Ancient predators just gained a new player, as remains at the San Diego Natural History Museum's Paleontology Collection have revealed an exclusive meat-eater from the Eocene that was tearing up flesh around 42 million years ago. The saber-toothed beast is a fascinating find, representing one of Earth’s earliest animals to go all-meat with their diet as well as filling in gaps in our understanding of the emergence of carnivory among mammals.
“Today the ability to eat an all-meat diet, also called hypercarnivory, isn’t uncommon… But 42 million years ago, mammals were only just figuring out how to survive on meat alone,” said postdoctoral researcher at the Nat, Dr Ashley Poust, in a statement.
“One big advance was to evolve specialized teeth for slicing flesh — which is something we see in this newly described specimen.”
Described in the journal PeerJ, the new-to-science predator has been named Diegoaelurus vanvalkenburghae in honor of the San Diego County where it was found (not the character in Ice Age), and scientist Blaire Van Valkenburgh, whose research into carnivore evolution was pivotal to the new paper. Its roughly 42-million-year-old remains consist of a lower jaw and well-preserved teeth which point towards its meat-heavy diet.
As an early predator, D. vanvalkenburghae joins the mysterious Machaeroidines: an extinct group of creatures about which very little is known, making this new member an exciting addition.
"We know so little about Machaeroidines, so every new discovery greatly expands our picture of them,” said co-author Dr Shawn Zack of the University of Arizona College of Medicine in a statement.
“This relatively complete, well-preserved Diegoaelurus fossil is especially useful because the teeth let us infer the diet and start to understand how Machaeroidines are related to each other.”
Investigations into the remains revealed that D. vanvalkenburghae was probably about the size of a bobcat but with teeth unlike any predator around at the time.
“Nothing like this had existed in mammals before,” Poust explained. “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 sabre-teeth in front and slicing scissor teeth called carnassials in the back.”
“It’s a potent combination that several animal groups have independently evolved in the millions of years since.”
Its deadly dentition represents one of evolution’s earliest attempts to support a hypercarnivorous diet, as well as being an example of convergent evolution as similarly saber-toothed animals later emerged among other cat-like creatures.
“Did these groups ever meet, or even compete for space and prey?” posits Poust. “We don’t know yet, but San Diego is proving to be a surprisingly important place for carnivore evolution.”
You can view D. vanvalkenburghae’s impressive gnashers in 3D via the San Diego Natural History Museum’s website.