Molecular phylogeny of the subfamily Stevardiinae Gill, 1858 (Characiformes: Characidae): classification and the evolution of reproductive traits

Abstract

BackgroundThe subfamily Stevardiinae is a diverse and widely distributed clade of freshwater fishes from South and Central America, commonly known as “tetras” (Characidae). The group was named “clade A” when first proposed as a monophyletic unit of Characidae and later designated as a subfamily. Stevardiinae includes 48 genera and around 310 valid species with many species presenting inseminating reproductive strategy. No global hypothesis of relationships is available for this group and currently many genera are listed as incertae sedis or are suspected to be non-monophyletic.ResultsWe present a molecular phylogeny with the largest number of stevardiine species analyzed so far, including 355 samples representing 153 putative species distributed in 32 genera, to test the group’s monophyly and internal relationships. The phylogeny was inferred using DNA sequence data from seven gene fragments (mtDNA: 12S, 16S and COI; nuclear: RAG1, RAG2, MYH6 and PTR). The results support the Stevardiinae as a monophyletic group and a detailed hypothesis of the internal relationships for this subfamily.ConclusionsA revised classification based on the molecular phylogeny is proposed that includes seven tribes and also defines monophyletic genera, including a resurrected genus Eretmobrycon, and new definitions for Diapoma, Hemibrycon, Bryconamericus sensu stricto, and Knodus sensu stricto, placing some small genera as junior synonyms. Inseminating species are distributed in several clades suggesting that reproductive strategy is evolutionarily labile in this group of fishes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0403-4) contains supplementary material, which is available to authorized users.

Molecular phylogeny and biogeographic history of the Neotropical tribe Glandulocaudini (Characiformes: Characidae: Stevardiinae)

“…Furthermore, it includes the most comprehensive taxon-sampling published up to date, including all genera and most species (80%), with DNA sequences of two species, Glandulocauda caerulea and Mimagoniates sylvicola, analyzed for the first time. The molecular phylogenetic hypotheses presented herein supports Glandulocaudini as a monophyletic group to includes Lophiobrycon, Glandulocauda, and Mimagoniates, as previously proposed by both morphological (e.g., Menezes, Weitzman, 2009;Mirande, 2010) and molecular (e.g., Oliveira et al, 2011;Thomaz et al, 2015a) analyses. Thomaz et al (2015a: 18) placed Argopleura Eigenmann as 8 e170157 [8] an incertae sedis genus in Stevardiinae since its relationships with the tribes Glandulocaudini and Stevardiini were not clearly resolved.…”

“…Although this is not the first work based on molecular data to test the hypothesis of the monophyly of the Glandulocaudini as currently recognized (see Oliveira et al, 2011 andThomaz et al, 2015a), the present analysis is the first that focused on the tribe. Furthermore, it includes the most comprehensive taxon-sampling published up to date, including all genera and most species (80%), with DNA sequences of two species, Glandulocauda caerulea and Mimagoniates sylvicola, analyzed for the first time.…”

“…According to Thomaz et al (2015a), Glandulocaudini is sister to Stevardiini, however, this clade was not strongly supported (ML = 44%, see their fig. 3).…”

“…Since M. microlepis is the only widespread species, it was sampled across its distributional range and this species had more sequences included in the analyses. The representatives of all remain tribes of Stevardiinae proposed by Thomaz et al (2015a) Thomaz et al (2015a); sequences of S. leptoura were deposited by Oliveira et al (2011). All glandulocaudin specimens' vouchers, including L. weitzmani, were identified to species level based on diagnostic morphological traits.…”

“…2). Representatives of Glandulocaudini were included in phylogenetic studies based on molecular data by Calcagnotto et al (2005), Javonillo et al (2010), Oliveira et al (2011), and Thomaz et al (2015a). However, neither of them focused their work on the tribe as a whole and just a few species were analyzed leaving evolutionary issues involving the tribe unsolved.…”