Phylogenetic Relationships and Molecular Dating of the Major Groups of Catfishes of the Neotropical Superfamily Pimelodoidea (Teleostei, Siluriformes)

Abstract

ABSTRACT. We present a molecular phylogenetic study of the major lineages of the Pimelodoidea, the second largest and most widespread clade of Neotropical catfishes, in which we examine the affinities of two incertae sedis genera, Conorhynchos and Phreatobius with respect to 24 pimelodoid terminals within the families Pimelodidae, Pseudopimelodidae and Heptapteridae. We include Diplomystes mesembrinus and 11 siluroid, non-pimelodoid taxa as outgroups. Data are more than six kilobases of aligned sequence from the rag1 and rag2 nuclear genes and 12S and 16S rDNA from the mitochondrial genome. Results provide strong support for the monophyly of Pimelodoidea, for the families Pimelodidae, Pseudopimelodidae and Heptapteridae individually, and for the interrelationships described in parenthetical notation as ((Conorhynchos, Heptapteridae), (Phreatobius, Pseudopimelodidae, Pimelodidae)). Within this latter group, analysis of the data using parsimony favors ((Phreatobius, Pseudopimelodidae), Pimelodidae), while B...