Wits plays key role in discovery of new dinos

A fossil expert from Wits University has played a key role in discovering two new species of insect-eating dinosaurs.

Jonah Choiniere‚ of the Evolutionary Studies Institute at Wits‚ was a leading member of a team which discovered Xiyunykus and Bannykus after their fossils were dug up in China in 2005 and 2009‚ respectively.

The dinosaurs are both alvarezsaurs‚ carnivorous creatures that have many similarities with birds. According to Choiniere‚ they have features thought to be related to eating insects that live in colonies. “Alvarezsaurs are weird animals. With their strong‚ clawed hands and weak jaws‚ they appear to be the dinosaurian analogue to today’s aardvarks and anteaters‚” he said. The earliest known alvarezsaurs had more typically meat-eating teeth and hands‚ useful for catching small prey.

Only later-evolving members reduced their teeth and evolved a hand with a huge‚ single claw capable‚ perhaps‚ of tearing open rotting logs and anthills. Choiniere’s co-author of a paper in the journal Current Biology announcing the discovery‚ Roger Benson of Oxford University‚ said: “The new fossils have long arms‚ and so show that alvarezsaurs evolved short arms only later in their evolutionary history‚ in species with small body sizes.

“This is quite different to what happens in the classic example of tyrannosaurs‚ which have short arms and giant size.”

Palaeontologists say Bannykus and Xiyunykus are important because they show transitional steps in the process of alvarezsaurs adapting to new diets. “The fossil record is the best source of information about how anatomical features evolve‚” said James Clark‚ co-author and an honorary professor at Wits.

“Like other classic examples of evolution ... these dinosaurs show us how a lineage can make a major shift in its ecology over time.” Xiyunykus was discovered in 2005 in Xinjiang‚ north-western China. Bannykus was discovered in 2009 in Inner Mongolia‚ north-central China. Both research trips were joint expeditions co-led by Clark and Xu Xing‚ of the Institute for Vertebrate Palaeontology and Palaeoanthropology in Beijing.

The study of the fossils was funded by a grant from South Africa’s National Research Foundation. “China and South Africa have a great deal of overlap in palaeontology‚ and it has been a privilege to cross-train students there over the last two years‚” said Choiniere.