UT’s CT lab helps classify beardog fossils

Lawrence Goodwyn

With nothing but a skull and a jawbone to study, UT’s Computed Tomography, or CT, lab recently helped researchers classify two 38-million-year-old fossils as belonging to a group of animals called beardogs.

Jack Tseng, assistant professor of pathology and anatomical sciences at SUNY Buffalo, and Susumu Tomiya, a researcher at the Field Museum in Chicago, worked as a team to reclassify two new species of beardogs, Gustafsonia cognita and Angelarctocyon australis

Tomiya said he and Tseng classified two species of beardogs, the smaller one the size of a chihuahua and weighing around five pounds. These beardogs probably resembled tiny foxes. 

“Google beardogs and you’ll see illustrations of very large bear or wolf-looking thing, but the ones we study are very far from attaining that size or having that sort of adaptation,” Tseng said. 

Tomiya said these smaller beardogs were older and further back in the beardog lineage. 

“They’re important because they are some of the smallest and earliest beardogs, and it allows us to place them in order chronologically and see if these fossils are more close to bears or dogs,” Tomiya said. 

Tseng said that initially the fossils of the two species were misidentified as members of the Miacis genus, a group of carnivorous mammals which have five claws and were around the size of a weasel. 

Tseng said the ears and teeth of the first fossil they found were strong indicators that the fossil was probably not Miacis, but a beardog. The UT-Austin CT Lab kept data on the Gustafsonia skull, which helped the researchers with their study. 

The researchers used high resolution data from the scan to reconstruct the internal structure of the skull, which revealed that the fossils had significant similarities to beardogs. The fossil’s ears in particular were reminiscent of the much larger, younger beardogs, revealing that these fossils could be the beginnings of the first true beardogs. 

These two beardog fossils are most likely closer in evolution to modern dogs than to bears, according to Tseng. He also said beardogs could have been top predators, scavengers or possibly a combination of both. 

“[These fossils] are important because they are the smallest and the earliest known beardogs,” Tseng said. “That is really the key to fitting the beardogs into a place in the carnivore group. You have to go back and look at the very earliest forms.”