Chromosomes of Pisidium coreanum (Bivalvia: Veneroida: Corbiculoidea: Pisidiidae), a Korean freshwater clam

Abstract

Polyploidy is reported as occurring in Pisidiidae, being found in Pisidium coreanum from Korea. The chromosome number is n = 95 and 2n = 190. Because of the large number of its chromosomes, P. coreanum is obviously a polyploid species. The basic chromosome number for the superfamily Corbiculoidea is X = 18 and X = 19. The polyploid condition found in P. coreanum probably originally resulted from a single event. Once the polyploid condition was reached, the stability of this number has been maintained.