Gymnocypris potanini

Herzenstein, 1891

Synonym: Schizopygopsis lifanensis Chang, 1944

Order: Cypriniformes
Family: Cyprinidae
Genus: Gymnocypris

Environment: Freshwater; benthopelagic
Climate: Subtropical

Description. D iii, 8; A iii, 5; P i, 18; V ii, 8.  Body subcylindrical, elongate. Head moderate; snout obtusely pointed. Mouth inferior, arched. Lips thin and continuous at mouth angle. Labial fold interrupted at middle. Barbels none. Lower jaw leathery, never forming horny edge. Third simple dorsal ray slender, articulated, with several fine serrations at the basal half. Caudal fin forked. Lateral line complete, nearly straight, running along the middle of body and tail. Body almost entirely naked, with a few scales behind the gill-opening and a series of 7-9 scales in the anterior end of lateral line and an anal sheath consisting of 20 enlarged scales on each side lining the base of anal and extending anteriorly beyond the midway between the ventral and anal. Pharyngeal teeth in a rows, 4.3-3.4, hooked and pointed at tips. Color in living condition greyish above and pale below; upper part of head and body, as well as dorsal and caudal fins mottled with dark spots.

Material examined. Five mature specimens (3 female and 2 male) from Mongtun Stream near Hopachai, Ssumaliukou, and Taszepa at Lifan, in August, 1941, and many young fish from different localities of the same stream during that summer. Adult female specimens, Nos. 530, 531, 534, 180-210 mm. in total length, 151-177 mm. in standard length. Depth in standard length 5.6-6.2; width 7.3-8.8; head 4.7-5.3. Depth of head in its length 1.4-1.6, width of head 1.7-1.8; eye 4.5-5.2; snout 3.1-3.6; interorbital space 3.0-3.3; postorbital space 1.7-2.0; least depth of caudal peduncle 2.3, its lenght 1.2-1.4; longest ray of dorsal 1.3-1.6, of anal 1.1-1.2. Predorsal space 44-45% of standard length. Two mature male specimens, Nos. 527, 528, 135-155 mm. in total length, 126 mm. in standard length, were collected from a large side-pond along lower Mongtun Stream near Ssumaliukou, Lifan. Depth in standard length 5.2-5.5; width 8.3-8.4; head 4.3-4.4. Eye in head 4.5-4.8; snout 3.0-3.2; interorbital space 3.2-3.3, postorbital space 2.0-2.1; least depth of C-peduncle 2.7-2.9, its length 1.3-1.5; longest ray of dorsal 1.4-1.7, of anal 1.2-1.5; pectoral 1.2-1.3; ventral 1.2-1.3. Predorsal space 43-45% of standard length.

The coloration, the presence of few scales on the naked body, and the number of pharyngeal teeth as well as other details are similar to those of females. The male  character, however, may be easily distinguished by: 1) presence of pearl organs on head, lateral line, dorsal, anal, and the enlargerd scales of anal sheath, 2) shorter and rather compressed body, 3) longer head, 4) shorter and slender C-penducle, 5) an elongated dorsal base, which is longer or equal to the longest ray, 6) a squarish anal with rays thickened throughout, of which the last second is unbranched. The small male individual (96 mm. total length, found among the young specimens) is almost indistinguishable from the young females except that the rays are already  thickened in the shorter anal.

This species adapts very well to low temperature*  and is found prosperous in such cold water. Local name is „Lung-shui-yu” or „Cold-water-fish”. This new fish differs from the S. stoliczkai in having a leathery lower jaw instead of a sharp horny one, and an arched mouth instead of a transverse one. It can be distinguished from S. stoliczkai sverzowi in having smaller eye, shorter head and  slender body.
*On Aug. 16th, 1941, the water temperature of Mongtun Stream at Hopachai was 5° C, while the air temperature was 13° C. at 7:00 a.m.

Gymnocypris potanini potanini Herzenstein 1891.
Gymnocypris potanini firmispinatus Wu & Wu, 1988 (Jinsha River basin)

Distribution. Asia: China. Zadoi, Qinghai, drainage Zu Qu (Lancang River), Heishui, Marlkang; Sichuan, drainage Yangtze River, Mongtun stream, Lifan, western Sichuan, a branch of the Blue River (Yangtzekiang) situated at an altitude of about 1,830 m.