Esmaeilius persicus, Jenkins, 1910

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 740-742

Esmaeilius persicus

Common name. Maharlo killifish.

Diagnosis. Distinguished from other species of Esmaeilius by: ● female with distinct, brown bars along lateral midline / ○ male with narrow white anal, dorsal, and pelvic margin / ○ female with a distinctive black spot at caudal base / ○ 24–29 total scales along lateral series. Size up to 35 mm SL.

Distribution. Iran: Lake Maharlo basin.

Habitat. Small freshwater or brackish springs and pools, usually without vegetation.

Biology. Live up to 4 years, mature in a few months, usually late in year of birth. Males establish territories along banks, usually in dense vegetation, but also between rocks, which they defend against rivals. Spawns April–November (Barm-e Shur spring). Females spawn with one or more males, usually in vegetation near surface or in gravel beds. Few eggs are laid in substrate during a spawning event. Individual females may produce several clutches in one day. Feeds on algae, detritus and small invertebrates.

Conservation status. Extinct in the wild; found only in one spring in 2013 but seems to have disappeared from nature since. Water abstraction, habitat destruction, pollution, introduction of non-native species and reduced

rainfall due to climate change have caused all populations to vanish and springs to dry up.

Remarks. Very few female E. persicus lack the diagnostic narrow brown bars on the flanks but have a mottled pattern. This species was called Aphanius farsicus between 2011 and 2020.

Further reading. Monsefi et al. 2009 (reproduction); Teimori et al. 2011 ( A. farsicus ); Esmaeili et al. 2020b (molecular data and distribution); Freyhof & Yoğurtçuoğlu 2020 (generic position, discussion of Brachylebias , E. persicus ).

Aphanius persicus : Forward and back again. Aphanius persicus (Jenkins, 1910) was previously known as the scientific name of the Maharlo killifish. When Gaudant (2011) studied the fossil killifish Brachylebias persicus Priem, 1908 , he concluded that this must be a species of Aphanius and thus transferred B. persicus to Aphanius . Consequently, A. persicus (Jenkins, 1910) became a junior secondary homonym of A. persicus (Priem, 1908) . As the name A. persicus was no longer available for the Maharlo killifish, it was redescribed as A. farsicus . However, upon the separation of the phylogenetic groups of Aphanius into different genera, Brachylebias was considered incertae sedis, as there were no arguments to place it in one of the recognised genera, and it could not be excluded that it represents a distinct (extinct) evolutionary lineage. As it is highly unlikely that Brachylebias might have been a species of Esmaeilius , it was transferred back to Brachylebias . As a result of this reclassification, Aphanius farsicus became a junior synonym of A. persicus (Jenkins, 1910) , and the latter name is once again available for the Maharlo killifish. This species was then transferred to the new genus Esmaeilius . Further reading. Freyhof & Yoğurtçuoğlu 2020 ( A. persicus and Brachylebias ).

Water is extracted from springs everywhere in West Asia,such as in Pirbanoo in Iran. The picture was taken a few weeks before the spring dried out and one of the last populations of Esmaeilius persicus vanished in 2007.

Esmaeilius shirini ; Khosroshirin spring, Iran; female, ~ 35 mm SL. Esmaeilius shirini ; Khosroshirin spring, Iran; male, ~ 30 mm SL.