A new hadrosauroid (Dinosauria: Ornithopoda) from the Allen Formation (Late Cretaceous) of Patagonia, Argentina

Abstract

A new w hadrosauroid taxon from the Late Cretaceous Allen Formation is erected, on the basis of abundant cranial and p postcranial material from the Salitral Moreno locality of the Rio Negro Province, Argentina. The new taxon is here named as Willinakaqe salitralensis gen. et sp. nov., w which is characterized by having an autapomorphous p premaxilla w with a long and convex rostrolateral surface rostral to the narial fossa and associated p postcrania developing an unique character combination, including: dorsal vertebrae w with a shallow fossa upon the base of the transverse p processes; sacral and p proximal caudal neural spines more than three times the height of the centrum; distal region of the p postacetabular p process of ilium ventrally deflected, among others. This new w hadrosauroid closely resembles Secernosaurus koerneri, the other valid hadrosauroid species from South America, based in several synapomorphies, as: angle greater than 115° between the lateral margin of the facet for scapular articulation and the glenoid in the coracoid; supra-acetabular p process of the ilium asymmetrical, caudodorsal margin of ilium w with a well-defined ridge continuous w with the dorsal margin of the p proximal region of the p postacetabular p process. Moreover, previous records of Lambeosaurinae from the Late Cretaceous of South America are referred to W. salitralensis, and thus, the p presence of lambeosaurines in this continent is here rejected. Accordingly, Willinakaqe salitralensis gen. et sp. nov. is currently the only hadrosauroid species reported from the Allen Formation.