Southern Banjo

description

is the first species of the Aspredinidae family cytogenetically described. The modal diploid number determined for the individuals of Bunocephalus doriae examined was 50 chromosomes (Fig. 1 a), with no chromosomal differences detected between males and females. Within the order Siluriformes, the only species with 2 n = 50 chromosomes studied so far belong to the Pimelodidae family (i. e. Pinirampus pirinampu, Calophysus macropterus, Luciopimelodus pati) (Swarça et al., 1999; Vasconcelos & Martins-Santos, 2000; Sanchez, 2006). Oliveira & Gosztonyi (2000) reported that karyotypes of 2 n = 56 have been reported in thirteen genera of Siluriformes, suggesting that this could be the basal chromosome number for the order. However, considering the few cytogenetic data available for some groups, generalizations should be carefully revised (Swarça et al., 2007). The chromosome formulae established consisted of 6 m, 10 sm, 6 st, and 28 a and the fundamental number (FN) was 72 (Fig. 1 a). A very interesting and exclusive characteristic observed was the presence of the first pair of subtelocentrics as the largest chromosome pair of the complement. The presence of an asymmetric karyotype with a

Cytogenetic description of Bunocephalus doriae Boulenger, 1902 (Siluriformes: Aspredinidae) from the Paraná River (Misiones, Argentina)