Spintherobolidae Mirande, 2019, new usage

Type genus: Spintherobolus Eigenmann, 1911.

Included genera: Amazonspinther Bührnheim et al., 2008 and Spintherobolus.

Definition: The least inclusive crown clade that contains Amazonspinther dalmata Bührnheim et al., 2008 and Spintherobolus papilliferus Eigenmann, 1911. This is a minimum-crown-clade definition. See Figure 3 for a reference phylogeny of Spintherobolidae.

Etymology: From the ancient Greek σπινθΗΡο (spɪnθˈɜːɹo͡ʊ) meaning a spark and Βόƛος (bˈo͡ʊlo͡ʊz) meaning a throw with a casting net.

Remarks: We delimit the family Spintherobolidae to include Amazonspinther and all species of Spintherobolus as the sister-lineage of a clade containing Stevardiidae, Characidae, and Acestrorhamphidae (Figs 2, 3). Spintherobolidae are supported by 15 unambiguous synapomorphies relative to Cheirodontinae (Bührnheim et al. 2008), 10 of which are extensively discussed as synapomorphies for Spintherobolus (Malabarba 1998; (Weitzman and Malabarba 1998) or a clade containing A. dalmata and Spintherobolus (Bührnheim et al. 2008). The lack of the mesocoracoid was also proposed as a synapomorphy for Amazonspinther and Spintherobolus (Mirande 2019), thus reinterpreted here as synapomorphic for the Spintherobolidae.

Bührnheim et al. (2008) hypothesized Spintherobolus and Amazonspinther as sister to Cheirodontinae. The clade Spintherobolus and Amazonspinther has not been resolved as closely related to Cheirodontinae, but rather the sister-group of all other characids (Mariguela et al. 2013, Melo et al. 2022a). Phylogenies inferred from a combined molecular and morphological dataset resolved former Spintherobolinae (Amazonspinther, Atopomesus Myers, 1927, and Spintherobolus) as the sister-group of all characids except former Stethaprioninae (Mirande 2019). Only morphological data were available for Atopomesus and its resolution within Spintherobolinae had low statistical support (Mirande 2019); phylogenetic analysis of the UCE loci resolves Atopomesus with high support in a distinct clade within the Characinae. The phylogeny inferred from the UCE loci offers a compelling hypothesis that Spintherobolus and Amazonspinther form the sister-group of a clade containing Acestrorhamphidae, Stevardiidae, and Characidae (Betancur-R et al. 2019, Melo et al. 2022a; present study).