REMAINS of the earliest known sauropod, a relative of the largest dinosaurs to roam the Earth, have been unearthed in South Africa.
The new species has been named Antetonitrus ingenipes. Antetonitrus means 鈥渂efore the thunder鈥�, marking the species鈥� evolution into the brontosaurus or 鈥渢hunder lizard鈥� some 65 million years later. It weighed about 2 tonnes. But at 10 to 12 metres long, with a hip height of 2.2 metres, it was dwarfed by its later relatives.
A. ingenipes appears to be the missing link between the sauropods and their mainly two-legged predecessors, the prosauropods. 鈥淚t鈥檚 an excellent example of a transitional animal,鈥� says Adam Yates, who analysed the bones at the Bernard Price Institute for Palaeontological Research at the University of Witwatersrand in Johannesburg.
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Despite its relatively modest size, A. ingenipes was probably the largest dinosaur around during the Late Triassic, about 215 million years ago. Yates concludes that it was a plant-eater. And while it retained the ability to grip with its front claws, just like prosauropods abundant at that time, it did most of its walking on four legs. 鈥淚鈥檓 certain it walked on all fours almost all its life,鈥� says Yates.
The bones of A. ingenipes were discovered near Bloemfontein by Yates鈥檚 colleague James Kitching and were originally misidentified as a late prosauropod called Euskelosaurus. But a reanalysis by Yates and Kitching shows that the dinosaur鈥檚 forelegs were almost as long as its hind legs, and its vertebrae had fused in the laminar pattern unique to sauropods (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2003.2417).