In the scrublands of central Argentina, scientists have discovered a fearsome predator dinosaur that lived in the time of T-Rex and likely dominated parts of prehistoric Patagonia thanks to its enhanced sense of hearing.
(CN) — It could be as long as an elephant, had hyena-strong jaws and huge claws on its feet to stab prey. And its keen sense of smell, coupled with its impressive size, likely made escape impossible once the creature started hunting you.
Yet this top predator dinosaur remained unknown for millions of years — until now.
In the scrublands of central Argentina, scientists have discovered the fossilized remains of a fearsome killer that lived in the time of T-Rex and likely dominated parts of prehistoric Patagonia, according to research published in the Journal of Vertebrate Paleontology. They named this carnivore Llukalkan aliocranianus — the “one who causes fear” from the native Mapuche and Latin.
One of 10 currently known species of abelisaurids that flourished in the southern continents around 80 million years ago during the Late Cretaceous, Llukalkan walked upright on powerful hind legs like tyrannosaurs, but looked distinctive due to its head.
It had a short, deep skull with unique crests, bumps, and horns and a shorter snout like some current reptiles such as the Gila monster or iguanas. However, unlike other abelisaurids, the make-up of its skull suggests Llukalkan had a heightened sense of smell similar to that of modern-day crocodiles.
Abelisauridae were “a striking family of theropod dinosaurs” averaging 16 to 29 feet long that prowled the ancient subcontinent Gondwana, which included present-day Africa, India, Antarctica, Australia and South America.
Scientists think Llukalkan lived in the same small area and time period as another species of furileusaurian (stiff-backed lizard) abelisaurid — Viavenator exxoni — near the end of the dinosaur age. Fossil remains of the two species were found less than half a mile apart in the Bajo de la Carpa Formation, near the same famous fossil site at La Invernada in Argentina.
“This is a particularly important discovery because it suggests that the diversity and abundance of abelisaurids were remarkable, not only across Patagonia, but also in more local areas during the dinosaurs’ twilight period,” said lead author Federico Gianechini, a paleontologist at the National University of San Luis, Argentina, in a statement.
The well-preserved Llukalkan fossil included an intact braincase, revealing larger than expected holes in the skull through which the veins passed. But its most distinctive feature is a unique posterior air-filled sinus in the middle ear zone. Scientists think this indicates Llukalkan had superior hearing to other abelisaurids.
“This finding implies a different hearing adaptation from other abelisaurids, and likely a keener sense of hearing,” explains co-author Ariel Mendez from the Patagonian Institute of Geology and Palaeontology in Argentina.
Adaptations in the Llukalkan fossil suggest that abelisaurids were flourishing right before the dinosaurs went extinct.
“These dinosaurs were still trying out new evolutionary pathways and rapidly diversifying right before they died out completely,” says Mendez.