Anatomy and phylogenetic position of Venaticosuchus rusconii Bonaparte, 1970 (Archosauria, Pseudosuchia) from the Ischigualasto Formation (Late Triassic), La Rioja, Argentina

Abstract

Ornithosuchidae Huene, 1908 is a group of Late Triassic pseudosuchian archosaurs of controversial phylogenetic affinities. This clade currently comprises three taxa:, Venaticosuchus rusconii, and Riojasuchus tenuisceps, both from Argentina, and Ornithosuchus longidens, from Scotland. V. rusconii was erected in 1970 by Bonaparteon the basised ofn an incomplete skull with articulated lower jaws, and some elements of the postcranium that are currently are lost. Venaticosuchus rusconii is redescribed here and included for the first time in a phylogenetic analysis to test its affinities with ornithosuchids. The bizarre morphology of V. rusconii has a unique combination of traits that distinguishes it from the other ornithosuchids, such as basipterygoid processes directed ventrally, dentary with the dorsal margin of the anterior end dorsally expanded, articular without a foramen on its medial side, and the absence of a surangular foramen, corroborating the validity of this taxon. V. rusconii is recovered as an ornithosuchid more closely related to R. tenuisceps than to O. longidens, based on the presence of a nearly pointed anterior margin of the antorbital fenestra, and a vertical bony strut of the jugal that separates the antorbital fenestra from the infratemporal fenestra.