THE FOSSILISED skull of a big cat unearthed in north-west China has been identified as the most primitive cheetah ever found. The skull, which is between 2.16 million and 2.55 million years old, is superbly preserved and its location casts doubt on ideas that cheetahs evolved in the Americas.
One theory is that modern cheetahs shared a common ancestor with pumas, but the fossil record of the puma goes back only about 400,000 years in the US. Because the current find is so much older, it is strong evidence for an evolutionary origin for cheetahs in Asia.
Cheetahs are the fastest land animal, using bursts of speed in excess of 110km/h to capture prey. They are now found almost exclusively in Africa and are classified by the International Union for the Conservation of Nature’s Red List of endangered species as vulnerable to extinction.
One sub-species called the Asiatic cheetah still exists in Iran. Numbering between 60 and 100 animals, it represents the remnants of a population that was once widespread across Asia but was devastated by human-induced habitat destruction and hunting.
The new find, from the Linxia basin in Gansu province, suggests Asia was the evolutionary cradle for the fleet felines.
The nearly complete skull is about the same age as a 2.5 million-year-old related species found in Casablanca, Morocco, in 1997.
But according to its discoverers, Dr Per Christiansen at the Zoological Museum in Copenhagen, and Dr Ji Mazak of the Shanghai Science and Technology Museum in China, the new find – Acinonyx kurteni – has a unique set of characteristics.
“We present a new discovery from the late Pliocene of China of a new species of primitive cheetah, whose skull shows a unique combination of primitive and derived characters,” they wrote in Proceedings of the National Academy of Sciences. The big cat’s evolutionary history is poorly understood because few fossils have been found.
The skull is about the same size as living cheetahs, but has a very wide braincase relative to skull length. It also has enlarged frontal sinuses and “surprisingly primitive” teeth.
The researchers suggest that other specimens known only from fossilised teeth may have been misidentified. – (Guardian service)