A small skull wrongly attributed to an ancient feline has been re-identified as belonging to an ancestor of weasels, wolverines, minks and modern otters.
Presentation Corumictis wolsani, the first known mustelid in North America, according to research published in Zoological Journal of the Linnean Society. Mustelids are a diverse family of carnivorous animals, including weasels, badgers, ferrets, wolverines and similar creatures. Now off, C. wolsani lived about 26 million years ago in what is now Oregon.
“His teeth are incredibly sharp, sharper than some weasels today,” Ryan Paterson, paleontologist at Carleton University in Ottawa and lead author of the new study, told CBC News. “It was probably a fierce little thing, despite the size of the smallest weasel on the planet.”
Indeed, you must not let the small size of this animal fool you. Despite a skull just 4 centimeters (1.56 inches) long, C. wolsani was probably an adept killer, feasting on small land mammals like ground squirrels, gophers and rabbits, according to the new research. And in fact, their small size may have allowed them to “slip into rodent holes”, as the authors have written.
The skull was discovered in the 2000s in the John Day formation in northern Oregon, which is between 28.8 million and 25.9 million years ago. Its discovery confirms the presence of mustelids at the start and end of the Oligocene in North America, and it is about a million years older than other mustelids on the continent. The oldest known mustelids come from Europe and lived around 2 million years before C. wolsani.
When it was first discovered, the specimen was originally identified as an ancient cat and quickly exhibited in an Oregon museum, according to the CBC. The skull was re-analyzed by Paterson, who was looking for an intermediate species connecting modern seals and sea lions to their extinct land ancestors, reports the CBC. C. wolsani was not the missing link that Paterson was looking for, but it was nevertheless a fascinating and important discovery.
Distinctive features, such as the unique shape of his brain and inner ear, allowed Paterson and his colleagues to identify the species as new to science. C. wolsani is thought to be related to modern North American wolverines, minks, otters and weasels. As noted in the CBC article, researchers refer to him as “the great-grandfather of wolverines”.
As for the name, Corumictis means “northwest” in Latin, and wolsani is a nod to the Polish paleontologist Mieczysław Wolsan, “who has thoroughly studied fossil musteloids and worked to reveal their evolutionary history”, as the authors wrote in the article.
It is not uncommon for artifacts to be misidentified at first. In 2018, an ancient Egyptian mummy of a “hawk” turned out to be stillborn human baby, for example.