FOSSIL DECAPOD CRUSTACEANS FROM THE JAGUEL AND ROCA FORMATIONS (MAASTRICHTIAN-DANIAN) OF THE NEUQUEN BASIN, ARGENTINA

Ten species of macruran, anomuran, and brachyuran decapod crustaceans, arrayed in eight families, were collected from seven localities in th e Jaguel and Roca Formations, west-central Argentina. All of the decap ods were collected from the Maastrichtian Jaquel Formation and a part of the Roca Formation dated as Maastrichtian-Danian. All but one of th e taxa, Xanthilites gerthi Glaessner, represent first occurrences in t he unit and six had not been described previously from Argentina. Six taxa, Thaumastoplax rocaensis n. sp., Proterocarcinus lophos n. gen. a nd sp., Lobonotus lobulata n. sp., Glyphithyreus wichmanni n. sp., and Costacopluma australis n. sp. are new. Comparison of the fauna with C retaceous and Paleogene faunas in Chile, Antarctica, and New Zealand i ndicates that the Argentinian fauna was strongly influenced by dispers al from lower latitude, Atlantic and Tethyan sources in marked contras t to the high latitude, Pacific affinities of the other faunas. There is no evidence that the Argentinian brachyuran fauna was seriously aff ected by the K-T extinction event. Seven of the genera from the Roca F ormation are known from Cretaceous and Paleogene rocks.