diadema, Acara Heckel [J. J.] 1840:344 [Annalen des Wiener Museums der Naturgeschichte v. 2; ref. 2064] Marabitanos, River Negro, Venezuela. Syntypes: NMW 33791 (1), 33797 (1). •Valid as Aequidens diadema (Heckel 1840) -- (Kullander 1986:348 [ref. 12439], Ortega & Vari 1986:20 [ref. 9708], Lasso & Machado-Allison 2000:34 [ref. 27968], Kullander in Reis et al. 2003:608 [ref. 27061], Barriga Salazar 2014:117 [ref. 35745] as cf. diadema, Hernández-Acevedo et al. 2015:104 [ref. 34438], DoNascimiento et al. 2017:99 [ref. 35633], Urbano-Bonilla et al. 2018:91 [ref. 35773], Meza-Vargas et al. 2021:27 [ref. 39298]). Current status: Valid as Aequidens diadema (Heckel 1840). Cichlidae: Cichlinae. Distribution: South America: Amazon and Orinoco river basins (Brazil, Colombia, ?Ecuador, Peru and Venezuela). Habitat: freshwater.