Eothoracosaurus is an extinct genus of gavialoid crocodilian. It was one of the earliest and most basal gavialoids known. Fossils are present from the Ripley Formation in Mississippi, and date back to the early Maastrichtian stage of the Late Cretaceous. Some fragmentary material from the Coon Creek Formation of western Tennessee dating back to the late Campanian (slightly older than the specimens from Mississippi) has been referred to Eothoracosaurus as well. The Coon Creek Formation seems to have been deposited in a marine setting, with oceanic fauna such as the sharks Otodus and Squalicorax, the sea turtle Toxochelys, and mosasaurs including Plioplatecarpus and Globidens present from these strata. This suggests that Eothoracosaurus may also have led a marine lifestyle. Certain aspects o