sábado, 21 de enero de 2012

Palaeontology - South America's oldest fossil predator revealed

An international team of palaeontologists from Brazil, South Africa and Turkey have described the oldest predator known from South America in the prestigious journal Proceedings of the National Academy of Sciences (PNAS) on Monday, 16 January 2012. 

The animal is a dinocephalian therapsid (mammal-like reptile), an ancient group of vertebrates that is distantly related to mammals. The fossil, comprising a complete and well preserved skull that measures 35cm in length, was discovered in 2008 on a farm in the pampas region of Rio Grande do Sul, in southern Brazil [Credit: Voltaire Neto / University of Witwatersrand]

The fossil was discovered by Dr Juan Cisneros and Cesar Schultz from Brazil, while the Wits team included Dr Fernando Abdala, Prof. Bruce Rubidge and Ms Saniye Atayman-Guven. Dr Cisneros is a former doctoral student from Wits University. The paper is entitled Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea. 

Accordingly the new species has been named Pampaphoneus biccai. The genus name means “pampas killer” (pampas are the flatlands of southern Brazil, Uruguay and Argentina). The species name is in honour of José Bicca, landlord of the farm where the fossil site is located. Rubidge, Director of the Bernard Price Institute (BPI) for Palaeontological Research at Wits says: "The new species from Brazil is very closely related to a South Africa dinocephalian known as Australosyodon which we discovered on a farm close to Prince Albert Road in the southern Karoo in the late 1980’s”. 

The find is important for two reasons. Firstly, it is the oldest land-living flesh eating animal yet discovered in South America and is about 265 million years old. Secondly it provides new evidence of the continental configuration of the supercontinent of Pangeae in the Middle Permian Period. 

The skull [Credit: University of Witwatersrand]

The Karoo rocks of South Africa are internationally renowned for their wealth of fossil therapsid mammal-like reptiles which provide the best record of the evolutionary transition between ancient reptiles and mammals. A long term and extensive research programme of the BPI for Palaeontological Research has demonstrated that the Karoo has the oldest and most diverse primitive fauna of therapsid mammal-like reptiles in the southern hemisphere. 

Comparable fossils have also been discovered in Russia and China. The new Brazilian discovery now demonstrates that a similar diverse middle Permian therapsid fauna is present in South America as well. 

“Ten years ago we only had a poor idea of terrestrial vertebrate faunas from South America. New findings like this allow us not only to know with more detail how the Permian fauna from South America was but also recognise that this Brazilian fauna, together with those from South Africa, China and Russia, have the oldest mammal-like therapsids in the world, says  Abdala, a senior researcher at the BPI for Palaeontological Research. 

The new discovery, which is very closely related to the carnivorous dinocephalians already known from Russia and South Africa, indicates the global distribution of terrestrial faunas in the super-continent of Pangaea already in the Middle Permian. This demonstrates that land-living vertebrate animals were able to move over land from Gondwana (south Pangaea) to Laurasia (north Pangaea) more than 260 million years ago.  

Click here for the complete paper. 

University of the Witwatersrand

Source: The Archaeology News Network

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