A giant mammal with huge fangs roamed around what is now Kenya about 22 million years ago, researchers say.
It has been dubbed "Simbakubwa kutoka Afrika" - Swahili for "big African lion".
But it was probably bigger than a polar bear and is - according to National Geographic magazine - 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 lower jaw, teeth and other bones of the animal were found in a museum in Kenya's capital, Nairobi.
"Based on its massive teeth, Simbakubwa was a specialised hyper-carnivore that was significantly larger than the modern lion and possibly larger than a polar bear," US-based Duke University co-researcher Matthew Borths told AFP news agency.
He co-led the research with colleagues at Ohio University, and their findings have been published in the Journal of Vertebrate Paleontology.