Red mangrove crab Ucides occidentalis (Ortmann, 1987) (Brachyura: Ocypodidae): complete embryonic development under laboratory conditions

Abstract

The red crab Ucides occidentalis (locally called "guariche") is widely distributed along Ecuador's coastline and is the most important crustacean fishery exploited by local coastal communities. However, a lack of information on the species' reproductive cycle has hindered conservation and sustainable management initiatives. Here we documented for the first time the complete embryonic development of U. occidentalis, based on its morphological traits. Thirteen ovigerous females were collected in the field, maintained in captivity, and fed with leaves and tender mangrove propagules. Egg samples were taken every 12 h and analyzed under the microscope to evaluate embryonic development. U. occidentalis eggs had eight different embryonic stages, which maintained their spherical shape during the entire developmental. The eggs were relatively small and uniform in size. The tenuous heart beating of the precursor coincided with the formation of chromatophores in stage V and became more frequent at stage VIII, just before hatching. The incubation period lasted 15 days. Despite the rapid development, the increase in egg size and volume was not uniform during sequential stages.