Microphysogobio punctatus, Sun & Tang & Zhao, 2024

Sun, Zhi-Xian, Tang, Wen-Qiao & Zhao, Ya-Hui, 2024, Redescription of Microphysogobio tungtingensis (Nichols, 1926) with the description of a new species of the genus (Cypriniformes, Gobionidae) from southern China, ZooKeys 1214, pp. 161-186 : 161-186

publication ID	https://doi.org/ 10.3897/zookeys.1214.127061
publication LSID	lsid:zoobank.org:pub:170C71D6-7A51-4FF6-AEA4-AD98875AF769
persistent identifier	https://treatment.plazi.org/id/F4C9B518-70FC-4A3B-928C-A305F9511A78
taxon LSID	lsid:zoobank.org:act:F4C9B518-70FC-4A3B-928C-A305F9511A78
treatment provided by	ZooKeys by Pensoft
scientific name	Microphysogobio punctatus
status	sp. nov.

Treatment

Microphysogobio punctatus sp. nov.

Figs 5 View Figure 5 , 6 View Figure 6 ; Table 3 View Table 3

Microphysogobio kiatingensis View in CoL : Wen (2006): 226.

Microphysogobio tungtingensis View in CoL : Xiao and Lan (2023): 156.

Type material.

Holotype. • ASIZB 240329 View Materials , 75.4 mm SL; Lingchuan County, Guilin City, Guangxi Zhuang Autonomous Region, from the Huangshahe River , a tributary of the Lijiang River (25.3202379 ° N, 110.42292216 ° E, 166 m a. s. l.); collected by Zhixian Sun, Chen Tian, and Weihan Shao, 31 December 2023 GoogleMaps . Paratypes. • ASIZB 240330–5 View Materials (6 specimens), 240450–60 (11 specimens), 53.4–78.9 mm SL; IHB - T-A 0000009, 1 specimen, 73.7 mm SL; SHOU 20231231061 , 1 specimen, 73.8 mm SL; same collection information as holotype GoogleMaps .

Additional material examined.

• ASIZB 240528–38 View Materials , 11 specimens, 56.0– 75.2 mm SL; Guanyang County, Guilin City, Guangxi Zhuang Autonomous Region, from the Guanjiang River , a tributary of the Xiangjiang River; collected by Zhixian Sun; 5 December 2020 • ASIZB 240505–10 View Materials , 6 specimens, 53.9–73.1 mm SL; Guanyang County, Guilin City, Guangxi Zhuang Autonomous Region, from the Guanjiang River , a tributary of the Xiangjiang River; collected by Zhixian Sun; 20 January 2021 • ASIZB 240511–27 View Materials , 17 specimens, 47.4–78.2 mm SL; Guanyang County, Guilin City, Guangxi Zhuang Autonomous Region, from the Guanjiang River , a tributary of the Xiangjiang River; collected by Zhixian Sun; 31 December 2021 • ASIZB 240539–42 View Materials , 4 specimens, 58.1–70.7 mm SL; Yongfu County, Guilin City, Guangxi Zhuang Autonomous Region, from the Luoqingjiang River ; collected by Junhao Huang and Zhuocheng Zhou; 27 November 2020 • ASIZB 240300–14 View Materials , 240423–8 View Materials , 21 specimens, 65.0–76.0 mm SL; IHB - YF- 2024010201–3, 3 specimens, 71.3–76.9 mm SL; SOU 20240102121–3, 3 specimens, 69.2–74.0 mm SL; Shebian Village, Longjiang Township, Yongfu County, Guilin City, Guangxi Zhuang Autonomous Region, from the Xihe River , a tributary of the Luoqingjiang River (25.22972694 ° N, 109.83651085 ° E, 205 m a. s. l.); collected by Zhixian Sun, Chen Tian and Dong Sheng; 2 January 2024 GoogleMaps .

Diagnosis.

This new species can be distinguished from its congeners by a combination of the following characteristics: Posterior chamber of air-bladder small, globular or oval shaped, length 15.8 % – 26.4 % of head length, and 58.6 % – 82.8 % of eye diameter; upper jaw cutting-edge narrow, width less than half mouth width; caudal peduncle slender, depth 34.6 % – 48.5 % of length; lateral-line scales 37–40 (mode 38, mean 39); circumpeduncular scales 12; branched anal-fin rays 6; midventral region of body scaleless only before pectoral-fin base end; all fins with numerous small black spots.

Description.

Body elongated, thoracic region flattened, abdomen rounded, caudal peduncle slender, compressed laterally. 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, body depth 14.6 % – 19.5 % of standard length. Head elongated, length larger than body depth; snout blunt, with moderate concavity on top of snout before nostrils; eye diameter 30.7 % – 38.5 % of head length, positioned at dorsal half of head; interorbital region flattened, width smaller than eye diameter (39.2 % – 67.9 % of eye diameter). Anus positioned at anterior one-third of distance from pelvic-fin insertion to anal-fin origin.

Mouth horseshoe-shaped and inferior, with one pair of maxillary barbels rooted at extremity of upper lip, barbel length shorter than eye diameter (26.4 % – 79.3 % of eye diameter, 54.4 % in average); upper and lower jaws with thin horny sheaths on cutting margins, upper jaw cutting edge width smaller than half mouth width (22.0 % – 46.8 % of mouth width, 35.2 % in average). Lips thick, well developed, with pearl-like papillae; central portion of anterior papillae arranged in one row, usually consists 2–6 papillae, tightly contact with each other (occasionally separated, Fig. 3 C View Figure 3 ), size slightly larger than other lateral side papillae; lateral portions of anterior papillae in several rows; medial pad on lower lip heart-shaped, shallow grooved on surface; lateral lobes on lower lip covered with multiple developed papillae, posteriorly disconnected from each other behind medial pad and laterally connected with upper lip anterior papillae at mouth corner (Fig. 3 C, D View Figure 3 ).

Body covered with moderately small cycloid scales. Lateral line complete, almost straight in lateral center, slightly bent down under dorsal origin. Lateral line scales 37 (6 specimens), 38 (38), 39 (29), 40 (12); scales above lateral line 3.5 (72), 4 (13); scales below lateral line 2 (85); pre-dorsal scales 9 (23), 10 (60), 11 (2); circumpeduncular scales 12 (85). Midventral region of body scaleless only before pectoral-fin base end.

Dorsal fin with three unbranched and seven (76 specimens) branched rays; distal margin slightly concave, origin nearer to snout than caudal-fin base. Pectoral fin with one unbranched and 11 (2), 12 (57), 13 (26) branched rays; tip of adpressed almost reaching or slightly extending anterior margin of pelvic-fin base. Pelvic fin with one unbranched and seven (85) branched rays, inserted below 2 nd or 3 rd branched dorsal-fin ray; tip of adpressed reaching or extending midway to anal-fin origin. Anal fin with three unbranched and six (85) branched rays; origin almost equal-distant from caudal-fin base to pelvic-fin insertion. Caudal fin deeply forked, with nine branched rays on upper lobes and eight branched rays on lower lobes, lobes pointed.

Gill rakers rudimentary. Pharyngeal teeth “ 5–5 ” (in one row). Air-bladder small, anterior chamber enveloped in thick fibrous capsule; posterior chamber small, globular or oval shaped, length less than eye diameter (58.6 % – 82.8 %, mean 68.2 %), 14.6 % – 26.4 % (mean 22.8 %) of head length.

Coloration in life.

Dorsal side of head and body brownish grey, mid-lateral side shallow brownish grey, and ventral side grayish white. Dorsal side of body with five distinct black crossbars (1 st on back of nape, 2 nd and 3 rd at dorsal-fin base origin and ending respectively, 4 th at vertical position above anal-fin base origin, 5 th on caudal peduncle respectively). Lateral side with 8–10 different sized black blotches, some blotches sometime connect with the 3 rd, 4 th, and 5 th crossbar on the lateral side of body; scales above lateral line black pigmented, lateral-line scales with obvious black spots, margin of first row below lateral line black pigmented, and 2 nd row below lateral line slightly black pigmented. Interorbital region with a black crossbar. Operculum and suborbital region with two distinct black blotches (one between anterior margin of eye and upper lip, the other expanded from posterior orbit to opercular) and one small black blotch exist between 2 nd and 3 rd suborbital plate. One black blotch above pectoral-fin base. Fins membrane translucent, with numerous black pigments on some fin rays; dorsal-fin rays glittery green, with many black spots and dash lines; pectoral fin rays and pelvic fin rays glittery green, with many black spots and dash lines; anal fin rays with some black spots; caudal-fin rays with numerous black spots (Fig. 6 A, B View Figure 6 ).

Coloration in preservation.

Dorsal side of head and body brownish yellow, mid-lateral side shallow brownish yellow, and ventral side grayish white. Dorsal side of body with five distinct black crossbars in same position as live individual. Lateral side with 8–10 differently sized dark grey blotches; scales above lateral line black pigmented, lateral-line scales without obvious black spots, margin of first row below lateral line slightly black pigmented. Interorbital region with a black crossbar. Operculum and suborbital region with two distinct black blotches in same position as live individual, and one small black blotch exist between 2 nd and 3 rd suborbital plate. One black blotch above pectoral-fin base. Fins membrane pale, with numerous black pigments on some fin rays in same position as live individual, glittery green on fin rays faded.

Sexual dimorphism.

No significant sexual dimorphism observed.

Distribution.

According to the field collections, this species is distributed in the Guijiang and Liujiang rivers, two northern tributaries of the Xijiang River system, which belongs to the Pearl River basin. It is also found in the upper Xiangjiang River, which drains into the middle Yangtze River basin (Fig. 4 View Figure 4 ).

Habitat and biology.

Microphysogobio punctatus sp. nov. inhabits the slow flowing water of rivers approximately 30–40 meters wide. It usually appears in areas with sandy bottoms with gravel and pebbles. Co-exiting species includes e. g., Opsariichthys bidens , Acheilognathus tonkinensis , Squalidus argentatus , Sarcocheilichthys sp. Microphysogobio zhangi , and Cobitis spp.

Etymology.

The new species name punctatus is derived from the Latin punctum, meaning spot. The name refers to the numerous black spots on its scales and fin rays. Suggested Chinese name for this species is “ 斑点小鳔鮈 ”.