Samara de Paiva Barros-Alves

Nutritional vulnerability in early stages of the freshwater ornamental “red cherry shrimp” Neocaridina davidi(Bouvier, 1904) (Caridea: Atyidae)

This study evaluated the starvation resistance of the shrimp, Neocaridina davidi during the first and the third juvenile stages (named here as JI and JIII) by means of the estimation of point-of-no-return (PNR50). Two experiments were conducted with increasing numbers of days without food and two controls (one with continuous feeding, CF; the other, with continuous starvation, CS). Time to the first molt and number of molts did not differ among the treatments beginning at JI or JIII. Nevertheless, longer periods of starvation influenced growth and survival of juveniles beginning the starvation as JI, but these effects were not observed in JIII. The estimated values of PNR50 for JI and JIII were 16.15 ± 0.31 and 9.44 ± 0.26 days, respectively. The early stages of the life cycle are more tolerant to starvation than other decapods previously studied. Such ability indicates a great potential of this species for aquaculture.

Onset of sexual maturity and relative growth of the freshwater crab Trichodactylus fluviatilis (Trichodactyloidea) in south-eastern Brazil

The main purpose of this study was to provide an estimate for the onset of morphological sexual maturity in the freshwater crab Trichodactylus fluviatilis, from a population located in south-eastern Brazil, based on the relative growth relationships, as well as the characterization of “handedness”. Monthly collections were carried out at night, from January 2006 to January 2007, in a small water body. In the laboratory, the crabs were sexed; the following body structures were measured and the estimate of onset of sexual maturity was given by the logistic function, as y = a/(1 + be − cx ), for 50% of the population to reach the adult phase (CW50carapace width). Right propodus length and abdomen width were the best-fit relationships to represent the onset of sexual maturity for males and females, respectively. Based on the logistic function, the onset of sexual maturity was estimated to occur at around 18 mm CW for both sexes. The relative growth recorded for this species is consistent with the model for brachyuran crabs (Hartnoll RG. 1982, Growth. In: Bliss, DE, editor. The biology of Crustacea: embryology, morphology and genetics. New York: Academic Press. p. 111–196), except for the abdomen growth, which is likely to be an adaptive condition related to protection of the newly hatched young.

Checklist of the brachyuran crabs (Crustacea: Decapoda) in the rocky subtidal of Vitória Archipelago, southeast coast of Brazil

Biodiversity can be useful as an ecosystem indicator for conservation and monitoring, through continuous assessment of its main properties including stability, primary productivity, exploitation tolerance and even global environmental changes. The main purpose of this study was to provide a checklist of the crabs associated with subtidal rocky bottoms at the Vitoria Archipelago, southeastern Brazilian coast. Monthly collections were carried out from February 2004 through January 2006 on three islands at the Vitoria Archipelago (23°44’S-45°01’W). The crabs were hand-caught by SCUBA divers during the daytime, in rock subtidal. A total of 3084 individuals were caught, belonging to 42 species, 28 genera, and 12 families, highlighting Mithraculus forceps (1528) and Stenorhynchus seticornis (407) representing more than 60% of the sample. On the other hand, Dromia erythropus , Moreiradromia antilensis , Ebalia stimpsoni , Garthiope spinipes and Tumidotheres maculatus had only one individual sampled.

Comparison of the population biology of Epialtus bituberculatus from two rocky shores with distinct hydrodynamic patterns

Departamento de Zoologia Instituto de Biociencias Universidade Estadual Paulista-UNESP, Distrito de Rubiao Junior, s/n, CEP: 18618-970, Botucatu, Sao Paulo

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.

Mithracinae (Decapoda: Brachyura) from the Brazilian coast: review of the geographical distribution and comments on the biogeography of the group

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.

Nutritional vulnerability in zoeal stages of the yellowline arrow crab Stenorhynchus seticornis (Brachyura: Majoidea)

Knowledge of the critical points in larval stages is essential to evaluate the physiological state of the larvae in their natural environment. This study investigated the nutritional vulnerability index (NVI) of the first (ZI) and second (ZII) zoeal stages of Stenorhynchus seticornis. Zoeae were assigned to two experiments: (1) point of no return (PNR), consisting of treatments with increasing days of starvation and subsequent days of feeding; and (2) point of reserve saturation (PRS), consisting of treatments with increasing days of feeding and subsequent days of starvation. There were two control groups: continuous starvation (CS) and continuous feeding (CF). Mortality was used to estimate the time when 50% of initially starved larvae (PNR50) lost the ability to moult to the next stage and when 50% of initially fed larvae (PRS50) were capable of moulting to the next stage. The mean (±s.d.) development time of ZI and ZII under CF was 4.4±1.2 and 5.1±1.8 days respectively. Mortality in the CF groups was 30 and 52% for ZI and ZII respectively. For ZI, PNR50 and PRS50 were 1.0±0.0 and 2.1±1.0 days respectively. The estimated NVI for ZI was 2.2, which indicates that S. seticornis depends on exogenous food and is considered planktotrophic during the first larval stage.

Reproductive output of the ornamental shrimp Lysmata vittata (Stimpson, 1860) (Decapoda: Caridea) in wild populations and under different maturation diets

ABSTRACT Reproductive output parameters (fecundity and egg volume) of Lysmata vittata were examined in a population in northeastern Brazil. Effect of maturation diets on the reproductive output of these shrimp under laboratory conditions was evaluated. Reproductive output was estimated for 25 shrimp collected in the wild. Another 45 pairs of shrimp were used for diet experiments, 15 pairs per treatment (T1: industrialized food, T2: fresh food, T3: mixed diets). For wild population, mean fecundity and egg volume were differed between developmental stages of the eggs. Fecundity was significantly lower in the specimens subjected to T1 diet (267 ± 141 eggs) compared with shrimp from the wild population (393 ± 183 eggs). Egg volume was significantly lower in shrimp subjected to three diets tested compared with those from wild population. Egg loss during embryonic development in L. vittata may be caused by several factors (e.g. aborted development and maternal cannibalism). Fresh food proved to be important for improving reproductive output in L. vittata reared in culture. We emphasize the significance of improving nutritional value and palatability of diets to improve cultivation efficiency. Lysmata vittata can be used as a model organism for future studies aiming to improve the cultivation techniques for shrimp of the genus. Abbreviations PSH: protandric simultaneous hermaphroditism; ARS: artificial refuge structures; CL: carapace length; EV: egg volume; L: largest diameter of the egg; S: smallest diameter of the egg; T1: industrialized pellets; T2: fresh ingredients; T3: mixed diets; ANCOVA: analysis of covariancr; SD: standard deviation.