Figure 2.

Meiotic cells in different phases with B chromosomes evidenced after C-banding - Platydoras armatulus a spermatogonial metaphase with 58 chromosomes and 2 B chromosomes b late pachytene with bivalents in advanced condensation stage, note two B chromosomes forming univalents without homologies of standard complement c metaphase I with 27 bivalents and two B chromosomes. Pterodoras granulosus d spermatogonial metaphase composed by 58 chromosomes and one B chromosome e late pachytene, the isolated univalent probably correspond to B chromosome f diplotene/diakinesis with 27 bivalents and one B chromosome, note the high number of chiasms. Ossancora punctata g spermatogonial metaphase with 66 chromosomes and one B chromosome h metaphase I reveals heterochromatic B chromosome and 33 bivalents i anaphase I, observe the late segregation of B chromosomes.