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

Li, Jinlu, Liu, Naifa & Yang, Junxing, 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 : 48-54

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° N76° 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, 0 488, 0 493, 0 496, 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. 2 a, 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. 2 b); 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. 2 c), 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. 2 d). 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 ).

Triplophysa papilloso-labiatus ( Kessler 1879), one of the dominant Triplophysa species in the Tarim Basin, has been recently regarded as a synonym of T. tenuis ( Day 1877) by many authors ( Zhu 1989; Wu & Wu 1991; Yang & Zhang 1991; Ren et al 2005), but other authors regard it as a valid species name ( Wu & Wu 1990; Wu & Tan 1991; Zhao 1991; Yang & Jing 1991; Yang & Tang 1995). Triplophysa tenuis was originally described as “Air-vessel in two portions, enclosed in bone”. The posterior portion of air bladder is rudimentary and reduced ( Day 1877); however, T. papilloso-labiatus has a free posterior portion of the air bladder, so T. tenuis Day is different from T. papilloso-labiatus and T. papilloso-labiatus is a valid species. Li (1979) regarded T. tenuis (Day) as a synonym of T. stoliczkae , but Wu et al (1999) regarded it as a synonym of T. tenuicauda ( Steindachner 1866) . We are inclined to support Wu’s view on the basis of the round caudal peduncle, dorsal fin origin position and thick lips, but the status of T. tenuis requires more study, especially its type material.

Triplophysa papilloso-labiatus (Kessler) has been regarded as a subspecies of T. strauchii ( Kessler, 1874) ( Herzentein 1888; Zugmeyer 1910; Berg 1933; Li 1979), but most authors regard it as a distinct species ( Rendahl 1933; Zhu 1987, 1989; Wang 1991; Wu 1991). Besides its different distribution, T. papilloso-labiatus can be distinguished from T. strauchii by the lip structure (papillae with 2 lines vs. undeveloped), fin ray number and shape of the pectoral fin (10–11, tip formed by 3rd–4th branched ray vs. 12–14, tip formed by 5th branched ray), intestine loop number (2 vs. 3), different body color (black spots small and indistinct vs. big and distinct) ( Li 1979), and dorsal fin position (close to snout tip vs. caudal base) ( Zhu 1987, 1989). While our results generally support Li (1979) and Wang’s (1991) data, the dorsal fin position of T. papilloso-labiatus is variable in Kashigar and the Aksu River, Xinjiang, and also in Hexi Corridor, Gansu.

Triplophysa incipiens ( Herzenstein, 1888) was originally described as a subspecies of Nemachilus bombifrons , and given species rank by Prokofiev (2002) in a paper about the T. bombifrons group. Prokofiev’s redescription of the air bladder (free posterior part of air bladder reduced and rudimentary) differs from the original description and those of many authors ( Herzenstein 1888; Li 1979; Zhu 1989; Wu 1991). This discrepancy is attributed to the long storage of the specimen (Prokofiev, personal communication, 7 Nov 2005). “I suggest that in a case of absence of free swim bladder this case is artificial and is result of long time storage (+/-150 years). ...by my observation swim bladder of T. bombifrons , incipiens and edsinica is the same in shape as in T. strauchii for example”.

In our collection, five species ( T. yarkandensis yarkandensis , T. papilloso-labiatus, T. stewarti , T. orientalis and T. laterimaculata sp. all live in the Kezile River system; T. stewarti and T. orientalis are rare. The last four species possess two types of free posterior portion of air bladder, and two types of caudal peduncle. The degree of development of the posterior chamber is an adaptative character, and the different forms of the air bladder have general phylogenetic significance ( Hora 1937; Zhu 1986; Bănărescu & Nalbant 1995). The shape of the caudal peduncle is related to the strength of the current ( Hora 1922). Different types of air blad- der and caudal peduncle are related to different types of habitats. T. laterimaculata and T. papilloso-labiatus are probably closest relatives.

In our collection in the Kezile River system, only one specimen referred to T. orientalis was present. It has the following special characteristics: lips papillated strongly; small free posterior portion of air bladder elliptic, about size of eye, reaching the posterior extremity of pectoral fin base; pelvic fins insertion under the base of 2nd branched dorsal fin ray; and PDL/SL=52%; vertebrae 4+33. More research work and more possible specimens are required to affirm its species status.

At present, there are 13 valid species of genus Triplophysa recorded in the Tarim Basin.

Figures

FIGURE 1. Collection locality of Triplophysa laterimaculata, new species.

FIGURE 2. Triplophysa laterimaculata (Holotype KIZ 200408220489, 43.33 mm SL): (A) lateral view; (B) mouth; (C)

Tables

TABLE 1 Main morphomeristic characters of Triplophysa laterimaculata.

Characters	Holotype Range	Mean±SD
In % of standard length (SL)
Lateral head length (HL)	26.5 23.8–26.7	25.4±1.06
Dorsal head length	21.6 20.7–22.7	21.8±0.73
Predorsal length (PDL)	56.9 53.0–56.9	55.3±1.56
Preventral length	60.5 56.3–60.5	58.3±1.45
Preanal length	76.2 71.7–76.2	73.8±1.45
Pre-anus length	71.5 68.6–71.5	70.5±1.30
Distance from pectoral fin to pelvic fin origin	32.5 29.6–34.1	31.9±1.92
Caudal peduncle length (CPL)	18.1 18.1–22.6	20.0±2.05
Caudal peduncle depth (CPD)	7.8 6.7–9.1	7.9±0.97
Body depth (at dorsal origin) (BD)	16.0 12.4–17.1	14.5±1.75
Body depth (at nape)	14.1 13.0–14.2	13.7±0.41
Body width (at dorsal origin)	11.6 9.4–12.1	11.0±1.01
Head width (maximum)	16.2 14.5–16.4	15.2±0.85
Head height (at eye)	12.7 8.2–14.4	11.6±2.13
Height of dorsal fin	17.2 16.9–19.0	18.0±0.83
Length of pectoral fin	18.8 18.8–22.0	21.2±1.18
Length of pelvic fin	17.0 14.4–17.6	16.2±1.10
Length of anal fin	18.0 17.3–19.4	18.3±0.77
Length of caudal fin	23.0 22.5–24.7	23.2±0.78
Length of median caudal ray	17.7 17.7–21.5	20.3±1.39
In % of dorsal head length
Snout length	38.0 38.0–48.1	43.1±3.36
Eye diameter (ED)	18.2 18.2–27.5	22.5±3.02
Interorbital width	26.7 23.2–35.1	28.0±5.18
Head width (maximum)	74.8 65.8–74.8	69.6±3.65
Head width (at nare)	50.4 30.9–50.4	45.8±7.41
Head height (at eye)	59.0 36.3–63.8	53.1±10.00
Outer rostral barbel length	45.6 28.8–50.9	43.4±7.66
Maxillary barbel length	45.8 34.5–53.4	41.9±7.27
In % of lateral head length (HL)
Snout length	31.0 31.0–41.4	37.1±3.66
Eye diameter (ED)	14.8 14.8–23.7	19.4±2.89
Interorbital width	21.8 19.6–30.7	24.2±4.97
In % of head width (maximum)
Mouth width	52.3 37.2–52.3	45.2±5.46
Body width(at dorsal origin)	71.9 64.5–82.9	72.6±5.90
Body width (at anal origin)	54.9 44.2–55.8	49.0±5.11
Caudal peduncle width (CPW)	34.3 30.7–37.3	34.3±2.39
Caudal peduncle: length/depth (CPL/CPD)	2.3 2.3 – 3.3	2.6±0.40
Caudal peduncle: width/depth (CPW/CPD)	0.7 0.6 – 0.7	0.66±0.04

TABLE 2 Main morphometric and morphological characters of T. laterimaculata and 13 similar species in the Tarim River and China (mean value in parentheses).

Characteristic	T. laterimaculata (n=6)	T. dalaica (n=75)	T. strauchii (n=39)	T. papillosolabiatus (n=43)	T. stewarti (n=183)
SL (mm)	36.8–43.4	46–130	65–143	71–121	40–94
D A	iii, 7 iii, 5	iii–iv, 7–8 (7) iii–iv, 5	iv, 7–8 iii–iv, 5	iii–iv, 7–8 (7) iii, 5	iii–iv, 7–10 (8) ii–iii, 5–6
P	i, 10–11	i, 10–12	i, 10–13	i, 10–11	i, 9–13
V C	i, 7 15–16(15)	i, 7 16–17 (16)	i, 6–8 15–16 (16)	i, 7 14–18 (15–16)	i, 5–8 13–16
Gill rakers	12	10–14	12–16	12–15	11–19
Vertebrae HL % SL	4+33–35 23.8–26.7	4+34–36 20.0–25.6	4+37–38 20.4–25.0	4+36–38 16.7–25.6	4+33–38(35) 18.2–27.8
BD % SL	12.4–17.1	13.9–22.7	15.2–19.6	11.5–18.2	11.0–22.7
CPL % SL CPL/CPD	18.1–22.6 2.3–3.3	14.3–23.3 1.5–2.8	20.0–25.0 3.1–5.5	23.3–29.4 3.9–9.1	21.3–30.3 3.2–7.3
CPW <CPD	Yes	Yes	No	No	No
PDL % SL Position of pelvic fin origin compared with dorsal fin origin Lips papillae developed	53.0–56.9 Below 2nd–3rd branched dorsal ray Yes	50–56 Below 3rd–7th branched dor- sal ray No	50–54 Below 1st – 2nd branched dor- sal ray Yes	44–50 Below the last unbranched, 1st –2nd branched dorsal ray Yes	47–52 Opposite, or 1st – 2nd branched dorsal ray Yes
Intestine, anterior bend reaching which part of the U-shaped stomachic dilatation	2 coils, mid part	3–5 coils, ante- rior part	2 coils, anterior part	2 coils, anterior part	2 coils, mid part
Shape and structure of posterior part of air bladder	Ovoid, with a long tube	Ovoid, with a short tube	Ovoid, with a long tube	Ovoid, with a long tube	Long bag shaped, no tube,
Caudal fin	Slightly emargin- ate	Slightly emar- ginate	Lunate	Emarginate	Lunate
continued.