pygmaeus, Corydoras Knaack [J.] 1966:168, 2 figs. [Die Aquarien- und Terrarienzeitschrift (DATZ) v. 19 (no. 6); ref. 19253] Near Calama, 8°05'S, 62°52'W, along Rio Madeira near mouth of Rio Jipiraná (= River Machado), Rondônia State, Brazil. Holotype: ZMB 21620. Paratype: ZMB 21621 (1). Type catalog: Ferraris 2007:123 [ref. 29155]. Appeared first as above, then in Knaack 1966:364 [ref. 19252]. •Valid as Corydoras pygmaeus Knaack 1966 -- (Nijssen & Isbrücker 1980:214 [ref. 6910], Burgess 1989:367 [ref. 12860], Isbrücker 2001:233 [ref. 26805], Britto et al. 2002:733 [ref. 26546], Reis in Reis et al. 2003:302 [ref. 27061], Ferraris 2007:123 [ref. 29155], Tencatt et al. 2013:258 [ref. 32752], Barriga Salazar 2014:111 [ref. 35745], Ohara et al. 2016:550 [ref. 34772], Tencatt & Ohara 2016:[13] [ref. 34353], Tencatt et al. 2016:[17] [ref. 34388], DoNascimiento et al. 2017:73 [ref. 35633], Grant 2019:7 [ref. 37238], Meza-Vargas et al. 2021:25 [ref. 39298]). •Valid as Gastrodermus pygmaeus -- (Dias et al. 2024:24 [ref. 41219]). Current status: Valid as Gastrodermus pygmaeus (Knaack 1966). Callichthyidae: Corydoradinae. Distribution: South America: Amazon basin (Brazil, Colombia, Ecuador and Peru). Habitat: freshwater.