Schizopygopsis, Steindachner, 1866

Tian, Fei, Liu, Sijia, Chen, Shengxue & Zhao, Kai, 2025, Revision of Schizopygopsis chengi Fang 1936 (Cypriniformes: Cyprinidae), with a description of a new subspecies, Zootaxa 5590 (4), pp. 481-506 : 502-503

Comparisons with Schizopygopsis fishes

Schizopygopsis chengi differs from Schizopygopsis pylzovi , Schizopygopsis kessleri , Schizopygopsis kialingensis and Schizopygopsis anteroventris in the commencement of the ventral fin under the 4–5 th branched ray of the dorsal fin ( Table 3). It is distinguished from S. malacanthus , Schizopygopsis stoliczkai and Schizopygopsis thermalis by differences in strength of unbranched rays and serratures in the dorsal fin. Compared to Schizopygopsis younghusbandi , S. chengi has a wider mouth and horny layer of the lower jaw and fewer branched rays in the pelvic fin.

Key to the species of the genus of Schizopygopsis

1 (14) Inside gill raker of the first gill arch more than 20

2 (11) Commencement of the ventral fin under the 4–5 th branched ray of the dorsal fin

3 (6) The strong unbranched rays of the dorsal fin with obvious serratures

4 (5) Anal scale reaching the base of the ventral fin (the distribution in river systems in the western QTP).......... S. stoliczkai

5 (4) Anal scales reaching the midpoint between the ventral and anal fins (the distribution in the upstream of Yangtze River)............................................................................................. S. malacanthus

6 (3) The weak unbranched rays of dorsal fins with few serratures or no serratures

7 (8) Anal scales reaching the base of the ventral fin...................................................... S. s. chengi

8 (7) Anal scales reaching the midpoint between the ventral and anal fins

9 (10) Oral fissure hooked, outside gill raker on the first gill arch 10–15, inside gill raker on the first gill arch 16–23 (the distribution in the Baoxing River)................................................................... S. s. baoxingenesis

10 (9) Oral fissure transverse, outside gill raker on the first gill arch 17–21, inside gill raker on the first gill arch 25–37 (the distribution in the Duoke River)...................................................................... S. s. duokeheensis

11 (2) Commencement of the ventral fin under the 2 nd –3 rd branched ray of dorsal fin

12 (13) The last unbranched ray of dorsal fin weak with few tiny serratures, the first outside gill raker outward hooked with small serrations.................................................................................... S. kessleri

13 (12) The last unbranched ray of dorsal fin strong with obvious serratures, the first outside gill raker normal without serrations............................................................................................... S. pylzovi

14 (1) Inside gill raker of the first gill arch less than 20

15 (18) Commencement of the ventral fin under the 4–5 th branched ray of the dorsal fin

16 (17) The last unbranched ray of dorsal fin strong with obvious serratures (the distribution in hot springs in Tanggula Mountains)............................................................................................ S. thermalis

17 (16) The last unbranched ray of the dorsal fin weak with few tiny serratures or without serratures............ S. younghusbandi

18 (15) Commencement of ventral fin under 2 nd –3 rd branched ray of dorsal fin (the distribution in the Jialingjiang River).................................................................................................... S. kialingensis