Family Cobitidae

Spined loaches

A family of small, slender fishes found in Morocco, Europe, and Asia. It is most diverse in Southeast and East Asia, with approximately 240 species in 18 genera. Two genera are found in West Asia. They are distinguished by an erectile, movable, usually bifid, suborbital spine, hidden under the skin in some species. Many spined loaches exhibit external sexual dimorphism. In Cobitis, the male has a modified pectoral, which is usually much larger than the female’s pectoral, and the male is smaller than the female. In Sabanejewia, there are no size differences between the sexes, but the male exhibits vertical swellings of the flanks. All Cobitidae are benthic, living on the substrate, and all prey on small invertebrates. The pigmentation of spined loaches is a useful diagnostic feature. Its pattern is organised in one series of blotches on the back and up to four pigmentation zones on the flank, described as Gambetta’s longitudinal pigmentation zones. These zones are abbreviated as Z1 to Z4, starting with Z1 as the narrow line immediately below the mid-dorsal row of blotches and Z4 as the midlateral row of blotches. Furthermore, most species exhibit one or two black spots on the caudal base, which may be fused to form a bar in Sabanejewia. In Sabanejewia and several Cobitis species, the Gambetta zones are either incompletely developed or dissociated.

Three East Asian species of weatherfish (Misgurnus anguillicaudatus, M. bipartitus, Paramisgurnus dabryanus) are non-native in Europe and are anticipated to be found in West Asia in the near future. Their spread is facilitated by the use of non-biosave stocking materials of carp and other aquaculture fishes and through the pond and aquarium trade. East Asian weatherfish are pale-brownish with numerous dark-brown spots and small blotches, forwarddirected barbels, and a mental lobe that is prolonged into two long, barbel-like projections (vs. mental lobe absent or with one very short projection in Cobitis and Sabanejewia).

Further reading. Gambetta 1934 (pigmentation pattern); Nalbant 1963 (genera); Sawada 1982 (morphology); Ludwig et al. 2001 (molecular phylogeny); Kottelat 2012 (diversity); Geiger et al. 2014 (molecular diversity in Mediterranean); Zangl et al. 2020 (Misgurnus invasion).

Key to genera of Cobitidae in West Asia

1a - Body pigmentation usually organised in 1 dorsal and 2 lateral longitudinal zones; 12 branched caudal rays. ……………… Sabanejewia

1b - Body pigmentation usually organised in 1 dorsal and 4 lateral longitudinal zones; 14 branched caudal rays. ……………… Cobitis