HABITAT PREFERENCES AND SPECIES ASSOCIATIONS OF SHALLOW-WATER MARINE TUBIFICIDAE (OLIGOCHAETA) FROM THE BARRIER-REEF ECOSYSTEMS OFF BELIZE,CENTRAL-AMERICA

The marine tubificid oligochaete fauna of Belize is the most diverse t hat has been described for the Caribbean Sea, with records for over 50 % of all known Caribbean species. Tubificids were sampled at 77 statio ns around the outer barrier of the coral reefs off the Belize mainland . A total of 1,529 individuals representing 52 species were collected. Species distribution patterns were controlled mainly by sediment type and the presence or absence of mangroves. Six species (Phallodrilus m olestus, Tubificoides bermudae, Inanidrilus leukodermatus, Heterodrilu s flexuosus, Bathydrilus formosus, Smithsonidrilus hummelincki) with d iverse life history characteristics were common and had broad habitat preferences being found in various types of heterogeneous sandy sedime nts. Heterodrilus flexuosus was the only common species in these sampl es known only in Belize. The other five common species range from Beli ze to Florida or Bermuda. Most other species have narrower habitat pre ferences and are limited to specific habitats. For example, one group of gutless species was restricted to organically enriched fine to medi um sands, a group of Limnodriloidinae occurred only in mud around mang rove cays, and a group of meiofaunal species were restricted to saline groundwater.