The relative growth and sexual maturity of the freshwater crab Dilocarcinus pagei (Brachyura, Trichodactylidae) in the northwestern region of the state of São Paulo

The aim of the present study was to determine the size at sexual maturity in the freshwater crab Dilocarcinus pagei Stimpson, 1861, from a population located in Mendonça, state of São Paulo, Brazil. The crabs were sampled monthly (July 2005 to June 2007), at Barra Mansa reservoir. The specimens were captured manually or in sieves passed through the aquatic vegetation. The crabs were captured and separated by sex based on morphology of the pleon and on the number of pleopods. The following dimensions were measured: carapace width (CW); carapace length (CL); propodus length (PL); and abdomen width (AW). The morphological analysis of the gonads was used to identify and categorize individuals according to their stage of development. The morphological maturity was estimated based on the analysis of relative growth based on the allometric equation y = ax b. The gonadal maturity was based on the morphology of the gonads by the method CW50 which indicates the size at which 50% of the individuals in the population showed gonads morphologically mature to reproduction. The biometric relationships that best demonstrated the different patterns of growth for the juvenile and adult stages were CW vs. PL for males and CW vs. AW for females (p<0.001). Based on these relationships, the estimated value to morphological sexual maturity was 21.5 mm (CW) in males and 19.7 mm (CW) in females. The determination of the size at sexual maturity and the adjustment of the data based on the logistic curve (CW50) resulted in a size of 38.2 mm for males and 39.4 mm for females (CW). Based on the data obtained for sexual maturity for D. pagei, we can estimate a minimum size for capture of 40 mm (CW). This minimum size allows at least half of the population to reproduce and retains the juveniles and a portion of the adults in the population.

Crescimento do caranguejo de água doce, Dilocarcinus pagei Stimpson (Crustacea, Brachyura, Trichodactylidae)

A biologia de caranguejos de água doce tem sido pouco enfocada na literatura carcinológica, especialmente em relação ao crescimento das espécies da família Trichodactylidae. Este estudo visa determinar as curvas de crescimento em tamanho e peso, bem como a longevidade e a idade na muda pubertária dos caranguejos de água doce Dilocarcinus pagei Stimpson, 1861. As amostras foram obtidas mensalmente na Represa Municipal de São José do Rio Preto (São Paulo), de outubro/1994 a setembro/1996. Os indivíduos tiveram o sexo determinado, sendo também mensurados (LC = largura do cefalotórax) e pesados (PE = peso úmido). O crescimento dos indivíduos foi determinado pelo método de distribuição dos exemplares em classes de tamanho, sendo utilizado o programa FiSAT para a determinação das curvas através do ajuste não linear dos dados pelo modelo de Bertalanffy. Foram analisados 962 exemplares (534 machos e 428 fêmeas) e as curvas de crescimento em tamanho foram expressas pelas equações LC Machos = 61,7[1-e-0,97(t+0,041)] e LC Fêmeas = 57,1[1-e-1,41(t+0,031)], enquanto o crescimento em peso foi melhor representado por PE Machos = 65,2[1-e-0,97(t+0,041)]3,08 e PE Fêmeas = 44,9[1-e-1,41(t+0,031)]2,82. O tamanho assintótico dos machos (61,66 mm) foi pouco superior ao das fêmeas (57,09 mm), ocorrendo o inverso para a longevidade, estimada em 2,4 e 2,7 anos, respectivamente. O tamanho máximo estimado com base em 95% do tamanho assintótico foi de 58,6 mm para os machos e 54,2 mm para as fêmeas, valores muito próximos dos maiores tamanhos registrados na natureza para cada sexo (55,8 mm). A muda da puberdade dos machos ocorreu com idade superior à das fêmeas (tMachos = 1,2 anos e tFêmeas = 0,9 anos). Os resultados obtidos neste trabalho são inéditos na literatura carcinológica, sendo de grande valia no manejo populacional e preservação desta espécie, que vem sendo intensamente explorada e usada como isca na pesca esportiva.

Dinâmica populacional do caranguejo dulcícola Dilocarcinus pagei Stimpson, 1861 (Brachyura, Trichodactylidae), na represa da Usina Hidrelétrica de Furnas/Marimbondo, Icém, SP

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

JUVENILE DEVELOPMENT OF DILOCARCINUS PAGEI STIMPSON, 1861 (BRACHYURA, TRICHODACTYLIDAE) REARED IN THE LABORATORY, WITH EMPHASIS ON SETAE MORPHOLOGY

The juvenile development of the freshwater crab Dilocarcinus pagei Stimpson, 1861 was studied under laboratory conditions, focusing on setae morphology. The ovigerous females were collected manually associated with water hyacinth at the Municipal Dam of Sao Jose do Rio Preto (Sao Paulo, Brazil). The specimens were raised in the laboratory under constant aeration, photoperiod (12: 12 h) and temperature (27 +/- 1 degrees C). Twelve juvenile stages were obtained with descriptions of the main morphological characters that allow their identification are presented. Fourteen types of setae were discovered: dentate, denticulate, serrulate, papposerrate, cuspidate, plumose, plumodenticulate, plumoserrulate, simple, pappose, brush, curved, nail and setules. The greatest diversity of setae was found on the mouth appendages, especially the maxillule. The gill ontogeny and sexual dimorphism becomes apparent from the second juvenile stage onwards. At the third juvenile stage, the carapace begins to exhibit a wider shape, becoming similar to that of the adults.

ATP pulse and calcium homeostasis in cells from hepatopancreas of Dilocarcinus pagei, a freshwater crab

Calcium (Ca) is critical for crustaceans due to their molting cycle and its presence in the carapace as calcium carbonate, apart from the usual functions of Ca, such as cell signalling. Ca transport in Dilocarcinus pagei, a freshwater crab, was studied in isolated cells from hepatopancreas to further characterize Ca transport mechanisms in these crabs. Cells were isolated and loaded with Fluo-3, a calcium fluorescent dye. Three different cell treatments were performed: Group 1 cells were Ca free during cell dissociation, and calcium was present (at 1mM) for fluorescence cell loading and transport experiments (FC); Group 2 cells were calcium free during cell dissociation and for transport experiments, but not during cell loading (LC); and Group 3 cells were Ca free during cell dissociation, cell loading and transport experiments (WC). Intracellular Ca was recorded through time after ATP was added to the cells and ATP caused an increase in Ca efflux within 30s in all cells. WC cells showed the smallest Ca efflux compared to the other cells, probably because it was intracellularly Ca ""depleted"". Vanadate and amiloride decreased the Ca efflux when ATP was added to the cells, while verapamil did not cause any effect in Ca efflux, confirming the presence of a Ca(2+)-ATPase sensitive to vanadate in hepatopancreas of D. pagei. In a different set of experiments, cells were also exposed to a Ca pulse of 1 and 10mM during 180s. 10mM Ca increased intracellular Ca compared to 1mM, and the increase was not recovered during the experimental time. Additionally, Ca influx was reduced by verapamil and amiloride, but not completely. The results suggest that Ca influx probably occurs through an undefined exchanger, apart from Ca channels (verapamil sensitive) and electrogenic 1Na(+)(1H(+))/1 Ca(2+) exchanger (amiloride-sensitive). Similarities between freshwater and seawater crabs, lobsters and crayfish in relation to plasma membrane Ca transporters, although the environment where they live is quite diverse, suggest that universal mechanisms for Ca homeostasis are widespread among crustaceans. (C) 2010 Elsevier Inc. All rights reserved.

Análise comparativa entre a fecundidade de Dilocarcinus pagei Stimpson e Sylviocarcinus australis Magalhães & Turkay (Crustacea, Decapoda, Trichodactylidae) no Pantanal do Rio Paraguai, Porto Murtinho, Mato Grosso do Sul

The aim of this study was to estimate the fecundity of Dilocarcinus pagei Stimpson, 1861 and Sylviocarcinus australis Magalhães & Turkay, 1996, collected in the Paraguay River, Porto Murtinho County, State of Mato Grosso do Sul, Brazil, between coordinates 21º42,000'S 57º33,649'W and 21º41,449'S 57º33,770'W, in the period of April 1999 to March 2000. After general collection procedures, the specimens were measured and processed in laboratory conditions. The river water crab species hatch like juveniles and, frequently, female specimens were observed carrying eggs in different stages of development, besides juveniles and eggs at the same time. It was apparent in the frequency distributions that D. pagei has a carapace width average greater than S. australis. The number of eggs and juveniles transported varied amongst species and amongst size class. A size superposition was observed between young and adult females for both species. According to the calculated fecundity index, D. pagei presented slightly more elevated values (7.41) than S. australis (6.65). Eggs are spherical and are not adhering to pleopods. Egg size did not varied during development, continuing with 2mm diameters.

Relação peso/largura da carapaça e fator de condição em Dilocarcinus pagei Stimpson (Crustacea, Trichodactylidae), em São José do Rio Preto, São Paulo, Brasil

A biologia de caranguejos de água doce tem sido pouco enfocada na literatura carcinológica, especialmente em relação à Dilocarcinus pagei Stimpson, 1861. Este estudo visa analisar a relação peso/tamanho e variações temporais/sazonais do fator de condição, comparando com a biologia da espécie. Os exemplares foram coletados mensalmente na Represa Municipal de São José do Rio Preto (São Paulo), durante um período bianual (outubro/1994 a setembro/1996). Foram obtidos 962 espécimes (534 machos e 428 fêmeas), que foram mensurados (LC = largura do cefalotórax) e pesados (PE = peso úmido total). Os pontos empíricos da relação PE/LC foram analisados para cada sexo e submetidos à análise de regressão pela função potência (y = ax b) e representadas por: PE Machos = 0,0002LC3,º8 e PE Fêmeas = 0,0005LC2,82. O fator de condição foi calculado mensal e sazonalmente, sendo o das fêmeas cerca de 2,5 maior que o dos machos, possivelmente devido ao maior tamanho/peso das gônadas. de modo geral o verão foi caracterizado pela menor média de fator de condição (época reprodutiva), contrastando com a maior verificada no inverno (reorganização gonadal). Os resultados obtidos são enfocados pela primeira vez na literatura carcinológica, sendo de grande valia no manejo populacional e preservação desta espécie, que vem sendo intensamente explorada e usada como isca na pesca esportiva.

Population dynamics of the freshwater crab Dilocarcinus pagei in tropical waters in southeastern Brazil

In the northwestern region of the state of São Paulo, Brazil, the freshwater crab Dilocarcinus pagei Stimpson, 1861 is usually sold as bait for several fish species for sport fishing. Thus, knowledge of the reproductive biology of this species is essential to provide information for maintaining natural stocks and implementing future farming initiatives. The objective of this study was to investigate the population dynamics of the red freshwater crab D. pagei, focusing on reproductive and juvenile recruitment periods, sex ratio, and individual growth. Sampling was performed monthly from October 2005 to September 2007 in the Marimbondo-Fumas Hydroelectric Plant reservoir, Rio Grande, municipality of Icém in northwestern São Paulo state. The individuals were sexed, carapace widths were measured, and the gonads were examined macroscopically. In total, 1002 individuals were analyzed, consisting of 568 males and 434 females, of which 4 were ovigerous and 35 carried early juveniles in the incubatory chamber. The largest numbers of reproductive individuals of both sexes were recorded during the winter and spring months before spawning, which occurred in the spring. Intense juvenile recruitment and the highest rainfall levels were observed during the Southern Hemisphere summer. The results indicate that spawning can be considered seasonal, and the simultaneous emergence of juveniles with high rainfall levels is probably the result of the higher availability of food and potential sites for protection against predators. The skewed sex ratio (♂ 1:0.76 ♀) may be associated with growth rates, mortality, food restriction, behavioral differences, migration, and differential habitat use between the sexes. The similar maximum size (CW∞) and growth constant (k) for males (k = 1.78 y-1, CW = 61.43 mm) and females (k = 1.67 y-1, CW = 60.66 mm) may be associated with different energy investment strategies between the sexes. Additionally, a closed season is proposed for the species. © The Crustacean Society, 2013. Published by Brill NV, Leiden.

Influência da temperatura nas respostas aos biocidas diazinon e carbaril em Dilocarcinus pagei Stimpson, 1861

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Kinetic Analysis of Gill (Na+,K+)-ATPase Activity in Selected Ontogenetic Stages of the Amazon River Shrimp, (Decapoda, Palaemonidae): Interactions at ATP- and Cation-Binding Sites

We investigated modulation by ATP, Mg2+, Na+, K+ and NH4 (+) and inhibition by ouabain of (Na+,K+)-ATPase activity in microsomal homogenates of whole zoeae I and decapodid III (formerly zoea IX) and whole-body and gill homogenates of juvenile and adult Amazon River shrimps, . (Na+,K+)-ATPase-specific activity was increased twofold in decapodid III compared to zoea I, juveniles and adults, suggesting an important role in this ontogenetic stage. The apparent affinity for ATP ( (M) = 0.09 +/- A 0.01 mmol L-1) of the decapodid III (Na+,K+)-ATPase, about twofold greater than the other stages, further highlights this relevance. Modulation of (Na+,K+)-ATPase activity by K+ also revealed a threefold greater affinity for K+ ( (0.5) = 0.91 +/- A 0.04 mmol L-1) in decapodid III than in other stages; NH4 (+) had no modulatory effect. The affinity for Na+ ( (0.5) = 13.2 +/- A 0.6 mmol L-1) of zoea I (Na+,K+)-ATPase was fourfold less than other stages. Modulation by Na+, Mg2+ and NH4 (+) obeyed cooperative kinetics, while K+ modulation exhibited Michaelis-Menten behavior. Rates of maximal Mg2+ stimulation of ouabain-insensitive ATPase activity differed in each ontogenetic stage, suggesting that Mg2+-stimulated ATPases other than (Na+,K+)-ATPase are present. Ouabain inhibition suggests that, among the various ATPase activities present in the different stages, Na+-ATPase may be involved in the ontogeny of osmoregulation in larval The NH4 (+)-stimulated, ouabain-insensitive ATPase activity seen in zoea I and decapodid III may reflect a stage-specific means of ammonia excretion since functional gills are absent in the early larval stages.

Hemolymph ion regulation and kinetic characteristics of the gill (Na+, K+)-ATPase in the hermit crab Clibanarius vittatus (Decapoda, Anomura) acclimated to high salinity

We examine hemolymph ion regulation and the kinetic properties of a gill microsomal (Na+, K+)-ATPase from the intertidal hermit crab, Clibanarius vittatus, acclimated to 45 parts per thousand salinity for 10 days. Hemolymph osmolality is hypo-regulated (1102.5 +/- 22.1 mOsm kg(-1) H2O) at 45 parts per thousand but elevated compared to fresh-caught crabs (801.0 +/- 40.1 mOsm kg(-1) H2O). Hemolymph [Na+ (323.0 +/- 2.5 mmol L-1) and [Me2+) (34.6 +/- 1.0 mmol L-1) are hypo-regulated while [Ca2+] (22.5 +/- 0.7 mmol L-1) is hyper-regulated; [K+] is hyper-regulated in fresh-caught crabs (17.4 +/- 0.5 mmol L-1) but hypo-regulated (6.2 +/- 0.7 mmol L-1) at 45 parts per thousand. Protein expression patterns are altered in the 45 parts per thousand-acclimated crabs, although Western blot analyses reveal just a single immunoreactive band, suggesting a single (Na+, K+)-ATPase alpha-subunit isoform, distributed in different density membrane fractions. A high-affinity (Vm = 46.5 +/- 3.5 U mg(-1); K-0.5 = 7.07 +/- 0.01 mu mol L-1) and a low-affinity ATP binding site (Vm = 108.1 +/- 2.5 U mg(-1); K-0.5 = 0.11 +/- 0.3 mmol L-1), both obeying cooperative kinetics, were disclosed. Modulation of (Na+, K+)-ATPase activity by Mg2+, K+ and NH4+ also exhibits site-site interactions, but modulation by Na+ shows Michaelis-Menten kinetics. (Na+, K+)-ATPase activity is synergistically stimulated up to 45% by NH4+ plus K+. Enzyme catalytic efficiency for variable [K+] and fixed [NH4+] is 10-fold greater than for variable [NH4+] and fixed [K+]. Ouabain inhibited approximate to 80% of total ATPase activity (K-I=464.7 +/- 23.2 mu mol L-1), suggesting that ATPases other than (Na+, K+)-ATPase are present. While (Na+, K+)-ATPase activities are similar in fresh-caught (around 142 nmol Pi min(-1) mg(-1)) and 45 parts per thousand-acclimated crabs (around 154 nmol Pi min(-1) mg(-1)), ATP affinity decreases 110-fold and Na+ and K+ affinities increase 2-3-fold in 45 parts per thousand-acclimated crabs. (C) 2012 Elsevier Inc. All rights reserved.

Exotic species of freshwater decapod crustaceans in the state of São Paulo, Brazil: records and possible causes of their introduction

Based on recent surveys of the freshwater decapod fauna, distributional data of five exotic species of freshwater decapod crustaceans for the hydrographic basins of the state of São Paulo are presented, as part of a large initiative for a comprehensive survey of the state's biodiversity (BIOTA-FAPESP Program). These species are the North American crayfish Procambarus clarkii (Girard) (Cambaridae), the crab Dilocarcinus pagei Stimpson (Trichodactylidae) from the Amazon and Paraguay/lower Parana River Basins, and the palaemonid shrimps Macrobrachium rosenbergii (De Man), from the Indo-Pacific region, Macrobrachium amazonicum (Heller) and Macrobrachium jelskii (Miers), both from the Orinoco, Amazon and the Paraguay/lower Parana River Basins. Possible modes by which their introduction might have occurred are commented upon and potential consequences are discussed.

Foregut morphology of Pseudothelphusidae and Trichodactylidae (Decapoda: Brachyura) from northeastern Pará, Brazil

The gross morphology of foregut was investigated and described in detail for four freshwater crab species: a pseudothelphusid, Fredius reflexifrons (Ortmann, 1897) and three trichodactylids - Sylviocarcinus pictus (H. Milne-Edwards, 1853), Valdivia serrata White, 1847, and Dilocarcinus septemdentatus (Herbst, 1783). In general, the gastric mills of freshwater crabs showed a similar degree of complexity in relation to other marine species of Anomura and Brachyura previously described in the literature. However, significant morphological differences were observed among the analyzed species, as in ossicle numbers, features and connection types. A total of 38 ossicles were described for S. pictus and V. serrata and 37 ossicles for D. septemdentatus and F. reflexifrons, respectively. The latter species can be distinguished from the others by the presence of a wide cardiac sac resembling two sacs. Most of the ossicles were connected through a rigid connection, and few ossicles were fused. The degree of calcification varied little among the studied species. The differences found among the species suggest that the morphological aspects of the foregut may be useful in the identification of similar species.

Phylogeny of the freshwater crabs of the Western Ghats (Brachyura, Gecarcinucidae)

The Western Ghats mountain range in India is a biodiversity hotspot for a variety of organisms including a large number of endemic freshwater crab species and genera of the family Gecarcinucidae. The phylogenetic relationships of these taxa, however, have remained poorly understood. Here, we present a phylogeny that includes 90% of peninsular Indian genera based on mitochondrial 16S rRNA and nuclear histone H3 gene sequences. The subfamily Gecarcinucinae was found to be paraphyletic with members of two other subfamilies, Liotelphusinae and Parathelphusinae, nesting within. We identify a well-supported clade consisting of north Indian species and one clade comprising mostly south Indian species that inhabit the southern sky islands' of the Western Ghats. Relationships of early diverging genera, however, were resolved with low support. This study also includes newly sampled material from an isolated mountain plateau in the northern part of the Western Ghats, representing a new species of Gubernatoriana, which we describe here as Gubernatoriana basalticola sp. n. The new species is immediately distinguished from its congeners and the related genera Ghatiana and Inglethelphusa by its carapace and cheliped morphology, which are unique among Indian freshwater crabs. This study highlights the urgent need for continued faunistic studies to assess the true diversity of gecarcinucid crabs on the Indian subcontinent, to fully understand the basal phylogenetic relationships within the freshwater crab family Gecarcinucidae, and to evaluate the conservation threat status and biogeography of the montane freshwater crabs of the Western Ghats.

Los crustáceos decápodos Brachyura del litoral bonaerense (R.Argentina)

In this work the taxonomy of the Brachyura Decapod Crustacea from fthe shelfwaters of the Province of Buenos Aires, Argentina (South Atlantic Ocean) is described, with particular reference to the biology and zoogeography. The material and methods are described and various zoogeographical problems are considered. A total of 25 species were encountered, and each one is briefly described together with its ecological and biological data. In many cases the geographical distribution has been extgended. Keys are given for the identification of the more common Brachyura from Argentina, as also for the sub-divisions of the Brachyura, including ffamilies, subfamilies and genera. The so-called "cangrejal" community (community composed of semiaquatic crabs) of the river Salado was studied, which was composed of Chasmagnathus granulata crabs. The species Uca uruguayensis formed the outer limit of the "cangrejal" community.