The increasing number of taxa and loci in molecular phylogenetic studies of basal euteleosts has brought stability in a controversial area. A key emerging aspect to these studies is a sister Esociformes (pike) and Salmoniformes (salmon) relationship. We evaluate mitochondrial genome support for a sister Esociformes and Salmoniformes hypothesis by surveying many potential outgroups for these taxa, employing multiple phylogenetic approaches, and utilizing a thorough sampling scheme. Secondly, we conduct a simultaneous divergence time estimation and phylogenetic inference in a Bayesian framework with fossil calibrations focusing on relationships within Esociformes+Salmoniformes. Our dataset supports a sister relationship between Esociformes and Salmoniformes; however the nearest relatives of Esociformes+Salmoniformes are inconsistent among analyses. Within the order Esociformes, we advocate for a single family, Esocidae. Subfamily relationships within Salmonidae are poorly supported as Salmoninae sister to Thymallinae+Coregoninae.
Keywords: CAT-GTR; DNA; Dirichlet process mixture of profiles of equilibrium frequencies combined with general exchange rates; Divergence time estimation; ESS; Esociformes; GTR; HKY; HPD; Hasegawa, Kishino, and Yano model of nucleotide evolution; I; MCMC; ML; MRA; Ma; Markov chain Monte Carlo; Mitogenomics; NADH-ubiquinone oxidoreductase chain 6; ND6; PCR; Phylogenetics; RNA; RY; Salmoniformes; TE; deoxyribonucleic acid; effective sample size; four-category gamma distributed rate variation among sites; general time reversible model of nucleotide evolution; highest posterior density; maximum likelihood; million years ago; most recent common ancestor; n; nucleotide; polymerase chain reaction; proportion of invariant sites; purine and pyrimidine recoding; rRNA; ribonucleic acid; ribosomal RNA; tRNA; transfer RNA; tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetic acid; Γ.
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