Aetosaurs - Distribution

Distribution

Aetosaur fossils have been found on all continents except Australia and Antarctica, giving them a nearly worldwide distribution during the Late Triassic. Many aetosaur remains have been found from the Chinle Group in the southwestern United States. Most fossils have been found from Arizona, New Mexico, and Texas. Some remains have also been found from Utah, particularly in Canyonlands National Park and Zion National Park. Aetosaurs are also known from the Newark Supergroup along the East Coast of the United States in states such as Connecticut and North Carolina. Two genera are known from Greenland: Aetosaurus and Paratypothorax. They have been found from the Fleming Fjord Formation in Jameson Land. Longosuchus is the only aetosaur known from Africa, with scutes having been found from the late Carnian Timesgadiouine Formation in Morocco. During the Late Triassic, Morocco would have been in close proximity with the Newark Supergroup of North America in the supercontinent of Pangaea. It is also possible that Desmatosuchus was present in Africa, as fossils have been found from the Zarzaitine Series in Algeria that were referred to the genus.

South American aetosaurs have been found from Argentina, Brazil, and Chile. In Argentina, they are known from the Carnian Ischigualasto Formation. Common genera from Ischigualasto include Aetosauroides and Stagonolepis. In Brazil, fossils have been found in the Santa Maria and Caturrita Formations in Rio Grande do Sul (Paleorrota). Chilean aetosaurs are represented by one genus, Chilenosuchus, from the Antofagasta Region. Aetosaurs have also been found from India, which, along with South America, was part of Gondwana during the Late Triassic. Early descriptions of aetosaurs included material from the Maleri Formation in south-central India, although it was too inadequate to assign specimens to any particular genus. Based on such descriptions, the Indian aetosaurs most closely resemble Longosuchus and Paratypothorax. Reports of aetosaurs from Madagascar are based on probable crocodylomorph scutes.

Footprints belonging to the ichnogenus Brachychirotherium are often associated with aetosaurs. Brachychirotherium has been found from Rio Grande do Sul in Paleorrota, Brazil as well as Italy, Germany, and the eastern United States. They are also common in the southwestern United States, having been found from Canyonlands National Park and Dinosaur National Monument. Many of these tracks have a narrow gauge (meaning left and right prints are placed closely together) and nearly overstep each other. A 2011 functional analysis of the skeleton of Typothorax coccinarum indicated that it had the range of movement necessary to produce the tracks.