taxonID	type	description	language	source
EF4287F1FFFEFFDC08A7E29FFDB9F8CB.taxon	description	Morphological, genetic and phylogenetic evidence supports Schizopygopsis chengi as a valid species. Schizopygopsis chengi is distinguished from other Schizopygopsis fishes by having an outside gill raker number of the first gill arch greater than 10, an inside gill raker number of the first gill arch greater than 16 and the commencement of a ventral fin under the 4 – 5 th branched ray of the dorsal fin (Table 3). Schizopygopsis chengi differs from S. malacanthus in the following characteristics: soft unbranched rays of dorsal fins with small and fewer serratures at the posteriors edge (vs. strong unbranched rays of dorsal fin with obvisous serratures in S. malacanthus); no black dots on the dorsal fin (vs. black dots on the dorsal fin of S. malacanthus); large black spots on the body (vs. small dots on the back of the body or above the lateral line in S. malacanthus); and an independent distribution area in the headstream of the Dadu River in western China (vs. the distribution of S. malacanthus in the upstream of the main stream of the Yangtz River in western China) (Fig. 2 and Tables 3 – 4). The measurements of morphological characteristics are shown in Table 4. PCA revealed that 49 % of the total variance was explained by the first three components, including 24 %, 14 % and 11 % for PC 1, PC 2 and PC 3, respectively (Table 5). Along PC 1, the specimens were clearly separated into two groups, corresponding to S. chengi and S. malacanthus (Fig. 3 a). PC 1 loaded heavily on head length, preventral length, eye diameter, and IEW / ED, which distinguished S. chengi from S. malacanthus. Morphometric analysis indicated that S. chengi had longer predorsal, prepectoral, and preventral lengths than S. malacanthus. Furthermore, PCA revealed that DK populations of Schizopygopsis chengi were separated from S. c. baoxingensis, MK and KK populations, and the latter two populations could not be partitioned by traditional morphometric data (Fig. 3 b and Table 6). ...... continued on the next page ...... continued on the next page ...... continued on the next page Sequencing of the Cyt b gene generated 36 haplotypes, including 24 in S. chengi and 12 in S. malacanthus. Additionally, we included 2 haplotypes of S. c. baoxingensis and S. m. malacanthus obtained from public databases (Liu, et al. 2015). Therefore, 26 and 14 haplotypes of S. chengi and S. malacanthus, respectively, were subjected to phylogenetic analysis. The haplotype network demonstrated the clear separation between S. chengi and S. malacanthus without any common haplotypes (Fig. 4 a). The BI and ML trees yielded identical topologies, revealing that S. chengi did not form a sister lineage with S. malacanthus (Fig. 4 b). Schizopygopsis malacanthus was grouped with other Schizopygopsis fish and Heizensteinia microcephalus, while S. chengi formed an independent lineage with strong support. Within S. chengi, samples from the DK River formed a monophyletic group, and the MK and KK populations were grouped together without phylogenetic differentiation. Two haplotypes of S. c. baoxingensis formed a monophyletic group in S. c. chengi (Fig. 4 b). Based on Cyt b haplotypes, the interspecific genetic distance among these species ranged from 0.019 (between S. pylzovi and S. microcephalus) to 0.091 (between S. anteroventris and G. potanini). The genetic distance between S. chengi and S. malacanthus was 0.076, which was greater than that of the other 13 comparisons (Table 7). The genetic differentiations (F st) ranged from 0.654 (between S. malacanthus and S. microcephalus) to 0.966 (between S. kialingensis and S. chengi). The genetic differentiation between S. chengi and S. malacanthus was 0.834, which was greater than that between S. malacanthus-S. kialingensis, S. malacanthus-H. microcephalus, S. malacanthus-S. anteroventris, and S. malacanthus-S. pylzovi. (Table 7). The genetic distance was 0.022 between the DK and MK populations and reached 0.024 between the DK and KK populations (Table S 1). The genetic distances within S. chengi were even greater than that between H. microcephalus and S. pylzovi (0.019) as well as those between H. microcephalus and S. kessleri (0.018). The F st values were 0.473 and 0.487 between DK populations and and S. c. chengi as well as between DK populations and S. s. baoxingensis, suggesting genetic differentiation among the geographic populations (Table S 1). Additionally, we found that the nucleotide and haplotype diversities were greater in the MK / KK populations than in the DK populations, which might be associated with the more restricted range of the DK population (Table S 2). Species delimitation was carried out using bPTP and ASAP, both of which decisively supported that S. chengi and S. malacanthus represented two distinct species (Fig. 5). Based on the bPTP model, 14 species were defined, with Bayesian support values ranging from 0.93 to 1.00. Schizopygopsis chengi and S. malacanthus were delimited as two species, which was supported by the posterior probabilities of 0.98 and 0.97 for the two lineages. ASAP identified the 14 best partitions based on pairwise genetic distance using Cyt b sequences (Table S 3). According to the lowest score of 2.0, the ASAP method delimited all the samples into 13 species, and S. chengi and S. malacanthus were separated into two taxonomic classifications (Fig. 5). It has three subspecies, i. e. Schizopygopsis chengi chengi, Schizopygopsis chengi baoxingensis and Schizopygopsis chengi duokeheensis, subsp. nov.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF4FFD908A7E798FC5AF978.taxon	materials_examined	Materials examined NWIPB 2107001 – 19 (19 specimens), 67 – 253 mm SL, collected in Western China: Qinghai Province: Kepei Village: Marke River, one of the headstreams of the Dadu River; 100.92 E, 32.66 N; collected by S. Liu and K. Zhao, July 2021. NWIPB 2107019 – 28 (10), collected in Western China: Qinghai Province: Jiangritang Village: Keke River, one of the headstreams of the Dadu River; 101.12 E, 32.24 N; collected by S. Liu and K. Zhao, July 2021.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF4FFD908A7E798FC5AF978.taxon	diagnosis	Diagnosis Schizopygopsis chengi chengi is distinguished from Schizopygopsis chengi baoxingensis by having a greater number of gill rakers in the first gill arch. The numbers of outside and inside gill rakers ranged from 15 – 20 and 25 – 37, respectively, in S. c. chengi and from 10 – 15 and 16 – 23, respectively, in S. c. baoxingensis. It differed from S. c. duokeheensis by having anal scaly sneath terminating at the base of the ventral fin.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF4FFD908A7E798FC5AF978.taxon	description	Description D. iv, 8; P. i, 19 – 21; V. i, 9; A. iii, 5; vertebrae 4 + 42 – 46. The morphometric measurements are shown in Table 7. Body elongate, slightly flat. Snout obtuse and round. No barbels. Mouth inferior, oral fissure nearly straightly transverse, inner side of the lower jaw sharp with a strong horny layer. Head large and convex. Dorsal profile convex and sloping. Ventral profile flat. Nostrils 2 on each side, close together, near eye edge relative to tip of snout. Gill rakers of the first gill arch long and dense. Pharyngeal teeth in 2 rows, 4.3 / 3.4; slightly hooked and pointed at the tip and with a concave grinding surface. Last unbranched dorsal fin ray weak with small and few serratures at the posterior edge. Body naked with a group of minute scales bordering the scapular region. The lateral line is complete and straight along the middle of the body and tail. The origin of the dorsal fin closer to the tip of the snout than to the base of the caudal fin. Commencement of the ventral fin under the 4 – 5 th dorsal branched ray. The anterior and posterior angles of dorsal fin squarish. Anal opening proximity to the origin of the anal fin. The tip of the anal fin reaches the base of the caudal fin. Caudal forked. Anal sneath consisting of enlarged scales on each side, extending anteriorly and terminating at the base of the ventral region. Color pattern Alcohol-preserved specimens black-gray, abdomen yellowish, whole body with black spots. The dorsal and caudal fins yellow to pale brown, and the ventral and anal fins yellow.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF4FFD908A7E798FC5AF978.taxon	distribution	Distribution and habitats Schizopygopsis chengi chengi is distributed in the headstreams of the Dadu River, the Marke River and the Keke River in Bama County, Qinghai Province, China (Fig. 7). The coexisting fishes included Gymnocypris potanini, Schizothorax davida, Schizothorax prenanti, Triplophysa markehenensis, Triplophysa stenure, Triplophysa leptosome, Triplophysa orientalis and Triplophysa microps. Schizopygopsis chengi chengi dwells in cold highland streams with a substrate of sand, pebbles and gravels at altitudes of 3000 – 4000 m above sea level. It feeds on plant fragments and algae on pebbles and gravels as well as insects such as Gammaridea sp. (gammarid) and Chironomus sp. (chironomid).	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF4FFD908A7E798FC5AF978.taxon	etymology	Etymology The subspecies Schizopygopsis chengi chengi was named after W. C. Cheng (Ệ 万 ṱ), an assistant botanist at the Herbarium of the Biological Laboratory of Science Society of China, who identified and presented the specimen. The Chinese name for this species is suggested as 大ă ẹṳaeḛẽ 名亚ª.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF6FFC708A7E56CFBEFF823.taxon	description	Schizopygopsis malacanthus baoxingensis (Fu, Ding and Ye), 1994, The Fishes of Sichuan, 399 – 401 (The Baoxing River).	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF6FFC708A7E56CFBEFF823.taxon	materials_examined	Materials examined NWIPB 231201 – 17 (17), collected. 45 – 54 mm SL. collected in Western China: Sichuan Province: Baoxing County; 102.81 E, 30.38 N.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF6FFC708A7E56CFBEFF823.taxon	diagnosis	Diagnosis Schizopygopsis chengi baoxingensis is distinguished from S. c. chengi and S. c. duokeheensis by having fewer outside and insider gill rakers on the first gill arch. The numbers of outside and insider gill rakers ranged from 10 – 15 and 16 – 23 in S. c. baoxingensis, from 15 – 20 and 25 – 37 in S. s. chengi, and from 17 – 21 and 27 – 36 in S. c. duokeheensis. The oral fissure is slightly hooked in S. c. baoxingensis, and nearly transverse in S. c. chengi and S. c. duokeheensis.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF6FFC708A7E56CFBEFF823.taxon	description	Description D. iii, 8; P. i, 17 – 20; V. i, 9 – 10; A. iii, 5; vertebrae 4 + 44 – 46. The morphometric measurements are shown in Table 7. Body elongate, slightly flat. Greatest depth at origin of dorsal fin, dorsal profile arched, ventral profile curved. Snout obtuse and round. Lip narrow with two lateral lobes, posterior groove of the lower lip discontinued. Mouth inferior, oral fissure slightly hooked, and the lower jaw sharp with a strong and flat horny layer. No barbels. Eye big, round, forward in the middle of the head. Gill rakers long and sparse, outer gill rakers small. Pharyngeal teeth in 2 rows, 4.3 / 3.4; hooked, pointed at the tip and with a concave grinding surface. Body entirely naked with 1 – 4 rows of scales above the pectoral axil. Lateral line complete, along middle of flank and caudal peduncle, anterior portion skinfold-like. The last unbranched dorsal fin ray weak with small serratures at the posterior edge. The origin of the dorsal fin closer to the tip of the snout than to the base of the caudal fin. Commencement of the ventral fin under the 4 th branched ray of the dorsal fin. The anterior angle of dorsal fin round and posterior angle squarish. Anal sneath consisting of enlarged scales on each side, and the anal sneath reaching or slightly exceeds the midpoint between the ventral and anal fins. Caudal deeply forked, the lower lobe slightly longer than the upper one. Color pattern The back yellowish brown to blackish brown, the abdomen greyish white, without black dots or spots on the body, the dorsal, ventral and anal fins yellow, and the caudal fin light pink in the living specimen.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF6FFC708A7E56CFBEFF823.taxon	distribution	Distribution and habitats Schizopygopsis chengi baoxingensis is distributed in the headstreams of Qingyijiang River, the Baoxing River in Baoxing County, Sichuan Province, China (Fig. 9). Schizopygopsis chengi baoxingensis inhabits cold highland streams with a substrate of pebbles and gravels at altitudes of 1500 - 2000 m above sea level. It mainly feeds on plant fragments and algae.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFF6FFC708A7E56CFBEFF823.taxon	etymology	Etymology The name of the subspecies, baoxingensis, is derived from the Baoxing River (Ī Ẋñ), where the holotype was collected. The Chinese name for this species is suggested as 大ă ẹṳaeḛĪẊ 亚ª.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFEBFFC208A7E6BBFBFCFA22.taxon	materials_examined	Holotype NWIPB 2107029, total length 218.00 mm; standard length 183.40 mm; Western China: Qinghai Province: Zhiqin Village: Duoke River, one of the headstreams of the Dadu River; 100.46 E, 32.57 N; collected by S. Liu and K. Zhao, July 2021 Paratypes NWIPB 2107030 – 53 (24), 48 – 276 mm SL, collected with the holotype.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFEBFFC208A7E6BBFBFCFA22.taxon	diagnosis	Diagnosis Schizopygopsis chengi duokeheensis is distinguished from S. c. chengi by having an anal scaly sneath ending nearly or slightly in front of the midpoint between the ventral and anal fins. It differed from S. c. baoxingensis by having dense outside and inside gill rakers on the first gill arch.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFEBFFC208A7E6BBFBFCFA22.taxon	description	Description D. iv, 8; P. i, 18 – 21; V. i, 9; A. iii, 5; vertebrae 4 + 44 – 46. The morphometric measurements are shown in Table 7. Body elongate, slightly flat. Greatest depth at origin of dorsal fin. Dorsal profile convex and sloping. Ventral profile flat. Head slightly conical. Snout obtuse and round. Mouth inferior, oral fissure transverse, ventral view of margin of lower jaw horseshoe-shaped. Lip narrow, and the inner side of the lower jaw sharp with a strong horny layer. Lower lip with two lateral lobes, posterior groove of the lower lip discontinued. No barbels. Eye round, moderate. Nostrils 2 on each side, above the anterior edge of eye, near eye edge relative to tip of snout. Gill rakers short and dense. Pharyngeal teeth in 2 rows, 4.3 / 3.4; slightly hooked and pointed at tip and with a concave grinding surface. Body entirely naked with 2 – 4 rows of scales above the pectoral axil. Lateral line complete, flat and straight, along middle of the body and caudal peduncle. Last unbranched dorsal fin ray weak with small and few serratures at the posterior edge. The anterior and posterior angles of dorsal fin roundish corner. The origin of the dorsal fin almost at the midpoint between the tip of the snout and the base of the caudal fin. Anal scaly sneath ending nearly or slightly in front of the midpoint between the ventral and anal fins. Anal opening proximity to the origin of the anal fin. Caudal forked, the lower lobe slightly longer than the upper one. Color pattern For alcohol-preserved specimens, back gray to brown, abdomen yellowish, whole body with blackish brown spots, and the dorsal and caudal fins with black spots.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFEBFFC208A7E6BBFBFCFA22.taxon	biology_ecology	Ecology Distribution and habitats Schizopygopsis chengi duokeheensis is distributed exclusively in the Duoke River in Bama County, Qinghai Province, China (Fig. 11). The coexisting fish was Triplophysa markehenensis. Schizopygopsis chengi duokeheensis inhabits cold highland streams with a substrate of sand, pebbles and gravels at altitudes of 3000 – 4000 m above sea level. It mainly feeds on plant fragments and algae growing on pebbles and gravels.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFEBFFC208A7E6BBFBFCFA22.taxon	etymology	Etymology The name of the new subspecies, duokeheensis, is derived from the Duoke River (多 ḁñ), where the species inhabits. The Chinese name for this species is suggested as 大ă ẹṳaeḛ 多 ḁ 亚ª.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
EF4287F1FFECFFC008A7E476FA2EFC12.taxon	description	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.	en	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): 481-506, DOI: 10.11646/zootaxa.5590.4.2, URL: https://doi.org/10.11646/zootaxa.5590.4.2
