A Christmas visit to South Africa and an introduction through friends to palaeontology experts from Wits University have had exciting scientific consequences for New Zealand student Blair McPhee. It has provided him with the honour of taking the lead in describing yet another new South African dinosaur species.
He is the lead author of a paper in Nature’s Scientific Reports that describes Pulanesaura eocollum (which means “Rain lizard”). Pulanesaura was an early member of the long-necked sauropod lineage of dinosaurs, famously represented by Brontosaurus.
His co-authors are Dr Matthew Bonnan (Richard Stockton University), Dr Jonah Choiniere (Evolutionary Studies Institute at Wits), Dr Adam Yates (scientist at the Museum of Central Australia) and Dr Johann Neveling (geologist from South Africa’s Council of Geoscience).
McPhee visited South Africa at the end of 2010, at a time when he was wondering what to do next after completing his honours degree in biological anthropology from the University of Auckland. A friend completing a PhD in archaeology at Wits introduced him to Dr Yates, who at the time was working at the University and was busy excavating a site on the farm Heelbo in the eastern Free State.
As the saying goes, the rest is history. He has since had the chance to delve into South Africa’s rich palaeontological history for both his Masters and PhD.
The discovery
Pulanesaura was excavated in 2010 during a particularly wet season by Dr Yates, who subsequently has taken on a job at the Central Australian Museum in Alice Springs..
In honour of the late Naude Bremer, former owner of Heelbo, the new species was partly named after one of his daughters. “Pulane” was the childhood Sesotho nickname of his daughter Panie. Roughly translated, “Pulane” means “comes with rain”.
The researchers involved believe that Heelbo is probably one of the richest dinosaur localities in Southern Africa.
Dr Yates believes that the environments represented by Heelbo Farm were possibly 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.
Dr Neveling says what makes Heelbo unique is the fact that unlike the majority of localities of this age which represent dry flood plains, its geology is characterised by a dense concentration of river channel deposits.
“Similar to modern arid environments, the river banks would have supported much denser vegetation that would have provided plenty of food to budding giants,” Neveling adds.
According to McPhee’s supervisor, Dr Jonah Choiniere, Pulanesaura eocollum is the third new species of dinosaur to have been described from Heelbo farm since 2010. The others are Aardonyx and Arcusaurus. They are both more primitive members of the same lineage as Pulanesaura eocollum.
“That’s approximately 25% of the total diversity of sauropodomorpha in the Karoo Basin,” he explains.
“There are also lots of bits of dinosaur that haven’t been described from there yet,including huge teeth from what we just call ‘Predator X’,” he sheds light on the discoveries that still need to be explained and documented for scientific purposes.
More about Pulanesaura
In a press release by Wits University, the researchers explain that the specialised teeth, vertebrae, and forelimb of Pulanesaura was an indication that the new species 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.
Early sauropods like Pulanesaura are incredibly rare in the fossil record, with only a handful of good sauropod specimens known from the Early Jurassic, a time period between 200 and 180 million years ago, when Pulanesaura would have lived.
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 Choiniere.
- Pulanesaura was relatively small (for a sauropod), at about eight metres in length, two metres at the hips, and 5 tonnes in body mass.
- 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.
- Flexibility in the neck meant that the forelimb of Pulanesaura was able to shift to a position entirely beneath the body, thus better supporting the weight of the animal.
- Modifications of the neck may have also meant that it would not have needed to move its body around as much to feed – and less movement means less energy expended. This method of feeding was taken to extreme lengths by all gigantic sauropod species.
“The traditional picture of sauropod evolution is that when they came onto the scene, the other sauropodomorphs were pushed aside,” adds Dr Bonnan. “Pulanesaura turns this notion on its head. Sauropod evolution was occurring alongside and influenced by competition with their sauropodomorph brethren.”