Gobio kizilirmakensis Common name. Filyos gudgeon. Diagnosis. Distinguished from other species of Gobio in Anatolia by: ○ 40–43 total lateral-line scales / ○ chest completely scaled, scales extending forward to or almost to isthmus / ○ head length 26–29 % SL / ○ scales on belly smaller than pupil / ○ caudal-peduncle length 2.1–2.7 times its depth / ○ 5–6 scale rows between anus and anal origin / ○ 8–10 scale rows between posterior extremity of pelvic base and anus / ○ 8–9 mid-lateral blotches. Size up to 111 mm SL. Distribution. Türkiye: Ulusu in Filyos drainage. Habitat. Moderately fast-flowing streams and small rivers with sandy or gravelly bottoms. Biology. No data. Conservation status. EN; appears to be declining within its very small range. Some food factories around Çerkes heavily pollute the Ulusu. Remarks. Despite its name, this species does not occur in Kızılırmak drainage. The Ulusu was considered a tributary of Kızılırmak, but it belongs to Filyos. Further reading. Turan et al. 2016a (description); Yoğurtçuoğlu et al. 2020a (distribution).

Published as part of Freyhof, Jörg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, GmbH, Berlin / Boston :De Gruyter on page 260, DOI: 10.1515/9783111677811, http://zenodo.org/record/17881367