A giant lion with enormous fangs that roamed the Kenyan savannah more than 20 million years ago was one of the largest ever meat-eating mammals, researchers said Thursday.
A team unearthed the lower jaw, teeth and other bones of a new species, Simbakubwa kutokaafrika — Swahili for "big African lion".
They calculated it would have weighed up to 1,500 kilograms and could have preyed upon the elephant-like creatures that lived there at the time.
Bigger than any carnivorous land mammal alive today - even a polar bear - Simbakubwa's skull was the size of a rhino's, its eight-inch (20-cm) canine teeth as large as bananas. It weighed about a ton and was 8 feet long (2-1/2 meters) snout to rump.
According to the research published in the Journal of Vertebrate Paleontology, the fossils were excavated around 1980 in western Kenya and never closely examined.
"Most of the specimens that I study are quite small, so you can imagine my surprise when I opened a drawer that I hadn't examined yet, and saw the enormous teeth glinting up at me. The specimen had been collected decades before, and the team that discovered this fossil was more focused on other parts of the fauna, particularly primates," Stevens said.
Simbakubwa was a member of a group called hyaenodonts that appeared 62 million years ago, 4 million years after the extinction of the dinosaurs paved the way for mammalian dominance, and went extinct 9 million years ago.
Hyaenodonts preceded carnivore groups like cats, bears, hyenas and wolves, and were closely related to none of them.
"At first glance, it would have looked like a gigantic hyena or long-tailed wolf with a head that was a little too big for its body. I imagine something like the 'wargs' from 'Lord of the Rings,'" said Borths, a Duke Lemur Center paleontologist, referring to fictional monstrous wolves.
Simbakubwa's name means "big lion" in Swahili though it was not a cat. It was the largest predator in its ecosystem, a fragmented forest inhabited by early apes, hippo relatives and elephant relatives, and was probably the largest carnivorous land mammal in Africa up to that time.
"It was not an animal built for long efficient runs across open ground. Instead, its foot was flexed. Carnivores with this posture tend to be ambush hunters like tigers rather than pursuit hunters like wolves," Borths said.