volcanus, Gnatholepis Herre [A. W. C. T.] 1927:131 [Monographs, Bureau of Science Manila Monogr. 23; ref. 2104] Lake Taal, Batangas Province, Luzon Island, Philippines. Holotype (unique): BSMP 10569 (destroyed, seen by Koumans). Type catalog: Koumans 1940:184 [ref. 2676]. •Possibly in the genus Istigobius or Aulopareia -- (Randall & Greenfield 2001:1 [ref. 25675]). •Possible species of Arcygobius -- (Larson & Wright 2003:128 [ref. 27481]). •Possible in Exyrias -- (Larson & Buckle 2012:5 [ref. 32272]). •Valid as Exyrias volcanus (Herre 1927) -- (Jamandre 2023:168 [ref. 40455]). •Species inquirenda in Exyrias Jordan & Seale 1906 -- (Kottelat 2013:407 [ref. 32989], Parenti 2021:440 [ref. 38603], Larson & Jaafar 2022:494 [ref. 39363]). Nomen Dubium. Oxudercidae: Gobionellinae. Habitat: freshwater.