Juvenile development of Dilocarcinus pagei Stimpson, 1861 (Brachyura, Trichodactylidae) reared in the laboratory, with emphasis on setae morphology

Abstract

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 São José do Rio Preto (São Paulo, Brazil). The specimens were raised in the laboratory under constant aeration, photoperiod (12 : 12 h) and temperature (27 ± 1°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.