Armless But Skilled Dinosaur Captures Prey Using Head and Jaws, New Study Says

Scientists from the National History Museum in London discovered an armless dinosaur that likely roamed in Argentina 70 million years ago. Analysis of the fossilized new species suggests it was a skilled predator despite having shorter limbs than a T. Rex.

They named the new species Guemesia ochoai, which they believed could be a species of abelisaur, a clade of dinosaurs with tiny front limbs and rely on their powerful head and jaws to hunt. The museum's leader and study co-author Professor Anjali Goswami said that this new dinosaur is one of a kind with several characteristics suggesting that it is a new species.

(Photo : Pixabay/PiotrZakrzewski)
Fossils of An Armless Dinosaur Suggest It Was A Skilled Predator Relying on Its Head, Jaws to Capture Its Prey

Armless Dinosaur is Not Harmless

Hundreds of millions of years ago, Pangaea still existed. However, over time, the tectonic plates shifted, breaking it into Gondwana and Laurasia. Then these two massive continents also started to split in which Gondwana started to form the major continents in the southern hemisphere.

But according to Natural History Museum, animals from these split continents were still able to move between them, which led scientists to believe that the fauna in each of them remained the same. One group that lived in Gondwana at that time was the abelisaurid dinosaurs.

They were a group of predatory theropods that fed on large dinosaurs, such as titanosaurs, despite being smaller and without useful arms due to their tiny size. Abelisaurs have shorter front limbs than T. Rex, which renders these limbs relatively useless. Since could not use their front arms to grasp anything, they relied on their powerful head and jaws to haunt.

Scientists found fossils of this species around the world, particularly in Africa, South America, India, and Europe, which all dated back to the late Cretaceous, just before they went extinct around 60 million years ago. In Argentina, scientists were able to identify around 35 species from the abelisaur fossils they dug, mostly in Patagonia.

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Are These Armless Dinosaurs Descendants of Abelisaurs?

The new species found in Argentina has a skull that is remarkably small with a cranium that is about 70% smaller than any of its relatives., MailOnline reported. Scientists said that the skull provides vital new knowledge for researching this period of history when dinosaurs once roamed the planet.

The small-sized dinosaur skull might point to a juvenile dinosaur. However, there is conflicting evidence on this claim. Professor Goswami said that dinosaurs in the region where they found the fossils were quite different from those in other parts of Argentina, which supports the idea that parts of South America hosted dinosaurs during the Cretaceous.

Researchers said that the front of the skulls of the armless dinosaur contain rows of small holes that may have helped them stay cool in which blood was pumped to their think skin to release heat. Meanwhile, the armless dinosaur seems to lack horns commonly seen in abelisaurids. The team suggests that the new species could either be near the bottom of the family tree or closely related to abelisaurids.

The team hopes to find more specimens of the new species to further understand it and know more about the ancient life in Argentina. Professor Goswami said that understanding huge global mass events, such as extinction, needs huge global datasets, and there are more sites and tons of fossils that are yet to be discovered.