Garra gymnothorax

biology_ecology

Habitat. Streams and rivers of all kinds, as long as there are at least small areas of rock or gravel. Biology. Lives up to 4 years. Spawns March−September with a peak in May−June. Usually total spawners. Benthic grazer feeding on algae, cyanobacteria, and small invertebrates scraped from hard surfaces such as stones, roots, and plants.

Handbook of Freshwater Fishes of West Asia

diagnosis

Diagnosis. Distinguished from other species of Garra in Persian Gulf and endorheic basins in Iran by: ○ chest without or with normally sized, often embedded scales / ○ mid-dorsal area in front of dorsal origin covered by embedded scales / ○ usually 8 ½ branched dorsal rays / ○ 9 + 8 branched caudal rays / ○ 17 − 23 gill rakers / ○ 32 – 37 total scales along lateral line / 13 – 17 circumpeduncular scale rows / ○ two pairs of normally developed barbels / ○ gular disc fully developed / ○ lateral and distal margin of labrum of gular disc free from skin of chin / ○ body brown or grey, usually mottled / ○ eye fully developed. Size up to 151 mm SL.

Handbook of Freshwater Fishes of West Asia

discussion

Remarks. Garra gymnothorax was described based on fish from the Karun having a naked chest, whereas most Garra from the Euphrates, Tigris, Karun (and Karkheh) have a scaled chest. In the Karun and Karkheh, there is an endemic mtDNA lineage of Garra that is well differentiated from G. rufa. This endemic mtDNA lineage is found in fish with naked as well as with scaled chests. Fish containing mitochondria with this endemic sequence have been identified as G. gymnothorax. No known morphological characters distinguish fish with mtDNA of “ G. gymnothorax ” from those with mtDNA of G. rufa. While all fish in Karun and Karkheh have G. gymnothorax mtDNA, genome-wide SNP data show that many populations in Karun (including fish at the type locality of G. gymnothorax) are hybrids between “ G. gymnothorax ” and G. rufa. Both G. gymnothorax and G. rufa mtDNA are found in Karun, suggesting extensive hybridisation between the two species.

Handbook of Freshwater Fishes of West Asia

distribution

Distribution. Iran: Karun and Karkheh drainages. Most populations in Karun are hybrids with G. rufa.

Handbook of Freshwater Fishes of West Asia