Karyotypes of three species of Corbicula (Bivalvia : Veneroida) in Korea

The chromosome numbers of three species of Korean Corbicula an investigated here: C. fluminea 54, C. papyracea 54, and C. colorata 38. In C. fluminea and C. papyracea, the mitotic chromosomes from 18 sets of three chromosomes each showed that these two species are triploids. In C. colorata. the mito tic chromosomes from 19 groups with two chromosomes each indicated that it is a diploid. C. fluminea and C. papyracea have one set of metacentric chro mosomes, five sets of submetacentrics chromosomes. and 12 sets of subteloce ntric chromosomes. C. colorata has bren considered a subspecies of C. papyr acea, but its karyotype indicates that it is a distinct species since it is undoubtedly reproductively isolated from the other two Korean species stud ied.