“…The B microchromosomes were described in distinct neotropical fishes, including Schizodon Agassiz, 1829, Astyanax Baird et Girard, 1854, Moenkhausia Eigenmann, 1903, Cyphocharax Fowler, 1906, Steindacnerina Fowler, 1906, Prochilodus Agassiz, 1829, Rhamdia , Bleeker, 1858 Iheringichthys Eigenmann et Norris, 1900, Callichthys Scopoli, 1777, Megalonema Eigenmann, 1912, Pimelodella , Eigenmann et Eigenmann, 1888 and Loricaria Linnaeus, 1758 (Carvalho et al 2008, Lui et al 2009). An interesting hypothesis to explain the origin of these additional genomic elements is the fragmentation in standard karyotype (Sampaio et al 2015). Considering the morphological type, non-Mendelian segregation and low frequencies in mitotic cells, it seems likely that the B chromosomes observed in Platydoras
armatulus , Pterodoras
granulosus and Ossancora
punctata have a recent origin from fragmentation in chromosomes from A complement.…”