Evolutionary Relationships Among the Amazonian Catfish Genus Hypophthalmus Cuvier, 1829 (Siluriformes, Pimelodidae) Suggest Diversification During Plio‐Pleistocene

Abstract

The present study evaluated the phylogenetic relationships among the six valid species of catfish of the genus Hypophthalmus , estimated the divergence times among the different taxa and assessed the processes that influenced the evolution of the group. All the phylogenetic analyses, based on 6803 base pairs, including three mitochondrial and seven nuclear markers, support the monophyly of Hypophthalmus , and the arrangement of the species in two clades, one containing Hypophthalmus oremaculatus + Hypophthalmus donascimientoi , and the other, including Hypophthalmus marginatus + Hypophthalmus edentatus , which is the sister group of Hypophthalmus celiae , with Hypophthalmus fimbriatus appearing as the most divergent of this clade. These findings indicate that the genus originated some 4.4 million years ago (Ma), during the Pliocene, while most species diversified during the Pleistocene. The origin and diversification of Hypophthalmus coincided with the formation of the modern Amazon basin and the climatic fluctuations of the Plio‐Pleistocene, which likely determined modifications in the dynamics of the local rivers and influenced the evolution and diversification of the genus.

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