Integrating Molecular Evolution and Morphology to Study the Evolutionary History of Lizardfishes and Their Allies

Abstract

Evolutionary relationships of the Aulopiformes (Euteleostei: Cyclosquamata) are investigated from a molecular and total evidence approach that includes previous morphological datasets. Molecular and total evidence analyses recover Aulopiformes as monophyletic and sister to a monophyletic Ctenosquamata, supporting the monophyly of Eurypterygii with molecular data. The divergence times of Aulopiformes are estimated utilizing a Bayesian approach in combination with knowledge of the fossil record of teleosts. Also the character evolution of deep-sea evolutionary adaptations is explored. The stem species of the aulopiforms arose during the Early Cretaceous, and possibly Late Jurassic in a marine environment with separate sexes, and laterally directed, round eyes. Tubular eyes have arisen independently at different times in three deep-sea pelagic predatory aulopiform lineages. Simultaneous hermaphroditism evolved a single time in the stemspecies of the superfamily Alepisauroidei, the clade of deep-sea aulopiforms. The BiSSE likelihood model was implemented to explore whether simultaneous hermaphroditism is affecting diversification rates within lizardfishes. The evolution of simultaneous hermaphroditism or any other codistributed character does not seem to be influencing rates of speciation or extinction. An asymmetry in rate of character change is not found to be statistically significant, however there is some evidence that this asymmetry may explain why the preponderance of aulopiform taxa are simultaneous hermaphrodites.