For decades a fossilized carnivore jawbone sat largely unnoticed in a drawer at Chicago’s Field Museum.

Now the scientist who grew curious when he opened that drawer has established with a colleague that the fossil belonged to an early, long-extinct relative of dogs, foxes and weasels known as a beardog. The Field Museum fossil and another at the University of Texas each represent a new genus, the taxonomic rank above species.

The researchers believe these beardogs, which lived up to 40 million years ago, might eventually tell the world more about the evolution of dogs and other carnivores and how animals adapt to changes in climate.

According to a paper to be published Wednesday in the journal Royal Society Open Science, the jawbones belonged to two closely related types of Chihuahua-sized beardogs, new genera now named Gustafsonia and Angelarctocyon.

The Field Museum fossil set off the research by post-doctoral researcher Susumu Tomiya, who works at the museum and takes care of its fossils.

“In my spare time I like to walk around the aisles in the collections and open up drawers,” he said. “One day I just stumbled on these interesting-looking jaws of a little carnivore.”

The fossil was discovered in Texas in 1946 and 30 years ago was loosely classified as some type of carnivore. But no one knew where it fit into the carnivore family, said Tomiya, who authored the paper with Jack Tseng of the State University of New York at Buffalo.

The teeth stood out to Tomiya. They had flatter surfaces for crushing that suggested their owners ate more than meat – maybe berries and bugs, too, like present-day foxes.

The teeth reminded Tomiya of beardogs he was familiar with, he said.


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