Pronunciation: ah-SHEH-ro-RAP-tuh
Meaning: Acheron plunderer
Author/s: Evans et al. (2013)
Synonyms: None known
First Discovery: Montana, USA
Discovery Chart Position: #854
Acheroraptor temertyorum
Fossilized dromaeosaurids (aka "raptors") from the Maastrichtian period of North America are almost as rare as rocking horse droppings, and the few that have been discovered are represented mainly by isolated teeth. Acheroraptor is known from isolated teeth too, but its remains also include jaw bones to which teeth are still attached, and they sport enough diagnostic features to prove it was a member of Velociraptorinae: a subfamily of small, agile, sickle-clawed predators within Dromaeosauridae, anchored by the misrepresented media hog Velociraptor.
Despite its provenance, Acheroraptor is more closely related to Asian dromaeosaurids such as Tsaagan and Velociraptor than it is to Dromaeosaurus, Saurornitholestes, or any other critter from North America. Its discovery in latest Maastrichtian deposits makes Acheroraptor the last occurring species of dromaeosaurid, still plundering the Tyrannosaurus-dominated Hell Creek Formation at the twilight of the Cretaceous, blissfully unaware of the imminent K-Pg extinction.
Despite its provenance, Acheroraptor is more closely related to Asian dromaeosaurids such as Tsaagan and Velociraptor than it is to Dromaeosaurus, Saurornitholestes, or any other critter from North America. Its discovery in latest Maastrichtian deposits makes Acheroraptor the last occurring species of dromaeosaurid, still plundering the Tyrannosaurus-dominated Hell Creek Formation at the twilight of the Cretaceous, blissfully unaware of the imminent K-Pg extinction.
(Temerty's Acheron plunderer)Etymology
Acheroraptor is derived from "Acheron" (the underworld "River of Woe" in Greek mythology, alluding to its discovery in the Hell Creek Formation) and the Latin "raptor" (plunderer, robber, snatcher or thief).
The species epithet, temertyorum, honours James and Louise Temerty for their contributions to the Royal Ontario Museum.
Discovery
The first fossils of Acheroraptor were discovered in the Hell Creek Formation, 45 km southwest of Jordan, Garfield County, Montana, USA, on the 28th of August 2009, by private collectors who sold them to the Royal Ontario Museum.
The holotype (ROM 63777) is a complete maxilla (tooth-bearing bone of the upper jaw) with several teeth. A dentary (tooth-bearing bone of the lower jaw, catalogued as ROM 63778) was discovered four meters away a couple of years later by the same collectors and may belong to the same critter, judging by its size. Acheroraptor' teeth are recurved (curve backwards) and sport vertical grooves and rounded denticles (small serrations along the cutting edges of the tooth), but the denticles on the rear edge are much larger than those on the front edge.
