Rutilus

Rutilus are small- to large-sized fishes endemic to Europe, North-West, and Central Asia. In West Asia, only five species occur, with two endemic to Azerbaijan: R. atropatenus and R. sojuchbulagi. Both are poorly known and have been placed in the genus Pseudophoxinus until recently. Many subspecies and variants of the roach, R. rutilus, have been described, particularly from the Caspian basin. All can be identified as R. lacustris. Rutilus rutilus has a restricted range in West Asia, while R. lacustris and R. rutilus are largely allopatric in West Asia, both species have large hybrid zones in Europe. An attempt was made to split the genus Rutilus into three smaller genera (Leucos, Rutilus, and Sarmarutilus). Finally, most ichthyologists did not accept it as all these genera are poorly distinguished and closely related. We agree with this view and maintain the current classification of all Rutilus species as a single genus.

Further reading. Bianco & Ketmaier 2014 (molecular phylogeny, genera); Artaev et al. 2021 (R. rutilus, R. lacustris).

Key to species of Rutilus in West Asia

1a - 53–64+3 lateral-line scales. ……………… R. frisii

1b - 34–42+3 lateral-line scales. ………………2

2a - 34–38+2–3 lateral-line scales; 6–7 scales between dorsal origin and lateral line. ………………3

2b - 39–42+2–3 lateral-line scales; 7–9 scales between dorsal origin and lateral line. ………………4

3a - Tip of snout at or below horizontal level of lower eye margin. ……………… R. sojuchbulagi

3b - Tip of snout above horizontal level of lower eye margin. ……………… R. atropatenus

4a - Pectoral, pelvic, and anal orange to red; iris from yellow in juveniles to deep red in adults. ……………… R. rutilus

4b - Pectoral, pelvic, and anal hyaline, yellowish to dark-grey; iris whitish to pale yellow. ……………… R. lacustris