The decapod reptantia and stomatopod crustaceans of a typical high island coral reef complex in French Polynesia (Tiahura, Moorea Island): Zonation, community composition and trophic structure

Abstract

In a typical High Island coral reef complex of French Polynesia (transect of Tiahura, Hoorea Island, Society Archipelago!, 73 species of decapod Reptantia and stomatopod crustaceans were collected. Over 9 stations localised along the transect, 3 different units of hard coral substrate of simi1ar volume (about 17 litres each), were sampled at each station. The results are discussed from two aspects : the first shows that at least 50 carcinologic species occur within the cavitary biotopes ; 16 species (mainly Xanthid crabs), represent more than 90% of all collected individuals. Most of the dominant species are widely distributed along the transect (Chlorodiella barbata, Pilodius pugil, Lipcarpilodes integerrimus, Galathea aculeata), and locally, some others are numerically important (Chlorodiella Laevissima, Globopilumnus globosus, Daira perlata,Phymodius ungulatus, etc.). The second aspect concerns the repartition of species in the different biotopes in relation to their feeding habits. Based on the functional morphology of chelipeds, mouth-parts and gastric sill, and on gut content analysis, the species were placed into 5 MORPHO- LOGIC GROUPS : filter-suspension feeders, omnivores/herbivores, omnivores/carnivores, generalised omnivores and predators. The feeding habits and the distribution pattern of abundant species suggest that trophic and habitat partitioning say exist. The predominant species show either different nutritional modes, or inhabit different areas and/or biotopes. Distribution patterns of the morphologic groups ip the different substrates are proposed, and schemes of interspecific relation; are analysed.