Cyprinion milesi (Day, 1880)

Cyprinion milesi View in CoL View Figure

Common name. Bighead lotak.

Diagnosis. Distinguished from other species of Cyprinion in Persian Gulf and Iranian endorheic basins by: ● mouth subterminal, oblique in lateral view, clearly U-shaped / ○ no lateral lobes or pad on lower lip / ○ 11−12 gill rakers / ○ 34−39 total lateral-line scales / ○ last unbranched dorsal ray variably thick, weakly to strongly ossified and variably serrated / ○ dorsal margin straight / ○ 10−13½ branched dorsal rays / ○ back in front of dorsal usually without naked median area / ○ scales present on belly. Size up to 190 mm SL.

Distribution View Figure . Iran: Tang-e Sarhe toward Sarbaz and Mashkid, reported from Akar Kaur (Gwadar/ Pakistan), both adjacent in Makran region. Also, in endorheic basins in Pakistan such as Kalat and Quetta, in Bampur and near Guadjik in Baschakird mountains, and in Panjgur basin.

Habitat. Streams and pools with fresh or brackish waters.

Biology. No data.

Conservation status. VU; thought to be declining in its small range, mainly due to desiccation of streams.

Remarks. A subterminal and moderately oblique mouth (in lateral view) is also found in individuals identical to C. microphthalmum in their mitochondrial DNA. The taxonomic status of C. milesi -like fishes in Iran requires further study. Cyprinion milesi is very similar to C. watsoni from the Indus, and it needs to be clarified if both are distinct.

Further reading. Mirza 1972 (distribution); Howes 1982 (anatomy); Nasri et al. 2013 (morphometrics); Nasri et al. 2016 (morphology); Coad 2021a (biology, morphology).

Cyprinion milesi in Iran. Cyprinion milesi is readily distinguishable from other Cyprinion species in West Asia by its subterminal, clearly U-shaped mouth, which lacks the sharp cutting-edge characteristic of most Cyprinion . There are numerous records of C. milesi from the southern Persian Gulf basin in Iran, all based on Cyprinion with a subterminal, clearly U-shaped mouth, without a cutting edge on the lower jaw. These C. milesi are often found at the same localities as C. microphthalmum . It has been proposed that C. milesi is merely a morph of the latter species, retaining juvenile features in the mouth’s structure. During the fieldwork for this book, we examined such individuals. Except for the head and mouth shape, these fish are indistinguishable from the syntopic C. microphthalmum . Mitochondrial molecular data support the view that these are aberrant individuals of C. microphthalmum . However, it cannot be ruled out that these are C. milesi carrying mtDNA of C. microphthalmum due to past introgressive hybridisation. Cyprinion milesi carrying its own mtDNA has been found in a few rivers, e.g., Bahukalat, Tang-e Sarhe, and Iranian Sarbarz. However, it is expected to be more common in adjacent Pakistan. In the future, it would be beneficial to conduct further research into the evolutionary and ontogenetic background of “aberrant” individuals of C. microphthalmum .