New decapod crustacean fossils collected from Eocene rocks of Algarrobo, Chile, have yielded a new genus and species of callianassid, Melipal chilensis. The large sample size makes it possible to recognize marked sexual dimorphism of the major cheliped and pronounced heterochely in the new taxon. Cretaceous fossils from Algarrobo are referred to Protocallianassa saetosa (Fo¨rster and Stinnesbeck, 1987) new combination. That genus is rather large and unwieldy as currently understood, but examination of type material will be necessary to revise it.
Twelve species of Neogene decapod crustaceans are described from late Miocene and early Pliocene deposits in the Valdivia, Osomo-Llanquihue, and Chiloé basins as well as from Mocha Island, offshore from the Temuco Basin, southern Chile. New species of thalassinideans include Ctenocheles notialisand Axianassa? chilensis. Axianassa Schmitt, 1924, has not been reported previously in the fossil record. New species of brachyurans includeTrichopeltarion frassinetti. Pirulella antipodea, Chaceon quadrata, Geryon manningi, Phenophthalmus mochaensis, and Chasmocarcinus chiloeensis. Pirulella and Phenophthalmus are new genera and Geryon Krøyer, 1837, is noted in the fossil record for the first time. Extant congeners are primarily known from lower latitude regions. Only Chaceon Manning and Holthuis, 1989, is known from the Chilean coast at present.