An international team of researchers has announced inNaturethe discoverythe oldest fossil primate skeleton in the world. It belongs to a hitherto unknown species that lived 55 million years ago and has been baptized asArchicebus achilles. His remains were buried at the bottom of an ancient lake in China’s Hubei province, near the current Yangtze River.
The new fossil will be crucial in shedding light on the separation between the lineage that led to modern monkeys, apes and humans, and the branch that gave rise to today’s tarsiers, tiny nocturnal arboreal primates with huge eyes.
The skeleton ofArchicebusIt is 7 million years older than the earliest primate skeletons found to date, including the famousDarwinius masillaediscovered in 2009. And the most interesting thing is that “is radically different from any other primate, living or fossil, known to science“, according to Christopher Beard, researcher at the Carnegie Museum of Natural History (USA) and co-author of the work.” It seemsa strange hybridwith the feet of a small monkey, the limbs and teeth of a very primitive primate, and a primitive skull withsurprisingly small eyes-that is, more similar in size to humans than to tarsier monkeys. “
All the features point toArchicebusit was agood diurnal hunter and insectivore, who lived in the trees. It weighed around 20-30 grams, that is, considerably less than the smallest living primates, the Madagascar pygmy mouse lemur. And that makes one suspect that the first primates were tiny. The three-dimensional reconstruction of his anatomy has been possible thanks to a digital scanning technique with X-rays applied in theEuropean Synchrotron Radiation Facility, in Grenoble (France).
The name ofArchicebusderives from greekark, which means ‘beginning or first’ and frombored, which means ‘long-tailed monkey’. His epithet,achilles, refers to the mythological Greek hero and has been chosen for the strange anatomy of his ankles (the Achilles tendon passes behind the ankle).
Archicebus lived in the early part ofEocene, in a period when it is assumed that there was an intense greenhouse effect that caused much of the planet to be covered withtropical forests, and that palm trees grew even in Alaska.
