New Habitat Report for Maldivia trunguiculata (Borradaile) (Brachyura, Xanthidae), a Facultative Symbiont of Porites lobata Dana in Hawaii

Maldivia triunguiculata (Borradaile), a xanthid crab, lives within chambers in the skeletons oflive Porites lobata corals. The chamber openings are readily recognizable on the live surfaces of P. lobata heads, and chambers penetrate into coral skeletons up to 5.5 cm. Crabs inhabited an average of 85 percent of the chambers investigated. Occupied chambers contained males or females, but never more than one crab per chamber. Areal density of M. triunguiculata on P. lobata increased with increasing coverage of the reef by the live coral, indicating a strong association between the two species. Although M. triunguiculata may occur on dead coral reef, this study indicates that it is more frequently found in live P. lobata