Abstract
Oxynoemacheilus chaboras, new species, from the stream Beyazsu in the Euphrates drainage, belongs to the O. persa species group, being closely related to O. shehabi from the Orontes, O. sarus from the Seyhan and Ceyhan, O. euphraticus from the Euphrates and Tigris, O. karunensis from the Karkheh, and O. persa from Central Iran. The new species is distinguished from others in the O. persa group by having 8–9 pores in the supraorbital canal, two distinct black blotches at the caudal-fin base, a rudimentary and shallow pelvic axillary lobe, 6–10 irregularly shaped bars on the flank, and a deep head, body, and caudal peduncle. Oxynoemacheilus chaborassp. nov. is most closely related to O. euphraticus, from which it is differentiated by a mean uncorrected p-distance of 3.24% (min. 3.09%) in its COI barcode gene.