Achelousaurus (Achelous’s lizard)
Achelousaurus (Achelous's lizard)
Named By : Scott Sampson - 1995
Diet : Herbivore
Size : Around 6 meters long
Type of Dinosaur : Ceratopsian
Type Species : A. horneri (type)
Found in : USA, Montana - Two Medicine Formation
When it Lived : Late Cretaceous, 83-70 million years ago
Achelousaurus ( Achelousaurus (/@,ki:loU’so,Achelousaurus ( /@,ki:loU’so:) is one of the genus belonging to the centrosaurine, ceratopsid dinosaurs. They was present during the Late Cretaceous Period of what is today North America, about 74.2 million years ago. First fossils from Achelousaurus were discovered within Montana in 1987 by a group led by Jack Horner, with more discoveries being made in the year 1989. in 1994 Achelousaurus is described as horneri and identified in the work of Scott D. Sampson; the generic name is “Achelous lizard”, in reference to the Greek god Achelous and the particular name is in reference to Horner. The genus was discovered through a handful of specimens made mostly of skull material from individuals, which range from infants to adults.
A huge centrosaurine, known as Achelousaurus is believed to have been 6 meters (20 feet) longand had an estimated weight of 3 tonnes (3.3 small tons). As it was a ceratopsian that walked on four feet, had an elongated tail, and a big head with a beak that was hooked. It was an unnatural neck-frill located to the back of the skull. It featured a pair spikes that curved toward the outside. The adult Achelousaurus has rough bosses (roundish protuberances) just above the eyes as well as on the snout . Other centrosaurines had horns in the same places. The bosses were covered with the thick layer of keratin however their exact form in reality is unclear. Researchers have speculated these bosses could have been utilized for fighting, with animals fighting their heads against each other in addition to for display purposes.
Tim Evanson from Washington, D.C., United States of America, CC BY-SA 2.0, via Wikimedia Commons
In within the Ceratopsia, Achelousaurus lies within the clade Pachyrostra (or “thick-snouts”). It is believed to be the direct descendant of comparable Genus Einiosaurus (which featured spikes however no bosses) and was the closest ancestor to Pachyrhinosaurus (which had bosses that were larger). The two genera that were first proposed would be transitional which evolved via the process of anagenesis, which is derived from Styracosaurus. There is debate over the validity of this theory, but there have been more recent discoveries revealing the fact that Achelousaurus is closely connected to Pachyrhinosaurus within the group of Pachyrhinosaurini. Achelousaurus is found in the Two Medicine Formation and lived on an island in Laramidia. As an ceratopsian, Achelousaurus would have been an herbivore, and it is believed to possess a large metabolic rate, but less than birds and mammals of today.