A team of paleontologists announces the discovery of a new species of theropod dinosaur that evolved in present-day Argentina 80 million years ago. According to analyzes, it was among the most dangerous predators in its environment.
Around 80 million years ago, when tyrannosaurs ruled the northern hemisphere, abelisaurids (another family of theropod dinosaurs) flourished in the southern regions. To date, around 20 species of these formidable predators have been discovered, about half of them from Patagonia. Physically, the abelisaurids resembled the T-Rex. In contrast, they had shorter muzzles, as well as bony growths or horns above the eyes.
A new predator
Llukalkan aliocranianus (“the frightening one”), the newly described species, was one of them. The remains of this dinosaur (mostly pieces of its skull) were discovered in the Bajo de la Carpa Formation, near the same famous fossil site in La Invernada, Argentina. Not far away, about 700 meters, were also found the remains of another abelisaurid: Viavenator exxoni.
These two predators therefore evolved in the same area at the same time. “This is a particularly important find, as it suggests that the diversity and abundance of abelisaurids was remarkable, not only across Patagonia, but also in more local areas during the Dinosaur Twilight Period.“, Underlines Dr. Federico Gianechini, of the National University of San Luis, the main author of this work.
Hearing finer than average
Physically, the two dinosaurs looked very similar. In contrast, Llukalkan aliocranianus was somewhat smaller (around five meters long). Paleontologists also isolated a small posterior sinus filled with air isolated in the middle ear area. This is the first time that such a characteristic has been observed in an abelisaurid.
According to the authors, Llukalkan aliocranianus enjoyed better hearing than his peers thanks to this sinus. His hearing skills were probably similar to those of modern crocodiles.
This new fossil evidence suggests in passing that abelisaurids were still evolving just before dinosaurs became extinct.
With his remarkable size and hearing, not to mention his sharp teeth and claws, Llukalkan aliocranianus was thus among the “best predators in all of Patagonia”In the Upper Cretaceous according to paleontologists.
Details of the study are published in the Journal of Vertebrate Paleontology.