The handful of mysterious fossils sat unstudied for decades, tucked safely in a drawer at the Nairobi National Museum in Kenya. But now, analysis of the ancient remains has revealed that they belonged to a giant meat-eating mammal larger than a polar bear, a newly described species that’s been dubbed Simbakubwa kutokaafrika.

Reported this week in the Journal of Vertebrate Paleontology, the powerful predator prowled the Earth some 22 million years ago. Although Simbakubwa translates to “big lion” in Swahili, this behemoth was not a big cat. Instead, it is the oldest known member in a group of extinct mammals called hyaenodonts, so named due to their dental resemblance to hyenas, even though the groups are also unrelated.

The discovery