Gobio huanghensis Lo, Yao & Chen, 1977

Gobio huanghensis Lo, Yao & Chen, 1977

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , Table 2 View Table 2

Gobio huanghensis Lo, Yao & Chen, 1977: 496 View in CoL .

Gobio rivuloides View in CoL : Institute of Zoology, Chinese Academy of Sciences (1959, not Nichols, 1925): 43.

Gobio tchangi : Li (2015): 178.

Material examined.

• IHB 56–IX–004 (Syntype), 1 specimen, 121.9 mm SL, Lanzhou City , Gansu Province, China . ASIZB 56773–56778 View Materials , 6 specimens, 115.6–157.6 mm SL; near Lanzhou City , Gansu Province, from the main stream of the Yellow River; collected by Sizhong Li; 1958 . • ASIZB 232934 View Materials , 1 specimen, 80.4 mm SL; Liulin County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (37.3891°N, 110.6281°E, ca 630 m a. s. l.); collected by Xin Wang; 31 July 2022 GoogleMaps . • ASIZB 241489–241490 View Materials , 241497 View Materials , 3 specimens, 64.7–107.4 mm SL; Xing County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (38.5196°N, 110.9076°E, ca 770 m a. s. l.); collected by Yutian Fang, 20 October 2023 GoogleMaps . • ASIZB 242021–242024 View Materials , 4 specimens, 72.2–128.9 mm SL; Xing County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (38.5193°N, 110.9072°E, ca 780 m a. s. l.); collected by Yutian Fang, 22 May 2024 GoogleMaps . • 1 ASIZB 242025 View Materials , specimen, 99.5 mm SL; Baode County, Xinzhou City , Shanxi Province, from the main stream of the Yellow River (38.7821°N, 110.9691°E, ca 780 m a. s. l.); collected by Zhixian Sun, 21 May 2024 GoogleMaps . • ASIZB 242026 View Materials , 1 specimen, 106.3 mm SL; Liulin County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (37.3947°N, 110.6316°E, ca 630 m a. s. l.); collected by Yutian Fang, 26 May 2024 GoogleMaps . • ASIZB 242019–242020 View Materials , 2 specimens, 118.6–124.6 mm SL; Baode County, Xinzhou City , Shanxi Province, from the main stream of the Yellow River (39.0212°N, 110.0596°E, ca 810 m a. s. l.); collected by Zhixian Sun, 6 July 2024 GoogleMaps . • ASIZB 242029 View Materials , 1 specimen, 94.9 mm SL; Daning County, Linfen City , Shanxi Province, from the main stream of the Yellow River (36.4587°N, 110.4876°E, ca 600 m a. s. l.); collected by Zhixian Sun, 8 July 2024 GoogleMaps . • ASIZB 242030–242032 View Materials , 3 specimens, 66.8–80.3 mm SL; Hangjin Banner, Ordos City , Inner Mongolia Autonomous Region, from the main stream of the Yellow River (40.6085°N, 107.2969°E, ca 1040 m a. s. l.); collected by Junyuan Hao, 28 June 2024 GoogleMaps . • ASIZB 242040 View Materials , 1 specimen, 88.6 mm SL; Lin County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (37.6423°N, 110.7796°E, ca 670 m a. s. l.); collected by Zhixian Sun, 8 July 2024 GoogleMaps .

Vouchers for molecular study.

• ASIZB 242021–242022 View Materials , 2 specimens, Xing County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (38.5193°N, 110.9072°E, ca 780 m a. s. l.); collected by Yutian Fang, 22 May 2024 GoogleMaps . • ASIZB 242025 View Materials , 1 specimen, Baode County, Xinzhou City , Shanxi Province, from the main stream of the Yellow River (38.7821°N, 110.9691°E, ca 780 m a. s. l.); collected by Zhixian Sun, 21 May 2024 GoogleMaps . • ASIZB 242026 View Materials , 1 specimen, Liulin County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (37.3947°N, 110.6316°E, ca 630 m a. s. l.); collected by Yutian Fang, 26 May 2024 GoogleMaps . • ASIZB 242030 View Materials , 1 specimen, Hangjin Banner, Ordos City , Inner Mongolia Autonomous Region, from the main stream of the Yellow River (40.6085°N, 107.2969°E, ca 1040 m a. s. l.); collected by Junyuan Hao, 28 June 2024 GoogleMaps .

Diagnosis.

This species can be distinguished from other Gobio species in the Yellow River drainage by following characteristics: barbel reaching beyond posterior preopercle margin (vs. reaching between vertical of posterior orbit and posterior preopercle margin in G. rivuloides and G. coriparoides ); lateral-line scales 41–44 (mode 43, mean 42) (vs. mean 40 in G. coriparoides ); circumpeduncular scales 14–16 (mode 16, mean 16) (vs. mean 12 in G. rivuloides , 18 in G. coriparoides and 20 in G. guentheri ); longitudinal epithelial crests present on pre-dorsal scales (vs. absent in G. coriparoides and G. guentheri ); anus centrally located between pelvic-fin base and anal-fin origin (vs. positioned at posterior one-third of distance from pelvic-fin base end to anal fin origin in G. coriparoides and G. guentheri ).

Redescription.

Body elongated, dorsal body profile rising from nostrils to dorsal-fin origin, dropping along dorsal-fin base, then gradually sloping to caudal-fin base. Maximum body depth at dorsal-fin origin. Head elongated, length larger than body depth; snout pointed and elongated, with moderate concavity on top of snout before nostrils. Mouth horseshoe-shaped and inferior, with one pair of maxillary barbels root at extremity of upper lip, barbel elongated, extending over posterior preopercle margin. Upper lip thin, lower lip fused with throat, lateral lobes of lower lip well developed, lips connected at mouth corner, tiny papillae on lips, lateral lobes, and chin (Fig. 3 A View Figure 3 ). Eyes positioned on dorsal half of head; interorbital region flattened; width slightly larger than eye diameter. Thoracic region flattened, abdomen rounded, caudal peduncle robust, compressed laterally. Anus centrally located between pelvic-fin base and anal-fin origin.

Body covered with moderately large cycloid scales. Lateral line complete, almost straight in lateral center. Lateral line scales 41 (1 specimen), 42 (7), 43 (11), 44 (3); scales above lateral line 6 (2), 6.5 (19), 7.5 (1); scales below lateral line 3 (1), 4 (21); circumpeduncular scales 14 (2), 16 (20). Longitudinal epithelial crests present on pre-dorsal region scales (Fig. 3 B View Figure 3 ); ventral scaleless region only before pectoral-fin base end.

Dorsal fin with three unbranched and seven (22 specimens) branched rays; distal margin concave, origin closer to snout than caudal-fin base. Pectoral fin with one unbranched and 13 (3), 14 (19) branched rays; tip of adpressed not reaching anterior margin of pelvic-fin insertion. Pelvic fin with one unbranched and seven (22) branched rays; tip of adpressed reaching to posterior anus. Anal fin with three unbranched and six (22) branched rays; origin closer to pelvic-fin insertion than to caudal-fin base. Caudal fin deeply forked, with nine branched rays on upper lobes and eight branched rays on lower lobes, lobes pointed, upper lobes slightly more pointed than lower lobes.

Total vertebrae 4 + 37–38. Gill rakers rudimentary. Pharyngeal teeth “ 3, 5–5, 3 ”.

Coloration in life.

Dorsal side of head and body greyish brown, mid-lateral side shallow greyish yellow, and ventral side grayish white. Dorsal side of body with 5–6 black crossbars (first at posterior of head, second at dorsal-fin base origin, third at posterior of dorsal-fin base, fourth at vertical position above anal-fin base origin, fifth and sixth on caudal peduncle, respectively). Flank with 7–9 black blotches; margin of scales on back and flank slightly black pigmented. One slightly fluorescent yellowish-green stripe extends above lateral line. One distinct black stripe between anterior orbit and snout. Fins translucent, with slightly black pigments on dorsal fin, pectoral fin, and caudal fin rays; fins without black spots (Fig. 2 B View Figure 2 ).

Coloration in preservation.

Dorsal side of head and body yellowish grey, mid-lateral side shallow yellowish grey, and ventral side greyish white. Dorsal side of body with 5–6 black crossbars in same position as live individual. Flank with 7–9 dark grey blotches, first three or four blotches vague. Margin of scales on back and flank slightly black pigmented. The fluorescent yellowish-green stripe faded. One distinct black stripe between anterior orbit and snout. Fins pale, with slightly black pigments on dorsal fin, pectoral fin, and caudal fin rays; fins without black spots. The black pigments on fin rays faded after long-time preserve.

Sexual dimorphism.

No sexual dimorphism observed.

Distribution.

Gobio huanghensis is distributed in the main stream of the Yellow River drainage, from Lanzhou City, Gansu Province, to Yongji City, Yuncheng City, and Shanxi Province (Fig. 4 A View Figure 4 ).

Habitat and biology.

Gobio huanghensis inhabits the main stream of the Yellow River. It usually appears in fast-flowing water with sandy bottoms and high turbidity, which is caused by fine sediments. It feeds in sand on the bottom of the river.

Remarks.

Gobio tchangi was originally described by Li (2015). In the original description, G. tchangi is said to resemble G. huanghensis , the only difference between the two species being the location of the anus (3.5 scales from anus to anal-fin base in G. tchangi vs. 5 scales in G. huanghensis ). However, after carefully measuring specimens of both G. tchangi and G. huanghensis , the 3.5 scales from the anus to the anal-fin base in G. tchangi were found to be incorrect. The holotype of G. tchangi ( ASIZB 56774, Fig. 5 A View Figure 5 ) has 5 scales between the anus and anal-fin base, and other specimens of G. tchangi ( ASIZB 56773, 56775–56778) also had 5–6 scales between the anus and the anal-fin base. Additionally, the scales between the anus and anal-fin base are not neatly aligned, making this an unreliable taxonomic trait. Therefore, we use the pelvic fin-anus distance and anus-anal fin distance to measure the position of the anus. The position of the anus did not differ between the two nominal species (pelvic fin-anus distance averaged 94.0 % of anus-anal fin distance in G. tchangi , compared to 98.1 % in G. huanghensis ).

To further compare the morphological difference between Gobio huanghensis and G. tchangi , a PCA based on 22 specimens, including the holotype of G. tchangi , was generated. The first three components contributed 98.3 % of the variance. Principal component 1 (PC 1) primarily represents the body size of the specimens, while PC 2 and PC 3 reflect their morphology. PCA loadings (Table 3 View Table 3 ) indicate that body depth, pelvic-fin base length, and anal-fin base length contribute most to PC 2. Even these characters have high loadings; G. huanghensis and G. tchangi were not separated in PC 2 or in PC 3 (Fig. 6 View Figure 6 ).

Additionally, the type locality of Gobio tchangi is Lanzhou City, Gansu Province, which is the same as that of G. huanghensis . Based on the morphological comparisons and distribution, we treat G. tchangi as a junior synonym of G. huanghensis .