nigronotatus, Gobius Kessler [K. F.] 1877:31, Pl. 2 (fig. 7) [The Aralo-Caspian Expedition; ref. 2597] Fort Shevchenko [Aleksandrovskiy], Caspian Sea, Kazakhstan, depth 140 feet [20 Russian fathoms]. Holotype (unique): probably not at ZIN. Kessler specimens: ZIN 10907 (2) Baku. •Synonym of Mesogobius nonultimus (Iljin 1936) -- (Pinchuk & Miller in Miller 2004:132 [ref. 27853] with question). •Valid as Mesogobius nigronotatus (Kessler 1877) -- (Berg 1949:1099 [ref. 20662], Coad 1995:30 [ref. 23608] with question, Reshetnikov et al. 1997:755 [ref. 24702], Vasil'eva 1998:137 [ref. 23591], Bogutskaya & Naseka 2004:226 [ref. 28183], Neilson & Stepien 2009:97 [ref. 30487], Freyhof 2011:284 [ref. 31742] with question, Esmaeili et al. 2010:377 [ref. 33391], Jouladeh-Roudbar et al. 2015:898 [ref. 34062], Esmaeili et al. 2017:83 [ref. 35254], Esmaeili et al. 2018:64 [ref. 36089], Parenti 2021:72 [ref. 38603]). Current status: Valid as Mesogobius nigronotatus (Kessler 1877). Gobiidae: Gobiinae. Distribution: Eurasia: Caspian Sea basin. Habitat: brackish.