Ben Creisler
A new paper:
New ankylosaur remains for South America representing a small sized animal with long bones and osteoderms.
A new representative of the Gasparinisaura clade is here reported, extending this group of ornithopods to the Maastrichtian southern Patagonia.
The discovery of hadrosaurs allow us to correlate Chorrillo Formation with the adjacent Chilean Dorotea Formation.
The presence of ankylosaurs, hadrosaurs and two kinds of basal iguanodontians, categorize Chorrillo Formation as more diverse formation in ornithischian taxa of South America.
Abstract
The fossil record of ornithischians in South America is sparse, and they are clearly underrepresented when compared with sauropod dinosaurs. However, recent discoveries indicate that ornithischians were more diversified than thought. The aim of the present contribution is to describe isolated remains belonging to ankylosaurs, and ornithopods, including basal euiguanodontians and hadrosaurs coming from the Chorrillo Formation (upper Campanianâlower Maastrichtian), Santa Cruz province, southern Argentina. The fossil remains of ankylosaurs reported here are the southernmost recorded for the continent. They show a unique combination of plesiomorphic features, indicating that they may belong to a basal ankylosaur. Ankylosaurs and hadrosaurids are thought to have arrived in South America during the latest Cretaceous through Central America. However, a detailed overview of the fossil record of Gondwana indicates that both clades were present and probably diversified along southern continents. This indicates that their presence in South America may be alternatively interpreted as the result of migration from other landmasses, including Africa and Europe, or may even be the result of JurassicâEarly Cretaceous vicariance from their northern counterparts.