An exceptional neurovascular system in abelisaurid theropod skull: new evidence from Skorpiovenator bustingorryi

NOVAS, F.; CERRONI, M.A.; PAULINA CARABAJAL, A.; CANALE, J.I.

JOURNAL OF ANATOMY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

0021-8782

Abelisaurids were one of the most successful theropod clades duringCretaceous times. They are featured by numerous derived skull traits, such asheavily ornamented bones, short and tall snout, and a strongly thickenedcranial roof. Furthermore, nasals are distinctive on having two distinctpatterns, strongly convex and sculptured (e.g., Carnotaurus) or concaveand less ornamented (e.g, Rugops) in transverse section. Independentlyof the pattern, some abelisaurid nasals (e.g., Rugops) show adistinctive row of large foramina on the dorsal surface, which were in generalassociated to skin-structures (scales). CT scans of the skull of Skorpiovenatorindicate a novel feature within theropods: the row of dorsal foramina is linkedto an internal elongate canal that runs across the nasal bone. We compared thisfeature with Carnotaurus, which alsopossess an internal system as in Skorpiovenator,but notably smaller. The symmetry and disposition of the canals and foramina inboth abelisaurids would indicate a neurovascular origin (e.g. branch of thelateral nasal vessel as in extant archosaurs). The biological significance of such neurovascularsystem can be conjectured from several hypotheses. A possible one involves anenhanced blood volume in these bones linked to a zone of thermal exchange,which may helped avoid overheat of encephalic tissues. However, other morespeculative explanations like display skin-structures (in which higher bloodvolumes nourished the mineralized skin) and the correlation with integumentarysensory organs should not be discarded.