Abstract The present study provides a list of the freshwater crab species of the family Trichodactylidae recorded from the state of Maranhão, northeastern Brazil, along with information about their distribution. Eight streams were sampled with dip nets, sieves, gill nets, and drag nets. Four species were found: Dilocarcinus septemdentatus (Herbst, 1783), Goyazana castelnaui H. Milne Edwards, 1853, Sylviocarcinus pictus (H. Milne Edwards, 1853), and Valdivia serrata White, 1847. Our results increase the known distribution range of these species and add new records to more basins.

Abstract The caridean family Glyphocrangonidae Smith, 1884 is monotypic, including only the genus Glyphocrangon A. Milne-Edwards, 1881. The species of this genus are exclusively inhabitants of deep sea. The current contribution aims to enrich the knowledge of Glyphocrangon in the southwestern Atlantic, by reporting its occurrence and bathymetric distribution in the Potiguar Basin, northeastern Brazil. The samples were collected by R/V Luke Thomas and R/V Seward Johnson, with bottom trawling at isobaths of 400, 1,000 and 2,000 m, using an otter trawl semi-balloon. The specimens were identified and stored in the carcinological collection of the Museu de Oceanografia Prof. Petrônio Alves Coelho, in Recife, Brazil. A total of 810 specimens were examined from five species: Glyphocrangon aculeata A. Milne-Edwards, 1881, G. alispina Chace, 1939, G. longirostris (Smith, 1882), G. sculpta (Smith, 1882) and G. spinicauda A. Milne-Edwards, 1881. Glyphocrangon spinicauda was the most abundant with 334 individuals, and G. sculpta was the rarest, with only one individual. All species were recorded in the study area for the first time.

Abstract The crab Euchirograpsus americanus A. Milne-Edwards, 1880 (Plagusiidae) has so far only been recorded in Brazil in the state of Rio Grande do Sul. Here we report its first occurrence from northeastern Brazil, from the Potiguar Basin in the state of Rio Grande do Norte.

O objetivo deste trabalho foi conhecer a diversidade e alguns aspectos ecológicos dos caranguejos (Decapoda, Brachyura) nos estuários dos Rios Ariquindá e Mamucabas (PE), através da caracterização da estrutura de suas comunidades, com base na composição e diversidade desses crustáceos. As espécies foram amostradas mensalmente entre abril/2008 e março/2009. Foram coletados 8.394 exemplares, sendo 4.501 no manguezal do Rio Ariquindá (25 espécies e 14 gêneros) e 3.893 no manguezal do Rio Mamucabas (21 espécies e 12 gêneros). A maior frequência de espécies nesses manguezais foi dos representantes da Superfamília Ocypodoidea, em especial Uca spp. Comparando os dois estuários, nota-se que cinco espécies (Acantholobulus bermudensis, Austinixa leptodactyla, Callinectes exasperatus, Hexapanopeus caribbaeus e Uca maracoani) foram amostradas apenas no Rio Ariquindá, enquanto uma delas (Armases rubripes) foi encontrada apenas no Rio Mamucabas. A diversidade foi considerada média, de acordo com os índices ecológicos, com valores dentro do esperado para manguezais. Entretanto, nota-se que a diversidade foi menor no manguezal do Rio Mamucabas, resultado que pode estar relacionado aos impactos ambientais que esse estuário vem sofrendo nos últimos anos (represamento, desmatamento, deposição de resíduos sólidos e especulação imobiliária). O presente estudo, associado às medidas de proteção propostas, é de notável importância para a gestão dos crustáceos como recursos pesqueiros costeiros, especialmente se considerarmos que os crustáceos participam da teia trófica de diversos animais, entre eles o homem. A manutenção da diversidade de caranguejos em manguezais é considerada importante para a saúde dos ecossistemas costeiros.

It is important to study the diversity of a given area to comprehend the processes that rule the community and/or ecosystem. Several researches in tropical mangroves revealed that among the most abundant representatives, stand out the Crustacea Brachyura. The Brachyuran fauna of the littoral of Pernambuco (PE), Brazil, is well known, but the studies are mainly species lists. Thus, more detailed studies on the ecology of these communities are required, applying ecological indexes and multivariate analysis. The aim of this study was to know the biodiversity and some ecological aspects of crabs (Decapoda, Brachyura) found in the mangroves of Ariquindá and Mamucabas Rivers (PE), through the characterization of the structure of the community based on the composition and diversity of these crustaceans. For that, two hypothesis were proposed: H1 - The diversity of Brachyura is median for both mangroves, but it is higher at the Ariquindá River, due to its better state of conservation; and H2 - There are no dominant or very frequent species, indicating an environmental equilibrium in the communities. The species were monthly sampled from April 2008 to March 2009. A total of 8,394 individuals were sampled, being 4,501 in the mangrove of the Ariquindá River (25 species and 14 genera) and 3,893 in the mangrove of the Mamucabas River (21 species and 12 genera). The highest frequency of species in both mangroves is found in the Superfamily Ocypodoidea, especially Uca spp. Comparing both estuaries, it can be noticed that five species (Acantholobulus bermudensis, Austinixa leptodactyla, Callinectes exasperatus, Hexapanopeus caribbaeus and Uca maracoani) were sampled only at the Ariquindá River, while one of them (Armases rubripes) was found only at the Mamucabas River. The diversity was considered medium according to the ecologic index for both mangroves, and it is the expected for mangroves of Northeastern Brazil. However, it could be noticed that the diversity was lower at Mamucabas River, a result that might be related to the environmental impacts that this estuary has receiving in the last years (damming, deforestation, deposition of waste and housing occupation), which corroborates H1. The diversity was not high due to the dominance of one species, Uca thayeri, with 1,411 individuals at Ariquindá River and 1,300 at Mamucabas River, refuting H2. Besides, nine species were registered for the first time to the region of Tamandaré: Acantholobulus bermudensis, Armases rubripes, Austinixa leptodactyla, Hexapanopeus angustifrons, H. caribbaeus, Panopeus occidentalis, Sesarma curacaoense, Uca cumulanta and Uca victoriana. In the present study, it was possible to observe how the number of species of Brachyura behaves in the Brazilian coast. The highest number of species of crabs is observed in previous studies performed at mangroves of Pernambuco, with a tendency to decrease towards the South. The number of species recorded in the present study is expected for the Northeast region. In the Southern limit of the distribution of mangroves in South America (State of Santa Catarina), due to the colder climate, the development of mangroves is smaller, so as the diversity of crustaceans. With this, it is confirmed the greatest Brachyuran diversity in tropical areas, more stable ecosystems, such as the mangroves of Pernambuco. This study, coupled with the proposed protection measures, is of notable importance for the management of crustaceans as coastal fishery resources, especially considering that the crustaceans participate in the trophic web of various animals, including man. Maintaining the diversity of crabs in mangroves is considered important to the health of coastal ecosystems.

O objetivo deste trabalho foi estudar a ecologia populacional de Callichirus major (Say, 1818) na praia de Piedade, Estado de Pernambuco, Brasil, através da análise de parâmetros como proporção sexual, período reprodutivo e o recrutamento de juvenis nesta população. As coletas foram realizadas mensalmente entre dezembro de 2010 e novembro de 2011. A temperatura do ar e das tocas, além da salinidade da água do mar foram medidas in situ. O teste t de Student foi aplicado para comparar os valores dos fatores abióticos entre as estações seca e chuvosa. A proporção sexual foi analisada para cada mês e durante todo o período estudado, e o teste do qui-quadrado foi aplicado para verificar se desvia significativamente da proporção esperada. O período reprodutivo foi determinado com base na frequência de fêmeas ovígeras. O recrutamento foi obtido com base na frequência de indivíduos imaturos. A influência de fatores abióticos na população foi avaliada através do coeficiente de Pearson. A temperatura do ar e das tocas variou significativamente entre os períodos seco e chuvoso, com valores mais elevados no período seco. Um total de 389 indivíduos C. major foram amostrados (174 ♂ e 215 ♀). A razão sexual foi de 1:1,24 (♂:♀), as fêmeas foram mais abundantes que os machos. No presente estudo, foi observado que o pico da fase reprodutiva e frequência de fêmeas ovígeras de C. major ocorreu na estação seca (verão equatorial). O recrutamento de jovens na população ocorreu durante todo o ano, especialmente entre o verão e o outono. De acordo com a matriz de correlação, o fator abiótico mais influente na abundância de C. major, especialmente em fêmeas ovígeras, é a temperatura das tocas. Este estudo cria uma linha de base para futuras pesquisas com C. major no Nordeste do Brasil.

The aim of this paper was to study the population ecology of Callichirus major (Say, 1818) at Piedade Beach, State of Pernambuco, Brazil, through the analysis of parameters such as sex ratio, reproductive period and recruitment of juveniles into this population. Sampling was taken monthly from December 2010 to November 2011. The burrow and air temperatures, as well as the sea water salinity, were measured in situ. A Student t test was applied to compare the value of abiotic factors between the dry and rainy seasons. The sex ratio was analyzed for each month and for the total studied period, and a Chi-square test was applied to verify if it deviated significantly from the expected proportion. The reproductive period was determined based on the frequency of ovigerous females. The recruitment was obtained based on the frequency of non-mature individuals. The influence of the abiotic factors was evaluated through a Pearson’s coefficient. The air and burrow temperatures varied significantly between the dry and rainy periods, with the highest values in the dry period. A total of 389 individuals of C. major (174 ♂ and 215 ♀) were sampled. The sex ratio was 1:1.24 (♂:♀), with females being more abundant than males. In this study, the most active reproductive period of C. major and frequency of ovigerous females was observed in the dry period (equatorial summer). Recruitment of juveniles into the population occurred throughout the year, between the summer and the autumn. According to the correlation matrix, the main abiotic factor influencing the abundance of C. major, especially of ovigerous females, was the burrow temperature. This study creates a baseline for further research with C. major in Northeastern Brazil.

The purpose of the present study was to investigate the biodiversity, relative abundance and frequency of decapod crustaceans in the marine mangrove ecosystem at Gaibu Beach, Pernambuco State, Brazil. A total of eight samples were taken: four in the rainy season (August 2010) and four in the dry season (February 2011), during spring low tides and according to the phases of the moon. In all, 352 decapods were sampled. These specimens belonged to 17 species, 14 genera and 13 families. Pachygrapsus transversus (Gibbes, 1850), P. gracilis (Saussure, 1858), Panopeus americanus Saussure, 1857 and Uca (Leptuca) leptodactyla Rathbun, 1898 were very frequent. The three latter species occurred in all samples. The most abundant species was P. americanus. The Shannon-Wiener index (H') showed that, in general, the diversity level was medium for all samples. However, the sample taken at the time of the new moon during the rainy season was classified as highly diverse. These results contribute to the knowledge of the decapod fauna inhabiting mangroves associated with fringe reefs.

The present work aims to study the size vs. weight relationship and the condition factor of a commercially important crab, Callinectes danae, from an estuarine complex located at Pernambuco State, Northeastern Brazil. After sampled, the specimens were measured on their carapace width (CW; mm) and weighted on their wet weight (WW; g). A total of 1,635individuals of C. danae were analyzed, being 881 males (53.8%) and 754 females (46.2%). Males were significantly larger and heavier than females (p < 0.05), the expected pattern to many crabs. The relationship WW vs. CW, described through the potency equation, was allometrically positive for both males (b = 3.12) and females (b = 3.02), a result also observed in other swimming crabs. The mean condition factor of males was 8.0 10-5 ± 1.5 10-5, and that of females was 11.5 10-5 ± 2.8 10-5, being significantly higher in females (p < 0.05), due to the fact that female gonads are heavier than that of males. The condition factor oscillated throughout the sampling year, for both sexes, which was related to the reproductive cycle.

The aim of this study was to analyze reproductive aspects of Callinectes danae in one of the most productive estuarine systems in the Northeast Brazil, Santa Cruz Channel. A total of 1.573 individuals, being 756 females (23 ovigerous) and 817 males were examined from January to December 2009. Mature males and females, as well as couples of C. danae, occurred in all months of the year. Ovigerous females occurred in nearly all months. The reproductive activity, based on the macroscopic observation of the gonads, occurs continuously, with distinguishable peaks in February, March and September. Ovigerous females were only recorded nearest to the sea, while couples were only in the inner estuary. Thus, a migration pattern is proposed, with couples mating inside the estuary, followed by a migration of females to the area of greater marine influence for egg laying and, probably, larval release. After this, probably the females of do not return to the estuary, characterizing habitat partitioning. The present study is the first contribution on the reproductive period of C. danae in an estuarine ecosystem of the Brazilian northeast coast, and elucidates some aspects of its reproductive behavior.