The karyotypes of Biomphalaria tenagophila collected from Rio de Janeiro, Brazil were studied using the air-drying method. Somatic cells of this species had 2n=36. The 18 chromosome pairs were identified and classified into 3 groups. The diploid cell has 7 pairs of metacentric, 8 pairs of submetacentric, and 3 pairs of subtelocentric chromosomes. Observed chromosomes ranged from 2.4 to 6.4 microm, and the total length was 122.3 microm. This is the first report on the chromosome of B. tenagophila.
Animals ; Biomphalaria/*cytology/*genetics ; Brazil ; *Karyotype