Dinosaurus

Dinosaurus is an extinct genus of therapsid of controversial affinities. Its type and only species is Dinosaurus murchisonii. It is only known from a partial snout from the Permian of Russia. Its taxonomic history is intertwined with several other poorly-known Russian therapsids, particularly Rhopalodon, Brithopus, and Phthinosuchus.

Dinosaurus is not a dinosaur; the similarity in names is coincidental. Dinosaurs belong to the clade Dinosauria, a clade of reptiles which includes modern birds, whereas Dinosaurus is a therapsid, and as such, more closely related to mammals. Dinosauria was named only five years prior to Dinosaurus, in 1842. Dinosaurus also lived in the Permian period, which is part of the Paleozoic era, before dinosaurs existed, the first dinosaurs appeared in the following Triassic period of the Mesozoic era.