Esmaeilius, Freyhof & Yoğurtçuoğlu, 2020

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 736

Esmaeilius

Persian killifish is a genus of six species widespread in Iran and the lower Shatt al Arab in Iraq. All species inhabit inland habitats, such as the shores of rivers, streams, and springs. Many populations, often largely isolated, indicate a much wider distribution range in the recent geological past, and many populations might have become isolated only a few thousand years ago. The distribution of these fishes reflects the interesting geological history of the Zagros Mountains. Some geographically distantly isolated populations were described as separate species during their discovery. However, subsequent analysis revealed that many of these are very closely related, morphologically indistinguishable and that those previously identified as E. arakensis , E. kavirensis , E. mesopotamicus , or E. pluristriatus are now considered synonymous with E. sophiae . Many populations have been lost recently due to the unsustainable exploitation of freshwater resources and the increasing aridity of Central Iran, which is also a consequence of climate change.

Further reading. Freyhof & Yoğurtçuoğlu 2020 (description, species diversity).

Key to species of Esmaeilius

1a - Male with black dorsal, pelvic, and anal margins. ……………… E. isfahanensis

1b - Male with white dorsal, pelvic, and anal margins. ………………2

2a - Female with distinct, short, brown bars along lateral midline. ……………… E. persicus

2b - Female with irregular set brown or dark-grey spots and blotches, blotches sometimes slightly vertically elongated. ………………3

3a - 36–47 total scales in lateral series; female without bold black spot at middle caudal base. ……………… E. vladykovi

3b - 23–32 total scales in lateral series; female with bold black spot at middle caudal base, absent or very small in E. shirini . ………………4

4a - Male usually with 7–10 wide flank bars. ……………… E. shirini

4b - Male with 10–19, usually 11–16, narrow flank bars. ………………5

5a - Female with a midlateral series of short, slightly vertically elongated blotches. ……………… E. darabensis

5b - Female with a pattern of spots and irregularly shaped blotches not organised in a midlateral series. ……………… E. sophiae