Abstract
The Iwagaki oyster Crassostrea nippona is an important marine species in Japan. While some studies have reported the karyotype of oysters, inconsistencies among these results have been found, probably due to the small chromosome sizes and similarities among the species. Indeed, the karyotype of C. nippona has not been clearly established. In this study, we analyzed the karyotype of C. nippona and found that C. nippona contained seven pairs of metacentric, two pairs of metacentric/submetacentric, and one pair of submetacentric chromosomes. These results differ from those of previous studies.
