A new iguanodontian ornithopod from Neuquen Basin, Patagonia, Argentina

ABSTRACT The discovery of a new iguanodontian ornithopod in the lower units of the Neuquen Group (Rio Limay Formation, early Upper Cretaceous) increases the South American record of this kind of dinosaurs started few years ago with the report of Gasparinisaura cincosaltensis. Anabisetia saldiviai, gen. et sp. nov. is distinguished from all other ornithopods by several features, as a flattened fifth metacarpal, a scapula with a very strong acromial process, and an ilium with preacetabular process longer than 50% of the total ilium length. Anabisetia is more derived than Tenontosaurus and shares with Euiguanodontia (Gasparinisaura + Dryomorpha) the presence of one primary lateral ridge on each maxillary tooth, a broad brevis-shelf and a reduced first metatarsal. Derived features such as the transversely flattened prepubic process and an anteroventrally oriented ischiadic foot link Anabisetia with Dryomorpha (i.e., Dryosaurus, Camptosaurus and Iguanodon). Anabisetia strengths the hypothesis that basal iguanodontian ornithopods were present in South America before its with North America in the Late Cretaceous.