A NEW MARINE SPECIES OF SMITHSONIDRILUS (OLIGOCHAETA, TUBIFICIDAE) FROM THE FLORIDA KEYS

Smithsonidrilus exspectatus, new species, is described from barely subtidal sediments at Pigeon Key (near Marathon) and Bahia Honda, southern Florida. It appears phylogenetically intermediate between Smithsonidrilus hummelincki and the most apomorphic group within the genus (Smithsonidrilus marinus, Smithsonidrilus involutus, Smithsonidrilus westoni, and Smithsonidrilus multiglandularis); all these species show a northwest Atlantic distribution. The new species has the same kind of spermatheca as, but a less elaborate copulatory sac (pseudopenis) than, those of the species in the S. marinus group. The dilated, heavily muscular ejaculatory duct appears to be an autapomorphy of S. exspectatus.