New Decapod Crustaceans (Thalassinidea, Galatheoidea, Brachyura) from the middle Oligocene of Patagonia, Argentina

Abstract

A robust decapod fauna from middle Oligocene rocks near Bariloche, Argentina, has yielded several new forms. New genera include Baricarcinus and new species include Callianopsis australis. Proterocarcinus corsolini, Trichopeltarion levis, Baricarcinus mariae, and Asthenognathus microspinus. Munida casadioi (Schweitzer and Feldmann, 2000a) is also reported. This is the first notice of Callianopsis de Saint Laurent, 1973, in the southern hemisphere. The species of Trichopeltarion and Asthenognathus described herein are the oldest known representatives of their respective genera, and Asthenognathus is one of the oldest known genera within the Pinnotheridae de Haan, 1833. The fauna of the Foyel Formation is significantly different front that of the slightly younger Centinela Formation, exposed approximately 500 km to the south, suggesting that paleoecological conditions were conducive to specialization in the decapod fauna of southern South America.