Diversity of the Holothuroid Fauna (Echinodermata) at La Réunion (Western Indian Ocean)

Abstract

Echinoderms are conspicuous components of the tropical fauna and play important roles in the functioning of coral reefs. However, their diversity is not as well documented as that of other conspicuous reef organisms such as corals or fish. We review current knowledge of the diversity of the class Holothuroidea at La Réunion. Several recent initiatives that include MASMA (Conand & Muthiga 2007) and BIOTAS projects have considerably augmented the number of species recorded for the island. As a result of these surveys, the recorded holothuroid fauna has doubled. Thirty-seven species are presently recognized, 18 of which are new records for the island. The order Aspidochirotida, which includes the largest and most conspicuous holothuroids, is the most diverse, with 28 species. Seven species of Apodida and two species of Dendrochirotida constitute the balance of the fauna. These latter groups may prove more diverse with further investigation. The island’s holothuroid fauna is compared with data available from other areas of the Western Indian Ocean and the Indo-west Pacific to evaluate their biogeographic relationships.

Keywords: Holothuroidea, Echinodermata, diversity, abundance, Western Indian Ocean.