Affinities of sponges (Porifera) of the Marquesas and Society Islands, French Polynesia

摘要

This article reports on a survey of sponges from the higher-island reefs and slopes of the Marquesas and Society Islands archipelagos, French Polynesia, recording presence/absence and an estimate of local abundance at 109 sites from six and eight islands within each archipelago, respectively. Sponge distributions within archipelagos were relatively homogeneous, showing some differential patterns in affinities between north-south islands, and approximately one-third of the fauna apparently endemic to these archipelagos, but between-archipelago comparisons showed large heterogeneity, with only four of the 75 species shared between both archipelagos. The fauna of the Marquesas Islands (with sites consisting mostly of rocky slopes) was dominated by species in order Poecilosclerida and showed a range of taxonomic diversity similar to that of the remote fauna of the Hawaiian Islands. By comparison, the sponge fauna of the Society Islands sites was dominated by species of order Dictyoceratida, reflecting predominance of coral reef and lagoon sites and associated phototrophic feeding strategies. Parsimony and multivariate statistical analyses comparing French Polynesian sponge faunas with others in the southwestern Pacific showed closest nested faunal similarities between the (Marquesas Islands + Society Islands), (((Tonga + Fiji) + Vanuatu) + New Caledonia), and (North Great Barrier Reef + South Great Barrier Reef) but no or very low similarity between more geographically isolated faunas such as Palau and the collective Great Barrier Reef.