Triplophysa laterimaculata, Jinlu Li, Naifa Liu & Junxing Yang, 2007

Jinlu Li, Naifa Liu & Junxing Yang, 2007, A brief review of Triplophysa (Cypriniformes: Balitoridae) species from the Tarim Basin in Xinjiang, China, with description of a new species., Zootaxa 1605, pp. 47-58 : 48-51

Triplophysa laterimaculata , new species

(Fig. 1 and 2)

Holotype: KIZ 200408220489, male, 53.8 mm TL, 43.3 mm SL; from the Kezile River, a tributary of the Tarim River, [ca. 39° N 76° E, 1441 m asl], Huangdi Town, Shufu County, Kashigar City, Xinjiang, Northwest China (Fig. 1); Li Jinlu and Jin Yuanting; 22 August 2004.

Paratypes: KIZ 200408220470, 0488, 0493, 0496, 0991-0994, 8 specimens, 44.0- 53.8 mm TL, 36.8- 43.4 mm SL; collected with the holotype.

Diagnosis: Triplophysa laterimaculata can be distinguished from its congeners by the combination of the following characters: body compressed posteriorly; caudal peduncle width smaller than its depth; origin of dorsal fin closer to caudal base than to snout tip; tip of adpressed dorsal fin extending beyond vertical of anal fin origin; distal margin of dorsal fin straight; pelvic fin insertion below 2nd-3rd branched dorsal rays, fins extending beyond anus or nearly reaching anal fin origin; caudal fin slightly emarginate; body scaleless; lateral line complete; lips thick with strong furrows and papillae remarkable at mouth angle; anterior margin of lower lip covering anterior margin of lower jaw; outer rostral barbels longest, extending to vertical of anterior margin of eye or orbit center; intestine short with 2 coils; small free posterior portion of air bladder ovoid and nearly equal to eye diameter, connecting to anterior encapsulated portion with long tube.

Description: D iii, 7; A iii, 5; P i, 10-11; V i, 7; C 7-8+8; gill rakers: 12; vertebrae: 4+32~34+1=37~39 (n=6).

Body moderately elongate, slightly compressed anteriorly and more laterally compressed posteriorly. Dorsal profile slightly convex, ventral profile straight, and highest point of body usually in front of dorsal fin origin. Caudal peduncle relatively deep, width at its anterior origin smaller than caudal peduncle depth. Dorsal fin insertion nearer to caudal base than to snout tip; tip of adpressed dorsal fin extending beyond vertical of anal fin origin. Distal margin of dorsal fin straight. Basal part of last unbranched dorsal ray somewhat hard but not particularly thick. Anal fin origin closer to pelvic fin origin than to caudal base; distal margin straight and base short. Pectoral fin length about 2/3 of pectoral-ventral distance, with tip formed by 2nd and 3rd or only 2nd branched rays. No axillary pectoral or ventral lobe. Pelvic fin insertion below 2nd-3rd branched dorsal fin ray, fin extending beyond anus or nearly reaching anal fin origin. Vent situated at about posterior 1/3 to 1/4 of distance between posterior extremity of pelvic-fin base and anal fin origin. Caudal fin slightly emarginate, upper rays occasionally slightly longer than lower. Dorsal and ventral adipose keel adjacent to caudal base not welldeveloped, its length at least 1/3 of caudal peduncle length. Body entirely scaleless and smooth; lateral line complete and nearly straight (Fig. 2a, Table 1).

Head and snout depressed. Head longer than caudal-peduncle length and length of all fins. Snout length more or less equal to postorbital length. Both anterior and posterior nares closely situated, slit of posterior ones bigger; nasal flap short and triangular. Mouth inferior (Fig. 2b); mouth gape arched, width about 1.4-2.4 (average 1.8) times length. Posterior margin of mouth situated below anterior nostril. Lips thick with strong furrows and papillae; upper lip pectinate and lacking medial incision; lower lip wide, interrupted in middle, with mental lobes and pair of well-developed ridges. Lower jaw broadly round, completely covered by lower lip, without median notch but with weak median protrusion. No processus dentiformis or keel on upper jaw. Three pairs of barbels moderately long as compared to those of ordinary species of Triplophysa ; inner rostral barbels reaching corner of mouth; outer rostral barbel usually longest, extending beyond anterior margin of eye or orbit center; length of maxillary barbel 0.8-1.3 times in snout length, reaching center of orbit or posterior margin of eye. Eyes moderately large and dorso-lateral in position; eye diameter 4.2-6.8 times in head length and 0.9-1.6 times in interorbital width. Interorbital region flat. Upper corner of operculum situated level with upper margin of orbit, its lower corner extending beyond ventral side of chin. Gill membranes united with isthmus.

Intestine short with 2 coils, in the shape of Z (Fig. 2c), anterior bend reaching or extending beyond midpoint between anterior end and posterior end of the U-shaped stomachic dilatation. The bony air bladder capsule with well-developed manubrium and no posterior processes; posterior edge relatively straight. Small, free posterior portion of air bladder is ovoid and nearly equal to eye diameter, not reaching posteriorly beyond pectoral fin tip, connecting to anterior encapsulated portion with long tube (Fig. 2d). Sexual dimorphism exhibited, males with pads of breeding tubercles on sides of head and outer two or three broadened pectoral fin rays; absent in females.

Coloration in alcohol: Body darker than other species collected from the same river. On the dorsal body, two to four large irregularly shaped black blotches present on the anterior dorsum and four to five black vertical bars posterior to dorsal fin origin. A dark black spot conspicuous at origin of dorsal fin. About 10 black blotches and some irregular markings present along the lateral midline. Many tiny melanophores on dorsal and lateral parts of head and body, and rostral barbels as well. Lower part of head and body whitish. Two rows of distinct dark spots on the median and upper parts of dorsal fin, respectively. Three rows of vertical distinct dark stripes on caudal fin. Two black spots near the base of caudal fin, the lower spot larger. Irregular light black spots on at least the outer three rays of pectoral fins. Peritoneum silvery when dissected, becoming darker near vertebrae.

Habitat: The specimens were collected from a small ditch (about 0.5m in width and 0.5m in depth) with abundant macrophytes, muddy substrate, and clear water. The ditch flows into a small stream, a tributary of the Kezile River.

Etymology: From lateri (lateral in Latin) and maculata (spot in Latin), referring to its body colour pattern.

Remarks. T. laterimaculata is placed in the genus Triplophysa on the basis of males having pads of breeding tubercles on the side of head. T. laterimaculata is similar to 15 other Chinese Triplophysa species with scaleless bodies, a developed free portion of air bladder, normal eyes, compressed caudal peduncle and the last unbranched dorsal ray relatively soft and slim. Compared with these 15 species, T. laterimaculata is more similar to seven species ( T. dalaica (Kessler 1876) , T. orientalis , T. furva Zhu 1992 , T. zamegacephala , T. dorsalis (Kessler 1872) , T. obscura Wang 1987 , T. moquensis Ding 1994 ), in that they share a complete lateral line and long pelvic fins extending beyond the anus; the new species is different from the latter 6 species with a free posterior portion of air bladder directly connecting to the anterior encapsulated portion. Compared with all the Chinese species in the genus, T. laterimaculata is most similar to T. dalaica , but it can be distinguished from T. dalaica by the more anterior position of the pelvic fin (pelvic fin origin below 2nd -3rd branched dorsal rays vs. 3rd -7th branched dorsal rays), more developed lip papillae (strongly vs. indistinct) and shorter intestine (2 coils vs. 3-5 coils). T. laterimaculata can be distinguished from other similar species by several morphometric and morphological characters (Table 2).