nikkonis, Elxis Jordan [D. S.] & Fowler [H. W.] 1903:768, Fig. 1 [Proceedings of the United States National Museum v. 26 (no. 1332); ref. 2461] Chitose in Iburi, Hokkaido, Japan. Holotype: CAS-SU 7848. Paratypes or additional material: CAS-SU 7147 (1), 7485 (8). Type catalog: Böhlke 1953:39 [ref. 12291]. •Synonym of Lefua costata (Kessler 1876), but a valid subspecies -- (Kawanabe & Mizuno 1989:401 [ref. 25598], Pietsch et al. 2001:140 [ref. 25688]). •Valid as Lefua nikkonis (Jordan & Fowler 1903) -- (Okada 1961:549 [ref. 6363], Sawada in Masuda et al. 1984:59 [ref. 6441], Watanabe 1998:263 [ref. 23491], Nakabo 2000:277 [ref. 25086], Matsuura et al. 2000:169 [ref. 26000], Nakabo 2002:277 [ref. 26001], Mihara et al. 2005:157 [ref. 28201], Kottelat 2012:87 [ref. 32367], Dyldin & Orlov 2016:670 [ref. 34853], Hosoya et al. 2018:200 [ref. 36197], Ito et al. 2019:486 [ref. 36659], Ohgita & Matsunuma 2020:11 [ref. 37953], Dyldin et al. 2021:19 [ref. 38804], Dyldin & Orlov 2021:63 [ref. 38158], Dyldin et al. 2023:[9] [ref. 40328]). Current status: Valid as Lefua nikkonis (Jordan & Fowler 1903). Nemacheilidae. Distribution: East Asia: Hokkaido (Japan), Sakhalin Island (Russia). Habitat: freshwater.