Wednesday, 18 January 2012

The First Ever Predator On The Continent Of South America

An artist's impression of Pampaphoneus biccai
Today, much of South America is covered in grasslands and jungles, making it difficult to collect fossils. However, over the years palaeontologists have been able to reconstruct an evolutionary history for the continent. The range of flora and fauna is diverse and often bizarre due to its isolation from the rest of the world at different points in geological history. Now two undergraduate palaeontologists from the University of Wiltwatersrand, South Africa, believe that they have discovered the remains of the first ever predator to stalk the continent.

The skull and reconstruction of Pampaphoneus biccai
After looking at images of the Pampas Region of Rio Grande do Sul in Brazil on Google Earth in 2008, Juan Cisneros and Cesar Schultz decided to excavate exposed rock formations in the region. They discovered the skull of a creature which was a reptile, but had large tusk-like teeth and strange, mammal-like characteristics. They quickly identified it as a dinocephalian therapsid, on account of the mix of features. Yet it did not match any known creatures from the fossil record.

They concluded that it was a new species and gave it the name of Pampaphoneus biccai, after the Brazilian word 'pampas,' meaning open grassland and 'biccai' after the the man who last owned the land they were excavating. Using the basic morphology of other dinocephalians, it was identified as being most closely related to an Australian form called Australosyodon. Radioactive dating gave it an age of 265 million years old, middle Permian, at a time when the dinocephalians were becoming the dominant predators on the planet.

Its close relationship to other South African species as well as Australosyodon has given support to a theory about the shape of Pangaea, as palaeogeographists are in dispute about the super-continent's exact shape. This made Cisneros and Schultz believe Pampaphoneus or its ancestors originated away from South America and then migrated to the continent. Dinocephalians were herd-based animals (on the basis of large clusters of fossil tracks from the same species) which supports the idea that it was a migratory animal.