Larval development of Phylladiorhynchus pusillus (Henderson, 1885) (Decapoda, Anomura, Galatheidae)

Abstract

The larval development of Phylladiorhynchus pusillus is described from plankton specimens from the coast of Easter Island (27°20'S, 109°40'W). The morphological description of five zoeae and megalopae are given, comparing the meristic characters of the larvae with those of other galatheids, and the differences that allow their discrimination. The first larval stage of P. pusillus differs from the larvae described for the genus Galathea, by the slight segmentation between the basi and exopodite of the third maxilliped, in addition to the presence of four plumose setae at the distal end of the exopodite. The second zoea can also be differentiated because the number of plumose setae is maintained at the distal end of the exopodite, with two setae less than its congeners of the genus Galathea. The scientific name of the species is discussed, which is one of the two Galatheidae species from the coasts of Chile, according to Ahyong et al. (2010) classification. The most notable difference of the examined zoeae, concerning the other species, and what is described for P. integrirostris, is the slight segmentation between the exopodite and the basipodite of the third maxilliped and the presence of four plumose setae on the distal end of the exopodite.