ABSTRACT. The present study is a further contribution to the systematic knowledge of the shallow water marine ostracodes from the Brazilian oceanic islands. A total of 14 species belonging to 10 genera and eight families is herein identified. One new genus and species are described and illustrated: Berguecythere insularis gen. nov., sp. nov. In addition to this new taxon, the abundant species Loxocorniculum tricornatum Krutak, 1971, widely distributed in recent sediments in the Gulf of Mexico, Caribbean, north and northeast of Brazil and the Rocas Atoll, along with the cosmopolitan tropical ostracode Triebelina sertata Triebel, 1948, were also identified at specific level. The remaining 11 species were left at the genus level, and should provide new species. Ecological, zoo-and paleozoogeographical aspects were also briefly discussed.KEYWORDS. Taxonomy, new species, morphology, Atlantic Ocean. RESUMO. Ostracoda (Crustacea) do Arquipélago de São Pedro e São Paulo, Atlântico Equatorial, com ênfase em novo gênero deHemicytheridae. O presente estudo é uma contribuição para o conhecimento da sistemática dos ostracodes marinhos rasos das ilhas oceânicas brasileiras. Um total de 14 espécies pertencentes a 10 gêneros e oito famílias é aqui identificado. Um novo gênero e espécie são descritos e ilustrados: Berguecythere insularis gen. nov., sp. nov. Além desse novo táxon, foram também identificados Loxocorniculum tricornatum Krutak, 1971, espécie abundante amplamente distribuída em sedimentos recentes do Golfo do México, Caribe, norte e nordeste do Brasil e no Atol das Rocas, e o ostracode cosmopolita tropical Triebelina sertata Triebel, 1948. As 11 espécies restantes foram deixadas em nível de gênero e devem fornecer novas espécies. Aspectos ecológicos e zoo-e paleozoogeográficos também foram brevemente discutidos.

Vegetation and climate changes in southern Brazil are described based on the palynological analysis from marine core SIS 188, collected on the continental slope, which records the interval between 47.8 and 7.4 cal ka BP. The pollen record indicates that the grasslands dominated the landscape in southern Brazil throughout the studied period. During the last glacial period, the forests were reduced. Between 32.8 and 20.2 cal ka BP, there is an increase in grassland and reduction of arboreal palynomorphs, coinciding with colder and drier climatic conditions of the Last Glacial Maximum (LGM). From 30 to 25.2 cal ka BP, an increase in the sedimentation rate and concentration of most pollen indicators is observed. This change could be related to low sea level, which exposed the continental shelf to eolian erosion and fluvial inputs that transported sediments and palynomorphs to the ocean. A significant decrease in sedimentation rate is recorded between 19.5 and 12.6 cal ka BP, probably related to sea-level rise during deglaciation. During deglaciation and beginning of the Holocene, the increase in arboreal pollen indicates the expansion of forests, reflecting warmer and wetter climate. Heinrich event 1 is marked by a peak in the percentages of the arboreal vegetation at 15.9 cal ka BP. Around 8.5 cal ka BP, there seems to be another interval of higher moisture, indicated by the composition of the palynological association, formed by pteridophytes Blechnum, Huperzia, Polypodiaceae, Pteridaceae and Cyatheaceae. These results show that the palynological record from the SIS188 marine core is sensitive to global climatic changes and can provide a reliable paleovegetational reconstruction for the continental environment. Keywords: Pelotas Basin, paleoclimate, palynomorphs, palynology, Quaternary.

This study sought to understand the role of continental influence on ocean productivity along the late Quaternary based on the comparison between continental palynomorphs and paleoproductivity proxies from the marine sediment core SIS188. Retrieved from the slope of the Pelotas Basin at a depth of 1,514 m, the core documents the time interval between 47.8 and 7.4 cal ka BP, including the Marine Isotope Stages (MIS) 3, 2 and 1. The palynological content found in the core SIS188 indicates a typical flora of the southern Brazil highlands, which is at the same latitude as the core. Thus, continental input sources, such as wind-borne dust and discharges from the Mampituba and Araranguá rivers, would more likely account for the palynological content than the Brazilian Coastal Current (BCC). During the glacial intervals (MIS 3 and MIS 2), paleoproductivity (indicated by the proxies coccolith numbers, N Ratio, and TOC content) suggest the intensification of upwelling and transport of wind dust, the latter of which may have transported pollen grains to the core region. There is a concentration decrease of continental palynomorphs at the end of MIS 2, which is accentuated during MIS 1 when the sea level is higher. Paleoproductivity was high during MIS 1, especially from the Holocene onwards, although the concentration of continental-derived palynomorphs decreases sharply, showing that the rise in sea level interferes with the fertilization of marine waters far from the coast by continental input.