The four zoeal and one megalopal stages of the wharf crab Armases benedicti (Rathbun, 1897) larvae reared in the laboratory are described and illustrated in detail. The mean duration for each larval stage was 3, 2, 4, 4 and 13 days, respectively. The duration of the larval period from hatching to the first juvenile was 26 days. Morphologically, A. benedicti is very similar to the reported species of genus. However, a small lateral spine is clearly observed in the carapace of zoeal stages of this species. This feature appears to be unique among the family Sesarmidae. Another distinctive character for this species is the zoeal setation of the maxilla endopod (2+2) in which most of the sesarmids have setation (2+3) except for Sesarma tetragonum (Fabricius, 1798). Other comparisons with previous larval studies of the genus Armases Abele, 1992 are briefly discussed.
Caeté estuary; larval morphology; sesarmid
