Schizothorax heterophysallidos, Yang, Jian, Chen, Xiaoyong & Yang, Junxing, 2009

Yang, Jian, Chen, Xiaoyong & Yang, Junxing, 2009, The identity of Schizothorax griseus Pellegrin, 1931, with descriptions of three new species of schizothoracine fishes (Teleostei: Cyprinidae) from China, Zootaxa 2006, pp. 23-40 : 33-36

Schizothorax heterophysallidos , sp. nov.

Figure 10

Schizothorax griseus (non Pellegrin): Mo in Chu & Chen ed. 1989: 321. Fig. 291 (in part); Lu in Wu ed. 1989: 192 (in part); Huang, 1989: 222, Fig. 170; Chen & Huang, 1998: 222, Fig. 156 (in part); Chen & Cao, 2000: 333, Fig. 206 (in part).

Holotype: KIZ 20060038, 210.0 mm SL; China: Yingshang, Fuyuan County, Yunnan Province, 25°29΄26.5 ʺN 104°17 ΄12.3ʺE, 1733 m above sea level, 24 May 2006.

Paratypes: KIZ 20060037, 20060039–040, 3 specimens, 134.1−163.0 mm SL; China: same data as holotype. KIZ 60122−60125, 4 specimens, 127.4−197.0 mm SL; China: the Nanpan Jiang. KIZ 2000609−019, 2006021−023, 14 specimens, 53.2−150.0 mm SL; China: Xiaoshiqiao, Hongta, Yuxi, Yunnan Province. KIZ 775847−849, 775853–854, 775857−860, 775863−866, 7751000, 14 specimens, 96.4−165.0 mm SL; China: Luoping, Yunnan Province. KIZ 774717, 774718, 2 specimens, 88.4−159.0 mm SL; China: Fuyuan County, Yunnan Province. KIZ 874010, 1 specimen, 143.8 mm SL; China: Yiliang County, Yunnan Province. KIZ 791014, 1 specimen, 158.0 mm SL; China: Zhushan, Yiliang County, Yunnan Province.

Diagnosis. Schizothorax heterophysallidos can be distinguished from its congeners by a combination of the following characters: snout blunt; upper lip thin; lower lip developed, with three labial lobes; postlabial groove continuous, with a minute lobe present medially on lower lip; thorax scaleless in mature individuals; lower part of last unbranched dorsal-fin ray strong, its posterior edge with 15−23 serrae; pelvic-fin origin beneath or anterior to vertical from dorsal-fin origin; eye diameter 57.2–160.0 (mean 92.4) % of maxillary–barbel length; length of posterior chamber of air bladder three to six times that of anterior one. Schizothorax heterophysallidos is further distinguished from the sympatric S. lissolabiatus by the absence (vs. presence) of a horny sheath on lower jaw; having the lower lip with three (vs. two) lobes and the posterior groove continuous (vs. discontinuous).

Description. Morphometric data are given in Table 3 . Body elongate, laterally compressed. An inconspicuous shallow ethmoidal groove present before nostrils. Mouth inferior, horseshoe-shaped. Lips developed, lower lip fleshy, with three labial lobes; postlabial groove continuous, with a small median lobe of width greater than that of isthmus, posterior parts of both side lobes rugged ( Fig. 3 C). In some young specimens (<88.5 mm SL), lower lip with only two lobes; posterior groove discontinuous; a tiny crescent-shaped sheath present on the anterior edge of lower jaw. Two pairs of barbels: maxillary barbel equal to or longer than rostral barbel, which does not reach middle of eye; maxillary barbel extends or not beyond posterior border of eye. Scales minute, absent on the thorax. Lateral line straight, with 96−124 (27*) scales; scales in transverse series from dorsal-fin origin to lateral line 21−27 (16*); scales in transverse series from pelvic-fin origin to lateral line 19−30 (5*). Two rows of enlarged scales on each side, extending from base of vent to anal fin.

Dorsal fin with 3 simple and 8 (40*) branched rays, lower part of last simple unbranched dorsal-fin ray strong, with 16−23 (15*) serrae along its posterior edge ( Fig. 4 C), its distal one-fourth slender, soft; dorsal-fin origin above or posterior to pelvic-fin origin; predorsal length greater than distance from dorsal-fin origin to caudal-peduncle base. Pectoral fin with one simple and 17 (13*), 18 (13*), 19 (3*), 20 (2*) branched rays, its length 48.9−78.7 % of distance between pectoral-fin origin and pelvic-fin origin. Pelvic fin with one simple and 9 (23*), 10 (8*) branched rays. Anus located immediately anterior to anal-fin origin. Anal fin with three simple and 5 (40*) branched rays. Anal fin elongated, reaching caudal-fin base in mature females. Caudal fin forked, lower lobe slightly longer than upper one. Pharyngeal teeth in three rows, tooth pattern 2,3,5−5,3,2, tips of teeth hooked. Outer side of first gill arch with 12−16 (24*) gill rakers; inner side with 18−22 (24*). Air bladder with two chambers, length of posterior one 3−6 (4*) times that of anterior one ( Fig. 3 C).

Paratypes (n=39) Holotype Minimum Maximum Mean S.D. Pectoral-fin length/Length of pectoral-fin origin to 51.9 48.9 78.7 61.0 6.3 pelvic-fin origin

Coloration. After fixation in 10 % formalin and preservation in 75 % alcohol, upper body blackish grey, lower body yellowish; abdomen whitish.

Distribution. The species is known from the upper reach of the Nanpan Jiang in Yunnan Province ( Fig. 6 ).

Habitat and ecology. In Yingshang (a tributary of the Nanpan Jiang), Fuyuan County, Yunnan Province, these fishes occur in small streams. Here the river is 0.5−1.5 m deep, 5−15 m wide. The river substrate is comprised of sand and pebbles. At the time of capture the water was black-grey, most likely due to the presence of a coal mine upstream. In May, many young S. heterophysallidos 40−50 mm SL were seen to inhabit shallow water. Other sympatric fishes include the cyprinid species S. lissolabiatus , Abbottina rivularis (Basilewsky) , Pseudorasbora parva (Temminck & Schlegel) , Discogobio yunnanensis (Regan) , D. macrophysallidos Huang , and Sinocyclocheilus multipunctatus (Pellegrin) ; the sisorid catfish Pareuchiloglanis longicauda (Yue) ; and the cobitid loach Misgurnus anguillicaudatus (Cantor) .

Etymology. From the greek heteros, meaning special or different, and physallidos, from the greek “physal”, possessive, meaning air bladder or bleb. An adjective, in reference to the species having an unique air bladder.

Remarks. Schizothorax heterophysallidos is unique amongst the members of the ‘ S. griseus complex’ in possessing an elongated posterior chamber of the air bladder. The length of the posterior chamber of air bladder is three to six times greater than that of the anterior one ( Fig. 3 C). Schizothorax heterophysallidos is restricted to the Nanpan Jiang drainage area.

Figures

FIGURE 3. Ventral view of head of: (A) Schizothorax griseus, KIZ 20060175; (B) S. nudiventris, KIZ 20050507224; (C) S. heterophysallidos, KIZ 20060038; and (D) S. beipanensis, KIZ 20060065. Scale bar = 10 mm.

FIGURE 4. Lateral view of the last unbranched dorsal-fin ray of: (A) Schizothorax griseus, KIZ 20060206, 141.7 mm SL, China: the Sancha River, Yangchang Town, Nayong County, Bijie, Guizhou Province; (B) S. nudiventris, KIZ 20050507224, 148.0 mm SL; China: the Lancang Jiang, Wulonglong village, Badi Town, Weixi County, Yunnan Province; (C) S. heterophysallidos, KIZ 775854, 143.8 mm SL; China: Luoping, Yunnan Province; and (D) S. beipanensis, KIZ 20060064, 157.0 mm SL; China: the Suoqiao River, Shanbanqiao Town, Pu’an County, GuiZhou Province.

FIGURE 6. Map showing distributions of Schizothorax griseus, S. nudiventris, S. heterophysallidos and S. beipanensis.

FIGURE 10. Lateral view of Schizothorax heterophysallidos, KIZ 20060038, holotype, 210.0 mm SL; China: the Dahe River, Dalishu village, Yingshang Town, Fuyuan County, Yunnan Province.

Tables

TABLE 3. Morphometric data for Schizothorax heterophysallidos sp. nov.

SL (mm)	210.0	53.2	197.0	117.2 37.2
HL	47.0	15.4	57.6	29.6 9.4
% SL
Body depth	24.9	16.3	23.9	20.7 1.9
Head depth	13.7	13.6	18.1	15.3 1.0
Head length	22.4	22.1	29.2	25.4 1.8
Snout length	8.1	6.2	10.2	8.0 0.9
Longest branched dorsal-fin ray	15.3	13.6	19.2	15.8 1.5
Predorsal length	51.8	48.3	56.2	52.6 1.9
Caudal peduncle length	18.0	14.1	19.4	17.3 1.2
Caudal peduncle depth	9.2	7.6	11.0	9.0 0.8
% HL
Body depth	111.2	63.0	106.9	82.0 9.6
Head depth	61.1	51.8	68.5	60.2 3.1
Head width	58.5	45.0	59.2	51.4 3.1
Snout length	36.1	26.1	36.5	31.5 2.8
Eye diameter	15.6	16.4	25.0	20.0 2.6
Interorbital width	41.4	32.9	45.0	39.3 3.1
Rostral barbel length	17.7	10.3	24.1	17.0 3.2
Maxillary barbel length	19.9	15.6	31.4	22.5 3.4
Eye diameter/Rostral barbel length	88.2	69.7	209.9	124.3 33.0
Eye diameter/Maxillary barbel length	78.3	57.2	160.0	92.4 22.7
Caudal peduncle depth/Caudal peduncle length	51.3	41.0	63.8	52.2 4.9
Predorsal length/Prepelvic length	100.6	89.8	102.9	98.5 2.9