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

Thomaz AT, Arcila D, Ortí G, Malabarba LR - BMC Evol. Biol. (2015)

Bottom Line: The results support the Stevardiinae as a monophyletic group and a detailed hypothesis of the internal relationships for this subfamily.A 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology (EEB), University of Michigan, 1109 Geddes Ave., Ann Arbor, 48109, MI, USA. thomaz@umich.edu.

ABSTRACT

Background: The 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.

Results: We 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.

Conclusions: A 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.

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Section of the Stevardiinae phylogeny showing the relationships in Diapomini (in part, continues in Figs. 8 and 9). ML tree obtained with RAxML. Single name labels several terminals when they lead to same nominal species. Type species of each genus are highlighted in green when sampled in this study. Red sperm symbols highlight taxa with insemination strategy, while blue sperm symbols highlight taxa known to have external fertilization. Sperm types are indicated by M1 – M3. Absence of any symbols next to taxon names indicates lack of knowledge about reproductive characters. Bootstrap values indicated with dots placed on internal branches according to inset caption. Section of the full topology shown on the left (shaded) is expanded on the right. Node 9 subtends Piabarchus distributed in Rio São Francisco basin and upper Paraguay (P. analis is type species). Node 10 subtends Piabina from the Rio São Francisco, upper Paraná and Paraguay basins (P. argentea is type species). Node 11 subtends Diapoma from the Paraná, Uruguay and coastal systems in southern Brazil (type species D. speculiferum)
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Fig10: Section of the Stevardiinae phylogeny showing the relationships in Diapomini (in part, continues in Figs. 8 and 9). ML tree obtained with RAxML. Single name labels several terminals when they lead to same nominal species. Type species of each genus are highlighted in green when sampled in this study. Red sperm symbols highlight taxa with insemination strategy, while blue sperm symbols highlight taxa known to have external fertilization. Sperm types are indicated by M1 – M3. Absence of any symbols next to taxon names indicates lack of knowledge about reproductive characters. Bootstrap values indicated with dots placed on internal branches according to inset caption. Section of the full topology shown on the left (shaded) is expanded on the right. Node 9 subtends Piabarchus distributed in Rio São Francisco basin and upper Paraguay (P. analis is type species). Node 10 subtends Piabina from the Rio São Francisco, upper Paraná and Paraguay basins (P. argentea is type species). Node 11 subtends Diapoma from the Paraná, Uruguay and coastal systems in southern Brazil (type species D. speculiferum)

Mentions: The maximum likelihood tree obtained with RAxML is shown in Fig. 3 in a summarized view, rendered by collapsing major clades to single terminals. The three large clades previously reported for Characidae (clades “A”, “B” and “C” [10, 12, 30]) are well-supported by the data, with “clade A” (representing the monophyletic subfamily Stevardiinae) resolved as the sister group of “clade B”. Seven clades with high bootstrap support were obtained within Stevardiinae, some in agreement with previous classifications but most clades are new. Fig. 3 presents a phylogenetic classification for the subfamily Stevardiinae and a proposed definition of monophyletic tribes and genera based on the taxonomic sampling analyzed in this study. The complete tree is available in detail in Figs. 4–10 and in Additional file 4. The molecular markers used in this study provided good phylogenetic resolution with high bootstrap support throughout the tree, with an average value of 78 % across branches and with more than half of the values equal to, or higher than, 90 %. Landonia latidens was excluded from the analysis since most genes for this taxon could not be amplified and sequenced, resulting in an unstable phylogenetic position for this species. Clades defining genera and other monophyletic groups within tribes received higher bootstrap support than branches leading to larger clades, especially clades containing the particularly species-rich genera such as Bryconamericus and Knodus. When comparing the stability among all trees accessed in this study, the newly circumscribed groups (tribes and genera) proposed herein are largely obtained by all methods with high support values (Table 4), except for the highly species-rich genera (Bryconamericus, Hemibrycon and Knodus) that received low support. The trees obtained with Garli, TNT and STAR are not shown, but some results from these analyses are reported in Table 4. All trees and data matrix obtained in this study are available at Dryad repository (doi:"http://dx.doi.org/10.5061/dryad.7nd42).Fig. 3


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

Thomaz AT, Arcila D, Ortí G, Malabarba LR - BMC Evol. Biol. (2015)

Section of the Stevardiinae phylogeny showing the relationships in Diapomini (in part, continues in Figs. 8 and 9). ML tree obtained with RAxML. Single name labels several terminals when they lead to same nominal species. Type species of each genus are highlighted in green when sampled in this study. Red sperm symbols highlight taxa with insemination strategy, while blue sperm symbols highlight taxa known to have external fertilization. Sperm types are indicated by M1 – M3. Absence of any symbols next to taxon names indicates lack of knowledge about reproductive characters. Bootstrap values indicated with dots placed on internal branches according to inset caption. Section of the full topology shown on the left (shaded) is expanded on the right. Node 9 subtends Piabarchus distributed in Rio São Francisco basin and upper Paraguay (P. analis is type species). Node 10 subtends Piabina from the Rio São Francisco, upper Paraná and Paraguay basins (P. argentea is type species). Node 11 subtends Diapoma from the Paraná, Uruguay and coastal systems in southern Brazil (type species D. speculiferum)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4509481&req=5

Fig10: Section of the Stevardiinae phylogeny showing the relationships in Diapomini (in part, continues in Figs. 8 and 9). ML tree obtained with RAxML. Single name labels several terminals when they lead to same nominal species. Type species of each genus are highlighted in green when sampled in this study. Red sperm symbols highlight taxa with insemination strategy, while blue sperm symbols highlight taxa known to have external fertilization. Sperm types are indicated by M1 – M3. Absence of any symbols next to taxon names indicates lack of knowledge about reproductive characters. Bootstrap values indicated with dots placed on internal branches according to inset caption. Section of the full topology shown on the left (shaded) is expanded on the right. Node 9 subtends Piabarchus distributed in Rio São Francisco basin and upper Paraguay (P. analis is type species). Node 10 subtends Piabina from the Rio São Francisco, upper Paraná and Paraguay basins (P. argentea is type species). Node 11 subtends Diapoma from the Paraná, Uruguay and coastal systems in southern Brazil (type species D. speculiferum)
Mentions: The maximum likelihood tree obtained with RAxML is shown in Fig. 3 in a summarized view, rendered by collapsing major clades to single terminals. The three large clades previously reported for Characidae (clades “A”, “B” and “C” [10, 12, 30]) are well-supported by the data, with “clade A” (representing the monophyletic subfamily Stevardiinae) resolved as the sister group of “clade B”. Seven clades with high bootstrap support were obtained within Stevardiinae, some in agreement with previous classifications but most clades are new. Fig. 3 presents a phylogenetic classification for the subfamily Stevardiinae and a proposed definition of monophyletic tribes and genera based on the taxonomic sampling analyzed in this study. The complete tree is available in detail in Figs. 4–10 and in Additional file 4. The molecular markers used in this study provided good phylogenetic resolution with high bootstrap support throughout the tree, with an average value of 78 % across branches and with more than half of the values equal to, or higher than, 90 %. Landonia latidens was excluded from the analysis since most genes for this taxon could not be amplified and sequenced, resulting in an unstable phylogenetic position for this species. Clades defining genera and other monophyletic groups within tribes received higher bootstrap support than branches leading to larger clades, especially clades containing the particularly species-rich genera such as Bryconamericus and Knodus. When comparing the stability among all trees accessed in this study, the newly circumscribed groups (tribes and genera) proposed herein are largely obtained by all methods with high support values (Table 4), except for the highly species-rich genera (Bryconamericus, Hemibrycon and Knodus) that received low support. The trees obtained with Garli, TNT and STAR are not shown, but some results from these analyses are reported in Table 4. All trees and data matrix obtained in this study are available at Dryad repository (doi:"http://dx.doi.org/10.5061/dryad.7nd42).Fig. 3

Bottom Line: The results support the Stevardiinae as a monophyletic group and a detailed hypothesis of the internal relationships for this subfamily.A 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology (EEB), University of Michigan, 1109 Geddes Ave., Ann Arbor, 48109, MI, USA. thomaz@umich.edu.

ABSTRACT

Background: The 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.

Results: We 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.

Conclusions: A 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.

Show MeSH
Related in: MedlinePlus