Gobio guentheri ( Herzenstein, 1892 )

Fang, Yutian, Sun, Zhixian & Zhao, Yahui, 2025, Taxonomic revision on the Gobio group in the Yellow River drainage, with discussion on the validity of the genus Acanthogobio (Cypriniformes, Gobionidae), Zoosystematics and Evolution 101 (2), pp. 661-679 : 661-679

Gobio guentheri ( Herzenstein, 1892)

Fig. 13 , Table 2

Acanthogobio guentheri Herzenstein, 1892: 228.

Gobio guentheri : Tang et al. (2011): 103.

Material examined.

• ASIZB 78479–78487 , 9 specimens, 104.7–143.4 mm SL, Guide County , Hainan Tibetan Autonomous Prefecture, Qinghai Province, from the main stream of the Yellow River, 1958 . • ASIZB 242038–242039 , 2 specimens, 69.0– 81.3 mm SL; Jishishan Bonan , Dongxiang and Salar Autonomous County, Linxia Hui Autonomous Prefecture, Gansu Province, from the Yinchuanhe River, a tributary of the Yellow River drainage (35.7280°N, 103.0919°E, ca 1750 m a. s. l.), collected by Yutian Fang, 21 April 2024 .

Vouchers for molecular study.

• ASIZB 242038–242039 , 2 specimens, Jishishan Bonan , Dongxiang and Salar Autonomous County, Linxia Hui Autonomous Prefecture, Gansu Province, from the Yinchuanhe River, a tributary of the Yellow River drainage (35.7280°N, 103.0919°E, ca 1750 m a. s. l.), collected by Yutian Fang, 21 April 2024 . • ASIZB 242061 , 1 specimen, Liulin County, Lvliang City , Shanxi Province, from the main stream of the Yellow River (37.3891°N, 110.6281°E); 31 July 2022 .

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 position of posterior orbit and posterior preopercle margin in G. rivuloides and G. coriparoides ); lateral-line scales 40–43 (mode 42, mean 42) (vs. lesser than 40 in G. coriparoides ); circumpeduncular scales 20–24 (mode 20, mean 20) (vs. lesser than 20 in G. huanghensis and G. rivuloides ); anus positioned at posterior one-third of distance from pelvic-fin base end to anal-fin origin (vs. anus centrally located between pelvic-fin base and anal-fin origin in G. huanghensis and G. rivuloides ). The second unbranched ray of the dorsal fin forms a stiff spine (vs. the second unbranched ray of the dorsal fin is soft in G. huanghensis , G. rivuloides , and G. coriparoides ). No scales on pre-dorsal region (vs. present in G. huanghensis , G. rivuloides , and G. coriparoides ), ventral scaleless region extends beyond pelvic-fin base (vs. not extending beyond pelvic-fin base in G. huanghensis , G. rivuloides , and G. coriparoides ).

Redescription.

Body relative abbreviated, 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 lesser than body depth; snout relative obtuse, 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 to posterior opercular margin. Eyes positioned on dorsal half of head; interorbital region flattened; width larger than eye diameter. Thoracic region flattened, abdomen rounded, caudal peduncle robust, compressed laterally. Anus positioned at posterior one-third of distance from pelvic-fin base end to anal-fin origin.

Body covered with moderately large cycloid scales. Lateral line complete, almost straight in lateral center. Lateral line scales 40 (1 specimen), 41 (4), 42 (5), 43 (1); scales above lateral line 5 (1), 6 (4), 7 (3), 8 (3); scales below lateral line 4 (11); circumpeduncular scales 20 (7), 22 (3), 24 (1). No scales on pre-dorsal region, skin on pre-dorsal region tiny cortical protuberances. Ventral scaleless region extends beyond pelvic-fin base.

Dorsal fin with three unbranched and seven (11 specimens) branched rays, the second unbranched ray stiff, robust; distal margin concave, origin closer to snout than caudal-fin base. Pectoral fin with one unbranched and 14 (5), 15 (6) branched rays; tip of adpressed not reaching anterior margin of pelvic-fin insertion. Pelvic fin with one unbranched and seven (11) branched rays; tip of adpressed reaching to posterior anus. Anal fin with three unbranched and six (11) 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 + 35–36. Gill rakers rudimentary. Pharyngeal teeth “ 3, 5–5, 3 ”.

Coloration in life.

Dorsal side of head and body yellowish grey, mid-lateral side shallow yellowish grey, and ventral side grayish white. Flank with 6–8 vague black blotches; margin of scales on flank 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 fin rays; fins without black spots (Fig. 13 B ).

Coloration in preservation.

Color of aged specimen preservation in formalin brownish yellow. A series of black dots on upper lateral side, flank with 6–8 vague blotches. Color of specimen preservation in 95 % ethanol; dorsal side of head and body grey, mid-lateral side greyish yellow, and ventral side greyish white. A series of black dots on upper lateral side, flank with 6–8 vague blotches. One slightly silvery stripe extends above lateral line, margin of scales on flank black pigmented. Fins pale, without spots and pigmented.

Sexual dimorphism.

No sexual dimorphism observed.

Distribution.

Gobio guentheri is distributed in the upper reaches of the Yellow River drainage from Qushian Township to Liulin County (Fig. 4 D ).

Habitat and biology.

Gobio guentheri usually appears in fast-flowing water with sandy bottoms. It feeds in sand on the bottom of the river.

Figures

Figure 4. The distribution of the four Gobio species in the Yellow River drainage. A. Gobio huanghensis; B. Gobio rivuloides; C. Gobio coriparoides; D. Gobio guentheri.

Figure 13. General view of Gobio guentheri. A. Gobio guentheri, ASIZB 78482, 136.9 mm SL, photographed by Xueyuan Li; B. Live individual, uncatalogued, Jishishan Bonan, Dongxiang and Salar Autonomous County, Linxia Hui Autonomous Prefecture, Gansu Province, from the Yinchuanhe River.