The Cenozoic Ostracode Faunas of the São Paulo Plateau and the Rio Grande Rise (DSDP Leg 39, Sites 356 and 357)

Abstract

Forty-eight samples were examined from two sites(356 and 357) of DSDP Leg 39 from calcareous layersranging in age from Maestrichtian (Site 356) andDanian (Site 357) to late Neogene. Ostracodes werefound in almost all samples (20 cc in size), with 634specimens identified. The samples were small and thenumber of specimens would have been considered lessthan adequate, except for the ability to compare themwith the plentiful and complementary assemblages ofSites 21, 21 A, and 22 (Maxwell et al., 1970).The 28 samples examined from Site 357 had betterpreserved and more abundant specimens than those ofSite 356, possibly due to somewhat shallower condi-tions or a difference in sediment permeability. The totalnumber of taxa identified from all samples, for the mostpart to the generic level, is less than 25. In no singlesample were there more than 10 species; most sampleshad 5 or less.As stated in another recent preliminary report(Benson, 1974), the ostracodes of the deep sea are stillin the beginning stages of study. However, in spite ofthe lagging formal description of many of the new taxa,both morphologic and faunal trends are known(Benson, 1975a; Sylvester-Bradley and Benson, 1971).Several new taxa are described for the first time in thisreport. Tentative names of yet undescribed taxa aregiven in quotes. A census of the assemblages follows: