THE COASTAL MOLLUSCAN FAUNA OF THE NORTHERN KERMADEC ISLANDS, SOUTHWEST PACIFIC-OCEAN

A total of 358 species of molluscs (excluding pelagic species) is reco rded here from coastal marine habitats around the northern Kermadec Is lands. The fauna is dominated by species that are widely distributed i n the tropical western and central Pacific Ocean. The majority of thes e are restricted to the tropics and subtropics, but some range south t o temperate latitudes. Sixty-eight species, comprising 19% of the faun a, are thought to be endemic to the Kermadec Islands. That group inclu des several species that have an in situ fossil record extending back to the Pleistocene. The fauna also includes a number of non-endemic sp ecies that are restricted to subtropical or subtropical-temperate lati tudes in the southern Pacific Ocean. Some of these are restricted to t he southwestern Pacific, others are shared with subtropical central an d eastern Pacific islands. The Kermadec Islands' coastal molluscan fau na is depauperate at the species/genus level in comparison with faunas in the tropical western and central Pacific Ocean, and is less divers e than the subtropical south Pacific faunas of Lord Howe, Norfolk and Pitcairn islands. The species composition of the Kermadec molluscan fa una in part reflects the present-day biogeographic isolation of the is lands, their subtropical location and the small range of habitat types present. It is also an inheritance of a geological and paleo-oceanogr aphic history that gave rise to faunal turnover and allopatric speciat ion.