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A Museum’s

Monster Find

BY GEMMA TARLACH

49

i

It was the size of a polar bear,

with a mouth full of slash-

ing blades. Some 22 million

years ago, in what’s now

Kenya, the mega-carnivore

Simbakubwa kutokaafrika ruled.

Then it disappeared.

The last of Simbakubwa’s lineage,

carnivores known as hyaenodonts, went

extinct more than 10 million years ago.

Mostly fragmentary fossils of dozens

of species have been found around the

world, some smaller than house cats.

Other species were much larger, but

researchers had few clues about when

these giants evolved.

A dig in southwestern Kenya in the

late 1970s turned up a massive lower jaw-

bone — about twice the size of a modern

lion’s — and a few related teeth and other

bones. But that expedition focused on

Miocene primate fossils, and the team

didn’t pay much attention to the frag-

mentary mega-carnivore remains. The

bones ended up in a Nairobi museum

drawer, unstudied for years.

Decades later, two paleontologists

realized the jawbone belonged to a

new species, the oldest member of a

giant hyaenodont lineage known as the

hyainailourines, suggesting this mysteri-

ous group originated in Africa.

Simbakubwa finally got a name, and the

recognition it deserves. Announced to the

world in April in the Journal of Vertebrate

Paleontology, the animal reveals not only

the origins of these XXL carnivores, but

also how they adapted to a world of

colliding continents.

We asked paleontologists and study

authors Nancy Stevens of Ohio University

and Matt Borths, now at Duke University,

to share Simbakubwa’s s t o r y.

Paleontologist Matt Borths holds the jaw of mega-carnivore Simbakubwa kutokaafrika. In life, the animal

would have been about the size of a polar bear, with a mouth full of shearing, bladelike teeth.