Abstract in English:Described from a high-altitude lake in Peru, Bosmina huaronensis Delachaux, 1918 has been recorded in diverse kinds of water bodies in South and North America, suggesting that this species has high environmental tolerance and a wide niche breadth. The present study surveyed the occurrence records of B. huaronensis from 55 localities and, using multivariate analysis, investigated the niche differentiation among populations from different biogeographic regions, based on altitude and seven climatic variables. The first two principal components (PC) explained 73% of the overall variance. PC1 was related to annual mean temperature, precipitation of driest quarter, and annual precipitation. PC2 was related to temperature seasonality and precipitation of wettest quarter. The PCA diagram showed three population groups, occupying different climate niches: (1) tropical highlands; (2) Neotropical lowlands; (3) temperate zones of both hemispheres. These results point to the need for further evaluation of these populations under morphological, genetic and ecological aspects.
Abstract in English:The evaluation of population characteristics, particularly those of endemic species, aids in population preservation and management. Hermit crabs present an innate behavior of occupying shells, which tends to individual needs and limits their distribution. This study characterized the pattern of occupation of gastropod shells by the hermit Loxopagurus loxochelis in three bays of the southwestern coast of Brazil. Monthly collections were made from January/1998 to December/1999 in the bays Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV) with a shrimping boat. Overall, ten species of gastropod shells were occupied by L. loxochelis. The shell of Olivancillaria urceus represented 66.8% of those occupied. Morphometric relationships demonstrated a differential occupation of the more abundant shells among demographic groups, where most of the males occupied O. urceus, non-ovigerous females occupied O. urceus and Buccinanops cochlidium, and ovigerous females occupied B. cochlidium and Stramonita haemastoma. Most of the individuals occupied the more abundant shells, considered adequate for the morphology of this hermit crab species. Thus, the studied bays seem to be stable and propitious environments for population perpetuation and the settlement of new individuals.
Abstract in English:A study on the temporal distribution, sex ratio, reproductive period, recruitment of juveniles and size composition of individuals of the fiddler crab Uca (Leptuca) uruguayensis was carried out in a population living in the Garças River mangrove, Guaratuba Bay, Paraná State, Brazil. Eight square samples of 0.25 m² (0.50 m side) were obtained on a monthly basis, from April/2011 to March/2012. The crabs were collected through the excavation of burrows and their carapace width (CW) was measured. Air and water temperatures varied from 19.0 to 29.5ºC and 17.0 to 27.0ºC, respectively, the salinity from 7 to 23 and the soil temperature from 19.0 to 29.2ºC. A total of 1,099 fiddler crabs were collected, being 529 males, 520 females (of these, 9 ovigerous) and 50 sexually undifferentiated individuals. The average density of the population ranged from 12 (June/11) to 71 ind.m-² (May/11), but its annual fluctuation was not correlated to abiotic variables. The sex ratio was 1:1 all year round and in all CW classes. Although in low abundance, ovigerous females were recorded in six months and juvenile crabs were present all year round, indicating a continuous reproduction and recruitment of the species. The CW of males ranged from 2.33 to 8.33 mm and that of females, from 2.52 to 7.79 mm: these data showed that this population is composed of smallest individuals among those studied
Abstract in English:This study describes the histology and histochemistry of the male reproductive system in Callinectes ornatus, comparing juvenile and adult developmental stages. We also analyzed changes in the gonadosomatic (GSI) and hepatosomatic (HSI) indices, and the weights of the testis and vas deferens during the development. The results showed that all stages, beginning with the juvenile (JUV), through developing (DEV) and mature (MAT) adult males of C. ornatus produce sperm and spermatophores. During development, testicular lobes showed the same characteristics of production and release of sperm into the seminiferous duct. The vas deferens showed little histological and histochemical change in the epithelium in juvenile and adult males. The differences consisted of the larger amount of secretion in MAT males compared to JUV and DEV ones. The chemical composition of the seminal fluid was similar, but MAT males produced a more homogeneous secretion. Morphological and physiological maturation are not synchronized in C. ornatus, since JUV males produced spermatophores similar to those in DEV and MAT males. However, these JUV are not yet able to reproduce, since they still have the abdomen attached to the cephalothoracic sternum. The increase of the GSI during development was significant for MAT males, and is related to the production of sufficient volume of seminal fluid to form the sperm "plug" in the female seminal receptacle. The HSI decreased from DEV to MAT adult stages, indicating that reserves from the hepatopancreas are used to develop the reproductive system after the pubertal molt.
Abstract in English:Tropical coral reefs are known to exhibit high levels of biodiversity. Amphipod crustaceans are successfully adapted to a wide range of marine habitats in coral reefs, but some regions, such as the Campeche Bank in southern Gulf of Mexico, are poorly studied or even unsurveyed for amphipods. To begin to address this paucity of information, the present study records amphipod species from Isla Pérez, an island of the Alacranes Reef National Park, southern Gulf of Mexico. Twenty sites were sampled in the intertidal zone and shallow water adjacent to the island. Thirty-one species of amphipod were identified, 15 of which represented a geographical range extension to the northern Yucatan Peninsula, with four new records for the Mexican south-east sector of the Gulf of Mexico; nine for the Gulf Coast of Mexico; and two for the entire Gulf of Mexico. Significantly, a difference in faunal composition between windward and leeward areas of the intertidal zone was found.
Abstract in English:A new species of Hourstonius is described from the northern coast of São Paulo State. Hourstonius wakabarae sp. nov. is distinguished from the other species of the genus by the morphology and the size of the accessory flagellum of antenna 1, the articles of antennae 1 and 2, the mandibular molar, and the telson. The new species H. wakabarae lives associated with macroalgae growing on rocky shores, especially the brown alga Sargassum, at depths up to 2-3 m. This is the first species of the genus Hourstonius recorded from Brazilian waters.
Abstract in English:The pinnotherid crab Clypeasterophilus stebbingi (Rathbun, 1918), previously known from Florida, USA, Colombia and Brazil, is reported for the first time from Central America, on the east coast of Nicaragua. A single female specimen was collected on the sand dollar Clypeaster subdepressus (Gray, 1825), at 4 m depth, among turtle grass on sandy bottom. The specimen fits well with the description provided by M.J. Rathbun and observations made on photographs of the male holotype. Comparison of the material described from Florida (including the type material), Colombia and Brazil to the Nicaragua specimen, however, indicates that C. stebbingi shows some variation in the shape of the third maxilliped.
Abstract in English:Aeglidae are anomuran freshwater "crabs" found only in southern South America. In Brazil, the greatest species diversity occurs in hydrographic basins of the state of Rio Grande do Sul. Two new species, Aegla georginae and Aegla ludwigi, are described from the Ibicuí and Ijuí Rivers, respectively (Uruguay River Basin). The new taxa can be distinguished from other Aegla species based on both morphological and molecular characters. The two new species have a very restricted distribution and are categorized as endangered (A. georginae) and critically endangered (A. ludwigi) using IUCN Red List criteria. We also summarize and present new records of the Aegla species occurring in the Uruguay River Basin.
Abstract in English:The northern coast of the Mexican state of Yucatán has only been cursorily sampled in the past, with most of this effort concentrated on the largest coral reef in the Gulf of México, Arrecife Alacranes. The present study reports on recent collections (June 2008 - September 2013) of caridean shrimp in Yucatán, including Arrecife Alacranes and other reefs, as well as coastal lagoons and beaches. Additionally, a number of species are reported based on older, unidentified museum material. Six species represent new records for the Gulf of México [Janicea antiguensis (Chace, 1972), Gnathophyllum modestum Hay, 1917, Lysmata jundalini Rhyne, Calado and dos Santos, 2012, Periclimenes sandyi De Grave, 2009, Rapipontonia platalea (Holthuis, 1951a), Typton tortugae, McClendon, 1911], and 11 species are confirmed new records for México [Lysmata ankeri Rhyne and Lin, 2006, L. pederseni Rhyne and Lin, 2006, L. rafa Rhyne and Anker, 2007, Ascidonia miserabilis (Holthuis, 1951b), A. quasipusilla (Chace, 1972), Neopontonides chacei Heard, 1986, Periclimenaeus maxillulidens (Schmitt, 1936), P. pearsei (Schmitt, 1932), P. schmitti Holthuis, 1951b, Typton prionurus Holthuis, 1951b, Processa manningi De Grave and Felder, 2012], adding up to a total of 17 newly reported species for the East coast of México. Further, the colour pattern of several species is documented for the first time.
Abstract in English:This paper evaluates the malformation in the left third maxilliped of a specimen of the fiddler crab Uca rapax from Venezuela. There are some hypotheses and the cause of the malformation remains unknown, but the results are indicative that is most likely due to errors in morphogenetic processes.