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 morpho logy of the juvenile skeletons of three laboratory-reared pocilloporids, Se riatopora hystrix, Stylophora pistillata and Pocillopora damicornis, were c ompared to determine whether they could be reliably distinguished. The patt ern of skeleton formation, including the origin and structure of the septa, columella and corallite wall was similar in all species. Following the com pletion of the primary corallite wall after 4-5 days, these species could b e identified by differences in the diameter of the primary corallite. The m ean 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 400-55 0 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 o btained from the field.