Wednesday, 17 August 2011

Discoveries Of Primate Fossils Shed Light Upon The Diversification Of Primates

Teeth from Teilhardina brandti.
The black line represents 1 centimetre 
Fingernails are a very important part of our fingers. Apart from protecting the dense cluster of nerves and soft tissue in the finger tip, it also provides counter-pressure on the other side of the finger, allowing for more precise control and a more delicate sense of touch. The evolution of fingernails was a vital step in primate evolution as it gave our ancestors far greater control over their hands with which they could begin to manipulate their environment, eventually leading to the first ever human which could use stone tool - Homo habilis.

A team of palaeontologists from the University of Florida have found what they believe to be the oldest fossil primates which bear fingernails. The fingernails come from 55 million year old fossils of the primate Teilhardina brandti. This creature, based upon the morphology of the single tooth that it is known from, is thought to be the common ancestor of tarsiers, strange bush-baby like mammals, and simians. However these new fossils consist of ankles and fingers alongside teeth, giving us a more complete picture of what this creature was like.

We now think that it was a tree dweller and its newly evolved fingernails would have given it greater agility. Over the last seven years, fossils of Teilhardina have been discovered in Wyoming's Bighorn Basin. Despite the fact that the genus contains several species, the American specimens are almost exactly the same in terms of age and morphology as the European specimens found by the team from Florida.

Teilhardina was less than 6 inches long, but possessed a full set of nails, forward facing eyes, an enlarged brain and was omnivorous - the trademarks of highly intelligent and succesful primates. All the fossils date from a time known as the Palaeocene - Eocene Thermal Maximum and are so wide spread, that it suggests that this creature would give rise to the diversity of primates known both from the fossil record and today.