Einiosaurus
| Key | Value |
|---|---|
| Name Meaning | “buffalo lizard” |
| Location | United States (Montana) |
| Time Period | c. 74 million years ago (Late Cretaceous) |
| Length | 15 ft (4.5 m) |
| Weight | 1.5 tons (1,350 kg) |
| Locomotion | Quadruped |
| Diet | Herbivore |
| Described | 1995 (Sampson) |
| Geological Formation(s) | Two Medicine |
| Valid Species | Einiosaurus procurvicornis (type) |
Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Cerapoda > Marginocephalia > Ceratopsia > Neoceratopsia > Coronosauria > Ceratopsoidea > Ceratopsidae > Centrosaurinae > Pachyrhinosaurini
Overview: Among the ceratopsids, dinosaurs famed for their bizarre skull ornamentation, that of Einiosaurus is among the most striking. While it lacked brow horns, or at most had small ridges over the eyes, its nasal horn was extremely prominent. It was robust, forward-curving and downward-pointing. The bony core we see on the skull of Einiosaurus probably doesn’t represent the full scale of this horn. In life, it was covered by a sheathe of keratin, extending its length. Einiosaurus, like the rest of the ceratopsids, had a frill of bone extending from the back of the skull. In its case, this was a small, rounded frill with two large openings. The most notable trait of the frill was a pair of long, pointed hornlets that extended from the very top of its rim. Its nasal horn, while large, may’ve been mainly used for display or intraspecific combat between competing males, as its downward curve made it ill suited for defense. The spines on the frill were also likely used mainly for courtship.
Einiosaurus was a medium-sized ceratopsid at maybe four to five meters long, its bulk supported by four strong legs. Most of its food was made up of low-lying vegetation, cropped by its parrot-like beak and sheared by the rows of teeth farther back in the jaws. Within the Ceratopsidae, this genus is classified within the subfamily Centrosaurinae. It was a relative of Centrosaurus itself, but its closest relatives were genera like Pachyrhinosaurus and Styracosaurus. Some scientists suggest Einiosaurus may’ve been an evolutionary transitional form between the earlier Styracosaurus and the more derived Pachyrhinosaurus, though this is contested by others. Fossils of Einiosaurus were first discovered on a Blackfeet Indian reservation in the late 1980’s, leading to it eventually being described as a genus in 1995. Its generic name means “buffalo lizard”; a combination of Greek and the Blackfeet language. Recovered fossils are known from the Two Medicine Formation.