Article: The oldest freshwater decapod crustacean, from the Triassic of Arizona

The oldest known freshwater crayfish is described here from a nearly complete specimen found in the Chinle Formation of Late Triassic (Late Carnian) age in Petrified Forest National Park, Arizona, USA. It differs significantly from other Triassic crayfish and is placed in Enoplodytia porteri sp. nov. in the family Erymidae (Malacostraca, Decapoda). Except for clam shrimps (Eubranchiopoda) and notostracans E. porteri sp. nov. is the only crustacean that has been described from the non-marine Upper Triassic strata of North America.