Possible Common Origin of B Chromosomes in Neotropical Fish (Siluriformes, Auchenipteridae) Reinforced by Repetitive DNA Mapping

The aim of this paper was to present the second case B chromosomes in Auchenipteridae (Trachelyopterus sp.), and test hypothesis that species Parauchenipterus galeatus might have a common origin, since these two phylogenetic proximity. Both 58 A complement, heterochromatin preferentially located at terminal region most chromosomes, simple Ag-NORs short arm subtelocentric pair, which confirmed by hybridization with 18S rDNA, submetacentric pairs carrying 5S rDNA sites, presence chromosomes. are small, metacentric, almost totally heterochromatic, variation number intra interindividual. In addition, for first time fish, telomeric sequence [TTAGGG]n dispersed along (both species). [GATA]n microsatellite were scattered all complement absent both species. These aspects confirm proximity between genus Trachelyopterus, they suggest previous diversification genera.