'One who causes fear': Newly discovered dinosaur was a top predator © Journal of Vertebrate Paleontology

‘One who causes fear’: Newly discovered dinosaur was a top predator

The abelisaurid family were all good hunters, but Llukalkan aliocranianus’s hearing set it apart from its relatives.

A species of dinosaur newly discovered in Patagonia, Argentina, has been given a name meaning ‘One who causes fear’ in the indigenous language Mapuche for its deadly hunting abilities.

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With its sharp teeth, long claws and powerful bite, Llukalkan aliocranianus is as formidable as other species in its family, the abelisaurids. It moved quickly on its powerful hind legs, and had a keen sense of smell.

Its short skull had rough bones, so in life it probably had lumps and ridges on its skull like iguanas or Gila monsters. But what sets it apart is its remarkable sense of hearing.

Artist's impression of Llukalkan aliocranianus © Jorge Blanco and Journal of Vertebrate Paleontology
Artist’s impression of Llukalkan aliocranianus © Jorge Blanco/Journal of Vertebrate Paleontology

Palaeontologists in Argentina found fossil remains of Llukalkan at a site called the Bajo de la Carpa Formation, only 700m from the remains of a closely related species named Viavenator exxoni.

“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,” says lead author Dr Federico Gianechini, a palaeontologist at the National University of San Luis, Argentina.

The Llukalkan specimen was superbly preserved, including an uncrushed cranium. In the skull, the researchers found an air-filled sinus in the middle ear that no other abelisaurids have.

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What this means is that Llukalkan most likely had better hearing than its abelisaurid relatives – like that of a modern crocodile, says study co-author Dr Ariel Méndez from the Instituto Patagónico de Geología y Paleontología. “This finding implies a different hearing adaptation from other abelisaurids, and likely a keener sense of hearing,” he said.

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Llukalkan lived only a few million years before the dinosaurs went extinct. “These dinosaurs were still trying out new evolutionary pathways and rapidly diversifying right before they died out completely,” Méndez said.

Reader Q&A: What did dinosaurs evolve from?

Asked by: Adam King, Huddersfield

Dinosaurs are a type of reptile, and they evolved from another group of reptiles called ‘dinosauromorphs’ around 250 million years ago. The dinosauromorphs were small and humble animals, and they didn’t look anything like T. rex or Brontosaurus.

Instead, they were the size of house cats, walked on all fours, and had long, skinny limbs like a greyhound. The dinosauromorphs weren’t at the top of the food chain, but their speed and agility ensured their success.

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