Population parameters of the shrimp Xiphopenaeus kroyeri (Heller, 1862) (sex ratio, length-frequency distributions (carapace length, CL), growth, life

This study investigated the importance of variations in environmental factors affecting the abundance patterns of decapods on the southeastern Brazilian coast. Sampling was carried out monthly from January 1998 through December 1999 in Ubatumirim and Mar Virado, Ubatuba region, using a commercial shrimp fishing boat equipped with double-rig nets. Six areas adjacent to rocky shores were chosen. Bottom-water samples were collected using a Nansen bottle, to measure the temperature and salinity. Sediment samples were also obtained by means of a Van Veen grab, for determination of texture and organic-matter content. The association of environmental factors with species abundance was evaluated by Canonical Correspondence Analysis (α = 0.05). Forty-one species of Decapoda were used in the multivariate analysis. The analysis indicated that sediment texture (phi) and bottom temperature were the main factors correlated (p < 0.05) with the spatial and temporal abundance of the species. Considering the study region as faunal transition zone, including a mixture of species of both tropical and subantarctic origin, the species responded differently to environmental factors, mainly temperature. It is conceivable that the decapods adjust their distribution according to their intrinsic physiological limitations, possibly as a result of the available resources.

The objective of this study was to estimate the size of morphological sexual maturity based on the study of relative growth, to determine the maximum size of individuals, and to determine if there are different morphotypes of males in a population of Macrobrachium amazonicum with an entirely freshwater life cycle. Collections were made monthly, with the use of a net, from September 2006 through August 2007. In each individual, the following structures were measured: carapace length (CL, in mm), width of the second pleuron (PlL, mm), length of the carpus (CaL, mm), and length of the propodus (PrL, mm). Relative growth was analyzed by observing the change in growth patterns of certain parts of the body in relation to the independent variable CL. The maximum sizes found were 8.5 and 11.4 mm CL for males and females, respectively. The morphometric variables: length of the carpus (CL × CaL) for males, and width of the second pleuron (CL × PlL) for females gave the best estimates for the size at maturation, which was 4.26 mm CL for males and 5.39 mm CL for females. The growth pattern in the different stages and the beginning of differential growth seemed to be closely related to reproductive aspects. No indices were found that separated the males into four different morphotypes, as proposed in the literature for coastal or artificially farmed populations. Only the male morphotype termed translucent claw was found in this population. The different morphological patterns in different regions are probably explained by ecological differences in the environments inhabited by these groups, principally in the availability of nutrients and the salinity in which the larvae develop.

This checklist is the third part of a series derived from a long-term multidisciplinary project on the biodiversity of decapod crustaceans from marine and coastal environments of São Paulo state (Brazil). We integrated molecular techniques (DNA markers) and morphological analyses of adult specimens for accurate identifications. We compilated 185 species from the literature, but we confirmed the presence of 168 species: 130 of which we sampled, analyzed and obtained sequences (COI and/or 16S totalizing 113 sequences) and 38 that were not directly collected but were confirmed by analyses. In addition, 27 had their distribution removed from São Paulo due to uncertainties, and absence of material as voucher. Five species were reported for the first time on the coast of São Paulo (Calappa ocellata, Neohelice granulata, Teleophrys pococki, Teramnonotus monodi, Tetraxanthus rathbunae) and one on the Brazilian coast (Pseudomedaeus agassizi). Most of the non-sampled species previously reported on the coast of São Paulo might be considered doubtful records stablished in the past by inaccurate analyses, which assumed extended distribution to the area and/or misidentifications. At this time and based on our refined compilation, we can estimate the brachyuran diversity on the coast of São Paulo in 168 species. This detailed inventory contributes to the knowledge on the local decapod fauna by checking available dataset, adding new species records in São Paulo and new sequences to GenBank database. These data may serve as baseline for future identifications and studies on conservation, population genetics, biogeography and phylogenetics, which might flag species that deserve further investigations and concerns.

After being stable for nearly a century, the taxonomic history of the genus Xiphopenaeus has been marked by many changes in the last three decades. The taxonomic status of the Atlantic species has a low resolution, and many species are still undefined and grouped as cryptic species. Here we employed an integrative approach to define the species of Xiphopenaeus and the morphological characters needed to differentiate them. We combined the analyses of two molecular markers (COI and 16 S rDNA), scanning electron microscopy and light microscopy. Based on specimens from 17 localities from the Atlantic and Pacific oceans, we detected five divergent genetic groups, three in the Atlantic (A1, A2, A3) and two in the Pacific (P1, P2). Male secondary sexual characters were able to differentiate four out of the five genetic groups. Group A1 corresponds to X. kroyeri, and A2 and A3 correspond to new species. We redescribed the genus and two new species are described and illustrated: Xiphopenaeus dincao nov. sp. (A2) and Xiphopenaeus baueri nov. sp. (A3). Since the holotype of X. riveti was missing and the specimen analysed from group P2 was a female, the status of the species of Xiphopenaeus from the Pacific remains unresolved.

O objetivo do presente estudo foi analisar a carcinofauna acompanhante da pesca do camarão-setebarbas (Xiphopenaeus kroyeri) em Macaé/RJ, uma região sob influência da ressurgência de Cabo Frio. As coletas foram realizadas mensalmente com um barco de pesca camaroneiro, de julho/2010 a junho/2011. A carcinofauna esteve representada por 15 famí­­lias, 24 gêneros e 30 espécies. As famí­­lias com maior riqueza de espécies foram Portunidae (7) e Penaeidae (5), representando correspondendo a 23,33% e 16,66% do total capturado, respectivamente. Para cada indiví­­duo de X. kroyeri foram capturados em média 2,94 indiví­­duos de carcinofauna, com as maiores discrepí­¢ncias no verão (1 : 4,82) e no outono (1 : 5,76). Os principais componentes dessa carcinofauna (Artemesia longinaris e Pleoticus muelleri) são importí­¢tes importantes como recurso pesqueiro na região, devido í­Â sua grande abundí­¢ncia, e merecem estudos contí­­nuos sobre os diversos aspectos da biologia populacional, visando a í­Â adequação de medidas de gestão e conservação.