#llukalkan

(Skull reconstruction of Llukalkan aliocranianus, from Gianechini et al., 2021)

Meaning of name: Llukalkan = one who causes fear; aliocranianus = different skull

Age: Late Cretaceous (Santonian)

Where found: Bajo de la Carpa Formation, Neuquén, Argentina

How much is known: A partial skull, including a complete braincase.

Notes: Llukalkan was an abelisaurid ceratosaur, making it a close relative of genera like Carnotaurus and Aucasaurus. It lived alongside another abelisaurid, Viavenator, which is known from the partial skeleton of a slightly larger individual. However, Llukalkan differed from Viavenator in several anatomical details, most notably in the presence of a hollow depression in the back of the braincase that probably housed an air sac. As it is rare for air sac openings in the skeleton to be reduced during growth, the authors consider it unlikely that Llukalkan represents a specimen of Viavenator at a younger growth stage.