Integrative phylogeny of Corydoradinae (Siluriformes: Callichthyidae) with an emphasis on northwestern La Plata species, including descriptions of a new genus and species

Abstract

The knowledge about the diversity and phylogeny of South American callichthyid armored catfishes of the subfamily Corydoradinae is still growing, after important recent contributions, and many species have uncertain relationships. In this study, we present the first combined phylogenetic hypothesis for the genus based on five genes, 83 morphological characters, and 153 species, providing synapomorphies for some of the main genera of Corydoradinae, as recently defined. The inclusion of species not previously analyzed in a phylogenetic context challenged the monophyly of Hoplisoma and required the definition of a new genus for endemic species from the Andean portion of the northwestern La Plata basin (ANWLP): Hoplisoma gladysae, Hoplisoma micracanthum, and Hoplisoma petracinii. We found Hoplisoma non monophyletic with Hoplisoma sensu stricto not sister to a clade of species herein named the ‘Hoplisoma’ paleatum clade. In this clade we recovered a new species of Hoplisoma, which is endemic to the upper Bermejo basin, as sister to ‘Hoplisoma’ paleatum from the lower La Plata basin. The new species is distinguished from all congeners by a unique coloration similar to that of the syntopic H. micracanthum, suggesting a putative case of Müllerian co-mimicry.