First zoea ofpetrolisthes trilobatus(crustacea: Decapoda: Anomura: Porcellanidae) hatched in the laboratory

The first zoea of Petrolisthes trilobatus Osawa, 1996, from a female collected in Japan is described and illustrated. Its morphological characteristics are compared with those of other known species of the genus Petrolisthes. The first zoea of P. trilobatus appears very similar to those of P. lamarckii, P. asiaticus and P. hastatus. However, it could be distinguished from the others in having a spine on the lower posterior margin of the carapace, three pairs of setae on the postero‐dorsal surface of the telson and minute spinules on the dorsal margins of the abdominal somites 2–5. Based on zoeal morphology, it is suggested that the zoeas of Petrolisthes could be divided into two groups: the first group (P. coccineus, P. moluccensis, P. lamarckii, P. trilobatus, P. asiaticus, P. hastatus, P. pubescens, P. tomentosus, and P. carinipes) and the second one (P. ohshimai, P. armatus, P. boscii, P. tridentatus, P. tonsorius, and P. japonicus).