Paleontologists Discover New Species of Megaraptor, And It Was Pretty Badass


An artistic rendering of Tratayenia rosalesi. Photo credit: Andrew McAfee, Carnegie Museum of Natural History

A massive, talon-wielding predatory dinosaur belonging to the mysterious Megaraptora group has been described by Argentinian and American researchers.

Evidence for the new species came from the discovery of just a few vertebrae, ribs, and hip bone fragments unearthed in the Tratayén region of northwestern Patagonia by fossil hunter Diego Rosales. Fittingly bestowed the name Tratayenia rosales, the predator is estimated to have roamed the South American continent during the late Cretaceous period approximately 85 million years ago.


Although the fossil recovered represents only a small fraction of the creature’s body, the team, led by paleontologist Juan D. Porfiri, used comparisons to previously found megaraptors to reconstruct a rough sketch of how Tratayenia might have looked in life. The results, published in Cretaceous Research, paint a formidable portrait.

The fossilized vertebrae and right hip bone of Tratayenia rosalesi. Porfiri et al./Cretaceous Research, 2018

Based on the size of the vertebrae, Tratayenia appears to be the largest terrestrial animal found in the Bajo de la Carpa Formation, helping to confirm the hypothesis that megaraptors were at the top of the food chain in the ancient tropical ecosystem of modern-day Argentina. Skulls recovered from other species are long and thin, filled with a wealth of sharply serrated teeth. Megaraptor bones are lightweight and porous, yet their long forearms appear to have been well-muscled. This strength was likely used to slash at and subdue prey using the insane claws at the tip of the inner two fingers of their hands.  

“Megaraptorid claws are the stuff of nightmares – razor-sharp meat hooks more than a foot long,” said co-author Matt Lamanna in a statement. “Wolverine from the X-Men has nothing on these guys.”

A reconstruction of Tratayenia rosalesi showing which bones were recovered. Porfiri et al./Cretaceous Research, 2018

Despite the new insights gleaned from Tratayenia, paleontologists still know little about the natural history of megaraptors, a branch of the large dinosaur order theropoda that have been found in Patagonia, Brazil, and Australia. Pretty much all the upright-walking carnivorous dinosaurs that we know from popular culture (such as the quintessential Tyrannosaurus. rex and Velociraptor) are theropods, and it is from this lineage that birds evolved.


After Pangea separated during the Jurassic period, different lineages of theropods evolved on the newly separated continents during the Cretaceous. How, exactly, megaraptors like T. rosalesi emerged during this time is hotly contested. Some researchers argue that the group is most closely related to the North American lineage of coelurosauria dinos, a clade that includes the T. rex and modern-day birds; whereas others believe they descended from allosauroids, a clade that includes the other South American behemoth, the allosaur.

Due to the scarcity of fossil specimens, it is also unknown precisely when megaraptors went extinct. 

Tratayenia is just one of many exciting megaraptorid fossils that have been found in recent years. After these specimens are studied, many questions surrounding these puzzling meat-eaters may finally be answered,” said Porfiri.


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