Saturday 3 March 2012

A Triassic Parareptile from South Africa.

The Parareptiles were a group of early Reptiles that flourished in the Permian. They were heavily depleted in the End Permian Extinction, but did survive into the Triassic. However they were never again a significant part of the fauna and disappeared before the start of the Jurassic, apparently unable to cope with competition from the emerging dinosaurs. The name 'Parareptiles' means beside the Reptiles, implying they might not be true members of that group, however it implies that they are a sister group to the crown Reptiles (i.e. all surviving Reptile groups shared a common ancestor more recently than the split with the Parareptiles), not that they should be seen as significantly different (like, for example, mammals are).

The Earl Triassic Parareptile Sauropareion anoplus was described in 2001 from a skull found in Barendskraal in the Middelberg District of Eastern Cape Province, South Africa. This specimen had a flattened, spade shaped head suggesting a burrowing lifestyle, but its post-cranial skeleton was only represented by a few vertebrae, making a detailed analysis of the animal's lifestyle impossible.

In a forthcoming paper in the journal Acta Palaeontologica Polonica, a team of scientists lead by Mark MacDougall of the Department of Biology at Cape Breton University in Sydney, Nova Scotia, describe three new Sauropareion anoplus from Vangfontein, also in Middelberg; a juvenile with a partially ossified skeleton, and two nearly complete adult skeletons.

One of the new skeletons (A) with interpretive drawing (B). Scale bar is 1 cm. From MacDougall et al. (2012).

The new skeletons have short, powerful limbs, but not the very developed spade-like limbs of a specialist burrower such as a mole, suggesting that while Sauropareion anoplus was capable of burrowing, it was probably not a specialist. It may have burrowed to escape predators, or to nest, but was unlikely to have spent its whole life digging.

Reconstruction of the life posture of Sauropareion anoplus. Scale bar 2 cm. From MacDougall et al. (2012).

See also Identifying Triassic footprints and Reptiles on Sciency Thoughts YouTube.