Origin of species diversity in the catfish genus Hypostomus (Siluriformes: Lori- cariidae) inhabiting the Paraná river basin, with the description of a new species

YAMILA P. CARDOSO; A. ALMIRON; J. CASCIOTTA; D. AICHINO; M. LIZARRALDE; J. I. MONTOYA-BURGOS

ZOOTAXA

MAGNOLIA PRESS

Lugar: Auckland; Año: 2012 vol. 3453 p. 69 - 83

1175-5326

Within the Loricariidae, the genus Hypostomus is one of the most diversified freshwater catfish groups. Using new se- quence data from the mitochondrial Control Region (D-loop) we examined the phylogeny of this genus. Our phylogenetic analyses suggest that, in the Paraná river basin, species diversity in the genus Hypostomus has been shaped by two proc- esses: 1) by inter-basin diversification, generating groups of species that inhabit different basins, as a result of dispersal events; and 2) via intra-basin speciation as a result of basin fragmentation due to past marine transgressions, which pro- duced groups of species within a basin. Using the D-loop as a molecular clock, each event of diversification was dated and linked with documented hydrological events or sea level changes. We also assessed the possible dispersal routes be- tween the Paraná and Uruguay rivers, in addition to the obvious dispersal route via the Río de la Plata estuary. Finally, we describe a new species of Hypostomus inhabiting Middle Paraná river, Hypostomus arecuta n. sp. This species can be sep- arated from all other Hypostomus by having light roundish dots on a darker background and by number of premaxillary/ dentary teeth.