Comparative Morphology and Evolution of Genital Papillae in a Genus of Darters (Percidae:Etheostoma)

Abstract

A morphological study of female genital papillae of Etheostoma was conducted to examine the evolution of papillae as predicted by molecular phylogenies, and to examine correlations between papilla morphology and spawning behaviors and oviposition. Thirteen characters were used to describe variation in papillae in 128 species. Based on maximum likelihood ancestral state reconstructions, we corroborated several molecular phylogenetic hypotheses with morphology and developed hypotheses on several functional traits/adaptive traits and their associations with spawning behaviors. Papillar synapomorphies supported a close relationship between Allohistium and (Etheostoma + Nanostoma) + Ulocentra, a monophyletic Catonotus, and a sister-group relationship between E. vitreum and Boleosoma. Results suggest that the most recent common ancestor of Etheostoma buried eggs and had a simple tube with a distal, posteriorly oriented genital pore. All egg-burying species, except species of Nothonotus, have tube papillae that ...