Hidden genetic diversity and distinct evolutionarily significant units in an commercially important Neotropical apex predator, the catfish Pseudoplatystoma corruscans

In the South American Neotropics, several fish taxa with distributions ranging over multiple river basins might actually represent cryptic species or distinct evolutionarily significant units (ESUs). Defining hidden genetic diversity within species is of great significance to inform on programs aimed at maintaining the evolutionary potential of natural populations and to conduct appropriate fisheries management. This is particularly important in commercially exploited species, such as the "surubim" catfishes (genus Pseudoplatystoma). Here, based on evidence of reciprocal mtDNA monophyly and significant nuclear divergence in eight microsatellite markers we report on two ESUs in the widely distributed Pseudoplatystoma corruscans. The implications of these results for the conservation management, traceability of fish products and for identifying breeders for restocking programs in this important apex predator are discussed.