New saber-toothed mammals are among the first hyper predators.

Nearly 42 million years ago, terrifying creatures the size of a cat roamed the forests of today's San Diego. Unlike best animals at the time, it was a hyper predator, designed to eat meat and almost any flesh.

Meet Diegoaelurus vanvalkenburghae - a recently identified species in the mysterious and now extinct family of machaeroidins, believed to be the first mammal with sword-like and sharp teeth.

So far, only about a dozen other macheroid fossils have been described, mainly from Wyoming but few from Asia. However, paleontologists have identified this new predator, described March 15 in PeerJ, thanks to a 71-millimeter mandible with teeth found initially in fossils in San Diego County.

Fossils say the creature had canine teeth that were long like swords because its chin bone was lowered to protect its teeth, and there was a gap in its lower teeth, said Ashley Pust, a paleontologist at the San Museum of Natural History in Diego. However, the dogs themselves were not found. "These large teeth are used to bite the throat of prey or are used to tear and tear flesh," said Post. Now we know there may be a saber-toothed primate lurking in the branches or perhaps a tapir in the leaves below."

Today's hyper predators range from giant polar bears and ferocious tigers to your furry (or not) domestic cat. But this way of life was unusual for predators from the Eocene, which ended about 34 million years ago, and not many of these predators have been known since.

Thus, D. vanvalkenburghae provides early insight into how animals independently developed the ability to cut meat easily (SN: 31/5/19). Dagger-like teeth have appeared in various ancient animals, from anchovies to more recent saber-toothed cats such as Smilodon, which materialized on Earth millions of years after D. vanvalkenburghae became extinct.