Tuesday, 2 August 2011

Ancient Ape Skull found in Uganda.

Palaeontologists Martin Pickford of the College de France and Brigitte Senut of the Musee National d'Histoire Naturelle in Paris announced the discovery of an almost complete skull of the extinct ape Ugandapithicus major in the Karamoja Region of northeast Uganda.

The Karamoja Skull.

The generic name 'Ugandapithicus' was created by Pickford and Senut in 2000 to describe a group of African ape fossils from between 20 and 14 million years ago; prior to this almost all ape fossils were referred to as 'Proconsul', a name created in 1933 by Arthur Hopwood, a colleague of Louis Leakey. Unfortunately the holotype used by Pickford and Senut to define Ugandapithicus (BNMH M16648) was the same as that used by Hopwood to describe Proconsul.

This deserves a little explanation. When biologists or palaeontologists describe a new species they nominate a specimen as the Holotype. In any future dispute over the classification of new specimens this Holotype is referred to. If they are determined to belong to the same species as the Holotype then they share the same species name, if not then a new species can be created. This also helps resolve issues of precedence. When a scientist describes a new species they have the privilege of naming it. If two scientists are found to have described the same specimen (which can quite easily happen) then the one to publish first has priority, it is their name that remains and the other name is discarded. For this reason the dinosaur name Brontosaurus disappeared a few years ago, when scientists discovered that the holotypes of Brontosuarus and the earlier described, but more obscure Apatosuarus belonged to the same species.

All this caused considerable controversy, and not all scientists in the field accept Ugandapithicus as a proper name. It is clear that the use of Proconsul as a catch all for a wide variety of fossil apes was not helpful. Pickford and Senut divide Ugandapithicus into four species (U. major, U. meswae, U. legetetensis and U. gitongai) and exclude many specimens from the genus. Proconsul is currently divided into at least four species (P. africanus, P. heseloni, P. major and P. nyanzae) with Proconsul meswae as a synonym (alternative name) of U. meswae (the species is not universally accepted as it is described from a single, juvenile specimen). I may have missed some names here; this sort of rivalry, with multiple names for species and occasionally more names than specimens, is common in palaeoanthropology (the study of fossil humans and their relatives).

A reconstruction of Proconsul at the University of Zurich.

Martin Pickford is no stranger to controversy. In the 1990s he had a very public falling out with Richard Leaky, the son of Louis Leakey and at that time the Cabinet Secretary to Kenyan President Daniel Arap Moi (i.e. the head of the Kenyan Civil Service), which lead to Pickford having hit excavation permit revoked then being arrested and Leakey being forced to resign.

The skull is described as having been found in an extinct volcano in the Karamoja Region of Uganda. It was about 10 years old when it died, 20 million years ago. The skull is roughly the same size as that of a chimpanzee, but the brain case is only about the same size as that of a chimpanzee. It is not thought to be an ancestor of modern apes.

Pickford and Senut intend to clean and prepare the specimen, then return it to Uganda.

See also Out of Africa(?) and Mammals on Sciency Thoughts YouTube.

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