Embryonic development and duration of incubation period of tropical intertidal hermit crabs (Decapoda, Anomura)

Abstract

The description of the embryonic development of the hermit crabs Clibanarius antillensis Stimpson, 1859, C. sclopetarius (Herbst, 1796), C. vittatus (Bosc, 1802), and Pagurus criniticornis (Dana, 1852) and preliminary observations on the development of Pagurus brevidactylus (Stimpson, 1858) and Paguristes tortugae Schmitt, 1933 were done. The analysis of the external morphology of the embryos of the studied species allowed the identification of seven stages: Stage 1, Zygote and cleavage; Stage 2, Homogeneous mass (advanced cleavage and gastrulation); Stage 3, Initiation of the germinal disc (yolk-free area); Stage 4, Percentage of yolk-free area from 5% to 50-70%; Stage 5, Eye pigmentation (comma-shape) and heart beating; Stage 6, Percentage of yolk-free area from 70-80% to 95%) and eye development to a darkened irregularly-rounded shape; Stage 7, Zoea visible and hatching. Despite all stages were recorded in all species, interespecific differences were recorded in relation to zygote size and embryo color; cleavage, absolute and relative developmental time, and moment eye pigmentation appeared. Such morphological differences may be associated to variations in the yolk amount and composition and reveal different reproductive strategies at least between P. criniticornis and all studied species of Clibanarius.