Hidden Diversity in the Populations of the Armored Catfish Kner, 1854 (Loricariidae, Hypostominae) from the Paraná River Basin Revealed by Molecular and Cytogenetic Data.

Only one species of armored catfish, Valenciennes 1836, has been historically described in the basin of the Paraná River, from Misiones (Argentina). However, the ample variation found in the morphology and coloration of the populations sampled in the tributaries of the Brazilian state of Paraná makes it difficult to establish the real taxonomic status and evolutionary history of the specimens, suggesting that is not the only species found in this basin. By combining data on mitochondrial DNA (COI gene) and chromosomal markers from different populations, totaling 144 specimens, in the tributaries of the Paraná, and specimens from Misiones (type-locality of ), we detected five distinct evolutionary lineages.