ALLOZYMIC CHARACTERIZATION AND GENETIC-RELATIONSHIPS AMONG 4 SPECIES OF TAPETINAE (BIVALVIA, VENERIDAE)

Allozyme structures of Tapes philippinarum, Tapes decussatus, Venerupi s aurea and Paphia undulata were electrophoretically analysed and spec ies similarities established. High rates of polymorphism and significa nt Hardy-Weinberg disequilibria were found. In T. decussatus and V. au rea high levels of both intra- and interpopulation genotypic structuri ng, possibly related to year-cohort heterogeneities, were ascertained. In T. philippinarum no intrapopulation genotypic variance was found, bur a high level of an interpopulation genotypic heterogeneity was app arent, as a possible outcome of its introduction in the Adriatic lagoo ns from different hatchery stocks. Nei's generic distances were also e valuated and dendrograms obtained. A clear inconsistency emerged betwe en the generic allocation of the taxa and allozyme data, since T. phil ippinarum proved the most dissimilar to the congeneric T. decussatus.