SINGAPORE REEF ECHINODERMS AND THEIR ASSOCIATES WITH EMPHASIS ON CRINOIDS

Abstract

Thirty-three species of echinoderms were recorded from this survey conducted in selected reefs of Singapore: 2 from from the family Asteroidea; 15 from Crinoidea; 2 Echinoidea; 6 from Holothuroidea; and 8 from Ophiuroidea. Twenty species were new records. Four rediscoveries were made, while the rest have been previously recorded. The crinoid Comaster gracilis and the echinoid Diadema setosum are the most common echinoderms in our reefs. Raffles Lighthouse supported the richest echinoderm fauna, while the poorest was found in Cyrene patch reef. Six main groups of associates were recorded on crinoids : Crustacea (Decapoda and Copepoda); Polychaeta (Polynoidae and Myzostomidae) and Mollusca (Gastropoda). This report presents the first record of the crab Harrovia albolineata on the crinoid host Comaster gracilis and C. multifidus. Seven species of crinoids exhibit polychromatism. Comaster gracilis, Lamprometra palmata and Stephanometra indica show g reater colour variations than crinoids of reefs elsewhere.