Canadian dire wolf fossil officially identified

There was a grinning-toothed monster lurking in the basement collection of a museum in Canada: the fossilized jaw of a monster that once roamed the bluffs along a southern Saskatchewan river, competing with saber-toothed cats (Smilodon) in hunting horses, bison, camels, and mammoths.

Researcher Ashley R. Reynolds in the Department of Natural History, Royal Ontario Museum, Toronto, decided to closely examine some of the earlier finds while taking advantage of the new knowledge accumulated since the time of discovery. This practice gained renewed popularity in groups around the world during the pandemic and led to many interesting discoveries, including work published by Reynolds in Quaternary Science Journal.

Previous efforts by Reynolds and colleagues showed the first evidence of a Canadian saber-toothed cat (Smilodon fatalis) in the museum’s collection. In the current study, “Direwolf (Canis dirus) from Late Pleistocene Southern Canada (Medicine Hat, Alberta),” Reynolds analyzed more fossil material from the same excavation site to formally identify a dire wolf from a fossilized jawbone in the group.

The fossil, which was originally found in 1969, was identified as a dire wolf by CS Churcher (author on the current paper) in an unpublished report to the Canadian Geological Survey in 1970, based on its large size. They are not illustrated or described in detail to confirm the initial identification.

Dire wolves are a larger, extinct cousin of the gray wolf with a more muscular build and more powerful jaws. Three species of dire wolves ranged from North and South America to eastern China. They must be fierce competitors because their territory ranges often overlap with other large predators, saber-toothed cats often three times their size.

It is unusual for the jaw to be left unexamined for so long as the specimen would be the first and only dire wolf ever found in Canada and the northernmost known limit for this species is 500 km. This could be because initial observations lacked the confidence to make a more formal identification.

There is some difficulty in distinguishing a gray wolf from a dire wolf from a poorly preserved fossil because the two are morphologically so similar, although it is estimated that the two separated from a common ancestor by more than 5.5 million years.

With the complete fossil jaw in good condition, the identification would be obvious, as size and the distinct patterns on the teeth could clearly separate the two. The fossil that was found in 1969 was in poor condition, broken in multiple places and missing the most obvious evidence on the tooth surfaces because some teeth were missing, and the teeth that were preserved in the jaw were either poorly preserved or were worn down naturally by a wolf-tooth advanced.

Without the more obvious identifiers, the researchers took multiple measurements and plotted them against known dire wolf fossils, modern-day gray wolves, and ancestral fossils of the gray wolf. In the analysis there was some overlap with outliers between dire wolves and gray wolf ancestors, but the fossilized jaw pieces placed it firmly in the dire wolf category as originally suggested in the unpublished 1970 report. The radiocarbon-dated woodcuts are believed to date from somewhere near Jaw found about 45,000 years ago.

The study is a long overdue investigation, adding to the range of known areas inhabited by the dire wolf. The recent identification of a 40,000-year-old dire wolf fossil in northeastern China, reported in the paper, indicates animal migrations around the time frame of the Canadian dire wolf, indicating that it crossed the land bridge formations between Asia and North America. until the last ice age. Since dire wolves may have lived as recently as 9,500 years ago, it is likely that they crossed paths with the first humans who migrated to Beringia.

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