For fans of the series Game of Thrones, the giant wolves (Canis dirus), an extinct species of canid, will be familiar to you because they were inspired to create the fictional direwolves. An international team of scientists, with the participation of the University of Zaragoza (Unizar), has discovered that they were the last wolves of an ancient lineage. It was, therefore, a different genre from the grey Wolf (Canis lupus).
“The main implication of this study is that the phyletic line –evolutionary process of speciation– of the giant wolves (Canis dirus) or wargs (making a nod to the Game of Thrones series) is independent of that of wolves (Canis lupus). Until now the two species had been considered closely related, some authors even considered them to be the same species and there was some opinion that supposedly there could be hybrids ”, he explains to SINC Pere Bover, co-author of the study and researcher ARAID and the University Institute for Research in Environmental Sciences of Unizar.
He paleogenomic study, published in the journal Nature, rejects that there was any type of hybridization and, in fact, places the giant wolves as very distant cousins of the gray wolves. “In the article it is even suggested that its generic name be changed from Canis to Aenocyon dirus (terrible wolf), as it was already proposed about 100 years ago by other authors. In this case, the parallel evolution of two lines of wolf-type canids would be confirmed, one in America and the other in Eurasia-Africa ”, continues Bover.
Dire wolves were large animals that inhabited all of North America, until a few 13,000 years become extinct. This species is one of the most famous prehistoric carnivores from Pleistocene America and fed on large mammals such as the bison.
Of similar morphology, but not genetic
Different studies on their morphology had led scientists to the conclusion that they were closely related to current wolves. However, this research indicates that they were phylogenetically separated from other wolves about six million years ago and are only distant relatives of today’s wolves.
Dire wolves were large animals that inhabited all of North America, until about 13,000 years ago they became extinct
African jackals parted with it lineage of canids right after the giant wolves made it into their own genus, millions of years ago. It appears that the lineage that led to gray wolves, coyotes, dogs, and other wolf-like canids later split off. African jackals are also far removed from these other canids, “he tells SINC. Angela R. Perri, a researcher at the University of Durham (UK) who co-directs the work.
These results support the idea that gray wolves probably arrived in the Americas more recently, surely at the end of the last Ice Age.
Skeleton of ‘Canis dirus’ in the George C. Page Museum. / Wikipedia
DNA from five North American wolves
To reconstruct the evolutionary history of the giant wolves, the scientists sequenced five genomes from fossil remains dating to between 50,000 and 13,000 years ago. The results indicate that although they were indeed morphologically similar to the gray wolf, the dire were a highly divergent lineage that split from living canids about 5.7 million years ago. All the fossil samples came from North American deposits: Tennessee, Wyoming, Ohio and two from Idaho.
“The bones were processed in specific laboratories for the study of old samples and following specific protocols common in these types of laboratory. In addition, the sequencing data was analyzed using the bioinformatics and analytical methods frequently used in these types of studies, ”says Bover.
They were heat-adapted animals and didn’t necessarily like being in the cold northern climates.
It seems that the ancestor of the giant wolves came to the Americas probably millions of years ago and was there alone, for a long period of time. The first evidence we have is from a few 250,000 years. No other similar canids entered the continent at that time, nor did the giant wolves come out of it. This is probably due to the fact that they seem to be heat-adapted animals and did not necessarily like to be in the cold northern climates, “adds the researcher from the British university.
The ancestors The gray wolf and the coyote evolved in Eurasia and are believed to have moved to North America less than 1.37 million years ago, relatively recently in evolutionary time. The dire wolf, meanwhile, is now believed to have originated in America.
“Dire wolves are sometimes portrayed as mythical creatures – giant wolves roaming bleak frozen landscapes – but the reality turns out to be even more interesting,” he suggests. Kieren mitchell, from the University of Adelaide (Australia) and co-author of the research.
The evolutionary isolation of the giant wolf put them to the limit
The absence of gene transfer in your DNA suggests that dire wolves evolved in isolation from the Ice Age ancestors of gray wolves and coyotes, even though they coexisted for at least 10,000 years. “We have shown that the dire wolf has never crossed paths with the gray wolf,” he reaffirms. Alice mouton, co-author of the study at the University of California (USA).
To which Laurent Frantz, professor at Ludwig Maximillian University and Queen Mary University of the United Kingdom adds: “When we started this study, we thought that dire wolves were gray wolves, so we were surprised to learn how extremely genetically different they were. So much so that they probably couldn’t have crossed ”.
Dire wolves evolved in isolation from the Ice Age ancestors of gray wolves and coyotes
The profound evolutionary differences of the current species and the extinct wolf imply that they would be strongly equipped to adapt to changes in conditions at the end of the ice age. However, it is believed that due to the large size of his body he was more specialized in hunting of large prey and could not survive extinction due to its regular sources of food.
“Dozens of genera of species over 45 kg have gone extinct. This wolf, an animal that could weigh about 60 to 70 kg presented a body and dental structure that suggests that it was a hypercarnivore. Likewise, their isolation could also influence their disappearance ”, affirms the scientist from Unizar.
Although genetic isolation did not lead to extinction, it didn’t help them. “It was possibly the result of a combination of things: climate change, the arrival of humans in America, and the introduction of disease. The fact of not being able to reproduce with other canids such as wolves, coyotes and dogs means that the giant wolves could not potentially obtain advantages that favor their survival ”, Perri concludes.
This article was originally published in Agencia Sinc
The article Sequencing the DNA of the giant wolf that inspired the creation of the ‘Game of Thrones’ wargs was published in Hypertext.