DIVERSITY DIFFERENCES OF EOCENE DECAPOD CRUSTACEANS BETWEEN ATLANTIC AND GULF COAST, USA AND VENETO REGION, ITALY

Systematics of the decapod crustaceans from carbonate formations amd facies of the North American Atlantic and Gulf Coast was conducted in order to compare the diversity of decapods from Europe, mainly Italy.

Nineteen families, twenty eight genera, and forty species of brachyuran decapod crustaceans, including three new genera and sixteen new species, were recorded from the middle Eocene and Oligocene Atlantic and Gulf Coast formations, including the Santee Limestone and Tupelo Bay Formations from South Carolina, Castle Hayne Formation from North Carolina, Ocala Limestone and Trivola Limestone from Georgia, Glendon Formation from Alabama, and Cane River Formation from Louisiana. This study is based on the evaluation of two large collections of over 400 specimens of decapod crustaceans, one in the Charleston Museum, South Carolina, and a collection from the Museum of Geology, South Dakota School of Mines and Technology, South Dakota. Specimens collected from the Santee Limestone and Tupelo Bay Formation, South Carolina, during summer of 2010 were also included in the study.

There are significant observed differences between the diversity of decapods from Europe and North America that can be related to differences in carbonate environments. The large number of decapod taxa described from Eocene carbonate rocks of Italy, approximately 47 families compared to only 19 families from the Atlantic Gulf Coast, with 15 families in common, suggests that the European sites were more varied in the type of carbonate environments in which the faunas occurred. Collected specimens from the USA were found in highly fossiliferous, bryozoan-rich carbonate rocks. The specimens from Europe were collected primarily from coral-dominated limestones. Museum work was funded by NSF EF-0531670 to Feldmann and Schweitzer.