Critters: Unearthed in Oceanside

Hello Kitty! Our kitty, known as Diegoaelurus (San Diego’s cat) recently introduced by the San Diego Natural History Museum, is a breed of saber tooth cat-like mammals who once roamed west of the Rocky Mountains and, in this case, remained incognito for 42 million years.

Illustration of Diegoaelurus, living in our area during the Eocene. Image Credit: Erick Toussaint, San Diego Natural History Museum.

The formidable fossil, a lower jaw, serious saber-toothed fang, and some serrated back teeth turned up in Oceanside in 1988 when a young boy named Jeff spotted the lot at the construction site when Interstate 5 was widened. The fossil went to the San Diego Natural History Museum. It sat safely in storage. During the pandemic when his active research was stalled, Paleontologist Ashley Poust, who previously studied and identified the Wulong bohaiensis (“dancing dragon”), a 100 million year old feathered dinosaur in China and an even older dinosaur fossil from the Cretaceous period 145 million years ago that had unlaid eggs inside its skeleton, turned his attention to the locally found fossil.

Image credit: By Zack et al, CC BY-SA 4.0,

Collaborating with fellow researchers online, the bone and teeth were identified as belonging to a novel species unique to our region. This bobcat-sized creature lived among the ancestors of lemurs, miniature rhinos and other possible prey for this hyper-carnivore during the Eocene epoch when the land was a floodplain thick with rainforests. At that early time mammals were figuring out what foods were available that would work for them. The cat’s sizable fangs and super sharp slicing teeth, tailored to take cat nips at neighbors, were this animal’s key to evolving to be an early meat eater. Through the next millions of years other species experimented and evolved independently to become carnivores. If you have a cat, you have one of the descendants.

Photo by Elizabeth Zusev.