perdido, Oligosarcus Ribeiro [A. C.], Cavallaro [M. R.] & Froehlich [O.] 2007:44, Figs. 1-4 [Zootaxa No. 1560; ref. 29321] Bridge over Rio Perdido, Harmonia farm, Munic. area of Porto Murtinho, Mato Grosso do Sul, Brazil, 21°17"07"S, 56°41'45"W. Holotype: MZUSP 94691. Paratypes: LIRP 5890 (2), 5891 (1), 5893 (1), 5894 (2), 5896 (5, 2 c&s). Plus non-type materiaal. •Valid as Oligosarcus perdido Ribeiro, Cavallaro & Froehlich 2007 -- (Ribeiro & Menezes 2015:78 [ref. 33768], Wendt et al. 2019:5 [ref. 36952], Menezes & Camelier 2024:244 [ref. 40817]). Current status: Valid as Oligosarcus perdido Ribeiro, Cavallaro & Froehlich 2007. Acestrorhamphidae: Acestrorhamphinae. Distribution: South America: Apa River drainage, upper Paraguay River basin, Brazil. Habitat: freshwater.