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#Science

Researchers at Wits discover new dinosaur ‘Pulanesaura eocollum’

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Researchers at Wits have discovered a new dinosaur named Pulanesaura eocollum, which they say was an early member of the long-necked sauropod lineage of dinosaurs. The discovery is to be published in Scientific Reports on September 19, 2015.

The dinosaur, whose name means “Rain lizard”, has been described as a relatively small one at about eight metres in length, two metres at the hips, and 5 tonnes in body mass. Researchers say that unlike its bipedal ancestors, who used the forelimb as an additional means of gathering food, Pulanesaura would have had to rely on the flexibility of its long neck alone meaning that the forelimb of Pulanesaura was able to shift to a position entirely beneath the body, thus better supporting the weight of the animal.

According to study authors, the specialised teeth, vertebrae, and forelimb of Pulanesaura was an indication that the dinosaur would have spent all of its time on all fours, browsing lower vegetation. This novel feeding strategy would have resulted in a more energetically conservative feeding posture for Pulanesaura.

This is unlike more primitive prosauropod (scientifically referred to as “basal sauropodomorph”) dinosaurs, which still relied on the forelimb to aid in gathering food from across a broad range of the forest canopy, the researchers added.

Very few good sauropod specimens have from the Early Jurassic have been discovered including those of Pulanesaura, which are believed to have lived between 200 and 180 million years ago. According to PhD student Blair McPhee, much more common at that time in South Africa were bipedal or semi-bipedal sauropodomorph dinosaurs like Massospondylus and Antetonitrus.

This might have been because the unique feeding strategy of Pulanesaura restricted the number of lower-browsing dinosaurs that the early Jurassic landscape could have supported.

“This dinosaur showcases the unexpected diversity of locomotion and feeding strategies present in South Africa 200 million years ago. This has serious implications for how dinosaurs were carving up their ecosystems,” says McPhee.

We used to think that only two species of sauropodomorph dinosaur were present in South Africa. Now we know that the picture was much more complicated, with lots of species present. But Pulanesaura is still special because it was doing something that all these newly discovered species weren’t,” says Dr Jonah Choiniere (Evolutionary Studies Institute at Wits).

The fossils of Pulanesaura were found at Heelbo, a farm in the Eastern Free State where two other recently described South African dinosaur species also come from – Aardonyx and Arcusaurus, both more primitive members of the same lineage.

The late Naude Bremer, former owner of Heelbo, was a strong proponent of palaeontology on his farm. “Pulane” was the childhood Sesotho nickname of Bremer’s daughter, Panie.

Roughly translated, “Pulane” means “comes with rain,” and Pulanesaura was excavated during a particularly rainy period on the property.

These species, along with limb bones of a small predatory dinosaur, the teeth of a huge predatory dinosaur and other bones of as-yet-unknown dinosaurs make Heelbo one of the richest dinosaur localities in southern Africa.

Dr Adam Yates (Scientist at the Museum of Central Australia), who excavated the fossil, believes that Heelbo Farm was different from the rest of South Africa 200 million years ago when Pulanesaura was alive.

“The dinosaur fossils we see at Heelbo are different from the typical South African Early Jurassic species and they might have been living in a rare habitat different than the drier ones favoured by famous species like Massospondylus,” he says.