caspius, Syngnathus Eichwald [C. E. von] 1831:61 [Zoologia specialis quam expositis animalibus tum vivis Pars posterior [3]; ref. 5562] Balkhan Bay, Caspian Sea. Syntypes: whereabouts unknown. Also appeared as new in Eichward 1838:106 [ref. 34622]. •Synonym of Syngnathus nigrolineatus Eichwald 1831, but a valid subspecies caspius Eichwald 1831 -- (Berg 1949:982 [ref. 20662], Mitrofanov & Dukravec 1989:121 [ref. 37748], Reshetnikov et al. 1997:748 [ref. 24702], Savvaitova 1998:114 [ref. 23594]). •Synonym of Syngnathus abaster Risso 1827 -- (Coad 1995:27 [ref. 23608], Kottelat 1997:167 [ref. 22952]). •Valid as Syngnathus caspius Eichwald 1831 -- (Esmaeili et al. 2010:375 [ref. 33391], Jouladeh-Roudbar et al. 2015:895 [ref. 34062], Esmaeili et al. 2017:94 [ref. 35254], Esmaeili et al. 2018:76 [ref. 36089], Jouladeh-Roudbar et al. 2020:224 [ref. 37983], Kuljanishvili et al. 2020:[7] [ref. 37535], Zarei et al. 2021:6 [ref. 38231], Çiçek et al. 2024:298 [ref. 40789]). Current status: Valid as Syngnathus caspius Eichwald 1831. Syngnathidae: Syngnathinae. Distribution: Eurasia: Caspian Sea basin. Habitat: freshwater, brackish.