Sternopygus xingu A new species of gymnotoid knifefish in the genus Sternopygus is described from the Rio Xingú of Brazil. A data matrix of 52 characters for the 4 recognized
species of Sternopygus and representative outgroup taxa is presented. The data include 12 characters diagnostic of the Sternopygidae, 11 characters supporting the
monophyly of Sternopygus, and 15 characters structuring a hypothesis of relationships among the four species of Sternopygus. [eng]