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 sabre-tooth,Â hyper-carnivorous predator that “precedes cats by millions of years,” a newly published study says.
In the 1980s, a 12-year-old boy discovered a fossil just north of San Diego in what was just the beginning of the fossil bed now known as the Santiago Formation.Â A few years later, researchers discovered a lower jawbone with teeth intact.Â
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 theÂ jaw belongs to a predator they namedÂ Diegoaelurus vanvalkenburghae, part of a “mysterious group” of mammals. Their findings were published in the journal PeerJ on Tuesday.Â
The fossil, named in honor of the San Diego area,Â is estimated to be around 42 million years old,Â and estimated to be alive during theÂ Eocene period when some modern animals began to appear. Much of the Earth was warming, and with San DiegoÂ closer to the equator at the time, conditions were like a rainforest.Â
What caught the attention of the scientists was they found out the creatureÂ belongs to Machaeroidines, an extinct group of animals that areÂ “the oldest known saber-toothed mammalian carnivores.” TheÂ DiegoaelurusÂ was aÂ hyper-carnivorous animalÂ â€“ with an all meat dietÂ â€“ at a time when mammals were trying to figure out how to surviveÂ on such a diet.Â
“Nothing like this had existed in mammals before,” Ashley Poust,Â postdoctoral researcher atÂ The San Diego Natural History Museum and co-author of the study, said in a statement. “A few mammal ancestors had long fangs, butÂ DiegoaelurusÂ and its few relatives represent the first cat-like approach to an all-meat diet, with sabre-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 MachaeroidinesÂ fossils have been found in Wyoming and Asia, andÂ it’s unknown what the bobcat-sized Diegoaelurus preyed on. Yet, Poust said there were plenty of options, such asÂ tiny rhinos and early tapirs.Â
“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.Â
Scientists hope their findings will help understand how these early mammals evolved into hyper-carnivore cats like lions and tigers around today. WithÂ fossils in a new area, it raises the possibility of more being found in the West and poses the question if the creature interacted with other cat-like sabre-tooth creatures.Â
“Did these groups ever meet, or even compete for space and prey? We donâ€™t know yet, but San Diego is proving to be a surprisingly important place for carnivore evolution,” Poust said.Â
Follow Jordan Mendoza on Twitter:Â @jordan_mendoza5.
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