Phylogenomic analysis of Fundulidae (Teleostei: Cyprinodotiformes) using RNA-sequencing data

Abstract

Fishes of the New World cyprinodontiform family Fundulidae display a wide variety of tolerance to environmental conditions, making them a valuable model system for comparative, evolutionary, and environmental studies. Despite numerous attempts to resolve the phylogenetic relationships of family Fundulidae, the basal structure of the phylogeny remains unresolved. The lack of a robust and fully resolved phylogeny for family Fundulidae and its most speciose genus Fundulus is an impediment to future research. This study utilized novel RNA-sequencing data for phylogenetic inference among16 members of Fundulidae to better refine the basal nodes of the family and confront long-standing questions regarding (1) the monophyletic status of genus Fundulus, and validity of the Lucania and recently synonymized Adinia genera; (2) the relationship of the west coast endemic Fundulus parvipinnis and F. lima to other Fundulus species; and (3) the validity of subgeneric classifications. In addition, previously published nuclear gene sequences for 32 Fundulidae species were re-analyzed in combination with novel RNA-sequencing data. Maximum likelihood and Bayesian analyses generated identical phylogenies with strong statistical support at nearly all nodes, demonstrating the utility of RNA-sequencing data in constructing robust phylogenies not achievable by previous methods. While many past hypothesized evolutionary relationships for Fundulidae were reinforced, several alternative relationships are hypothesized at basal nodes resulting in a re-analysis of the deeper structure of family Fundulidae. These results reveal family Fundulidae as a paraphyletic grouping of members of genus Fundulus and Lucania and supports the previous synonymy of genus Adinia with genus Fundulus.