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

ABSTRACT—

Ornithosuchidae 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 on the basis of an incomplete skull with articulated lower jaws and some elements of the postcranium that are currently 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.

SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

ACKNOWLEDGMENTS

We thank J. Powell for allowing us to study specimens under his care; M. Ezcurra for his help during the elaboration of the phylogenetic analysis; D. Gower and A. Lecuona for their useful comments; and M. Carrizo for his help with the edition of the images. We thank the reviewers M. Stocker and R. Butler for their useful comments and suggestions that improved the quality of the manuscript. Financial support was provided by the Agencia Nacional de Promoción Científica y Técnica, Argentina, through the project PICT-2010-207 granted to J.B.D.