Interspecific relationships and the evolution of sexual dimorphism in pygmy sunfishes (Centrarchidae: Elassoma)

Phylogeny and time scale of diversification in the fossil-rich sunfishes and black basses (Teleostei: Percomorpha: Centrarchidae)

Species of the North American freshwater fish lineage Centrarchidae are apex predators in their habitats and are among the world's most popular sport fishes. Centrarchids boast a rich fossil record that extends from the latest Eocene to the Pleistocene. To investigate the phylogeny and timing of diversification of Centrarchidae, we deploy a dataset of DNA sequences of 16 nuclear genes sampled from nearly all of the recognized and undescribed species. We also utilize previously published morphological datasets to assess the phylogenetic placement of one of the oldest known centrarchid fossils, †Plioplarchus whitei. A Bayesian multispecies coalescent species tree analysis provides insight on relationships that evaded resolution in earlier studies, such as the relationships of Acantharchus pomotis, the resolution of a clade consisting of species previously synonymized under the Spotted Bass, Micropterus punctulatus, and a clade of recently described species previously considered populations of the Redeye Bass, Micropterus coosae. This new molecular phylogeny and the inclusion of †P. whitei and other centrarchid fossils in the tip-dated fossilized birth-death analysis results in a new hypothesis of the timing of diversification in Centrarchidae that contextualizes the ages of centrarchid fossils to the timing of speciation among the extant species. In addition to providing new temporal perspectives on the diversification of freshwater fishes in North America, this study may close of the chapter of centrarchid phylogeny inferred using Sanger-sequenced genes, as the use of genomic-scale datasets becomes mainstream in the phylogenetics of fishes.