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Dreadful Wolves (The dog darkens) are considered one of the most common and widespread large carnivores in Pleistocene America, but relatively little is known about their evolution or extinction. Previous analyzes, based purely on morphology, had led scientists to believe that these long-extinct canids were closely related to modern gray wolves (Canis lupus). To reconstruct the evolutionary history of terrible wolves, an international team of genetic researchers sequenced five genomes from fossilized remains dating from 12,900 to more than 50,000 years ago. Their results, published in the journal Nature, indicate that terrible wolves were a distinct lineage that separated from living canids about 5.7 million years ago.
Somewhere in southwestern North America at the end of the Pleistocene, a pack of terrible wolves (The dog darkens) feed on their bison, while a pair of gray wolves (Canis lupus) approach in the hope of recovering. One of the terrible wolves rushes in to take on the gray wolves, and their confrontation allows for a comparison of the bigger, bigger, reddish-brown fearsome wolf to its smaller, gray relative. Image Credit: Mauricio Antón / Nature.
The dreaded wolves were large wolf-like canids – around 68 kg, about 25% heavier than gray wolves – and among the most common large extinct carnivores of the American Late Pleistocene megafauna.
Their remains are present in North American paleontological records from at least about 250,000 to about 13,000 years ago, at the end of the Pleistocene era.
Other species of canids present in the late Pleistocene in North America include the slightly smaller gray wolf, the much smaller coyote (Canis latrans) and the dhole (Cuon alpinus), although terrible wolves seem to have been more common overall.
The dreaded wolves are generally described as a sister species, or even conspecific with the gray wolves.
The main hypothesis for their extinction was that due to their larger body size than gray wolves and coyotes, terrible wolves were more specialized in hunting large prey and were unable to survive the extinction of their megafaunal prey.
“The dreaded wolves have always been an iconic representation of the last ice age of the Americas and now a pop culture icon thanks to Game of Thrones, but what we know of their evolutionary history has been limited to what we can see. from size and shape. their bones and teeth, ”said co-lead author Dr Angela Perri, researcher in the Department of Archeology at Durham University.
“With this first ancient DNA analysis of terrible wolves, we revealed that the story of the terrible wolves we thought we knew is actually much more complicated than we previously thought.
“Instead of being closely related to other North American canids, such as gray wolves and coyotes, we found that terrible wolves represent a branch that separated from the rest millions of years ago. , representing the last of a now extinct line.
“The terrible terrible wolf, legendary symbol of Los Angeles and the tar pits of La Brea, has earned its place among the many great unique species that became extinct at the end of the Pleistocene epoch,” said the co-author , Professor Robert Wayne, researcher in the Department of Ecology and Evolutionary Biology at the University of California, Los Angeles.
“The dreaded wolves are sometimes described as mythical creatures – giant wolves prowling in icy, dark landscapes – but the reality turns out even more interesting,” said co-lead author Dr Kieren Mitchell, researcher at the Australian Center for Ancient DNA at the University of Adelaide.
For the study, the researchers examined 46 sub-fossil specimens of terrible wolves for the presence of preserved DNA.
They identified five samples from Idaho, Ohio, Tennessee and Wyoming, dating from 12,900 to over 50,000 years ago, which had enough DNA to obtain the mitochondrial and nuclear genome sequences.
They found no evidence of gene flow between terrible wolves and North American gray wolves or coyotes.
The lack of any genetic transfer indicates that terrible wolves evolved independently from the Ice Age ancestors of these other species.
“We have discovered that the terrible wolf is not closely related to the gray wolf,” said co-author Dr. Alice Mouton, a researcher in the Department of Ecology and Evolutionary Biology at the University of California, Los Angeles.
“In addition, we show that the terrible wolf never crossed paths with the gray wolf. In contrast, gray wolves, African wolves, dogs, coyotes, and jackals can and do breed.
“Fearsome Wolves probably diverged from Gray Wolves over 5 million years ago, which was a big surprise that this divergence happened so soon. This finding highlights just how special and unique the terrible wolf was.
The ancestors of the gray wolves and much smaller coyotes evolved in Eurasia and are believed to have moved to North America less than 1.37 million years ago, relatively recently in evolution.
The terrible wolf, due to its genetic difference from these species, is now believed to be native to the Americas.
The authors also suggest that the clear evolutionary divergence of terrible wolves from gray wolves places them in an entirely different genus, Aenocyon, as first proposed by paleontologist John Campbell Merriam over 100 years ago.
“When we started this study, we thought that terrible wolves were just empowered gray wolves, so we were surprised to learn how extremely genetically different they were, so much so that they probably wouldn’t. could not reproduce, ”said the head teacher. Laurent Frantz, researcher at the School of Biological and Chemical Sciences at Queen Mary University in London and at the Department of Veterinary Sciences at Ludwig Maximilian University.
“It must mean that terrible wolves have been isolated in North America for a very long time to become so genetically distinct.
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AR Perri et al. The dreaded wolves were the last of an ancient New World canid line. Nature, published online January 13, 2021; doi: 10.1038 / s41586-020-03082-x
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