Taxonomy, Ecology and Physiology of the Geographically Restricted Scleractinian Species Ctenella chagius Matthai

The scleractinian coral Ctenella chagius is unusual in having a very restricted geographical range (Chagos Archipelago, Indian Ocean) and for being the only extant Indo-Pacific member of the family Meandrinidae. Several aspects of its biology were examined including its depth distribution, population structures, competitive ability, and rates of photosynthesis and calcification. In all these aspects the species falls well within ranges exhibited by the majority of coral species. No abnormalities were found which could account for its limited range. Although it is amongst the 25 commonest coral species in Chagos (out of 200) its taxonomic position suggests that it is a relict population.