An excavation in Argentina has unearthed a previously undiscovered species of dinosaur, and the tyrannosaurus-like predator has been given a name that fits what we know so far: Llukalkan aliocranianus, or ‘the one who causes fear’.
Able to grow as long as an elephant, and with sharp teeth and a powerful bite, L. aliocranianus It would certainly have been a terrifying sight for any other creature who crossed paths with it during the late Cretaceous period, leading to the extinction of the dinosaurs 66 million years ago.
The new species is an abelisaurid, although it probably has better hearing (similar to a modern crocodile) than the other nine species in the family found so far. The dinosaur also had huge claws on its legs and a keen sense of smell, the researchers say.
Artist’s impression of Llukalkan aliocranianus. (Jorge Blanco and Journal of Vertebrate Paleontology)
“This is a particularly important discovery because it suggests that the diversity and abundance of abelisaurids were remarkable, not only in Patagonia, but also in more local areas during the twilight period of the dinosaurs,” says paleontologist Federico Gianechini, from the National University of San Luis in Argentina.
Patagonia and other areas of the former supercontinent Gondwana, now divided into Africa, India, Antarctica, Australia, and South America, were where abelisaurids roamed.
While their short forearms gave them an appearance similar to that of the Tyrant Saurus Rex, they had unusually short and deep skulls, often with ridges, protrusions, and horns. This particular dinosaur would have had bumps on its head similar to the Gila monster lizard.
Researchers have determined that L. aliocranianus shared the same part of the world at the same time as another abelisaurid, Viavenator exxoni, although the new species would have been smaller.
“These dinosaurs were still testing new evolutionary pathways and rapidly diversified just before going completely extinct,” says paleontologist Ariel Méndez, from the Patagonian Institute of Geology and Paleontology in Argentina.
Llukalkan aliocranianus skull. (Journal of Vertebrate Paleontology)
Some of the fossilized remains of the ‘scarer’ include a skull, which shows a unique feature among abelisaurids: a small air-filled posterior sinus in the middle ear area, which helped with that crocodile hearing.
That hearing may well have enhanced the dinosaur’s abilities as a predator, and the research team says that both L. aliocranianus and V. exxoni it would have been among the most dangerous carnivores of the time.
Map and images showing where the specimen was found in Argentina. (Gianechini et al., Journal of Vertebrate Paleontology, 2021)
There is likely more to be found in the region as well, dating back around 80 million years, a period that appears to have been prosperous for the abelisaurids and furileusaurs (‘stiff-backed lizards’) that made up this part of the family.
“This discovery also suggests that there are likely more abelisaurids out there that we haven’t found yet, so we will be looking for other new species and a better understanding of the relationship between furysaurs,” says Gianechini.
The research has been published in the Journal of Vertebrate Paleontology.