ABSTRACT The siphonophores of the Brazilian coast are poorly studied, despite their abundance and ecological importance. Lensia is the most diverse genus within Siphonophora, with twenty-six valid species. A total of twenty species of Lensia are recorded for South American marine waters. This study presents morphological descriptions and an identification key to the species of Lensia that were collected in two oceanographic campaigns throughout the southeastern Brazilian coast. A total of sixty-one specimens were photographed, described, schematized and measured, and fifteen species of Lensia were identified.

We describe the species richness, distribution and composition of mesozooplankton over the continental shelf and slope, and in the water masses in the Campos Basin, southwest Atlantic Ocean. We analyzed the mesozooplankton from two oceanographic cruises (rainy and dry seasons, 2009) with samples taken in five different water masses from the surface to 2,300 m depth. In the Subsurface Water (SS), in both sampling periods, more species were recorded over the slope (rainy: 100; dry: 128) than the continental shelf (rainy: 97; dry: 104). Over the slope, species richness decreased with increasing depth: the highest values were observed in the South Atlantic Central Water (SACW), and the lowest values in the North Atlantic Deep Water (NADW), in both sampling periods. We recorded 262 species in 10 groups (Hydrozoa, Siphonophora, Ctenophora, Branchiopoda, Copepoda, Euphausiacea, Decapoda, Chaetognatha, Appendicularia e Thaliacea), with 13 new occurrences for the southwest Atlantic. Copepoda was the group with the highest species richness, containing 138 species. In both periods, the samples from SS, SACW and Antarctic Intermediate Water (AAIW)/Upper Circumpolar Deep Water (UCDW) were clustered in different faunistic zones, based on species composition. This study confirmed that zooplankton richness in the southwest Atlantic Ocean is underestimated, and suggests that additional efforts must be directed toward a better understanding of this fairly unknown region.

Trinta colônias de Eudendrium carneum e 100 colônias de E. glomeratum foram coletadas em placas de recrutamento em São Sebastião (SP, SE Brasil), estudadas quanto aos parâmetros morfométricos e comparadas com dados de outras regiões. Os resultados mostraram que as colônias de E. carneum encontradas no Brasil possuem variações morfométricas relativamente menores que as colônias de E. glomeratum brasileiras e de outros lugares. Tanto causas morfológicas quanto especiação são sugeridas como possíveis explicações para a grande variação em E. glomeratum.

Thirty colonies of Eudendrium carneum and 100 colonies of E. glomeratum, collected on recruitment panels in São Sebastião (SP, SE Brazil), were studied concerning morphometrical parameters and compared with morphometrical data available from other locations. The results show that E. carneum from Brazil has a relatively smaller morphometric variation than colonies of E. glomeratum for Brazil and other areas. Both morphological and speciation causes are suggested as possible explanations for the high variation of E. glomeratum.