December 16, 2013
New Hell Creek, Montana Raptor Species Named, Described
Lawrence LeBlond for redOrbit.com - Your Universe Online
The dinosaur, called Acheroraptor temertyorum, was approximately nine feet tall and weighed about 90 pounds when it was alive. The naming and description of this raptoran, which lived in what is now western North America some 66 to 67 million years ago, has been published in the latest issue of Naturwissenschaften (The Science of Nature).
The dinosaur’s description and naming is based on a pair of upper and lower jaws discovered in Montana’s Hell Creek Formation. It was relatively large for a raptor, with a long-snouted skull and dagger-like ridged teeth. Researchers assume it was likely covered in feathers, given its close heritage to birds and other feathered relatives.
Acheroraptor, which means “Acheron Plunderer,” comes from Acheron, the River of Pain in Greek mythology, and from the Latin word raptor, which means robber or plunderer. Its species name honors James and Louise Temerty, for their service, support and contributions to the Royal Ontario Museum.
When Acheroraptor roamed the landscape just a few million short years before the end-Cretaceous extinction event it was known as one of the last non-avian dinosaurs. It thrived in a world dominated by the apex predator Tyrannosaurus and the plant-eating Triceratops. Strangely enough, Acheroraptor was more closely related to other long-snouted Asian raptorans than older North American species.
"Acheroraptor gives us a more complete picture of the ecosystem in North America just before the great extinction that marked the end of the Age of Dinosaurs," said lead author Dr. David Evans, Curator of Vertebrate Palaeontology at the ROM. “The close evolutionary relationship of Acheroraptor to a small group of late-occurring Asian species that includes Velociraptor suggests migration from Asia continued to shape North American dinosaur communities right up until the end of the Cretaceous period."
“We have had scanty evidence for more than a century that “raptors” lived with Tyrannosaurs rex until the end of the Cretaceous,” says Dr. Phillip Currie, professor at the University of Alberta. “But the absence of clearly identifiable dromaeosaurid fossils has been perplexing to the dinosaur-hunters who have worked in the Hell Creek area, which has otherwise produced abundant fossils.”
Acheroraptor’s teeth have been recognizable for decades, but paleontologists had no other fossil evidence to add to the picture, allowing for a narrower description of the dinosaur that had these chompers, as well as a more general idea of the evolutionary relationships of Hell Creek dromaeosaurs.
“The most exciting aspect of the specimen is the teeth,” says co-author Derek Larson, a PhD student at the University of Toronto. “We now know that those teeth all belong to the same animal, and we now know enough about what that animal looks like to distinguish it as its own species.”
Analysis of the teeth in contrast to other small meat-eating dinosaur teeth from the same region and time suggests dromaeosaur diversity was faltering in North America just before dinosaurs became extinct.
The Acheroraptor specimens are now on display through the holiday season in the James and Louise Temerty Galleries of the Age of Dinosaurs at ROM’s Michael Lee-Chin Crystal.
“We are proud to support ground-breaking palaeontology research initiatives at the ROM, which provide fascinating insights into our history and the world we live in,” said Mr. Temerty.
Image Below: Upper and lower jaw bone of Acheroraptor temertyorum. Credit: Royal Ontario Museum