Diapominae Eigenmann, 1909

Melo, Bruno F, Ota, Rafaela P, Benine, Ricardo C, Carvalho, Fernando R, Lima, Flavio C T, Mattox, George M T, Souza, Camila S, Faria, Tiago C, Reia, Lais, Roxo, Fabio F, Valdez-Moreno, Martha, Near, Thomas J & Oliveira, Claudio, 2024, Phylogenomics of Characidae, a hyper-diverse Neotropical freshwater fish lineage, with a phylogenetic classification including four families (Teleostei: Characiformes), Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 202 (1), pp. 1-37 : 11

Diapominae Eigenmann, 1909 , new usage

Type genus: Diapoma Cope, 1894 .

Included genera: Atonitus Vari and Ortega, 2000, Aulixidens Böhlke, 1952 , Boehlkea , Bryconamericus , Ceratobranchia , Diapoma , Knodus , Phallobrycon , Piabarchus , Piabina Reinhardt, 1867 ,and Rhinopetitia . Not sampled: Bryconacidnus , Hypobrycon , Monotocheirodon Eigenmann and Pearson, 1924 , Nantis Mirande et al., 2004 , Odontostoechus Gomes, 1947 , Othonocheirodus Myers, 1927 , and Rhinobrycon .

Definition: The least inclusive crown clade that contains Diapoma speculiferum Cope 1894 , Diapoma alburnum (Hensel, 1870) , and Knodus breoiceps (Eigenmann, 1908) . This is a minimum-crown-clade definition. See Figure 3 for a reference phylogeny of Diapominae . Although Diapoma speculiferum is not included in the reference phylogeny it resolves with other species of Diapoma in phylogenies inferred from molecular and

combined molecular and morphological datasets ( Thomaz et al. 2015, Ferreira et al. 2021).

Etymology: From the ancient Greek διά (dˈa͡ɪə) meaning through and πῶμα(pˈo͡ʊmə) meaning lid or cover.

Remarks: Weitzman and Menezes (1998) identified a clade containing Diapoma , Acrobrycon ,and Planaltina .Thomaz etal.(2015) proposed a delimitation of Diapomini that included Atonitus, Bryconamericus , Bryconacidnus , Ceratobranchia , Cyanocharax , Diapoma , Hypobrycon , Knodus , Nantis , Odontostoechus , Piabina , Piabarchus , Rhinobrycon , and tentatively Lepidocharax and Planaltina . Ferreira et al. (2021) resolved a monophyletic Diapomini supported by five morphological synapomorphies and two subclades: one containing Bryconadenos Weitzman et al., 2005 , Knodus , Phallobrycon , and Rhinobrycon , and a second containing Atonitus, Ceratobranchia , Bryconacidnus , Bryconamericus , Diapoma , Monotocheirodon , Nantis , Odontostoechus , Piabina , and Rhinopetitia .

The UCE phylogeny resolves two monophyletic groups: the first containing a paraphyletic Bryconamericus , Diapoma , a paraphyletic Piabarchus , and Piabina , and the second containing Atonitus, Aulixidens , Boehlkea , Bryconamericus macarenae , Ceratobranchia , a paraphyletic Knodus , Phallobrycon , and Rhinopetitia ( Fig. 3). Given the disparities in clade composition between UCE phylogeny and that of Ferreira et al. (2021), we consider a deeper discussion of these relationships premature at this time.

Bryconadenos was treated as a synonym of Knodus ( Thomaz et al. 2015) . Although the type species of Knodus , K. meridae Eigenmann, 1911 , was not sampled in the UCE phylogeny, Bryconadenos tanaothoros Weitzman et al., 2005 is nested within Knodus , supporting Thomaz et al. ’s hypothesis that Bryconadenos is a junior synonym of Knodus ( Thomaz et al. 2015) .

Diapominae are the most species-rich clade of Stevardiidae , containing two of the family’s largest genera: Bryconamericus (54 species) and Knodus (39 species) (Fricke et al. 2023), indicating that numerous taxonomic issues at the specieslevel remain unresolved (García-Melo et al. 2019, Malabarba et al. 2021). Following Ferreira et al. (2021) and Thomaz et al. (2015), some genera not sampled in UCE phylogeny were provisionally included in Diapominae : Bryconacidnus , Hypobrycon , Monotocheirodon , Nantis , Odontostoechus , Othonocheirodus , and Rhinobrycon . The UCE phylogeny indicates the diversification of Bryconamericus , Diapoma , Piabarchus , and Piabina may be associated with the expansion from Paraguay basin to the upper Paraná, Uruguay, and São Francisco basins ( Fig. 3).