Plasticity of growth rates and sizes at sexual maturity in different populations of the fiddler crab Minuca vocator (Herbst, 1804) within the same latitudinal range.

The growth rates and size at maturity of decapod crustaceans usually vary throughout latitudes. Here, we evaluated whether these life history traits can be stable within the same latitude range, where some environmental factors are constant, especially temperature. To this end, we estimated and compared the growth rates and size at sexual maturity of three populations of the fiddler crab Minuca vocator, located at latitude 23° S, in mangroves of the subtropical Brazilian coast. Variations in the growth rate of the abdominal width of females and of the propodus of the major cheliped of males were assessed by the allometric technique. The abdomen growth rates of females and the cheliped growth rates of males varied among the three populations, resulting in different sizes at maturity. These results do not support our prediction that growth rates and size at sexual maturity would remain stable in populations of the same latitude range. The differences in these life history traits could be a consequence of contrasting local conditions among mangroves. Therefore, we suggest that these crabs show plasticity and responsiveness to local-scale environmental variations, to optimize the energy allocation for maintenance, reproduction, and somatic growth.

Juvenile development of Callinectes danae Smith, 1869 (Crustacea, Decapoda, Brachyura, Portunidae) under laboratory conditions.

The juvenile development of Callinectes danae was investigated from megalopae obtained in neuston samples at Ubatuba, São Paulo, Brazil. The individuals were raised in the laboratory under constant temperature (25 ± 1°C), filtered sea water from the collection location (35‰), and natural photoperiod. Newly hatched Artemia sp. nauplii were offered as food on a daily basis and ornamental-fish food was also provided for the juveniles from the 4th stage on. Twelve stages of the juvenile phase were obtained. The main morphological features that allowed recognition of the first juvenile stage were drawn and described. All the subsequent stages obtained were examined and measured, and the main changes in relation to the first stage were recorded. Sexual dimorphism becomes apparent from the fourth juvenile stage onwards. Some appendages and morphological features proved to be of great importance in the identification of species, including the number of segments of the antennal flagellum and the number of setae on the maxilla and on the 1st, 2nd and 3rd maxillipeds. These can probably be used for future comparisons and species identifications.

Brachyuran and anomuran crabs associated with Schizoporella unicornis (Ectoprocta, Cheilostomata) from southeastern Brazil.

The main goals of this investigation were to describe the community structure of anomuran and brachyuran crabs inhabiting reefs constituted by colonies of Schizoporella unicornis, and to provide a species importance ranking for this community. Collections were carried out on S. unicornis reefs at two-month intervals from May 2003 to May 2004, in the rocky sublittoral of the southeastern Brazilian coast. Relative abundance and occurrence were used to rank these species in the hierarchy importance. A total of 2,018 individuals were obtained, in 11 families, 22 genera and 31 species. Porcellanidae and Pilumnidae were the most abundant families, comprising respectively almost 60% and 15% of individuals sampled. The species ranking indicated four main groups A, B, C and D, with group A subdivided. Subgroup A1 contained 9 species, including the species of greatest ecological importance for community regarding abundance and occurrence. The great abundance of crabs associated with S. unicornis seems to be the result of its recognized importance during the crab developmental cycle, and as shelter and food for some Decapod species. These observations reveal the importance of conserving the areas occupied by these reef colonies, which appear to be an important environment for maintaining local biodiversity.

First zoeal stage of ?Cataleptodius parvulus (Fabricius, 1793) and Xanthodius denticulatus (White, 1848) (Decapoda: Brachyura): larval evidences and systematic position.

The first zoeal stages of ?Cataleptodius parvulus and Xanthodius denticulatus are described and compared with zoeae of other members of the subfamily Xanthinae. The larvae of ?C. parvulus and X. denticulatus differ mainly in: 1) spinulation of rostral and dorsal spines; 2) type of antenna; 3) setation of the basis of first maxilliped; and 4) type of telson. Features common to both species include a carapace provided with well-developed spines on the dorsal (1), rostral (1), and lateral (2) portions; and the antennal protopod and rostrum similar in length. The morphological differences between the zoea I of X. denticulatus and ?C. parvulus are nevertheless consistent enough to suggest that these species do not belong to the same genus Xanthodius Stimpson, 1859 as previously supposed. Also we presume that ?C. parvulus does not belong to the genus Cataleptodius.

Environmental factors modulated the fatty acid profile of the shrimp Xiphopenaeus spp. in Cananéia and Ubatuba southeast Brazilian coast.

Environmental characteristics influence the fatty acids (FAs) of aquatic organisms. Environmental factors and anthropic actions such as water pollution can impact FA composition. This directly affects the trophic network, especially when low-quality FA is provided to other trophic levels. The omnivore Penaeoidea shrimp is rich in proteins and polyunsaturated fatty acids (PUFA), representing an important node in the trophic web. We compared the FA composition of the commercially exploited seabob shrimp Xiphopenaeus spp. in two distinct coastal sites, Cananéia and Ubatuba, on the southeast Brazilian coast. Cananéia has a low human population density and is a preserved area with nearby mangroves, while Ubatuba is highly urbanised and influenced by tourism (increasing the domestic sewage), with diverse microhabitats but without mangrove influence. We found a total of 29 different FAs in seabob shrimp samples. Saturated FAs and PUFAS were the most representatives. For sex or age (juvenile and adult), deviations were found in the monosaturated FA, ω6, and ω3/ω6. However, FA composition was significantly different between sites, with Ubatuba presenting a lower abundance of FAs than Cananéia. The fatty acid composition of Xiphopenaeus spp. was influenced by environmental quality factors such as dissolved oxygen, chlorophyll, organic matter, and size gradient. The presence of high amounts of organic matter (especially sewage) during decomposition can decrease dissolved oxygen levels, reducing the quality of the first producers and limiting the availability of FAs for other trophic levels. The study suggests that water pollution and mangrove forests can impact the FAs of Xiphopenaeus spp., potentially reducing their nutritional value and causing an imbalance in the transference of FAs.

Juvenile morphology of the ornamental crab Mithraculus forceps A. Milne-Edwards, 1875 (Crustacea, Brachyura).

The morphology of juveniles of Mithraculus forceps A. Milne-Edwards, 1875, raised in the laboratory, is described. The larvae were obtained from ovigerous females collected in the wild, maintained in the rearing system for culture of crabs (400 L). A total of 229 larvae (zoea I), from 7 females were distributed in lots of 20 larvae kept in glass flasks (500 ml), with seawater circulation and temperature and salinity constants, which were checked daily for molts or deaths. After the larvae reached the juvenile stage, exuviae and dead specimens were deposited in a scientific collection. We analyzed the external morphology (N = 10 ind.) of each size class (total = 8). We determined the number of size classes, based on carapace width CW vs. carapace length CL (mm) and its dispersion points, in which we can observe non-hierarchical groupings with no size classes overlapping. We analyzed the relative growth of the juveniles using the technique "Standard Major Axis'' (Type II regression). The relationships CW vs. CL and CW vs. AW showed negative allometry (b < 1; p < 0.05). The relationships CW vs. CPH and CW vs. CPL are isometric (b = 1; p > 0.05). The most remarkable morphological characters of the juveniles (first size class) are the following: spines at the anterior margin of the carapace, inner marginal teeth in the propodus and dactylus of the chelipeds, number of articles in the antennular endopod and the maxillular endopod, absence of setae on the maxillar endopod, and absence of rudimentary pleopods.

Ontogenetic niche specialization of the spider crab Libinia ferreirae associated with the medusa Lychnorhiza lucerna.

Symbiotic relationships in marine environments are not fixed and can change throughout the animal's life. This study investigated the ontogeny of symbiosis of the spider crab Libinia ferreirae with the host medusa Lychnorhiza lucerna. We described the type of relationship, the temporal correlation among species, and food habits. More than 50% of the sampled crabs were symbionts, most in early life stages. The highest number of crabs found in a single medusa was 11. Symbiosis was observed throughout most of the year but was more evident in warm periods. The crab has many benefits in this relationship with a medusa. One is the use of food resources captured by the medusa, primarily copepods. Because the crab steals the medusa's food, it is a kleptoparasitic relationship. There is a niche partition between symbiont and the free-living crabs as they occupy different habitats and use nonoverlapping food resources. Previous research reported that symbiosis first developed during the crab's last larval phase (megalopa) when crab and medusa are in the same habitat. Observation of the crab's behavior shows that symbiosis occurs when the crab can grab to the medusa when the host touches the sea bottom. The crab also took advantage of water currents, releasing itself from the substrate and then drifting toward the medusa. The symbiotic relationship that crabs have with the medusa provides then with a nursery, food resources, shelter, dispersion, and decreased competition with free-living adult crabs, all essential for the crab's survival.

Is Potimirim potimirim (Crustacea, Decapoda, Atyidae) a protandric hermaphrodite species? Behavioral and morphological aspects of the reproductive system.

We evaluated the mating behavior of Potimirim potimirim in the laboratory based on the assumption that this caridean might be hermaphroditic. We also performed histology and scanning electron microscopy analyses of the reproductive system of females, males, and differentiated individuals. The mating experiments produced three behavioral stages, namely, interaction, lateral positioning, and copulation (which did not necessarily occur in this sequence). The hypothesis of a random pure searching mating was corroborated by the lack of male courtship, postcopulatory guarding, and the high aggregation of individuals. Three macroscopic ovarian stages were recorded in adult females: rudimentary, developing and mature. Secondary vitellogenesis begins at the developing stage, producing mature yolk. The male reproductive system is formed by testes and the vasa deferentia (VD), that is divided into three regions: proximal, middle, and distal. The proximal VD has a typhlosole that produces a thin layer of type II secretion around the central spermatozoa mass immersed in a type I secretion. External and adherent type III secretion is produced from the MVD to DVD, and both compound the primordial spermatophore. Potimirim potimirim has a gonochoric reproductive system and mating behavior and its sexual system does not fit into any of the previously described protandric systems.

Trophic relationships between the crab Libinia ferreirae and its symbionts.

Symbioses are ubiquitous in the animal kingdom. However, in most cases, the role of each member is relatively fixed, and it is rare for the same species to exhibit different symbiotic behaviours throughout its ontogeny. Here, we use stable isotope analyses of food resources to identify the relationships between the spider crab Libinia ferreirae as a symbiont of its jellyfish host during juvenile life stages and as a host for sea anemone epibionts on its carapace as an adult. We ask the following questions: How do the food sources used by the crab change between its juvenile and adult phase? How does the symbiotic relationship change when the crab develops from a juvenile into an adult? We were particularly interested in the extent to which L. ferreirae juveniles feed on jellyfish hosts versus planktonic prey during the juvenile symbiont phase and how adults feed on their epibionts during the free-living phase. δ13C of L. ferreirae differed between juvenile (associated with the jellyfish) and adult stages (free-living), unsurprisingly suggesting that there is little isotopic niche overlap between these life phases. SIMMr models using δ13C and δ15N of the crab and its potential food sources indicated that the juvenile crab symbionts did not derive any significant nutrition from medusae and relied predominantly on zooplankton prey. Since juvenile crabs do not have structures to capture zooplankton for feeding, we suggest that they may be kleptoparasites, stealing zooplankton food from their host, though further work is needed to identify the form that such a symbiosis might take. The nutrition of free-living crabs was predominantly derived from benthic algae and shrimps rather than from epibionts. These epibionts appear to use similar food resources as the host, suggesting a symbiotic relationship more akin to mutualism. Thus, the crabs move from a symbiosis in which they may act as parasites to one where they act as hosts. Such flexible approaches to symbioses may be more common than currently described, particularly in species with different functional roles during individual life stages.

Description of the newly-hatched juvenile of Aegla castro Schmitt, 1942 (Crustacea, Anomura, Aeglidae).

This study describes and illustrates the morphology of the first juvenile stage of Aegla castro Schmitt, 1942. Ovigerous females were collected from May to July 2013, in Couro River (Mauá da Serra, Paraná, Brazil). These females were kept individually under controlled feeding, aeration, water temperature and quality and checked daily for hatching of juveniles. The newly-hatched juveniles were fixed in alcohol series and kept in 70% alcohol with glycerin in a 2:1 ratio prior to study under light microscopy. The newly-hatched juvenile of A. castro is the largest among aeglid species whose juveniles have been described. Aegla castro has asynchronous hatching. Some specimens were analyzed using scanning electron microscopy, revealing details of the setal morphology, some cephalothoracic appendages and lineae aeglicae. The number of setae in newly-hatched A. castro is lower than that described for other species, but does not appear to be diagnostic. However, A. castro is the only species described that combines the presence of four plumose setae on the third maxilliped exopod and 63-65 plumose setae on the maxilla exopod.

Population structure of the red mangrove crab, Goniopsis cruentata (Decapoda: Grapsidae) under different fishery impacts: Implications for resource management / Estructura de la población del cangrejo rojo de manglar, Goniopsis cruentata (Decapoda: Grapsidae) bajo diferentes impactos de pesca: Implicaciones para la gestión de los recursos

The red mangrove crab, Goniopsis cruentata, influences the recruitment and composition of plant species in the mangrove ecosystem and it is an important fishery resource. Nevertheless, no current management and conservation plans are available for this species for the Brazilian coast. This investigation evaluated the population structure and reproductive biology in populations of G. cruentata under contrasting fishery pressures. The sampling program was carried out in two mangroves, Vaza-Barris and Sergipe River, from January through December 2011. Crabs from both mangroves were randomly collected by a professional fisherman during daytime low tide periods, using a fishing rod baited with pieces of a locally abundant gastropod, Pugilina morio, during 20min/area (catch per unit effort). Monthly measurements of air, sediment surface layer and water temperatures were obtained with a digital thermometer and salinity with an optical refractometer. Both crab populations were compared concerning their abundance, body size, sex ratio, size at onset of sexual maturity and fecundity (FI). Abiotic factors (air, water and mud temperature; and salinity) showed no significant differences between sampling localities. A total of 4 370 crabs were sampled, 2 829 from the Sergipe River and 1 541 from the Vaza-Barris River. The abundance and body size of crabs were compared between mangroves, and statistically significant differences were found. The sex ratio for both populations differed from the expected 1:1 ratio, and a significant deviation in favor of juvenile males was obtained, while adults showed a bias toward females. The estimated size at onset of sexual maturity for both sexes was similar in both populations. However, the populations differed significantly in the number and volume of eggs: a higher FI was obtained in females from the Sergipe River, while a higher egg volume was observed in females from the Vaza-Barris River mangrove. These results indicated a tendency to decrease the body size, the abundance of crabs and the reproductive potential of the species, with higher fishing intensities, reinforcing the need to develop a management plan as well as to establish conservation units for G. cruentata in the Northeastern Brazilian coast. Habitat loss in conjunction with long-term overfishing can have irreversible consequences, which can impact not only the populations of commercially exploited crabs, but the dynamics of virtually the entire mangrove ecosystem.

El cangrejo rojo Goniopsis cruentata influye en el reclutamiento y la composición de especies vegetales del ecosistema manglar y es un importante recurso pesquero. Sin embargo hasta la fecha, no se han desarrollado planes de manejo y conservación para esta especie en Brasil. La presente investigación evaluó la estructura poblacional y la biología reproductiva de las poblaciones de G. cruentata expuestas a diferentes presiones de pesca. El muestreo se realizó en dos manglares, Río Sergipe y Río Vaza-Barris entre enero y diciembre 2011. En ambos manglares, los animales fueron recolectados de día durante la marea baja por un pescador profesional, utilizando una caña de pescar con carnada del gasterópodo Pugilina morio, durante 20min/área (captura por unidad de esfuerzo, CPUE). Mensualmente con un termómetro digital se registró la temperatura del aire, agua y capa superficial del sedimento, mientras que la salinidad fue cuantificada utilizando un refractómetro óptico. Las poblaciones fueron comparadas en su abundancia, tamaño corporal, proporción de sexos, talla de primera madurez sexual y fecundidad. Los factores abióticos(temperatura del aire, agua y sedimento y la salinidad) no mostraron diferencias significativas entre ambos sitios de muestreo. Se recolectaron un total de 4 370 cangrejos; 2 829 en el río Sergipe y 1 541 en Vaza-Barris. Se registraron diferencias significativas entre los manglares con respecto a la abundancia y el tamaño corporal de los animales. La proporción de sexos de ambas poblaciones difirió de la relación 1:1 esperada y se obtuvo una desviación significativa en favor de machos jóvenes, mientras que los adultos mostraron una tendencia hacia las hembras. A su vez, las poblaciones difirieron significativamente en el número de huevos, con un mayor IF para las hembras del manglar del río Sergipe. El volumen de los huevos también mostró diferencias significativas entre ambas poblaciones. Estos resultados indican que la alta intensidad de pesca podría estar afectando dichos parámetros, lo que refuerza la necesidad de desarrollar un plan de manejo y la creación de unidades de conservación para G. cruentata en la costa noreste de Brasil. La pérdida del hábitat junto con la sobrepesca a largo plazo, pueden tener consecuencias irreversibles, que afectan no sólo a las poblaciones de cangrejos de importancia comercial, sino también la dinámica del ecosistema de manglar.

Physiologic sexual maturity of the fiddler crab Uca rapax ( Smith, 1870 ) ( Crustacea, Ocypodidae ) from two mangroves in Ubatuba, Brazil

A determinação do tamanho em que os caranguejos atingem sua maturidade sexual é um importante instrumento em estudos da dinâmica populacional e na determinação do potencial reprodutivo de uma espécie. O objetivo deste estudo foi analisar aspectos fisiológicos como o desenvolvimento gonadal para a determinação do tamanho na primeira maturação de Uca rapax. Os caranguejos foram coletados durante um ano (abril de 2001 a março de 2002) nos manguezais de Itamambuca e Ubatumirim, Ubatuba, SP. Os exemplares capturados foram mensurados quanto à largura da carapaça e o sexo e os estágios de desenvolvimento gonadal registrados. Os caranguejos com gônadas imaturas e rudimentares foram considerados jovens e os caranguejos nos demais estágios gonadais foram classificados como adultos. Os exemplares foram separados em 10 classes de tamanhos, sendo que para cada classe foram obtidas as freqüências de caranguejos jovens e adultos. A determinação da maturidade sexual foi obtida através de equação logística e o ajuste desta equação foi efetuado pelo método dos mínimos quadrados. O tamanho da largura da carapaça no qual 50% da população de Uca rapax foi considerada madura foi de 14,8 mm para machos e 12,1 mm de LC para fêmeas em Itamambuca e 13,6 mm para machos e 11,4 mm de LC para fêmeas provenientes do manguezal de Ubatumirim. O fato dos machos maturarem com tamanhos superiores ao das fêmeas, deve-se ao maior investimento em crescimento somático por parte desse sexo, sendo que as fêmeas investem mais em processos reprodutivos.

Reproductive pattern comparison of Uca thayeri Rathbun, 1900 and U. uruguayensis Nobili, 1901 ( Crustacea, Decapoda, Ocypodidae )

Fêmeas ovígeras de U. thayeri e de U. uruguayensis foram utilizadas para se avaliar e comparar o padrão reprodutivo. O tamanho médio das fêmeas foi de 6,6 ± 0,8mm para U. uruguayensis, variando de 17,3 ± 4,4mm para U. thayeri. A fecundidade média obtida para U. uruguayensis foi 1883 ± 490 ovos (N = 27) e para U. thayeri de 31068 ± 11185 ovos (N = 31). As diferenças observadas no padrão reprodutivo de U. thayeri e U. uruguayensis sugerem estratégias adaptativas: U. thayeri apresenta uma reprodução sazonal, com atividade pronunciada de janeiro a março e alta fecundidade, enquanto U. uruguayensis reproduz-se continuamente, mas com proles menores.