Garra motuoensis, Gong & Freyhof & Wang & Liu & Liu & Lin & Jiang & Liu, 2018

Gong, Zheng, Freyhof, Jörg, Wang, Jian, Liu, Meng, Liu, Fei, Lin, Pengcheng, Jiang, Yueliang & Liu, Huanzhang, 2018, Two new species of Garra (Cypriniformes: Cyprinidae) from the lower Yarlung Tsangpo River drainage in southeastern Tibet, China, Zootaxa 4532 (3), pp. 367-384 : 371-375

Garra motuoensis , new species

( Figs. 1–2 )

Holotype. IHB 20161470 , 162.5 mm SL; China: Tibet Autonomous Region: Motuo County: Xigong River, a tributary of the Yarlung Tsangpo River , 29°16'44"N, 95°14'56"E, 680 m above sea level; collected by Zheng Gong, Jian Wang, & Huaming Hu, October 2016.

Paratypes. IHB 20161471 , 1 specimen, 120.8 mm SL, April 2016 ; IHB 20161472 , 1 specimen, 154.1 mm SL, June 2016 ; IHB 20161473 , 1 specimen, 154.4 mm SL, July 2016 ; IHB 20171474–20171475 , 2 specimens, 129.8– 140.3 mm SL, November 2017 ; other data same as holotype .

Diagnosis. Garra motuoensis , a member of the proboscis species group, is distinguished from the other members of this group by the following combination of characters: a prominent, quadrate, and slightly bilobed proboscis covered with 6–20 small to middle-sized unicuspid tubercles; some middle-sized unicuspid tubercles on the transverse lobe of the snout and several small unicuspid tubercles on the lateral surface of snout; anus slightly closer to anal-fin origin than to pelvic-fin origin (distance from anus to anal fin 36–46% of pelvic-anal distance); 36–37 lateral-line scales; 12 circumpeduncular scales; and other morphometric features: body depth 16.7–22.5% SL, caudal-peduncle length 16.8–20.3% SL, snout length 42–49% HL, eye diameter 15–18% HL, and disc length 42–51% HL.

Description. Morphometric data of 6 type specimens in Table 3. Body elongate; cylindrical anteriorly, laterally compressed posteriorly. Head moderately large; head length greater than width, head width greater than depth; interorbital region slightly convex. Snout moderately rounded with transverse lobe covered with some middle-sized prominent unicuspid tubercles, demarcated posteriorly by deep transverse groove; several small unicuspid tubercles on lateral surface. Proboscis prominent, quadrate, and slightly bilobed, each lobe slightly elevated; anterodorsal region of proboscis covered with 6–20 irregularly arranged small to middle-sized unicuspid tubercles; tubercles more conspicuous in larger individuals. Eyes moderately large, situated dorsolaterally behind middle of head.

Barbels in two pairs; rostral barbels situated antero-laterally, shorter than eye diameter; maxillary barbels shorter than rostral barbel. Rostral cap with crenulated margin and numerous tiny papillae, separated from upper jaw by deep groove, posteriorly continuous with lower lip on each side. Edge of upper and lower jaws covered with thin horny sheath. Mental adhesive disc large and elliptical; disc length shorter than width, slightly shorter than half of head length; anteromedian fold densely covered with tiny papillae, separated from lower jaw by deep groove and posteriorly bordered by shallow notch from central callous-pad; lateral and posterior margins free; lateroposterior flap with densely arranged tiny papillae.

Dorsal fin with 3 simple and 8½ branched rays; distal margin slightly concave; first branched ray longest, nearly equal to head length; origin closer to snout tip than to caudal-fin base. Pectoral fin with 1 simple and 13 (1) or 14 (5*) branched rays; length shorter than head length; distal tip not reaching pelvic-fin origin and dorsal-fin origin. Pelvic fin with 1 simple and 8 branched rays; length nearly equal to head length; distal tip reaching beyond anus; origin closer to caudal-fin base than to snout tip. Anal fin with 3 simple and 5½ branched rays; distal tip not reaching to base of caudal fin; origin closer to caudal-fin base than to pelvic-fin origin. Caudal fin forked; lower lobe slightly longer.

Lateral line complete and horizontal; with 34 (2*) or 35 (4) scales plus 2 scales on the caudal-fin base. Transverse scale rows above lateral line 3½, between lateral line and pelvic-fin origin 2½ (5*) or 3 (1). Circumpeduncular scales 12. Predorsal scales 10 (2*) or 11 (4); smaller than flank scales. Chest and belly scaled; scales on chest smaller than on belly. One long axillary scale at base of each pelvic fin. Anus slightly closer to analfin origin than to pelvic-fin origin (see Fig. 1 , distance from anus to anal fin 36–46% of pelvic-anal distance); separated from anal-fin origin by 5 scale rows.

Coloration. In preserved specimens, head, dorsum, and flank dark gray. Mouth, chest, and belly faint yellow or slightly brown. Dorsal, pectoral, pelvic, anal, and caudal fins gray; pectoral fin darker than other fins. Interradial membranes of all fins covered with conspicuous black pigment. Smaller individuals paler than larger ones.

Distribution. Known from the Xigong River, a tributary of the lower Yarlung Tsangpo River in southeastern Tibet ( Fig. 3 ).

Ecology. This new species was caught from swift-flowing waters with numerous rocks in the Xigong River, where water is very clear ( Fig. 4 ). Macroscopic visual examination of the gonads suggests that its spawning period occurs in May when water temperature reaches 14°C. The eggs are yellow and demersal. Examinations of intestinal contents show that this species mainly feeds on periphytic algae.

Etymology. Named after its type locality, Motuo County. An adjective.

Figures

FIGURE 1. Garra motuoensis, holotype, IHB 20161470, 162.5 mm SL; China: Tibet: Xigong River, a tributary of the Yarlung Tsangpo River.

FIGURE 2. Garra motuoensis, holotype, IHB 20161470, 162.5 mm SL; China: Tibet: Xigong River, a tributary of the Yarlung Tsangpo River; dorsal and ventral views of head.

FIGURE 3. Map showing the sampling sites of Garra motuoensis (▲) and Garra yajiangensis (?).

FIGURE 4. Habitat of Garra motuoensis in the Xigong River.