New dwarf dinosaur species from SA

4 October 2012

Fossils from South Africa continue to produce the goods for palaeontology. The latest to emerge from one of the country’s rocks is a bizarre, tiny new species of parrot-beaked, vampire-fanged, plant-eating dinosaur dating back some 200-million years.

A specimen of the species – less than 60 centimetres long and no heavier than a house cat – was originally chipped out of rock in South Africa in the 1960s and discovered decades later in a collection of fossils at Harvard University in the United States by palaeontologist Paul Sereno from the University of Chicago.

Sereno published his findings in online scientific journal ZooKeys on Wednesday.

According to a statement from the University of Chicago, the new species is one of a number of small fanged plant-eaters called heterodontosaurs, or “different toothed reptiles,” thought to be among the first dinosaurs to spread across the planet.

Named Pegomastax africanus or “thick jaw from Africa,” the new species had a short, parrot-shaped beak, a frontal pair of stabbing canines and tall teeth tucked behind for slicing plants.

“The tall teeth in its upper and lower jaws operated like self-sharpening scissors, with shearing wear facets that slid past one another when the jaws closed,” the University of Chicago said. “The parrot-shaped skull, less than three inches [7.6 centimetres] long, may have been adapted to plucking fruit.”

Sereno argues that it is very rare “that a plant-eater like Pegomastax would sport sharp-edged, enlarged canines” like that of a vampire. While some scientists argue that heterodontosaurs’ diet included meat, Sereno says a microscopic examination of the teeth of Pegomastax suggest they were more likely used in self-defense and competitive sparring for mates.

Adding to the oddness of Pegomastax, Sereno believes they were probably mostly covered by porcupine-like bristles – basing his argument on the bristles found on a similar-sized heterodontosaur, Tianyulong, recently discovered in China.

In life, Sereno says, Pegomastax and its kin – “the most advanced plant-eaters of their day” – would have been found scampering around in search of edible plants, looking like “nimble, two-legged porcupine[s]”.

SAinfo reporter and UChicagoNews