Acheilognathidae, Bleeker, 1863

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 82-83

Family Acheilognathidae

Bitterlings

A family that includes about 75 species placed in seven genera distributed mostly in East Asia. Bitterlings are deep-bodied, compressed, and small-sized fishes. Males have plates bearing tubercles on the snout. All species have a complex reproduction cycle involving mussels. The female has a long, flexible ovipositor, which she inserts into the mussel’s exhalant siphon to deposit a few eggs. The diversity of Rhodeus in West Asia and Europe is likely overestimated. All populations are very closely related, and external characters distinguish only R. colchicus . The most comprehensive phylogenetic analyses identified six different molecular groups of populations. These include R. colchicus (eastern Black Sea basin), R. caspius (southern Caspian basin), R. meridionalis (Vardar & Pinios in Greece and North Macedonia), R. amarus (Europe from east to Elbe drainage, Black Sea basin). Two additional lineages occur, one in the Danube,the Ionian Sea basin,and Central Europe west of the Elbe drainage, and a last one in the Strymon and a few adjacent rivers in the northern Aegean basin. The phylogenetic structure of these six clades is poorly supported. Therefore, R. colchicus might be the sister group of all other western Palearctic bitterlings. This would mean that all these populations can be identified as R. amarus , as they are closely related and not distinguished by morphological characters. However, a consensus on the species status of R. colchicus has not yet been reached. Thus, we retain R. amarus , R. caspius , and R. colchicus as separate species in West Asia. Further reading. Arai & Akai 1988 (systematics); Okazaki et al. 2001 (genetics); Liu et al. 2006 (host specificity); Bartáková et al. 2019 (phylogeny).

Rhodeus amarus ; oviposition; Danube drainage, Germany; male (left) and female (right, with ovipositor), ~ 50 mm SL. © A. Hartl.

Open Access. © 2025 JÖrg Freyhof, Baran Yoğurtçuoğlu, Arash Jouladeh-Roudbar and Cüneyt Kaya, published by De Gruyter. the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

https://doi.org/10.1515/9783111677811-013

This work is licensed under Rhodeus amarus ; Odra drainage, Germany; female, ~ 45 mm SL.

Rhodeus amarus ; Sakarya, Türkiye; male, ~ 60 mm SL.