humerosus, Potamotrygon Garman [S.] 1913:419 [Memoirs of the Museum of Comparative Zoology v. 36; ref. 1545] Rio Parietuba at Monte Alegre, Pará, Brazil. Holotype (unique): MCZ 299-S. Type catalog: Hartel & Dingerkus 1997:xliv [ref. 23119]. Castex 1964:27 [ref. 20924] said there was a holotype and a paratype at MCZ. •Synonym of Potamotrygon orbignyi (Castelnau 1855) -- (Carvalho et al. in Reis et al. 2003:25 [ref. 27061]). •Valid as Potamotrygon humerosa Garman 1913 -- (Castex 1964:26 [ref. 20924] as humerosus, Hartel & Dingerkus 1997:xix [ref. 23119], Compagno 1999:495 [ref. 25589], Almeida et al. 2008:85 [ref. 40894], Carvalho et al. 2011:26 [ref. 31264], Fontenelle et al. 2014:150 [ref. 33180], Silva & Carvalho 2015:45 [ref. 33871], Weigmann 2016:155 [ref. 34211], Carvalho et al. 2016:581 [ref. 34422], Carvalho 2016:59 [ref. 34730], Carvalho 2016:635 [ref. 34997], Silvano et al. 2020:404 [ref. 38134], Roberts 2021:99 [ref. 38077], Carvalho-Filho 2023:321 [ref. 40480]). Current status: Valid as Potamotrygon humerosa Garman 1913. Potamotrygonidae: Potamotrygoninae. Distribution: South America: Amazon River basin (Brazil) and possibly Orinoco basin. Habitat: freshwater.