Abstract
The species comprehended by the genera Hyphessobrycon, Hemigrammus, Thayeria, Parapristella, and Bryconella, currently allocated either as a "Incertae sedis" or within the subfamily Tetragonopterinae (family Characidae), the so-called "tetras", are among the most taxonomically-challenging species assemblage within South American freshwater fishes. The present project intends to advance co…