(CN) — The first genome sequence from dire wolf subfossils confirms the carnivores that roamed North America some 13,000 years ago were terrible. But they weren’t exactly wolves, at least not as we know as wolves today.
According to research published in Nature on Wednesday, dire wolves do not belong with the gray wolves in the Canis genus, but alone in the genus Aenocyon — a name derived from the Latin for terrible or dreadful.
Although the dire is currently categorized as Canis dirus, paleontologist John Campbell Merriam first suggested dubbing the dire wolf Aenocyon dirus more than a century ago.
“With this first ancient DNA analysis of dire wolves we have revealed that the history of dire wolves we thought we knew — particularly a close relationship to gray wolves — is actually much more complicated than we previously thought,” said lead author Angela Perri from Durham University's archaeology department, in a statement.
"Instead of being closely related to other North American canids, like gray wolves and coyotes, we found that dire wolves represent a branch that split off from others millions of years ago, representing the last of a now extinct lineage,” Perri added.
Weighing around 150 pounds, dire wolves were "wolf-like canids" that originated in the North America and thrived during the late Pleistocene. But according to the analysis, the dires and grays haven’t shared a common ancestor for more than 5 million years.
The international team of 49 researchers collected genetic material from the remains of five specimen representing dire wolves from Idaho, Ohio, Tennessee and Wyoming, that lived between 12,900 and 50,000 years ago.
Named Canis dirus, dire wolves were previously thought to be related to gray wolves, based on the similarity of their bone structure and teeth. This genetic analysis, however, indicates dires were so distinct from grays and coyotes they didn’t even breed with each other. The dire’s genus may officially change from Canis to Aenocyon to reflect these findings if the research community and the International Union for Conservation of Nature reach a consensus.
"Despite anatomical similarities between gray wolves and dire wolves — suggesting that they could perhaps be related in the same way as modern humans and Neanderthals — our genetic results show these two species of wolf are much more like distant cousins, like humans and chimpanzees,” explained co-author Kieren Mitchell, from the University of Adelaide, in a statement.
"While ancient humans and Neanderthals appear to have interbred, as do modern grey wolves and coyotes, our genetic data provided no evidence that dire wolves interbred with any living canine species,” Mitchell added. “All our data point to the dire wolf being the last surviving member of an ancient lineage distinct from all living canines."
The research additionally presents evidence of a relationship between dire wolves and other wolf-like canids, although it is unclear which animal derived from which and when.
Although dire wolves were once one of the most common large carnivores in North America, they have no known living ancestors today.
"The leading hypothesis to explain their extinction is that, owing to their larger body size compared with gray wolves and coyotes, dire wolves were more specialized for hunting large prey and were unable to survive the extinction of their megafaunal prey,” researchers explained in the paper.
Additionally, when gray wolves gained new coat colors and immunity responses through interbreeding, researchers pose "reproductive isolation prevented dire wolves from acquiring traits that may have allowed them to survive into the Holocene epoch."
The extinct dire wolf of North America should not be confused with George R. R. Martin's fictional creature in “Game of Thrones,” the direwolf of Westeros.
Among others, the research was funded by the National Science Foundation and the European Research Council.
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