Paleontologists from the Case Western Reserve University have discovered a fossil of a kitten-sized predator that lived in what is now Bolivia during the middle Miocene, about 13 million years ago.

This image shows Arctodictis sinclairi. It belonged to the same order of mammals as the newly discovered Bolivian species. Image credit: Analia M. Forasiepi.

This yet-to-be-named animal is one of the smallest species reported in Sparassodonta, an extinct order of carnivorous metatherian mammals native to South America. Once considered to be true marsupials, these animals are now thought to be a sister taxon to them.

Its partial skull was unearthed at an unnamed formation of the Honda Group, Quebrada Honda local fauna, Bolivia.

The paleontologists refrained from naming the animal because the skull lacks well-preserved teeth, which are the only parts preserved in many of its close relatives.

The skull, which would have been a little less than 8 cm long if complete, shows the animal had a very short snout.

“A socket, or alveolus, in the upper jaw shows it had large, canines, that were round in cross-section much like those of a meat-eating marsupial, called the Spotted-tailed quoll, found in Australia today,” said Dr Darin Croft and Mr Russell Engelman, authors of the paper published in the Journal of Vertebrate Paleontology.

Although sparassodonts are more closely related to modern opossums than cats and dogs, the group included saber-toothed species that fed on large prey.

This image shows the skull fossil of the newly discovered sparassodont. Scale bar – 3 cm. Image credit: Rick Wherley / Cleveland Museum of Natural History.

The new Bolivian sparassodont probably fed on the ancient relatives of today’s guinea pigs and spiny rats.

“The animal would have been about the size of a marten, a catlike weasel found in the Northeastern United States and Canada, and probably filled the same ecological niche,” Mr Engelman explained.

Source: sci.news