New records and distribution of marine free-living nematodes in the Maldivian Archipelago.

Biodiversity estimations, in particular in tropical regions, are a useful tool in research focused on the knowledge and conservation of ecosystems. Inferences on the biogeography of marine nematodes are often difficult due to the poor knowledge of the species distribution. In particular, limited information on the composition of the free-living marine nematodes is available from the Indian Ocean and Maldivian Archipelago. This study aims at providing a checklist of the free-living marine nematodes associated with coral sediments of the Maldives. Forty-six species, in 28 genera and 10 families, are newly recorded for the Archipelago, increasing the number of known nematode species to 111, in 79 genera, and 25 families. The distribution range of the species is updated, and a noticeable faunistic richness is recorded for the southern archipelago. The presence of six species described first in Maldives by Gerlach and still known only for this region is confirmed. The present synthesis of the faunistic and taxonomic data available so far for the Maldives Islands integrates the global information on the distribution of this phylum and provides information for future interesting comparisons from a zoogeographical perspective.