Cobitis beijingensis Sun & Zhao, 2025

Sun, Zhi-Xian, Li, Xue-Yuan, Li, Xue-Jian, Hao, Jun-Yuan, Sheng, Dong & Zhao, Ya-Hui, 2025, Cobitis beijingensis, a new spined loach from northern China (Cypriniformes, Cobitidae), Zoosystematics and Evolution 101 (1), pp. 55-67 : 55-67

Cobitis beijingensis Sun & Zhao sp. nov.

Figs 2 , 3 , 4 ; Table 2

Type material.

Holotype. • ASIZB 240630 , male, 55.0 mm SL; Shilipu Township, Miyun District, Beijing, from the Chaobaihe River (40.33574769 ° N, 116.79236588 ° E, 52 m a. s. l.); collected by Zhixian Sun, Junyuan Hao and Dong Sheng; 13 June 2024.

Paratypes. Twenty-five specimens • ASIZB 240631–6 , 240689–95 , 3 males, 10 females, 50.2–75.3 mm SL; same collection information as holotype • ASIZB 240697–8 , 2 juveniles, 24.1–27.0 mm SL; same locality and collectors as holotype; 14 June 2024 • ASIZB 240682–4 , 3 males, 48.8–58.1 mm SL • ASIZB 240685–8 , 4 juveniles, 26.4–33.1 mm SL; same locality as holotype; collected by Zhixian Sun and Wenli Yu; 15 June 2024 • ASIZB 240605 , 240680–1 , 1 male, 2 females, 56.1–74.5 mm SL; Qiaozi Township, Huairou District, Beijing, from the confluence of the Huaijiuhe River and Huairou Reservoir (40.31521727 ° N, 116.57391776 ° E, 64 m a. s. l.); collected by Zhixian Sun, Yutian Fang and Dong Sheng; 10 May 2024 .

Additional materials examined.

Twenty-five specimens • ASIZB 62425–8 , 1 male, 3 females, 42.0–67.0 mm SL; Niulanshan Township, Shunyi District, Beijing, from the Chaobaihe River ; collected by Chunguang Zhang; 1992 • ASIZB 192934 ( FMZB 3861 ), female, 53.0 mm SL; Shahe Township , Changping District, Beijing; 1 June 1929 • ASIZB 16918 , female, 92.2 mm SL; Beijing • ASIZB 17732 , female, 75.8 mm SL; Beijing • ASIZB 17388 ( FMZB 6030 ), 17390 (6032), from one lot of specimens ( ASIZB 17388–99 ), 1 male, 1 female, 51.4–54.0 mm SL; Changxindian Township (originally in Hebei Province), Fengtai District, Beijing, from the Yongdinghe River ; collected by Yingxiang Du; 9 May 1930 • ASIZB 17297–802 , gender unidentified, 6 specimens, 59.4–68.5 mm SL; Liulihe Township, Fangshan District, Beijing, from the Liulihe River • ASIZB 103008–10 , 2 males, 1 female, 50.5–65.7 mm SL; Anxin County, Baoding City, Hebei Province, from the Baiyangdian Lake system ; collected by Shiyi Zhang and Wenbin Wang; October 1959 • ASIZB 16917 , female, 116.3 mm SL; Xinji Township, Sanhe City, Langfang City, Hebei Province, from the Juhe River ; 13 June 1930 • ASIZB 79421–5 , 5 females, 58.3–109.4 mm SL; Anxin County, Baoding City, Hebei Province, from the Baiyangdian Lake system • ASIZB 170316 , female, 62.4 mm SL; Xisiduhe Village, Jiuduhe Township, Huairou District, Beijing, from the Huaijiuhe River ; 1 June 1974 • ASIZB 240696 , male, 54.5 mm SL; Lvhu local market, Qiaozi Township, Huairou District, Beijing, from the Huairou Reservoir ; collected by Zhixian Sun, Junyuan Hao and Dong Sheng; 15 June 2024 .

Diagnosis.

The new species can be distinguished by the combination of the following characters: Lamina circularis on pectoral fin elongated, posterior margin slightly serrated; 14–18 (mode 15) prepelvic myotomes; pelvic fin inserted below 3 rd – 5 th branched dorsal-fin ray; total vertebrae 4 + 36–38 (mode 37); the second Gambetta line (L 2) does not exist or is fused with the first line (L 1).

Description.

Body elongated, laterally compressed. Dorsal body profile rising smoothly from nostrils to occiput, almost horizontal between occiput and dorsal-fin insertion, gradually sloping along dorsal-fin base, then horizontally extending to caudal-fin base. Maximum body depth at dorsal-fin origin, body depth 12.6–19.8 % of standard length. Lower surface of head flattened, abdomen rounded. Caudal peduncle short, depth almost equal to length, laterally compressed, with fleshy keels on dorsal and ventral sides. Head length greater than body depth (101.0–156.7 % of head length); snout elongated and blunt, snout length 36.9–50.1 % of head length; eye small, 11.2–20.3 % of head length, superior and laterally positioned, near gill opening than tip of snout; nostrils positioned close together, anterior nostril with short tube; interorbital region ridged and narrow. Anus positioned near anal-fin insertion.

Mouth inferior, lips fleshy. Upper lip without affiliated apparatus; lower lip two lobed, medial side elongate-oval shaped. Three pairs of barbels: rostral barbels shorter than maxillary and mandibular barbels; maxillary barbels length equal to mandibular barbels length; mandibular barbels not or almost reaching under the anterior edge of the orbit.

Body covered with tiny cycloid scales. Prepelvic myotomes 14 (3 specimen), 15 (26), 16 (7), 17 (2), 18 (1).

Dorsal fin with three unbranched and six (1) or seven (39) branched rays; distal margin slightly convex, inserted nearer to caudal-fin base than snout. Pectoral fin with one unbranched and seven (3), eight (32) or nine (5) branched rays. Pelvic fin with one unbranched and five (1), six (38) or seven (1) branched rays, inserted below third to fifth branched dorsal-fin ray. Anal fin with 3 unbranched and 5 (40) branched rays; inserted nearer to caudal-fin base than to pelvic-fin insertion. Caudal fin slightly truncated, with one unbranched principle ray and seven branched principle rays on upper part and seven branched principle rays and one unbranched principal ray on lower part.

Total vertebrae 4 + 36 (1), 37 (6), 38 (4). Suborbital spine bifurcated (Fig. 3 ), posteriorly reaching under the center of the orbit.

Coloration in live.

Dorsal side of head and body yellowish brown, mid-lateral side light yellowish brown, ventral side grayish white. A clear black stripe or “ tear mark ” runs from tip of snout, crossing the eye, to the occiput; two dark grey stripes distributed parallel to the clear black stripe, one on the dorsal side of the head; one runs across the nostrils; several vague and irregular patterns located under the eye and opercula, sometimes forming one or two grey stripes parallel to the clear black stripe. Four obvious lines of Gambetta’s pattern. The L 1 of Gambetta’s pattern on the dorsal of body, 7–10 black blotches before dorsal-fin insertion, 7–11 black blotches after dorsal-fin base end; L 2 not exist or fused with L 1; L 3 linear, interrupted into several small irregular blotches and fused with L 1 at caudal peduncle; L 4 linear, consisted of many tiny spots; L 5 obvious, extending along the mid-lateral side of body, consisted of 9–15 different sized black blotches, sometimes connected with each other with black strip. Three or four rows of pigmentation on dorsal-fin rays; three or four arcuate black bars on caudal fin. One big jet-black oval-shaped spot on upper caudal-fin base, size comparable to the eye diameter (Fig. 4 ).

Coloration in preservation.

Dorsal side of head and body yellow, mid-lateral side light yellow, ventral side pale. All patterns same position as living specimen.

Sexual dimorphism.

Males with elongated lamina circularis derived from the base of the first branched pectoral-fin ray; tip of the lamina circularis almost reaching the mid-point of the first branched ray; posterior margin of the lamina circularis usually serrated (Fig. 5 A ). The L 4 of Gambetta’s pattern in males, usually thin and short, sometimes disappeared. The blotches on L 5 in males usually merged into a line. Females usually larger and slender than males. The L 4 in females usually exceeds over dorsal fin insertion, sometimes reaching the caudal peduncle. The blotches on L 5 in females not fully merged into one line.

Distribution.

Based on our field collections and the historic specimens, Cobitis beijingensis is distributed in the Haihe River basin in northern China, including rivers in Beijing and the Baiyangdian Lake in Hebei Province. This species can be currently found in the Chaobaihe River system in Huairou and Miyun District, Beijing (Fig. 6 ).

Habitat and biology.

This species usually inhabits slow-flowing water or still water with plenty of submerged plants or filamentous algae. The benthic microhabitat is usually sand and silt mixed with some gravel. Coexisting species include Rhodeus ocellatus , Carassius auratus , Misgurnus anguillicaudatus , Oryzias latipes , Rhinogobius giurinus , etc.

Etymology.

The species name “ beijingensis ” was referred to the type locality of this species, Beijing, the capital city of China. The Chinese name for the new species is “ 北京花鳅 ”.

Genetic comparisons.

A total of 24 haplotypes from 30 Cobitis individuals were included in the analyses. The molecular phylogenetic results (BI and ML trees in Fig. 7 ) based on mitochondrial Cyt b sequences show that the new species C. beijingensis forms a monophyletic group itself, which is sisters to the group consists of C. lutheri , C. tetralineata , C. nalbanti , and C. hankugensis . The interspecific genetic distances between C. beijingensis and four congeners, C. lutheri , C. tetralineata , C. nalbanti , and C. hankugensis , are 13.1 %, 8.0 %, 12.5 %, and 8.3 %, respectively (Table 3 ). The intraspecific genetic distances in C. beijingensis , C. lutheri , C. tetralineata , C. nalbanti , and C. hankugensis are 0.2 %, 0.5 %, 0.0 %, 0.6 %, and 0.0 %, respectively (Table 3 ), which are much lower than the interspecific genetic distances. The molecular phylogenetic results support C. beijingensis to be a distinct species.

Figures

Figure 2. Cobitis beijingensis sp. nov., holotype, ASZIB 240630, 55.0 mm standard length; A. Lateral view; B. Dorsal view; C. Ventral view; D. Original drawing.

Figure 3. Right suborbital spine of Cobitis beijingensis sp. nov. A. Lateral view; B. Dorsal view.

Figure 4. Live individuals of Cobitis beijingensis sp. nov. A. Holotype, ASIZB 240630, male; B. Uncatalogued, female; C. Paratype, ASIZB 240682, male, photographed in aquarium.

Figure 5. Lamina circularis of Cobitis beijingensis sp. nov. (A) and C. lutheri (B).

Figure 6. Distribution of Cobitis beijingensis sp. nov. and C. lutheri; the zoom-in map shows detailed distribution (i. e., specimen locality records) of the new species in Beijing and the adjacent area.

Figure 7. Molecular phylogenetic trees of Cobitis beijingensis sp. nov. and other phylogenetically close related congeners based on Cyt b sequence (1140 bp). A. Bayesian Inference method; B. Maximum Likelihood method.