Abelisaurid Dinosaur Discovered in Argentina

Paleontologists have identified a brand new genus and species of Abelisaurid hailing all the way from Argentina! The preserved skull fragments from which it was identified are quite well preserved, allowing us to draw some reasonable conclusions about Abelisaurid diversity.

The dinosaur bears the name “Llukalkan aliocranianus“, meaning “The frightening one” in the native Mapuche language of the Argentinian pampas. Llukalkan would have stalked the plains of Argentina around 80 million years ago, placing it in the last epoch of the dinosaurs, the Late Cretaceous.

A restoration of Llukalkan. Artist Credit: Jorge Blanco.

Upon a closer inspection of Llukalkan‘s cranial features, paleontologists were able to identify a small air-filled sinus in the middle ear zone which has not been found in any other abelisaurid before, and is unique to Llukalkan. This means, according to Dr. Ariel Mendez of Argentina’s Patagonian Institute of Geology and Paleontology, that Llukalkan would have actually had much sharper hearing than its relatives, closer to that of a modern crocodile.

The implications of different hearing adaptations within abelisaurids are quite significant. Again, we are reminded of how dominant the dinosaurs truly were over our planet. The fact that abelisaurids were able to diversify into such specialized niches solidifies the fact that they were extremely successful animals from an evolutionary standpoint.

Reconstruction of the complete skull and mandible of Llukalkan aliocranianus, from the Late Cretaceous of Neuquén Province, Argentina, in left lateral view. The preserved bones are located in their supposed natural positions, whereas non-preserved parts and bones are in gray. The prearticular bone has a medial location, laterally covered by the angular and surangular. The maxilla, jugal and quadrate correspond to the right side, although they were mirrored to accommodate with the image. Scale bar – 5 cm. Image credit: Gianechini et al., doi: 10.1080/02724634.2020.1877151.

Llukalkan was found in the Bajo de la Carpa Formation, which would have likely sported dense tropical jungles, dotted with ancient life-giving waterways way back in the Cretaceous. Llukalkan would have shared it’s habitat with other abelisaurids as well, like the fearsome 6 meter long Viavenator exxoni, a genus described in 2016. This formation was also a haven of crocodylomorph diversity, hosting 9 known prehistoric crocodylomorph genuses, including the well-known Notosuchus. Towering above were the titanosaurs. 4 known genuses of titanosaur inhabited the area, and these included the (Thanks to Jurassic World: The Game) famous Bonitasaura. The treetops would have been alive with the flutter of enantiornithine birds like Nueqenornis, and the monstrous termite mounds on the ground would have been regularly raided by alvarezsaurids. The region also frequented by ornithopods, and was the home of the oldest known flightless bird: Patagopteryx. As you can tell, it was truly a magnificent example of Cretaceous biodiversity, and Llukalkan adds to an already fascinating picture of Cretaceous Patagonia.

Another reconstruction of Llukalkan. Artist Credit: Gabriel Ugueto.

  • Federico A. Gianechini et al. A New Furileusaurian Abelisaurid from La Invernada (Upper Cretaceous, Santonian, Bajo De La Carpa Formation), Northern Patagonia, Argentina. Journal of Vertebrate Paleontology, published online March 30, 2021; doi: 10.1080/02724634.2020.1877151

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