Cyprinion, Heckel, 1843

Cyprinion View in CoL

Lotaks are a small genus known from Arabia, the Persian Gulf basin, adjacent Iran and Pakistan, east to the Indus drainage. They are medium-sized fish that inhabit a wide range of running waters, from fast-flowing mountain torrents to brackish desert and coastal streams. Lotaks can be identified by their usually 7½, rarely 6½, branched anal rays (compared with 5−6½ in other barbels), laterally compressed body, the sharp edge on the lower jaw (except in C. milesi ), one pair of barbels,the serrated posterior margin of the last unbranched dorsal ray, and the 12½−17½ branched dorsal rays. They are related to South and Southeast Asian genera, such as Semiplotus and Scaphiodontichthys , but the relationships in this group of fishes are poorly understood.

To the extent that they have been studied, lotaks are diploid,with2 n = 50chromosomes.Molecular data suggest that

Cyprinion hybridised with the ancestors of Capoeta and Labeobarbus and was thus involved in the allo-polyploidisation event that led to the formation of these genera. All but one of the lotaks occur in West Asia. Only C. watsoni is described from outside the region, from the rivers of the Sind Hills and the Salt Range in the Indus drainage of Pakistan.

While Cyprinion is relatively tolerant of water pollution and salinisation, it is sensitive to low temperatures and absent from the mountainous headwaters of the Euphrates in Eastern Anatolia. They feed on a wide variety of food, usually periphyton, but will take whatever is available.They spawn in flowing water,laying their eggs between gravel and rocks.Nuptial male lotaks can be territorial and aggressively defend spawning sites against other males.

Further reading. Banister & Clarke 1977;Krupp 1983 (Arabian species,identification); Yang et al. 2015 (phylogenetic position).

Keys to Cyprinion in West Asia

Arabian Peninsula

1a - Last unbranched dorsal ray short, thin, serrated along proximal third of ray in large individuals;14−16 circumpeduncular scales. ……………… C. muscatense

1b - Last unbranched dorsal ray long, thick, serrated along almost entire length in large individuals; 16−22 circumpeduncular scales. ………………2

2a - 19−22 circumpeduncular scales; 8−9 scales between lateral line and dorsal origin. ……………… C. mhalense

2b - 16−18 circumpeduncular scales; 6−7 scales between lateral line and dorsal origin. ……………… C. acinaces

Persian Gulf and Iranian endorheic basin

1a - Mouth subterminal, oblique in lateral view, clearly U-shaped. ……………… C. milesi

1b - Mouth inferior, variably arched to transverse. ………………2

2a - Mouth semi-circular, lower jaw finger-like with papillious median pad on lower lip in adults larger than

100 mm SL. ……………… C. kais

2b - Mouth straight, with sharp cutting edge on lower jaw,without papillious central pad on lower lip; no large lateral lobes on lower lip. ………………3

3a - 9−12½, usually 10−11½, branched dorsal rays; orange spots along lateral line. ……………… C. microphthalmum

3b - 11−17½, usually 12−15½, branched dorsal rays; no orange spots along lateral line. ………………4

4a - Posterior dorsal margin moderately to markedly concave; 39−45, usually 40−44, total lateral-line scales. ……………… C. macrostomum

4b - Posterior dorsal margin about straight or slightly concave; 32−39, usually 34−38, total lateral-line scales. ……………… C. tenuiradius