A new member of the abelisauridae family of dinosaurs has been discovered. This group of dinos are large therapod carnivores characterized by their incredibly small forearms – so tiny that they are often considered armless.
The new species, Guemesia ochoai, is the first discovered in Northwestern Argentina.
The researchers recovered a nearly complete braincase showing characteristics found in other abelisaurids, which have been discovered in South America, Africa, India, and Madagascar. The specimen dates back to 70 million years ago, and back then, these regions were all fused together in the southern continent of Gondwana.
The discovery is reported in the Journal of Vertebrate Palaeontology
The team also suggests some characteristics from the skull remain that make it a distinct species. It is also 70 percent smaller than other abelisaurids, making Guemesia ochoai the smallest member of this family discovered.
“This new dinosaur is quite unusual for its kind. It has several key characteristics that suggest that is a new species, providing important new information about an area of the world which we don't know a lot about,” co-author Professor Anjali Goswami, Research Leader at The Natural History Museum, said in a statement.
“It shows that the dinosaurs that live in this region were quite different from those in other parts of Argentina, supporting the idea of distinct provinces in the Cretaceous of South America. It also shows us that there is lot more to be discovered in these areas that get less attention than some of the more famous fossil sites.”
The species lived just before the end of the Cretaceous period, when following an asteroid hitting our planet, 75 percent of plants and animals went extinct. That includes all the non-avian dinosaurs. So, studying this animal might give insights into what the Earth was like back then.
In the region this new specimen was discovered, researchers have also recovered fossilized specimens of Stupendemys geographicus, an ancient turtle and one of the largest ever marine reptiles. Researchers have also discovered fish and mammals, and are currently working on describing them.
“Understanding huge global events like a mass extinction requires global datasets, but there are lots of parts of the world that have not been studied in detail, and tonnes of fossils remaining to be discovered,” Anjali added.
“We left some exciting fossils in the ground on our last trip, not knowing that it would be years before we could get back to our field sites. Now we are hoping that it won't be too much longer before we can finish digging them up and discovering many more species from this unique fauna.”