Triplophysa waisihani, Cao, Liang & Zhang, E, 2008

Cao, Liang & Zhang, E, 2008, Triplophysa waisihani, a new species of nemacheiline loach from Northwest China (Pisces: Balitoridae), Zootaxa 1932, pp. 33-46 : 35-39

Triplophysa waisihani , sp. nov.

( Figs. 1–7 )

Barbatula labiata: Zhu, 1989: 28 (Ili River and Emin River drainages, Xinjiang); Wu & Wu, 1992: 583 (Manas River drainage, Xinjiang); Zhu, 1995: 108 (Ili River and Emin River drainages, Xinjiang).

Holotype: IHB 890064, 111.1 mm SL; Kax River, a tributary of the Ili River drainage at Dunmaza Town (81°53'E, 43°82'N; 1143m above sea level) in Yining County of Xinjiang; collected in 1989 by Chen, Yi-feng, He Shun-ping and He Chang-cai.

Paratypes: IHB 890035, IHB 890037–9, IHB 890041–52, IHB 890054–8, IHB 890060–3, IHB 890068– 70, IHB 890075, IHB 890078, 31 specimens, 70.2–140.3 mm SL, locality data same as that of holotype.

Diagnosis. Triplophysa waisihani belongs to the T. labiata species-group that is characterized by having widely separated anterior and posterior nostrils and no breeding tubercles on the sides of the head. It resembles T. labiata and T. herzensteini , with which it shares the presence of a columnar caudal peduncle with an approximately circular cross-section at its beginning, but differs from both in possessing supraorbital and infraorbital canals that are not confluent (vs. confluent); and the posterior chamber of the gas bladder connected to the anterior chamber by a long duct, twice as long as the posterior chamber (vs. connected to the anterior chamber by a shorter duct than the posterior chamber in T. labiata , or strongly reduced in T. herzensteini ). It further differs from T. labiata in the possession of an anteriorly bifurcated (vs. non-bifurcated) pelvic girdle and in the absence (vs. presence) of the fourth basibranchial, and from T. herzensteini in having a truncate or slightly convex (vs. concave) distal margin of the anal fin.

Description. Morphometric and meristic data are presented in Table 1 . Body elongate, subcylindrical, scaleless. Dorsal profile of head somewhat arched upwards, predorsal profile of body straight. Dorsal-fin base and postdorsal profile concave. Ventral profiles of head and body from pectoral-fin origin to anal-fin origin almost straight; anal-fin base and postanal profile slightly concave. Greatest depth of body at dorsal-fin origin, least depth of caudal peduncle nearer to base of caudal fin than to posterior end of anal-fin base. Caudal peduncle columnar with an approximately circular cross-section at its beginning, slightly compressed laterally at base; width at its beginning slightly less than its depth; length less than HL and 2.9 to 4.1 times its depth; depth 1.3 to 2.0 times in its width.

Head depressed in lateral view, wider than high, roughly triangular in dorsal view. Snout obtuse, shorter than postorbital length of head; eyes small (10.1–15.2 % of HL), close to dorsal profile of head; interorbital space rather wide (20.7–29.7% of HL); nostrils widely separated, anterior one at extremity of a short tube; distance between anterior edge of anterior and posterior nostrils 1.5 to 2.0 times length of posterior nostril.

Mouth inferior, arched. Lips greatly furrowed, papillated; no lateral extension of lower lip. Upper jaw unexposed or covered by upper lip, without processus dentiformis; lower jaw spoon-like, shaped with its median part exposed, lateral part covered by lower lip. Three pairs of barbels: two rostral, one maxillary; inner rostral barbels extending to corner of mouth; outer rostral ones reaching beyond vertical through posterior nostril to vertical of anterior margin of eye; maxillary ones extending to vertical of posterior margin of eye.

Lateral line complete, extending slightly above middle of flank anterior to posterior end of anal-fin base, thereafter along middle of caudal peduncle. Supraorbital canal uninterrupted, not confluent with infraorbital canal; occipital canal continuous, confluent with infraorbital canal. Count of pores in cephalic sensory canal system as follows: 7–8 in supraorbital canal, 13–15 in infraorbital, 3 in occipital, 10–13 in mandibulo-opercular, and 80–91 in lateral line.

Fins flexible, D. iii, 7; P. i, 13–15; V. i, 7–8; A. iii, 5; C. 7–8+8 = 15–16 branched rays. Dorsal fin with a straight or slightly concave distal margin; origin nearer to caudal-fin base than to snout tip; last unbranched ray thickened near base. Pectoral fin inserted immediately anterior to vertical through posteriormost point of operculum, adpressed fin reaching nearly halfway to pelvic-fin base. Pelvic fin inserted slightly anterior to vertical through dorsal-fin origin, adpressed fin reaching anus. Anal fin with a straight distal margin; origin closer to pelvic-fin origin than to caudal-fin base. Caudal fin emarginate or moderately forked, its upper lobe as long as lower one. Vertebral count 43–45.

Intestine forming a zigzag loop anteriorly, reaching ventral surface of U-shaped stomach. Gas bladder bipartite; anterior chamber fully enclosed in dumbbell-like capsule and posterior chamber free, oval and small, connected with encapsulated portion with a long duct, twice as long as posterior chamber; distal end of posterior chamber reaching vertical between tip of depressed pectoral fins and dorsal-fin origin.

Coloration. In live specimens, ground colour of back, and lateral body gray, somewhat lighter ventrally; ventral region of body yellowish white. Six or seven brown transverse bars on predorsal region, five or six bars on postdorsal region of body. Many spots on flank above lateral line and area directly below. A longitudinal light-yellow stripe running along lateral line, becoming increasingly narrower and ending at vertical through vent. Dorsal and caudal fins dusky. Dorsal surfaces of pectoral and pelvic fins gray. Anal fin hyaline. In formalin-preserved specimens, back and lateral body brownish, ventral body grayish. Dorsal and caudal fins dusky yellow, dorsal surfaces of pectoral, pelvic and anal fins gray. Spot and bars not clear sometimes.

Sexual dimorphism. Males with broadened and widened unbranched rays and 4–5 outer branched rays of pectoral fin. Pectoral fin covered with breeding tubercles on dorsal surfaces; no breeding tubercles on sides of head in males.

Osteology. Neurocranium rather broad, maximum width 1.7 to 1.9 times in its maximum length. Supraethmoid-ethmoid fused with prevomer. Anterior and lateral fontanelles absent; posterior fontanelle cylindrical, between frontal and parietal. Sphenotic disconnected from epiotic. Lateral foramen of exoccipital rather small, occupying much less than half lateral surface of exoccipital.

Premaxillary without an anterior process. Dentary with a process at its tip. Basihyal slightly concave anteriorly. Urohyal with a straight posterior broad and short lateral process. Basibranchial IV absent, epibranchial IV with a lateral plate-like expansion. Ceratohyal 5 devoid of rudimentary gill rakers. Three radials of pectoral bony elongate-cylindrical, but first one reduced; mesocoracoid not fused with cleithrum. Pelvic bone anteriorly bifurcated. Caudal skeleton with 5 hypurals and 1 epural.

Distribution. Triplophysa waisihani is known from the Kax River, a tributary to the Ili River drainage, at Dunmaza Town in Yining County (81°53'E, 43°82'N; 1143m above sea level) of Xinjiang-Uighur Autonomous Region, Northwestern China. It was also documented by Zhu (1989, 1995) from the Ili River and Emin River drainages of Xinjiang, without precise locality and by Wu & Wu (1992) from the Manas River drainage ( Fig. 8 ).

Etymology. The specific epithet is a reference to Wai Si Han, the Chinese spelling of the Wais Khan, (a tenth-generation male offspring of the Mongolian emperor Genghis Khan), whose mausoleum is located in the Dunmaza Town (in Yining County of the Xinjiang-Uighur autonomous region) where the type specimens were collected.

Remarks. Zhu (1989) reported 12 specimens from the Ili River and Emin River drainages in Xinjiang as B. labiata . This species was also documented by Wu &Wu (1992) from the Manas River drainage in Xinjiang. Zhu’s and Wu & Wu’s materials were not accessible to us, but their accounts showed that these specimens shared a small free posterior chamber of the gas bladder connected with the anterior or encapsulated chamber by a long duct, around twice or three times as long as the posterior chamber, which is diagnostic of T. waisihani . Our comparison indicates that there are no marked morphological differences between these specimens and the type material of T. waisihani . We therefore conclude that Zhu’s and Wu &Wu’s specimens were in fact representatives of T. waisihani .

Li et al. (1966) and Anonymous (1979) recognized specimens from the Ili and Emin River drainages as N. labiatus (= T. labiata ). We have no access to these specimens as well. Based on the descriptions of those authors, however, their specimens had a large, elliptical posterior chamber of the gas bladder. This character is shared with T. labiata . Besides, there are no marked morphological differences between Li et al. ’s and Anonymous’ materials and Prokofiev’s (2004) material of T. labiata . We suspect Li et al. ’s and Anonymous’ specimens were in fact examples of T. labiata .

Figures

FIGURE 1. Views of Triplophysa waisihani, IHB 890064, holotype, 111.1 mm SL (a, lateral view; b, dorsal view; c: ventral view).

FIGURE 2. Ventral view of mouthpart soft-tissue structures of Triplophysa waisihani, IHB 890064, holotype, 111.1 mm SL.

FIGURE 3 – 5. 3, Dorsolateral view of cephalic sensory canal system in Triplophysa waisihani; IHB 890059, paratype, 88.6 mm SL: cio = infarorbital canal of cephalic laterosensory system; cmo = mandibulo-opercular canal of cephalic laterosensory system; cso = supraorbital canal of cephalic laterosensory system; oc = occipital canal of cephalic laterosensory system. Scale bar = 1 mm. 4, Intestinal coiling pattern in Triplophysa waisihani; IHB 890059, paratype, 88.6 mm SL. Scale bar = 1 mm. 5, Ventral view of gas bladder in Triplophysa waisihani; IHB 890059, paratype, 88.6 mm SL. Scale bar = 1 mm.

FIGURE 6, 7. 6, Dorsal view of neurocranium in Triplophysa waisihani; IHB 890059, paratype, 88.6 mm SL: epo = epitoc; exo = exoccipital; fon = posterior fontanelle; fr = frontal; le = lateral ethmoid; pa = parietal; pto = pterotic; se = supraethmoid-ethmoid; soc = supraoccipital; spo = sphenotic. Scale bar = 1 mm. 7, Ventral view of branchial apparatus of Triplophysa waisihani; IHB 890059, paratype, 88.6 mm SL bb = basibranchial; bhy = basihyal; crb = ceratobranchial; eb = epihyal; hb = hypobranchial; ib = infrapharyngobranchial; lp = lower pharyngeal bone. Scale bar = 1 mm.

FIGURE 8. Map showing the type locality () of Triplophysa waisihani in the Ili River drainage and the localities () recorded from literature sources. a, Ili River; b, Kax River; c, Kunes River; d, Tekes River; e, Manas River; f, Emin River.

Tables

TABLE 1. Morphometric data of Triplophysa waisihani.

	Holotype	Paratypes (n=31)
		Min Max	Mean	SD
Standard length (mm)	111.1	70.2 140.3
% SL
Body height	12.2	9.8 15.6	12.0	1.4
Head length	21.0	19.9 24.6	21.9	1.2
Pectoral-fin length	15.0	13.9 19.7	16.7	1.3
Dorsal-fin length	20.9	15.1 23.3	20.3	1.5
Pelvic-fin length	15.2	14.4 20.1	16.5	1.3
Anal-fin length	15.7	13.2 18.2	15.7	1.0
Caudal-fin length	17.5	16.0 22.6	19.4	1.5
Caudal-peduncle length	20.7	17.5 23.1	20.0	1.4
Caudal-peduncle height	6	4.5 6.7	5.6	0.5
Caudal-peduncle width	3.4	2.3 4.5	3.2	0.5
Prepectoral length	21.5	12.2 25.2	21.9	1.8
Predorsal length	53.5	51.8 58.8	54.0	1.2
Prepelvic length	53.4	50.6 58.7	53.1	1.5
Preanal length	69.7	64.2 78.4	72.1	2.0
Pectoral-pelvic distance	32.5	27.8 34.9	31.6	1.4
Pectoral-anal distance	50.8	46.9 55.9	51.2	1.7
Pelvic-anal distance	22.7	15.8 23.0	19.3	1.4
% HL
Head height	47.0	38.6 51.6	45.6	3.1
Snout length	42.1	35.2 46.5	41.7	2.2
Inner rostral barbel length	25.6	16.9 27.4	21.4	2.5
Outer rostral barbel length	37.1	28.7 42.8	34.7	3.7
Maxillary barbel length	41.1	28.0 44.4	35.1	4.0
Eye diameter	13.8	10.1 17.2	13.0	1.4
Postorbital length	48.2	41.6 53.5	48.2	2.4
Interorbital length	26.9	20.7 29.7	24.5	2.2