This data set includes the results of the activities undertaken in the REVIZEE Program by the South Score/Benthos (Cabo de São Tomé, RJ – Arroio Chuí, RS). The main objectives of this sub-program are the knowledge of biodiversity and the evaluation of the sustainable potential of the faunistic resources of the exclusive economic zone of the southeastern and southern regions of Brazil
. The field collections were taken from December 13th 1997 to April 20th 1998 in the continental shelf and slope (60 – 810 m depth) with the Oceanographic Vessel Prof. W. Besnard (IO-USP). The fauna was collected using the benthic samplers van Veen and Box-corer and the rectangular dredge, summing up 322 samples. In some cases, data of organisms scrapped from hard substrates were also presented. The following groups are presented: Porifera, Cnidaria (Hydrozoa, Scyphozoaand and Anthozoa), Sipuncula, Mollusca (Gastropoda, Bivalvia, Cephalopoda, Polyplacophora and Solenogastres), Annelida (Polychaeta), Crustacea (Ostracoda, Cirripedia, Decapoda, Stomatopoda and Tanaidacea), Bryozoa, Brachiopoda, Echinodermata (Ophiuroidea, Asteroidea, Crinoidea, Holothuroidea and Echinoidea) and Chordata (Ascidiacea). A total of 131.369 individuals were recorded and classified into 28 higher taxa. The most abundant and frequent groups were Porifera, Cnidaria, Sipuncula, Gastropoda, Bivalvia, Scaphopoda, Polychaeta, Crustacea, Ophiuroidea, Bryozoa and Brachiopoda. Bryozoa was the most abundant group (30.501 records) followed by Polychaeta (22.412 inds), Ophiuroidea (16.918), Crustacea (14.240), Brachiopoda (12.834) and Bivalvia (11.761). The collected data reveal a very rich fauna. The structure of the benthic fauna in the study area was characterized by the association between higher abundances of organisms with sandy and muddy substrata, both with low contents of calcium carbonate (100 – 200 m). The bathymetric distribution of the higher taxa was also demonstrated to be associated with the substrate type. The higher taxa recorded in this study are being analyzed by experts to enable a more precise evaluation of the biodiversity. A total of 1012 taxa were identified up to date and a significant number of new occurrences and new species were reported. The identified material was placed in biological collections of museums or institutions with curatorial tradition.