retropinnus, Phenacogaster Lucena [Z. M. S. de] & Malabarba [L. R.] 2010:280, Fig. 10 [Zoologia (Sociedade Brasileira de Zoologia) v. 27 (no. 2); ref. 30880] Rio Aripuanã, 3 kilometers abaixo da cachoeira Dardaanelos, Rio Madeira system, Mato Grosso, Brazil. Holotype: INPA 31367. Paratypes: (many) at ANSP, INPA, MCP, MZUSP. Species epithet treated as a noun. •Valid as Phenacogaster retropinnus Lucena & Malabarba 2010 -- (Antonetti et al. 2018:279 [ref. 36204] as retropinna, Souza et al. 2023:15 [ref. 40222] as retropinna). Current status: Valid as Phenacogaster retropinnus Lucena & Malabarba 2010. Characidae: Characinae. Distribution: South America: Negro, Madeira, Xingu and Tapajós-Araguaia River basins, Brazil. Habitat: freshwater.