We described the ecology of the spider crab Libinia ferreirae testing the habitat segregation during the ontogenetic shifts. Collections were performed monthly by trawling along the coastal area of Cananéia, São Paulo State (southeastern Brazil). Medusae were examined for the presence of any symbionts, and crabs were classified as juveniles (abdomen sealed to the sternite), adults (unsealed abdomen), and ovigerous females (embryos adhered to the pleopods). The environmental factors related to the water column were obtained using a multiparameter probe. In total, 564 adults and 357 juveniles were collected. However, all juveniles were obtained in association with Lychnorhiza lucerna medusae. An increase in the abundance of ovigerous females was observed as chlorophyll levels (phytoplanktonic production) increased, which is consistent with the patterns proposed for crustaceans with planktotrophic larval stages, i.e., the association of larval hatching with oceanic productivity could explain the success in juvenile recruitment approximately two months after the peak in the abundance of ovigerous females (crosscorrelation: r = 0.96). This spider crab shows an ecological strategy of habitat segregation among juvenile and adult individuals, thus avoiding competition for resources among different life cycle stages.

O presente estudo analisou os hábitos alimentares e a estrutura da fauna de Chironomidae do córrego Vargem Limpa, em dezembro de 2004. O principal item alimentar ingerido pela maioria dos gêneros analisados (Beardius,

The goal of the present study was to assess the temporal and spatial distribution of L. schmitti in three bays of the northern coast of the State of São Paulo, Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV), over a period of two years (1998 and 1999). Abiotic factors were monitored to test their influence on the distribution of the species through redundancy analysis. The shrimp were captured using a commercial fishing boat equipped with double-rig trawling nets at six sampling points. A total of 5658 individuals were collected during the study (4437 and 1221 in the first and second years, respectively). The number of individuals differed between years, bays, seasons and sampling locations. The highest number of L. schmitti was collected in MV (N ¼ 2747), followed by UBM (N ¼ 1649) and UBA (N ¼ 1262). Shrimp abundance correlated positively with organic matter content, salinity and temperature, with the highest number of individuals collected from sites with intermediate levels of organic content (4 and 6%) and increasing when the sediment had a higher proportion of fine and very fine sand + clay. Abundance was also associated negatively with rainfall, given that the analysed population showed a seasonal pattern, with an increase in capture rate in those months following the rainy season. Average rainfall was 222.47 + 138.68 mm, with a maximum of 538 mm and a minimum of 22.4 mm. The results obtained in this study suggest that, in the region of Ubatuba, temperature, salinity, organic content and rainfall modulate the distribution of these animals.

No abstract

A new genus and species, Chicosciencea pernambucensisgen. nov., sp. nov., is described from two localities along the coast of Pernambuco state, northeastern Brazil. Considering the unresolved situation of the families of Stenopodidea in previous studies, the position of this new genus is discussed based on morphological, molecular (16S mtDNA), and ecological data. The morphological analysis revealed that Chicoscienceagen. nov. differs from all stenopodidean genera by a combination of characters. The inferred molecular phylogeny recovered a monophyletic group including Chicoscienceagen. nov., MacromaxillocarisAlvarez, Iliffe & Villalobos, 2006, and MicroprosthemaStimpson, 1860, which comprise free-living (i.e., not-sponge associated), shallow-water species. Based on this monophyletic group and on their morphological and ecological similarities, we herein formally propose the resurrection of Macromaxillocarididae Alvarez, Iliffe & Villalobos, 2006 to include those genera. We also provide an updated world list of Stenopodidea. With the description of Chicoscienceagen. nov., the infraorder Stenopodidea now comprises 13 genera and 92 species.