Phylogenetic Relationship of Alviniconcha Gastropods from the Indian Ocean to Those from the Pacific Ocean (Mollusca: Provannidae) Revealed by Nucleotide Sequences of Mitochondrial DNA

摘要

The deep-sea chemoautosynthesis-based communities in the Mariana Trough and the back-arc basins in the South Pacific are dominated by large gastropods of the family Provannidae, which harbor endosymbiotic chemoautosynthetic bacteria in their gills. The provannid species Alviniconcha hessleri Okutani & Ohta, 1988 was described based on specimens collected at the Alice Springs site at a depth of 3650 m in the Central Mariana Trough (Okutani & Ohta, 1988). This species also inhabits the much shallower Forecast Vent site in the Southern Mariana Ridge at a depth of 1470 m (Johnson et ai, 1993). No differences have been detected between specimens from these two sites using either morphologic or molecular analysis (Hasegawa et ai, 1997; Kojima et ai, 2001).