Cobitis oxycephala Chen YX & Chen YF, 2018

Chen, Yongxia, Chen, Hao, He, Dekui & Chen, Yifeng, 2018, Two new species of the genus Cobitis (Cypriniformes: Cobitidae) from South China, Zoological Systematics 43 (2), pp. 156-168 : 160-162

Cobitis oxycephala Chen YX & Chen YF , sp. nov. ( Figs 2–7 )

Cobitis sinensis Chen, 1986 (nec. Sauvage & Dabry, 1874): 145 (Hainan, fig. 81).

Cobitis taenia dolichorhynchus Nichols & Popo, 1927 (nec. Nichols, 1918): 335 (Hainan, fig. 8); Nichols, 1943: 197 (Fukien, Kwangtung, Hainan, fig. 81).

Holotype. ♂, IHB 0509273 , 67.7 mm TL, 57.9 mm SL, China, Hainan, Ding’an County (19°68′N, 110°36′E; elev. 65 m), the Nandujiang River , July 2005, leg. Kun Li. Paratypes. IHB 0509392–9 , 0509401–5 , 13♂, 63.1–70.3 mm TL, 51.8– 59.1 mm SL , IHB 509400 , 0509406–7 , 3♀, 74.6–84.7 mm TL, 61.6–71.6 mm SL, same data as holotype .

Diagnosis. The new species can be distinguished from its congeners by possessing the following combination of characteristics: 13–15 large rectangular blotches on L 1; 10–14 elongated blotches on L 5; snout sharp ( Figs 2–3 ); males with a semicircular lamina circularis at the base of the first branched pectoral fin ray ( Fig. 4 ); mental lobes undeveloped, three superficial longitudinal lobes short and bluntly rounded ( Fig. 5 ); suborbital spine thick and curved, with a short processus medio-caudalis ( Fig. 6 ). Cobitis oxycephala Chen YX & Chen YF , sp. nov. is similar to C. sinensis , C. dolichorhynchus and C. zhejiangensis in color pattern (with L 1 –L 5 line on the body) and lamina circularis morphology (plate-like), but differs from them in having snout sharp (vs. rounded); 10–14 horizontally elongated blotches and without the deeper faint dusky band on L 5 (vs. 11–12 rectangular and vertically elongate spots in C. sinensis (Son & Kim, 2002) ; a row of more or less oval blotches and with the deeper faint dusky band on the mid-lateral line in C. dolichorhynchus ( Nichols, 1918) ; 14–16 short vertical spots in C. zhejiangensis ). It further differs from C. dolichorhynchus and C. zhejiangensis in body slender, depth 7.6 in SL in male and 7.7 in female (vs. sturdy, depth 5.8 in SL in male in C. dolichorhynchus ( Nichols, 1918) ; 5.6–6.7 (mean 6.0) in males and 4.3–5.0 (mean 4.7) in females in C. zhejiangensis ); 13–15 large rectangular blotches on L 1 (vs. irregular dark cross blotches in C. dolichorhynchus ( Nichols, 1918) ; 13–19 rectangular blotches in C. zhejiangensis ).

Description ( Figs 2–7 , Table 2 ). D. III–7; A. III–5; V. I–6; P. I–6–7; C. IV–14–16–IV. Body moderately slender, compressed. Head small. Snout sharp. Eyes located on upper part and middle of head. Preorbital part of head equal to or longer than postorbital part of head. Mouth small, inferior, with three pairs of short barbels. Length of maxillo-mandibular barbels shorter than diameter of eye. Mental lobes undeveloped, three superficial longitudinal lobes short and bluntly rounded ( Fig. 5 ) Suborbital spine thick and curved, with a short processus medio-caudalis. Processus latero-caudalis long, less than one-third of processus medio-caudalis ( Fig. 6 ). Subdorsal scales small, oval, with a moderately large focal area, 18–20 radial grooves, and 3–5 supplementary ones ( Fig. 7 ).

Dorsal fin moderately long, inserted midway between nostril and base of caudal fin. In males, pectoral fins long, second pectoral fin ray longest ( Fig. 2 ). In females, pectoral fins slightly short, third pectoral fin ray longest ( Fig. 3 ). Ventral fins small and short, approximately at same level as second or third branched dorsal-fin ray. Anal fin short, located on half of space between ventral and caudal fins. Anal orifice close to anal fin. Caudal fin long, emarginated tip. Caudal peduncle with ventral adipose crest. Lateral line long, not exceeding length of pectoral fins in males, and exceeding in females.

Pigmentation pattern. Color characterized by pigmentation pattern with five longitudinal lines of dark speckles on dorsolateral sides of body (L 1 –L 5 from dorsal to ventral) ( Figs 2–3 ). Color pattern characteristic of sexual dimorphism not observed. Head sprinkled with many black dots, and a black stripe extended from insertion of rostral barbels through eye to occiput. L 1 consisted of a row of 5–6 large rectangular blotches before dorsal fin; 2 on dorsal fin and 6–7 behind dorsal fin. Gap of rectangular blotches smaller than width of blotches. L 2 composed of a line of irregularly small and solitary spots or blotches and not intermingle with gap of large rectangular blotches, and reaching beyond dorsal fin. L 3 composed a narrow stripe beyond anal fin and a row of rounded blotches behind anal fin. L 4 composed of a line of minute black dots, which fused to a line and diminished towards end of ventral fin. L 5 consisted of a row of 10–14 horizontally elongated blotches, without deeper faint dusky band. One small oblique vertical jet blotch at upper base of caudal fin base and far smaller than eye diameter. 4–5 narrow rows of dark dots on dorsal and caudal fins.

Sexual dimorphism. Males smaller than females with proportionally longer pectoral fins. In males, second pectoral fin ray thickened and elongated, a semicircular lamina circularis at base of first branched pectoral fin ray. In females, third pectoral fin ray elongated.

Distribution. This new species occurs in the Nandujiang River, Hainan, China ( Fig. 1 ).

Etymology. The species name is derived from the Greek oxys, meaning sharp, and kephale meaning head, in reference to the pointed head of the species.

Figures

Figure 1. Map showing the collection sites of the two new species of the genus Cobitis in Guangdong and Hainan Provinces of China.

Figures 2–7. Cobitis oxycephala Chen YX & Chen YF, sp. nov., Nandujiang River, Ding’an, Hainan, China. 2. Holotype, IHB 0509273, lateral view. 3. IHB 0509274, lateral view. 4. Lamina circularis in the pectoral in of male, dorsal view. 5. Mouth characters, front view. 6. Suborbital spine, left dorsal view, right interior view. 7. Subdorsal scales, dorsal view. Scale bars: 2–3 =1 cm; 4–6 = 1mm; 7=100μm.