Gustavo Luis Hirose

FIRST ZOEAL STAGE AND MEGALOPA OF UCA (UCA) MARACOANI (DECAPODA: BRACHYURA), WITH COMMENTS ON THE LARVAL MORPHOLOGY OF SOUTH-AMERICAN SPECIES OF OCYPODIDAE

Abstract On the Brazilian coast, ten species of fiddler crabs occur in the estuaries and mangrove systems. The larval development of only five of these species is completely known. Here we describe the first zoeal stage and megalopa of Uca (Uca s. str.) maracoani. Ovigerous females and megalopae were obtained at Jabaquara Beach, Paraty, state of Rio de Janeiro, Brazil. The first zoeal stage was obtained from ovigerous females in the laboratory, and the megalopae directly from the field. Both zoeae and megalopae were raised in laboratory conditions. The megalopae survived until the eighth juvenile stage, when they could be identified to species. The larval morphology was analyzed and compared with the species already known for the Brazilian coast, and some other species, such as the southeast Atlantic fiddler crab, Uca tangeri. The comparison showed that U. maracoani has some characteristics that are more similar to U. tangeri than the previously studied species from the Brazilian coast. This is the first description of the zoea and megalopa morphology of a member of the genus Uca from the southwest Atlantic, of which the adult has a narrow front sensu Crane (1975), and it is helpful for taxonomic, systematic and ecological purposes.

The megalopa and early juvenile development of Hepatus pudibundus (Crustacea: Brachyura: Aethroidea) reared from neuston samples

Hepatus pudibundus (Herbst, 1785) is a crab commonly found in shallow waters of the Western Atlantic. Its larval and early post-larval morphology have already been described from laboratory hatched material. Around 200 megalopae of H. pudibundus were collected in neuston samples from the Ubatuba region, Brazil, during the summer of 2005-2006 and were successfully reared under laboratory conditions. The size of the megalopae obtained in the neuston was similar to those specimens previously described in the literature, except that the juvenile crab stages reared in the laboratory were slightly larger, probably due to the better feeding conditions in the laboratory. The duration of the juvenile stages was shorter in the present study than in previous attempts at laboratory rearing, even if conditions appeared to be similar. The main differences observed between studies were in megalopal morphology, which may be attributable to intraspecific variation but, possibly, also due to differences in levels of detail than previously performed.

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.