Chondrostoma turnai

Common name. Menderes nase.

Diagnosis. Distinguished from other species of Chondrostoma in Aegean, Marmara, and Black Sea basins by: ○ 44−54 total lateral-line scales / ○ 6−6, rarely 5–6 or 5–5, pharyngeal teeth / ○ 8½ branched dorsal rays / ○ 9−10½ branched anal rays / ○ 19−27 gill rakers / ○ thick cornified sheath covering lower lip / ○ usually 8 branched pelvic rays. Size up to 240 mm SL.

Distribution. Türkiye: Tahtalı, Küçük, and Büyük Menderes drainages.

Habitat. Moderate to fast-flowing large to medium-sized rivers with rocky or gravel bottoms. Spawns in fast-flowing water on shallow gravel beds, often in small tributaries.

Biology. Feed on periphyton scraped from hard substrate.

Conservation status. LC; disappeared from the Küçük Menderes drainage, which is now dry in upper and heavily polluted in lower reaches.

Remarks. Populations from Tahtalı were described as C. smyrnae based on very small molecular differences only. Morphological characters distinguishing C. smyrnae from C. turnai could not be confirmed based on our material, and C. smyrnae is treated as a synonym of C. turnai.

Further reading. Güçlü et al. 2018 (description); Küçük et al. 2021 (phylogeny, description of C. smyrnae).