Differential population history in the migratory catfishes Brachyplatystoma flavicans and Pseudoplatystoma fasciatum(Pimelodidae) from the Bolivian Amazon assessed with nuclear and mitochondrial DNA markers

The catfishes Brachyplatystoma flavicans(n = 49) and Pseudoplatystoma fasciatum(n = 69) showed comparable low allozyme diversities (He = 0·012 and 0·009–0·028, respectively), but contrasting PCR-RFLP restriction site mitochondrial DNA diversities (three haplotypes: π = 0·034–0·092 and five haplotypes: π = 0·001–0·023, respectively) in the Rio Ichilo and Beni (Bolivia). Genetic homogeneity between samples was high for B. flavicans and lower for P. fasciatum. Based on mitochondrial diversity, both species probably experienced a historic population reduction but at different time scales