DNA traces the evolution of extinct sabretooths and the American cheetah-like cat

By analysing ancient DNA, an international team of researchers has obtained data that increases our knowledge about how the large predatory cats that once roamed the prehistoric New World were related to each other.

The research, published today (9 August) in Current Biology, was carried out by Ross Barnett from the University of Oxford and a team of researchers from Britain, the United States, Canada, Sweden, and Australia.

North and South America were once home to a variety of large cats such as the sabretooths and other now-extinct species. Of these big cats, only the puma and jaguar survive in the Americas today.

Using computer models the researchers created an updated family tree for the ancient cats by comparing 13,000 year old DNA extracted from the preserved bones of two sabretooths (a Smilodon specimen from Patagonia and a Homotherium specimen from the Yukon region) and the American cheetah-like cat (a Miracinonyx specimen from Wyoming) with DNA from modern cat-family and other carnivore species.

The evolutionary tree drawn from the new data shows that the American cheetah-like cat is genetically most closely related to the puma, rather than to the true African cheetah .The American cheetah-like cat and the true cheetah show remarkable similarity in their development, including elongated limbs and enlarged nostrils. But the genetic data indicates that this similarity is in fact an example of parallel evolution; the development of similar bodies in response to similar ecological pressures.

Ross Barnett said, “Our DNA data proves that Miracinonyx, the cheetah-like cat, is most closely related to the modern day puma. As the cat was so well adapted to fast running its evolution probably depended on having to catch fleet-footed prey that roamed the prairies of North America.”

The analysis also clearly shows that the sabretooth cats were a sister group to the modern cats — that is, they diverged early on from the ancestors of modern cats and are not closely related to any living cat species.

The evolutionary history of the extinct American cats has been closely studied by palaeontologists, but it has been difficult to determine the exact relationship of several groups. This new DNA data is an important breakthrough.