Carnivores chowed vegetarians on SA's heritage days of yore

About 210 million years before someone dreamt up the idea of national braai day, carnivores already ruled the roost in southern Africa.

Giant, predatory crocodile-like animals that lived during the Triassic period preyed on early vegetarian dinosaurs and mammal relatives, according to new findings by a Wits University master’s student.

Rick Tolchard studied fossils of predators known as “rauisuchians” from collections at Wits, the Iziko South African Museum in Cape Town and the National Museum in Bloemfontein.

“These ancient fossils provide us with evidence of how at least two predator species hunted these vegetarian dinosaurs 210 million years ago,” said Tolchard.

“It is amazing to follow the clues left behind in fossilised teeth, jaws, limbs and other fossils to help us tell the ancient story of life in southern Africa.”

The fossils studied by Tolchard include teeth, pieces of jaws, hind limbs and body armour, all from rauisuchians — which are closely related to crocodiles as we know them today.

The specimens described in the research include some of the largest carnivorous members of this group, possibly up to 10m long, with huge skulls full of serrated, curved teeth.

The study, published online in the Journal of African Earth Sciences, shows the rauisuchians were some of the latest-surviving members of their group, and that when they were alive they thrived close to the Antarctic circle.

“In the Triassic period, rauisuchians were widespread and their fossils are known from all continents except Antarctica,” said Tolchard.

“They went extinct about 200 million years ago, paving the way for dinosaurs to become the dominant large land animals.”

Jonah Choiniere, Tolchard’s adviser and professor of comparative palaeobiology at the Wits Evolutionary Studies Institute, said: “Rick’s study demonstrates the value of re-examining old specimens, and now we finally know what was preying on all those herbivorous dinosaurs.”

Tolchard was joined in the research by an international team, including researchers from the USA, Argentina and the UK.