Achelousaurus Temporal range: Late Cretaceous, 74.2 Ma |
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Type specimen MOR 485, Museum of the Rockies | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Dinosauria |
Order: | †Ornithischia |
Family: | †Ceratopsidae |
Tribe: | †Pachyrhinosaurini |
Subtribe: | †Pachyrostra |
Genus: |
†Achelousaurus Sampson, 1995 |
Type species | |
†Achelousaurus horneri Sampson, 1995 |
Achelousaurus (pronunciation: /əˌkiːloʊˈsɔːrəs/, less commonly: /ˌækᵻˌloʊəˈsɔːrəs/; "Achelous's lizard") is a genus of centrosaurine ceratopsid dinosaurs from the Late Cretaceous Period of what is now North America, dated to 74.2 million years ago.
They were quadrupedal herbivores with parrot-like beaks, rough bosses (raised bony areas) on their snouts and one pair behind their eyes, and a pair of horns on the end of their long bony frills. With body lengths of up to six meters (20 feet) and a weight of three tonnes,Achelousaurus were medium-sized ceratopsians.
The genus and the one named species (A. horneri) were both named by paleontologist Scott Sampson in 1995. The specific name honors Jack Horner, an influential American paleontologist famous for his Montana dinosaur discoveries, who in 1987 headed the team that excavated the holotype skull of Achelousaurus, MOR 485. The generic name Achelousaurus is a complex reference to Greek mythology. Achelous, an important Greek river deity, had one of his horns torn off by Hercules, in a mythological fight with the legendary hero. All three known skulls of Achelousaurus have rough bosses in the same places where other ceratopsians have horns, giving them the appearance of having had the horns ripped off. Achelous was also celebrated for his shapeshifting ability, just as Achelousaurus appear to combine features of other ceratopsian dinosaurs.