Nearly 42 million years ago, a fearsome bobcat-sized creature prowled the forests of what is now San Diego. Unlike most animals at the time, it was a hypercarnivore, built to eat meat and almost only meat.
Meet Diegoaelurus vanvalkenburghae — a newly identified species of the mysterious and now-extinct Machaeroidine family, thought to be the first mammals with saberlike fangs and sharp slicing teeth.
Until now, only about a dozen other Machaeroidine fossils have been described, most from Wyoming but a few from Asia. Paleontologists identified this new predator, described March 15 in PeerJ, thanks to a 71-millimeter-long lower jawbone with teeth that was originally found in a San Diego County fossil bed.
The fossil gives away that the creature had long saberlike canine teeth because the bony chin is downturned, to protect the fangs, and there is a gap in the lower teeth to fit them, says Ashley Poust, a paleontologist at the San Diego Natural History Museum. The canines themselves weren’t recovered.