USA TODAY International Edition
‘ Hypercarnivore’ predator roamed tropical California
Long before it was one of the most populated regions in the United States and full of freeways, Southern California had tropical forests and was also home to a saber- toothed, hypercarnivorous predator that “precedes cats by millions of years,” a newly published study says.
In the 1980s, a 12- year- old boy discovered a fossil north of San Diego in what was the beginning of the fossil bed now known as the Santiago Formation. A few years later, researchers discovered a lower jawbone with teeth intact.
Scientists knew it belonged to some sort of meat- eating animal, but they weren’t sure what type of creature it was. Now, scientists said the jaw belongs to a predator they named Diegoaelurus vanvalkenburghae, part of a “mysterious group” of mammals. Their findings were published in the journal PeerJ on Tuesday.
The fossil, named in honor of the San Diego area, is estimated to be about 42 million years old and estimated to have been alive during the Eocene period when some modern animals began to appear. Much of the Earth was warming, and with San Diego closer to the equator at the time, conditions were like a rainforest.
What caught the attention of the scientists was that the creature belongs to Machaeroidines, an extinct group of animals that are “the oldest known sabertoothed mammalian carnivores.” The Diegoaelurus was a hypercarnivorous animal – with an all- meat diet – at a time when mammals were trying to figure out how to survive on such a diet.
“Nothing like this had existed in mammals before,” Ashley Poust, postdoctoral researcher at The San Diego Natural History Museum and co- author of the study, said in a statement. “A few mammal ancestors had long fangs, but Diegoaelurus and its few relatives represent the first cat- like approach to an all- meat diet, with saber- teeth in front and slicing scissor teeth called carnassials in the back.“
Despite the scientists’ findings, very little is known about the species. Only a few Machaeroidines fossils have been found in Wyoming and Asia, and it’s unknown what the bobcat- sized Diegoaelurus preyed on. Yet, Poust said there were plenty of options, such as tiny rhinos and early tapirs.
“This richness of prey species would have been a smorgasbord for Diegoaelurus, allowing it to live the life of a specialized hunter before most other mammals,” Poust said.
Scientists hope their findings will help understand how these early mammals evolved into hypercarnivore cats such as lions and tigers today.