Acheroraptor

Acheroraptor was the first confirmed genus of dromaeosaurid dinosaur to be known as coming from the world famous Hell Creek Formation of North America.‭ ‬Dromaeosaurid teeth had been known before this time,‭ ‬but they had often been presumed to have come from either Dromaeosaurus or Saurornitholestes,‭ ‬though these teeth are now more commonly referred to Acheroraptor. At the time of writing Acheroraptor is only known from a maxilla and dentary with additional referred teeth.‭ ‬These however have been enough to at least confirm that Acheroraptor was actually a North American cousin of the famous Velociraptor that lived in Asia.‭ ‬Comparison of the known Acheroraptor fossils at least suggest that the total length of the holotype individual of Acheroraptor would have been somewhere in the region of about two meters in length. Acheroraptor was the only dromaeosaurid dinosaur known from the Hell Creek Formation until‭ ‬2015‭ ‬when the genus Dakotaraptor was named.‭ ‬At‭ ‬least five and half meters in length however,‭ ‬Dakotaraptor would have been significantly larger than Acheroraptor. Acheroraptor was first described and named by David C. Evans, Derek W. Larson and Philip J. Currie in 2013 and the type species is Acheroraptor temertyorum. The generic name is derived from the Greek Ἀχέρων, Acheron, "underworld", in reference to the provenance from the Hell Creek Formation, and the Latin raptor, "thief". The specific name honours James and Louise Temerty, the chairman of Northland Power and the ROM Board of Governors and his wife, who have supported the museum for many years. Acheroraptor is known from the holotype ROM 63777, a complete right maxilla with several maxillary teeth (some isolated), and from a referred dentary (lower jaw) ROM 63778, both housed at the Royal Ontario Museum, Canada. Both specimens were collected approximately four metres from one another, from the same mixed faunal bonebed that occurs in the upper part of the Hell Creek Formation of Montana, dating to the latest Maastrichtian stage of the Late Cretaceous, immediately prior to the Cretaceous–Paleogene extinction event. The holotype specimen was collected on August 28, 2009 by commercial fossil hunters, one of whom also collected the dentary several years later, and who were later able to provide detailed geographic data from GPS and photographs of the specimen in situ in the ground on the day of discovery. Both specimens were subsequently purchased by the Royal Ontario Museum from a private collector.