensis, and smaller tail vertebrae. S. parksi also had a more robust jaw, a shorter dentary, and the frill differed in shape from that of the type species. However, much of the skull consisted of plaster reconstruction, and the original 1937 paper did not illustrate the actual skull bones. It is now accepted as a specimen of S. albertensis.
In the summer of 2006, Darren Tanke of the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta relocated the long lost S. parksi site. Pieces of the skull, evidently abandoned by the 1915 crew, were found in the quarry. These were collected and it is hoped more pieces will be found, perhaps enough to warrant a redescription of the skull and test whether S. albertensis and S. parksi are the same. The Tyrrell Museum has also collected several partial Styracosaurus skulls. At least one confirmed bone bed (bonebed 42) in Dinosaur Provincial Park has also been explored (other proposed Styracosaurus bone beds instead have fossils from a mix of animals, and nondiagnostic ceratopsian remains). Bonebed 42 is known to contain numerous pieces of skulls such as horncores, jaws and frill pieces.
Several other species which were assigned to Styracosaurus have since been assigned to other genera. S. sphenocerus, described by Edward Drinker Cope in 1890 as a species of Monoclonius and based on a nasal bone with a broken Styracosaurus-like straight nose horn, was attributed to Styracosaurus in 1915. "S. makeli", mentioned informally by amateur paleontologists Stephen and Sylvia Czerkas in 1990 in a caption to an illustration, is an early name for Einiosaurus. "S. borealis" is an early informal name for S. parksi.
Styracosaurus ovatus