Larval stages of Macrobrachium australe (Guerin Meneville, 1838) (Decapoda: Palaemonidae), described from laboratory-reared material

Abstract

The larval development of the freshwater prawn, Macrobrachium australe (Guerin Meneville, 1838) is described and illustrated from laboratory-reared material. Although all larvae died before attaining the decapodid stage, thirteen zoeal stages were recognized. Morphological comparisons between the thirteenth zoea of M. australe and the last zoeal stages ofM. carcinus and M. rosenbergii indicate that M. australe possibly has at least one more zoeal stage before metamorphosis. The morphology of the first zoea ofM. australe is also compared with that of 7 other Japanese species. The present species most closely agrees with that of M. grandimanus, but it differs from the latter by the setation of the mandibles, maxillule, and second and third maxillipeds. Zoeas of M. australe survived for nearly 150 days, and presumably did not have a suitable settlement environment. This extended larval period may be one important factor explaining why this species is ubiquitously distributed throughout the Indo-Pacific region.