Abstract Crabs of the Dissodactylus genus are commonly found in symbiosis with other marine invertebrate organisms. This study describes the structure of the population of the Pinnotheridae crab Dissodactylus crinitichelis living in symbiosis with the sand dollar Encope emarginata on a temporal scale and over the size class distribution, sex-ratio, recruitment defined as the specimens of the two first size classes, and breeding period. Specimens were collected in sand bottoms at the infralittoral zone at Flamengo Beach in Ubatuba, in the northeastern coast of São Paulo state, using free diving performed by one diver from August 2017 to July 2018, for 30 minutes per month. 337 juvenile, 51 adult females, and 38 adult males were analyzed, comprising 12 ovigerous females. There was registered recruitment, in almost all months. The sex ratio was 1:1.3, with more females than males in the population. In March, there was a significant recruitment period with 337 juveniles in one sample. The maximum carapace width was 6.6mm in males and 7.65mm in females. The representative number of specimens in the first size class may provide information that D. crinitichelis presents some levels of spatial segregation in the population in this area and should be monitored for preservation.

Resumo Caranguejos do gênero Dissodactylus são frequentemente reconhecidos associados a alguma relação simbionte. O objetivo aqui é apresentar algumas características populacionais do caranguejo pinoterídeo Dissodactylus crinitichelis, em associação à bolacha-da-praia Encope emarginata, em escala temporal, destacando a distribuição em classes de tamanho, proporção sexual, recrutamento e período reprodutivo. Os caranguejos foram amostrados mensalmente, no infralitoral não consolidado, na Praia do Flamengo, Ubatuba, litoral norte paulista, junto às bolachas-da-praia, durante sessões de mergulho livre, mensalmente de agosto/2017 a julho/2018, com esforço amostral de aproximadamente 30 minutos/mês, por um coletor. Foram obtidos 426 caranguejos, dos quais 337 indivíduos jovens e 89 adultos sendo 51 fêmeas e 38 machos, incluindo 12 fêmeas ovígeras. O recrutamento foi registrado em praticamente todo o período amostrado, com pico de frequência em março, com 71 jovens. A proporção sexual verificada foi 1:1.3, desviada para as fêmeas. A maior da largura da carapaça para machos e fêmeas de D. crinitichelis foi de 6,6 e 7,65 mm, respectivamente. O principal caráter da população amostrada foi a presença dominante de jovens, o que sugere a existência de segregação espacial da população amostrada em simbiose à bolacha-da-praia, o que parece estabelecer regiões preferenciais de recrutamento nessa praia, o que torna a região de grande importância para a conservação dessa espécie de caranguejo.

ABSTRACT Hermit crabs are common and abundant members of the intertidal community and in sublittoral bottoms, where they play a fundamental role in the trophic chain. This study aimed to determine the composition of the hermit crab fauna, to quantify the density in the natural environment, and to register shells use by main species from subtidal boulder fields, in an island off the southeastern Brazilian coast. Monthly samples were taken from March 2010 to February 2011 on boulder fields on Couves Island, Ubatuba, Brazil, during scuba diving daytime sessions. Three hundred and eighty-three crabs were collected by hand, in a quadrat of 20 m2 belonging to five species: Calcinus tibicen, Dardanus venosus, Pagurus brevidactylus, Paguristes tortugae, and Petrochirus diogenes. The highest densities were recorded for P. brevidactylus and P. tortugae. Hermit crabs occupied shells of 15 gastropod species. Cerithium atratum, Gemophos auritulus, and Morula nodulosa comprised more than 80% of the occupation. The heterogeneity of boulder fields of Couves Island, composed almost entirely of small refuges and crevices, favors the exploration of hermit crab species recorded here, which are characterized by small size. These results, combined with the findings of further studies, can contribute to the development of effective monitoring programs for decapod crustacean species.

Abstract Mussel farms are one of the most important modalities of aquaculture and constitute almost 80% of the total bivalve production in Brazil, representing about 5% of the national production. Brachyuran crabs are common inhabitants of these environments and represent an important link in coastal marine food chains. The aim of this investigation is to describe the population structure of Panopeus austrobesus Williams, 1983 in a Perna perna (Linnaeus, 1758) farm located at the southeastern Brazilian coast. The samplings were carried out in the northeastern coast of São Paulo State. From May 2002 to April 2003, one mussel net was recovered monthly, and all individuals of P. austrobesus were collected. Population size-frequency analysis indicated a unimodal and non-normal distribution. Males were significantly larger than females, and the overall sex ratio significantly skewed from 1:1, female-biased. Recruitment occurred during the entire period, and ovigerous females were found in 11 months. The onset of sexual maturity was estimated around 5 mm cephalothorax width. Mussel farms represent an anthropogenic intervention in the sea landscape, causing environmental changes. However, these structures must allow species introduction, increasing their ecological and geographical distribution, and provide available space and food to establish new populations. This is particularly important for species with small populations, such as P. austrobesus. The results of this study attest the environmental counterpart role of the mussel farms. Once they can support populations, they may also help to reintroduce them into the area and could therefore be used in a consortium generating economic profits and acting as bioremediation tool, assuring the maintenance of the genetic patrimony.

ABSTRACT The morphology of the first zoeal stage of Domecia acanthophora (Desbonne, in Desbonne & Schramm, 1867) was described from laboratory-hatched material obtained from ovigerous females collected at Vitória Island on the southeastern Brazilian coast. We compared the larval morphology (zoea I) of fourteen species of the superfamily Trapezioidea, which Domecia glabra Alcock, 1899 is the only congeneric representative of the species described in this study. The morphological characteristics of the first zoea that distinguish D. acanthophora from D. glabra are: three aesthetascs on the exopod antennule; three pairs of lateral spines on carapace; bilobed basial endite of maxilla, with four plumodenticulate setae on each lobe; and telson furcae distally spinulated. It also provides information that may enhance some phylogenetic hypotheses within Trapezioidea crabs.

ABSTRACTThis contribution reviews the morphology and the main diagnostic characters of the peppermint shrimp Lysmata ankeri. Individuals were sampled by scuba divers from August 2008 to June 2013 on the subtidal rocky bottom at Couves Island, on the coast of São Paulo State, Brazil. In the laboratory, the individuals were analyzed morphologically, with emphasis on the characters used in the diagnosis of the species; measured as carapace length (CL); and photographed. Seventeen individuals of L. ankeri were analyzed with an average size of 6.9 ± 2.0 mm CL. From the morphological analysis the following variations of the diagnosis were observed: five teeth on the dorsal margin of the rostrum, in the diagnosis this was 6-8; five spines on the flexor margin of the dactyli of pereiopods 2-4, in the diagnosis this was 3-4. The records of this study extend the knowledge of the variation of some morphological characteristics for this species, resulting in an overlap among the species of the Lysmata wurdemanni complex.

The spatial and seasonal distribution of different demographic groups of the swimming crab Callinectes ornatus was analyzed with respect to its population biology in three bays (Ubatumirim, Ubatuba, and Mar Virado) in southeastern Brazil. In each bay, monthly sampling was performed during two years along six transects, established at 5, 10, 15, and 20 m depth (parallel to the beach line), in a wave-sheltered area (7.5 m depth), and at an exposed site (10 m depth). Total abundance of crabs was similar among the bays. The presence of immature individuals, adult females, and breeding females was positively correlated with the bottom and surface temperatures, whereas adult males showed an opposite trend with respect to these factors. Immature and smaller individuals were most abundant along the sheltered and shallower transects. Males were more abundant along the shallower transects, and females at 15 and 20 m. This study revealed that different demographic groups occupy the habitat in different ways, according to local features. In general, southeastern Brazil offers a range of conditions that favor reproduction and consequently the maintenance and growth of the local population of C. ornatus, contributing to the relatively high abundance of the species in this coastal area.

Se analizó la distribución espacial y temporal de distintos grupos demográficos del cangrejo nadador Callinectes ornatus en cuanto a su biologia poblacional en tres bahias (Ubatumirim, Ubatuba y Mar Virado) en el sureste de Brasil. En cada bahia se realizaron muestreos mensuales durante dos años en seis transectos, establecidos a 5, 10, 15 y 20 m de profundidad (paralelo a la linea de costa), en una zona protegida del oleaje (7.5 m de profundidad) y en un sitio expuesto al oleaje (10 m de profundidad). La abundancia total de cangrejos fue similar entre bahias. Se observó una correlación positiva entre la presencia de individuos inmaduros, hembras adultas y hembras ovigeras con la temperatura del fondo y superficial, mientras que los machos adultos mostraron una tendencia opuesta con respecto a estos factores. La mayor abundancia de individuos inmaduros y pequeños fue detectada en los transectos protegidos y menos profundos. Los machos fueron más abundantes en los transectos menos profundos, y las hembras a 15 y 20 m de profundidad. Este estudio reveló que los diferentes grupos demográficos ocupan el hábitat de diferentes maneras, de acuerdo con las caracteristicas locales. En general, el sureste de Brasil ofrece diferentes condiciones que favorecen la reproducción y consecuentemente la continuidad y el crecimiento de la población local de C. ornatus, contribuyendo a la relativamente alta abundancia de la especie en esta zona costera.

In order to better understand the ecology of the different growth phases of the stone crab, Menippe nodifrons, and provide information for conservation of the natural stocks, this study describes the utilization of different biogenic substrates by this species in the intertidal zone. Sampling was carried out by hand at Ubatuba, State of Sao Paulo, Brazil. Crabs were captured among rocks or in association with three different biogenic substrates: Phragmatopoma lapidosa, Sargassum cymosum and Schizoporella unicornis. In the laboratory, the substrates were sorted and scanned for specimens of M. nodifrons, which were separated and measured at their maximum carapace width (CW), and classified as juvenile or adult specimens. Sex ratio and size distribution of crabs were analyzed for each of the substrate types. A total of 686 specimens of M. nodifrons were obtained during the sampling, ranging in size between 2.4 and 82.5 mm CW. Different mean sizes were recorded in the different substrates (P < 0.05). The high prevalence of juveniles in the samples suggests that these microhabitats are fundamental for the juvenile development of M. nodifrons, as they provide refuge, protection and probably food for juveniles.

Para comprender mejor la ecología de las diferentes fases de crecimiento de los cangrejos de piedra, Menippe nodifrons, y proporcionar información para la conservación de sus poblaciones naturales, se describe la utilización de los diferentes sustratos biogénicos, para esta especie en la zona intermareal. El muestreo se efectuó en Ubatuba, Estado de Sao Paulo, Brasil. Los cangrejos fueron capturados entre las rocas o en asociación con tres diferentes sustratos biogénicos: Phragmatopoma lapidosa, Sargassum cymosum y Schizoporella unicornis. En el laboratorio, los sustratos se clasificaron y analizaron en busca de especímenes de M. nodifrons, que fueron separados y medidos en el ancho máximo del caparazón (CW), y se clasificaron como juveniles o adultos. La proporción de sexos y la distribución de tamaño de los cangrejos se analizó para cada uno de los tipos de sustrato. Se obtuvo un total de 686 ejemplares de M. nodifrons, que variaron entre 2,4 y 82,5 mm CW. Se registraron tamaños medios significativamente diferentes en los distintos sustratos (P < 0,05). El alto número de juveniles en las muestras sugiere que estos microhábitats son fundamentales para el desarrollo juvenil de M. nodifrons, ya que proporcionan refugio, protección y, probablemente, alimentación para estos juveniles.

OBJETIVO: A biologia populacional do camarão de água doce Macrobrachium jelskii foi investigada, com ênfase na distribuição de frequência em classes de tamanho, razão sexual, período reprodutivo e recrutamento juvenil. Além disso, a abundância dos indivíduos foi correlacionada com os fatores abióticos. MÉTODOS: Amostras foram coletadas mensalmente de julho de 2005 a junho de 2007, às margens do Rio Grande, região de Planura, estado de Minas Gerais, Brasil (20º 09' S e 48º 40' W), usando uma rede de arrasto (1.0 mm tamanho da malha e 2.0 × 0.5 m de largura). O equipamento foi arrastado por duas pessoas às margens da vegetação do rio por 100 metros de distância, percorridos por uma hora. Em laboratório, os espécimes foram identificados, mensurados e sexados. RESULTADOS: Um total de 2,789 espécimes foi analisado, no qual correspondem a 1,126 machos (549 jovens e 577 adultos) e 1,663 fêmeas (1,093 jovens, 423 adultos não ovígeras e 147 ovígeras). A razão sexual diferiu significativamente a favor de fêmeas de M. jelskii (1:1.48; χ² = 103.95; p < 0.0001). A média de tamanho do comprimento da carapaça (CL) das fêmeas (6.32 ± 1.84 mm CL) foi estatisticamente maior do que dos machos (5.50 ± 1.07 mm CL) (p < 0.001). A distribuição de freqüência em classes de tamanho dos espécimes revela um padrão de distribuição unimodal e não normal para machos e fêmeas (W = 0.945; p < 0.01). Não foi observada relação entre a abundância de M. jelskii e as variáveis ambientais (p = 0.799). CONCLUSÃO: A presença de fêmeas ovígeras e jovens na população sugere um padrão de reprodução e recrutamento contínuos para M. jelskii na região de Planura.

AIM: The population biology of the freshwater shrimp Macrobrachium jelskii was investigated here emphasizing the length-frequency distribution, sex ratio, reproductive period and juvenile recruitment. In addition, the abundance of individuals was correlated with the abiotic factors. METHODS: Samples were collected on a monthly basis from July 2005 to June 2007 along the river margin in shallow water of Grande River, at Planura region, State of Minas Gerais, Brazil (20º 09' S and 48º 40' W), using a trawl net (1.0 mm mesh size, and 2.0 m × 0.5 m wide). The fishing gear was handled by two people along the marginal vegetation of the Grande River in a course of 100 m, covered for one hour. In the laboratory, the specimens were identified, measured and sexed. RESULTS: A total of 2,789 specimens was analyzed, which corresponded to 1,126 males (549 juveniles and 577 adults) and 1,663 females (1,093 juveniles, 423 adults non-ovigerous and 147 ovigerous). The sex ratio differed significantly in favor of the females of M. jelskii (1:1.48; χ² = 103.95; p < 0.0001). The mean size of carapace length (CL) of females (6.32 ± 1.84 mm CL) was statistically higher than of males (5.50 ± 1.07 mm CL) (p < 0.001). The length-frequency distribution of the specimens revealed an unimodal pattern and non-normal distribution for males and females (W = 0.945; p < 0.01). No significant relationship between the abundance of M. jelskii and the environmental variables was observed (p = 0.799). CONCLUSION: The presence of ovigerous females and juveniles in the population suggests a continuous reproduction pattern and recruitment for M. jelskii at Planura region.

The geographical distribution of marine organisms, as a result of complex natural processes through geological time, has been changed, sometimes drastically, by species introductions. Instances of species introduction have been recorded worldwide, and the Brazilian coast is no exception. The present review provides an update of the geographical distribution of members of the brachyuran subfamily Mithracinae along the Brazilian coast. Of the 30 species of this subfamily recorded from Brazilian waters, the known geographical limits of more than 17 have been extended in recent decades. The records compiled here demonstrate the great importance of the Amazon River outflow on the geographical distribution of members of Mithracinae, acting as a biogeographical barrier for some species.

O objetivo deste trabalho é identificar os itens alimentares que compõem a dieta de L. spinosa, por meio da análise do conteúdo estomacal. Os caranguejos foram coletados no litoral norte paulista (23º25’S-45º00’W). No laboratório, todos indivíduos foram dissecados, os estômagos foram retirados e fixados em formol 10%. Os itens alimentares foram identificados sob estereomicroscópio, sendo que para a análise foi utilizado o método Freqüência de Ocorrência. Foram analisados 194 estômagos, nos quais foram encontrados nove itens alimentares. A maior freqüência foi para material não identificado, ocorrendo em 98% dos estômagos analisados e Porifera foi o item com a menor freqüência, ocorrendo em menos de 1% dos estômagos. Com base nos resultados obtidos, sugere-se que o caranguejo L. spinosa apresenta uma dieta diversificada, sugerindo a utilização de diferentes métodos para a obtenção de alimento e por conseqüência podendo ocupar vários níveis na cadeia trófica.

The main goal of this study was the identification of the items of the diet of the L. spinosa, based on the stomach contents analysis. The crabs were obtained from Ubatuba region north-eastern shore of São Paulo State. In the laboratory, all the individuals were dissected, the stomach was retreated and fixed in 10% formaline. The alimentary items were identified under stereomicroscope and analysed by the method of Frequency of Occurrence. A total of 194 stomachs was analysed and nine alimentary items were obtained. Unindentified material was found in 98% of analysed stomach and poriferan were present in less then 1% of stomachs. These results pointed a diversified diet explored by this crab, as well as the employment of some different methods for food intake. This suggested that these crabs could occupy different position in the trophic chain.

Este trabalho fornece informações sobre as relações entre a maturidade sexual e o crescimento do caranguejo Goniopsis cruentata (Latreille, 1803). Durante o período de janeiro de 1995 a dezembro de 1996 foram realizadas coletas mensais na região de Ubatuba, litoral norte do Estado de São Paulo. Os animais capturados foram reunidos em quatro grupos de interesse: macho jovem, macho adulto, fêmea jovem e fêmea adulta, em que estão incluídas as ovígeras. Para cada animal foi mensurada a largura da carapaça (LC) e anotadas a condição de muda e o estágio do desenvolvimento gonadal. A maturidade fisiológica foi observada entre 21.4 e 23.7mmLC para ambos os sexos. A população amostrada apresentou atividade de muda em todas as classes de tamanho durante todo o período estudado, o que sugere o estabelecimento de um padrão de crescimento contínuo e ausência de anecdise terminal para essa espécie. Esse fato pode estar associado com a habilidade desses animais em copular durante a intermuda, gerando uma grande quantidade de indivíduos maduros durante todo o ano, garantindo a continuidade do processo reprodutivo.

This investigation provided information on the physiological sexual maturity and relationships of growth and reproduction in Goniopsis cruentata (Latreille, 1803). Collections were made monthly from January 1995 through December 1996, on the northeastern coast of São Paulo State, Brazil. The crabs were grouped into juvenile males; adult males; juvenile females, and adult females, including ovigerous ones. For each specimen the carapace width (CW) was measured, and molt condition and macroscopic developmental stage of the gonad tissue were recorded. CWs of physiologically mature crabs were between 21.4 and 23.7 mm for both sexes. This population showed molt activity in all size groups throughout the study period, which suggests continuous growth and the absence of terminal anecdysis. This may be associated with the ability of these animals to copulate during the intermolt, supplying a high proportion of mature individuals over time and ensuring continuity of reproduction year-round.

This study evaluated the influence of the water and air temperatures, pluviosity and photoperiod on the breeding season of Goniopsis cruentata (Latreille, 1803), in Ubatuba littoral, southeastern Brazilian coast. Monthly collections were conducted out from January/95 to December/96 in an estuarine area from 23º29'10"-23º29'45"S to 45º09'10"-45º10'00"W. Water and air temperature variation showed the highest correlation coefficient with the frequency of ovigerous females, r² = 0.73 and 0.68, respectively. However, an analysis of the set of environmental variables, revealed the photoperiod as the factor of highest association with the ovigerous frequency (r² = 0.68). This degree of association allow us to suggest that the breeding season duration of G. cruentata might have some variations over different latitudes, and such results could be quite diverse in populations from different latitudes.

Investigations concerning to the breeding period of brachyuran crabs provide fundamental information to determine their reproductive cycle, and also to establish management plans for species mainly in protected areas. This study provides data on the breeding period of M.forceps (A. Milne Edwards, 1875) in the southeastern Brazilian coast. Monthly samplings were carried out during a one year-round. A catch effort of approximately four hours was allocated to each monthly survey. The breeding intensity was determined based on the percentage of ovigerous crabs within the whole adult female population. A total of 137 adult females was obtained, from which 80.3% presented eggs attached on their pleopods. Ovigerous females were observed yearround, usually comprising more than 60% of sampled adult females. The ovigerous frequency was not statistically correlated to the environmental analyzed factors.