Ponticola gorlap (Iljin, 1949)

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 669-670

Ponticola gorlap

Common name. Caspian bighead goby.

Diagnosis. Distinguished from other species of Ponticola entering freshwater in West Asia by: ○ lower jaw strongly prognathous / ○ lateral part of upper lip not swollen / ○ pelvic disc reaching 75–95 % of distance between its origin and anus / ○ 60–71 total scales in midlateral series / ○ 23–28 predorsal scales / ○ two suborbital transverse rows below suborbital longitudinal row b / ○ flank mottled / ○ first dorsal without bold, distal dark-brown band / ○ pectoral base with a black blotch / ○ no dark-brown blotches on anterior part of first dorsal / ○ pelvic-disc fraenum with angular lobes whose length is 1 ⁄ 6 – 1 ⁄ 2 of fraenum width at base. Size up to 200 mm SL.

Distribution. Coastal rivers of Azerbaijani and Iranian Caspian coasts. Also, in sea, Volga upstream to Astrakhan until 1977, then spread upstream to lakes Ivankovskoje and Rybinskoje (2000). Invaded Don drainage (Black Sea basin) through Volga-Don canal (first record 1972). Now abundant in Lake Tsimlyansk and lower Don.

Habitat. Inshore habitats, lakes, estuaries, brackish and freshwater lagoons, and large rivers, harbors, on rocky bottoms. Mainly found on well-vegetated or rocky bottoms.

Biology. Most females spawn for first time at 1 year, male at 2 years. Spawns April–May, rarely until July. Adhesive eggs laid on stones, shells, and aquatic vegetation. Male guard eggs until hatching. Feeds mainly on small fish and a variety of invertebrates.

Conservation status. LC.

Remarks. In the lower and middle Kura, it may occur in sympatry with superficially similar P. cyrius . Previously, P. iljini was treated as a synonym of P. gorlap . Still, new research has shown it to be a valid species restricted to the coast of Mangyshlak peninsula in Kazakhstan.

Further reading. Vasil’eva & Vasil’ev 1996 (description as N. iljini ); Kottelat 1997 (nomenclature); Vasil’eva & Vasil’ev 2003d (biology, description); Vasil’eva et al. 2016 (description of P. iljini ).