[Morphology of the first zoea of the marine crabs Petrolisthes haigae and P. nobilii (Decapoda: Porcellanidae)].

The porcellanid crabs Petrolisthes haigae Chace 1962, and P nobilii Haig 1960, are shallow-water species distributed along the tropical Eastern Pacific shores. Larvae of both species from eight and four females, collected at Taboga and Naos Islands, respectively, were hatched in the laboratory. First zoeal stages of these species are described and illustrated for the first time and compared to previously first zoeae of other congeneric species from western Panama. Characters of the first zoeae of both species most closely agree with those Osawa's (2002) Group 4 of larvae.