Key to Species of the genus Gonorhynchus A dichotomous key was constructed for Gonorhynchus based on data collected here and characters reported in Menon & Jacob (1996) for G. periyarensis. Species distributions by river basin are provided in parentheses after species names. 1 Triangular rostral flaps present on tip of snout......................................... G. bicor nis (Salween River) - Rostral flaps absent................................................................................... 2 2 Large specimens (> 65 mm SL) with tubercles on snout and cheeks............................................. 3 - Large specimens without tubercles....................................................................... 4 3 15–17 rakers on first gill arch, tubercles only on cheeks and snout....................... G. periyarensis (Periyar River) - 20–24 rakers on first gill arch, tubercles on head, occasionally extending onto humeral, breast, and predorsal regions.......................................................................... G. wattanah (Bhima and Godavari Rivers) 4 Thick midlateral stripe coloring entirety of midlateral scales and partially coloring scales above and below; dorsolateral spots, if present, form uniform reticulated pattern; crescent-shaped spot present on 5th–6th lateral-line scales and extending onto ante- rior halves of scales above and below................................ G. burmanicus (Irrawaddy and Salween Rivers) - Thick midlateral stripe absent, although thin stripe (less than one scale wide) may be present; dorsolateral spots, if present, forming irregular patches, not uniform reticulated pattern; crescent-shaped spot occasionally present on 5th–6th lateral-line scale.................................................................................................... 5 5 Total lateral-line scales 40 (rarely 36–38); restricted to drainages of the Bay of Bengal................................................................... G. latius (Ganges, Brahmaputra, Meghna, Subarnarerkha, and Mahanadi Rivers) - Total lateral-line scales 35–38; restricted to drainages of the Arabian Sea and the Gulf of Oman, and inland endorheic basins in Afghanistan and Iran .................................................................................. 6 6 Rostral fold without fringes....................................................... G. macmahoni (Dasht River) - Rostral fold with fringes........ G. diplochilus (Indus, Sistan, and Helmand Rivers; coastal drainages of the Gulf of Oman)

Published as part of Ciccotto, Patrick J. & Page, Lawrence M., 2016, Revised diagnosis of the genus Gonorhynchus McClelland (Teleostei: Cyprinidae: Labeonini) with redescription of G. latius (Hamilton) and revalidation of G. wattanah (Sykes), pp. 471-492 in Zootaxa 4127 (3) on page 489, DOI: 10.11646/zootaxa.4127.3.4, http://zenodo.org/record/271777