NOTES ON FISHES OF THE GENUS SCHIZOPYGOPSIS OF SOUTHERN TIBET, CHINA, WITH DESCRIPTION OF A NEW SPECIES AND A NEW SUBSPECIES
TCHANG TCHUNG-LIN AND YUEH TSO-HUO (Institute of Zoology, Academia Sinica) HWANG HWON-CHIN (institute of Hydrobiology, Academia Sinica)
The present paper deals with the Cyprinid fishes of the Genus Sckizopygopsis (裸裂尻鱼属), which were collected during May to October in 1961, from the two regions, namely, Gyantze(江孜). and Chigatze(日喀则), in southern Tibet. The material comprises 7 species of which one species and one subspecies are described as new:1. Schizopygopsis stoliczkae Steindachner2. Sckizopygopsis sewerzowi Hcrzenstein3. Schizopygopsis thermalis Herzenstein4. Schizopygopsis malacanthus Herzenstein5. Schizopygopsis younghsbandi Regan6. Sckizopygopsis kessleri makianensis, subsp. nov. (figs. 1-4)5 specimens (2 3 ): the females, Nos. TS-006 008; the males, Nos. TS-003-004 009; from Ma-Kiang (麻江) near Ma-Kiang-Tzon (麻江宗). Total length 318-228mm, standard length 267-186mm.The fish was collected in a rapid stream at Ma-Kiang, northern Tibet. It spawns usually in April. An adult female usually contains about 5,000 eggs, measuring 2.5-3 mm in diameter and being yellowish in colour. The young fish usually feed on plank-tonic crustaceans, insect larvae and other smaller animals, while the adults on algae.The new subspecies closely resembles Sckizopygopsis k. kessleri Herzenstein, but differs from the latter in having the tip of gill-rakers on the first arch are mostly bent inward, while in case of Schizopygopsis k. kessleri, most of the tips of the gill-rakers on the first arch are bent outward.7. Sckizopygopsis wui, sp. nov. (figs. 5-7)23 specimens: the females, Nos. TS-186, 188, 190, 192-193, 195-196, 198-200, 203, 210 215, the males, Nos. TS-194, 205-206, 208-209, 211, 214, 218-219 221; from On-zen (昂仁) (On-zen lake, Engbilinkin-Tso" 恩格必林开因错" or Gold lake "金湖"). Total length 280-130mm, standard length 232-104 mm.D. ii-iii 7-8, A. ii-iii 5-6, P. i-ii 15-17, V, i-ii 8-9, C. (branchial rays) 17. Gill-rakers on 1st. branchial bar: outer row 10-14, inner row 16-23. Pharygeal teeth 2 rows, 3-4/4-3. Lateral cannels on lateral line 84-98.Comparisons of the body length between the male and female specimens are shown in Tab. 3 (see text in Chinese).Body cylindrical, elongated. Head small and bluntly pointed. Mouth inferior, arched. The anterior border of upper jaw below the level of the lower edge of the eye, and the posterior border extending beyond the anterior edge of the eye. Lower jaw thickened, with soft horny (or leathery) edge. Barbel none. Nostrils nearer eyes than tip of snout. Eyes, rather small and rounded, situated on upper part of head. The width of isthmus natrow. Pharyngeal teeth scoop-shaped and curved at the tips.Body nearly entirely naked, with a few scales behind the gill-opening and in the anterior end of the lateral line, and an anal sheath consisting of 17-21 enlonged scales at the base of anal to behind the ventral. Lateral line complete, with scales only at the anterior region, mucous tubes about 90 or more. Anal opening near the commencement of the anal fin.Dorsal without spines, its origin nearer tip of snout than base of caudal. Origin of ventral fin under the 4-5th branched ray of the dorsal. Caudal forked.Color in spirit brownish above, white below. Upper body and head with numerous small blackish brown spots, some of the specimens with irregular and larger dark spots.The fish inhabits salt-water lake. It breeds during the last 10 days of July and first 10 days of August. An adult female usually contains about 3,000-5,000 eggs, each measuring 2.5-3 mm in diameter. The fish usually feeds on insect larvae and plank-tonic crustaceans. Its digestive canal is about 1.5-2.4 times as long as the body length.Vertebral column consisting of about 50-55 vertebrae. Air-bladder in two chambers, the anterior one larger than the posterior, and not enclosed in a fibrous capsule.This new fish closely resembles Schizopygopsis lifanensis Chang, 1944, but differs from the latter in having depth of body greater, snout shorter, caudal peduncle narrower, and lower lip thicker. Besides these morphological distinctions, the two species are also different in habitats as well as in geographical distribution. The new speciesis found in a salt-water lake——Engbilinkin-Tso (恩格必林开因错), which belongs tothe water system Sanpo (雅鲁藏布江) and is situated at an altitude of 4,300 m, while the species Schizopygopsis lifanensis inhabits in the Mongtun stream (孟屯沟), Lifan (理番), western Szechwan, a branch of the Yangtzekiang situated at an altitude of only about 1,830m.This new species is named in honor of Prof. H. W. Wu, for his contributions to Chinese ichthyology.