Decapod crustaceans from the Eocene Castle Hayne Formation, North Carolina: Paleoceanographic implications

Ten species of brachyuran decapod crustaceans, including four new species, Matutites miltonorum Pororaria? granulosa, Eocarpilius blowi, and Glyphithyreus sturgeoni, are described from the Eocene Castle Hayne Formation in North Carolina. In addition, claw fragments suggest the presence of an additional four species. Analysis of the fauna within the formation, coupled with data from the enclosing rocks, suggests an environment of deposition in subtropical, clear water at shallow shelf depths. Wave and current energy were variable. Although no corpses were recognized and all the taxa were represented either by claw fragments or isolated carapaces, little abrasion or breakage was observed, which suggests that the material was deposited near the living site of the organisms. Many of the decapod taxa are congeneric with contemporaneous forms from Italy and with Miocene species in Hungary. Paleoceanographic modeling, using the Parallel Ocean Climate Model (POCM), forced by the GENESIS atmospheric circulation model, produces conditions of temperature, salinity, and ocean circulation that corroborate conclusions drawn from analysis of the Castle Hayne sediments and fauna and, additionally, yields similar conditions for the northern margin of the Tethyan region in the Mediterranean basin. Ocean circulation patterns demonstrate the feasibility of dispersal of subtropical organisms from the Mediterranean part of the Tethys across the Atlantic Ocean to the North American coastline.