Genetic and morphometric characterization of mussels (Bivalvia : Mytilidae) from Mid-Atlantic hydrothermal vents

Mussels were collected from deep-sea hydrothermal vents along the Mid-Atlan tic Ridge. Specimens from the Snake Pit site were previously identified gen etically and anatomically as Bathymodiolus puteoserpentis, but the relation ships of mussels from other sites (Logatchev and Lucky Strike) were unclear . Molecular genetic and morphological techniques were used to assess differ ences among these mussel populations. The results indicate that the range f or B. puteoserpentis extends from Snake Pit to Logatchev, and that an unnam ed second species, B. n. sp., occurs at Lucky Strike. Analysis of mitochond rial NADH dehydrogenase subunit 4 (ND4) revealed 13% sequence divergence be tween the two species. Nei's genetic distance (D) based on 14 allozyme loci was 0.112, A multivariate morphometric analysis yielded a canonical discri minant function that correctly identified individuals from these sites to s pecies 95% of the time.