Provinciality of ostracoda (Crustacea) in the northeastern and eastern brazilian shelves based on neontological and paleontological analyses

Abstract

This study analyzes the geographical distribution of 131 podocopid ostracod species recovered from the Brazilian continental shelf between Cabo de São Roque (lat. 05°30’S) and Cabo Frio (lat. 23oS). This very large area corresponds to the northeastern and eastern Brazilian marine regions. The 104 samples studied were collected in water depths ranging from 12 to 110 m as part of the legs 4 and 7 of the REMAC Project. The cosmopolitan species, as well as those shared with the Caribbean and/or Gulf of Mexico region, represent a small part of the ostracods herein studied and it is assumed that their dispersion was prompted by processes linked to events of relative sea level changes during the Neogene and Quaternary. The fossil record of some species spans to the Neogene, mostly from the Atlantic coast of North and Central America, while one species has Tethyan origin. Three species known from the Neogene of the Caribbean have been recorded as relicts in the study area. From the 131 species herein identified, 36.5% are more widespread in temperate waters south of Cabo Frio town, 46.5% of warm waters north of Cabo Frio town, 4% are present only in the studied area, and 11.5% are rare and probably restricted to the E region. A new province – the Brazilian Province – is herein proposed based on the species occurrence.