Morphological differences among three species of newly settled pocilloporid coral recruits

Investigation of the life history of corals is hampered by an inability to identify early recruits. In this study, the pattern of formation and morphology of the juvenile skeletons of three laboratory-reared pocilloporids, Seriatopora hystrix, Stylophora pistillata and Pocillopora damicornis, were compared to determine whether they could be reliably distinguished. The pattern of skeleton formation, including the origin and structure of the septa, columella and corallite wall was similar in all species. Following the completion of the primary corallite wall after 4-5 days, these species could be identified by differences in the diameter of the primary corallite. The mean diameter (+/- SE) of each species differed markedly: S. hystrix 400 +/- 2.7 mu m, range 325-450 mu m; S. pistillata 505 +/- 3.5 mu m, range 400-550 mu m, P. damicornis; 697 +/- 7.5 mu m, range 492-885 mu m. Values for the primary corallite diameter overlapped in only 3% of samples, demonstrating the potential utility of this feature as a tool for classifying recruits obtained from the field.