Fossil of dog 12 million years old 'like mini bear' discovered in North America by researchers

Scientists have identified a new species of an ancient, ‘bone-crushing’ dog that roamed North America about 12 million years ago, at a time when massive sharks like megalodon swam in the oceans. The newly named species Cynarctus wangi was a member of the extinct subfamily Borophaginae, commonly known as bone-crushing dogs because of their powerful jaws and broad teeth.

“In this respect they are believed to have behaved in a similar way to hyenas today,” said Steven E Jasinski, a student at the University of Pennsylvania in US. Fossils from terrestrial species from this region and time period are relatively rare, thus the find helps paleontologists fill in important missing pieces about what prehistoric life was like on North American’s East Coast.

“Most fossils known from this time period represent marine animals, who become fossilised more easily than animals on land,” Jasinski said. “It is quite rare we find fossils from land animals in this region during this time, but each one provides important information for what life was like then,” he said. 

At first, the researchers presumed the specimen was a known species of borophagine dog, a species called marylandica that was questionably referred to as Cynarctus, a fossil of which had been found in older sediment in the same area. However, when they compared features of the occlusal surfaces, where the top and bottom teeth meet, of the previously known and the new specimens, they found notable differences.

They concluded that the specimen represented a distinct species new to science. “It looks like it might be a distant relative descended from the previously known borophagine,” Jasinski said.

Borophagine dogs were widespread and diverse in North America from around 30 million to about 10 million years ago.  The last members went extinct around 2 millions of years ago during the late Pliocene. C wangi represents one of the last surviving borophagines and was likely outcompeted by ancestors of some of the canines living today: wolves, coyotes and foxes. (Also read. NASA probes find magnetic reconnection in space for the first time ever)

Despite its strong jaws, the researchers believe C wangi would not have been wholly reliant on meat to sustain itself. “Based on its teeth, probably only about a third of its diet would have been meat,” Jasinski said.

“It would have supplemented that by eating plants or insects, living more like a mini-bear than like a dog,” he said. C wangi would have lived beside ancient pigs Desmathyus and Prosthenops, the horned artiodactyl Prosynthetoceras, an ancient elephant-like animal known as a gomphothere, and perhaps the ancient horse Merychippus, researchers said. The study was published in the Journal of Paleontology.