Beaufortia granulopinna Chen & Tang, 2024

Chen, Jing-Chen, Li, Jia-Jia, Tang, Wen-Qiao, Pu, Xin-Rui & Lei, Hao-Tian, 2024, Taxonomic resolution of the hillstream suck-loach Beaufortia pingi species group (Cypriniformes, Gastromyzontidae) and two new species from Southwest China – Beaufortia granulopinna and Beaufortia viridis, Zoosystematics and Evolution 100 (3), pp. 941-963 : 941-963

Beaufortia granulopinna Chen & Tang sp. nov.

Figs 2 , 3 , 4

Gastromyzon pingi Fang, 1930: 35–36, No. 955, paratype, former Lingyun County, near the border of Yunnan.

Beaufortia pingi : Chen and Zhang (2006): 376–377, Tianlin County, Guangxi (fig. X 98).

Type material.

Holotype. SHOU 20240103001 , 72.48 mm total length (TL), 57.17 mm standard length (SL), adult (Fig. 2 ). Collected by Jing-Chen Chen and Qian-Yu Liang on 24 December 2023, from Lizhou River , a stream tributary of Bo′ai River of Pearl River basin, at Tianlin County, Guangxi Province, China (24 ° 20.34 ' N, 106 ° 21.624 ' E; c. 470 m a. s. l.) (Fig. 5 ).

Paratypes. 21 specimens from the same locality as holotype, SHOU 20240103002-022, 21.41–54.00 mm SL, were collected by Qian-Yu Liang and Jing-Chen Chen on 24 December 2023; 12 specimens from Guangnan County, Wenshan Zhuang, and Miao Autonomous Prefecture, Yunnan Province, China, SHOU 20240115001-012, 31.86–44.07 mm SL, were collected by Xinrui Pu and Jing-Chen Chen on 08 January 2024.

Additional materials.

Seven specimens from the type locality, SHOU 20240103023-29, were collected by Qian-Yu Liang from December 2022 to April 2023; one specimen from Guangnan County, Wenshan Zhuang, and Miao Autonomous Prefecture, Yunnan Province, China, SHOU 20240115013 was collected by Lin Yang and Lao Xing in December 2022.

Diagnosis.

B. granulopinna sp. nov. shares typical characteristics with members of the B. pingi species group, with distinct vertical stripes on the flank, and a pinnate-type lower lip (vs. lacking prominent vertical stripes and having a dicot-type lower lip in other congeneric species apart from this group) (see Figs 6 D , 7 , Table 2 ). B. granulopinna can be clearly distinguished from B. pingi , B. zebroida , and B. viridis sp. nov. by the presence of well-developed tubercles on the anterior 6–9 pectoral fin rays (vs. absent or inconspicuous tubercles on pectoral fin rays). Moreover, B. granulopinna can be distinguished from B. pingi by generally fewer branched fin rays in the paired fins, with 18.5–22 (mean 20.11 ± 0.77) in pectoral fins (vs. 21–24 (mean 22.19 ± 0.78 )) and 15–18 (mean 16.51 ± 0.86) in pelvic fins (vs. 17–21 (mean 18.64 ± 0.97 )). It can be further differentiated from B. viridis sp. nov. and B. zebroida by a certain proportion (54.76 %) of individuals exhibiting blurred or vanished vertical stripes in the mid-section of the lateral body in adulthood (vs. stable presence of vertical stripes at all growth stages).

Description.

Dorsal iii- 6–7 (6.98 ± 0.15), anal ii- 4, pectoral i- 18.5-22 (20.11 ± 0.77), pelvic i- 15-18 (16.51 ± 0.86). Lateral-line canal pores and scales: 63–73 (68.76 ± 2.5) (see Table 2 ).

Morphometric measurements for the specimens examined are given in Table 3 . See Fig. 2 for lateral, dorsal, and ventral views of the body.

Head-thorax cylindrical, dorsal slightly humped medially, flattened ventrally, body compressed from pelvic fins to caudal peduncle. Head broad, blunt, length slightly less than width, more than depth, nuptial tubercles well-developed on lower half of head in mature individuals, snout rounded, length about half of head length. Mouth inferior, narrow, width about one-fifth head width, horseshoe-shaped, angle about 96 ° from midpoint to ends. Upper lip smooth, without distinct papillae; lower lip pinnate-type, slightly concave medially with multilobed sides; jaw edges slightly protrude. Shallow groove between upper lip and snout, extending to mouth corners. Lateral grooves shallow or indistinct. Two pairs of rostral barbels present, with outer pair slightly longer, space between rostral barbels with leaf-like folds, edges of which rounded and poor developed. One pair of maxillary barbels, length about equal to outer rostral barbels. Nostrils with tubular nasal flaps, distance between nostrils equals one-third head width. Eyes supralateral, medium-sized, eye diameter about one-quarter head length, interorbital space flat, width about half head width. Gill opening small, about equal to eye diameter, originated about vertically above the second branched pectoral fin ray, limited to dorsal side of head. Scales small, diameter smaller than pupil, dorsal surface of head, base of paired fins, and ventral area before pelvic fin bases nude. Lateral line complete, at midlateral.

Dorsal fin base about equal to pre-pectoral length, starting around midpoint from snout to caudal fin base, adpressed extending to about midway between dorsal fin origin and caudal fin base. Anal fin base length about half of that of dorsal fin base, adpressed extending slightly beyond caudal fin base. Paired fins extending outwards, forming disc-like structure with body. Pectoral fin base slightly longer than head length, starting at the posterior one-third point of head, pectoral fin length about twice head length, tips of which reaching pelvic fin base midpoint, pectoral disc width about 1.5 times head width at pectoral origin. Anterior 6–9 pectoral fin rays with nuptial tubercles in adults. Pelvic fin shorter than pectoral, well-developed fleshy flap at dorsal base, last 1–3 branched rays partially connected by fin membrane forming pelvic disc, connected part about two-thirds ray length, remaining parts separated, forming notch in middle rear edge, exposing anus. Pelvic disc width about equal to length. Anus at or near posterior edge of pelvic disc, distance to which less than to anal fin origin. Caudal fin length about equal to pelvic fin, slanted end, lower lobe slightly longer.

Coloration in preservation.

Preserved specimens from sub-adult to adult stage, body dark brown to grey, white ventrally. Head with black spots or vermiculations dorsally, 2–5 larger black blotches along mid-dorsal body anterior to dorsal fin. Sides with 4–15 thick dark vertical stripes, stripes posterior to dorsal fin origin wider than intervals. In smaller individuals, stripes clear and distinguishable, in larger individuals, stripes anterior to caudal peduncle sometimes blur or disappear. Paired fin with white margin, black arc, or dotted-arc line inside white ring. Dorsal fin with alternating black, white stripes, anal fin hyaline with black stripes.

Coloration in live.

In life, dorsal body dark brown to green. Mature individuals with metallic, green longitudinal band along lateral line, area below lateral line behind pelvic fins and base of paired fins sometimes light orange, more pronounced in Qing Shui River basin populations, Yunnan. Dorsal fin black pattern wider than white.

Juvenile morphology.

Pelvic fins completely separated, dorsal body side gray-brown, few wider vertical dark stripes on flank, 2–3 vertical black stripes on caudal fin, other fins hyaline or with inconspicuous black lines (see Fig. 3 ).

Sexual dimorphism.

In fully mature individuals, males slightly larger than females, with well-developed nuptial tubercles (see Fig. 8 E, F ).

Geographic variation.

Qing Shui River basin populations, Yunnan, more pronounced orange color below lateral line behind pelvic fins, dorsal side of paired-fins base after sexual maturity compared to type locality Tianlin County populations (see Fig. 4 B ).

Individual variation.

Among the 42 specimens examined, one ( SHOU 20240103017) with six branched rays in dorsal fin.

Ethology.

Inhabits shallow streams with rapid currents and smooth pebble substrates that adhere to crevices between stones. Feeds on algae and small invertebrates and consumes mucus from fresh fish carcasses. Exhibits strong territorial behavior and aggression; adults may head-butt and extend dorsal fins to drive away rivals.

Distribution.

Found exclusively in the small tributaries of the Bo′ai River basin, ranging from the northwestern part of Guangxi to the eastern part of Yunnan in China, as well as in the small tributaries of the Qingshui River section and its downstream Nanpan River basin, upper reaches of the Pearl River system (see Fig. 9 ).

Etymology.

The specific epithet granulopinna combines Latin “ granulo -, ” meaning grainy, and “ - pinna, ” meaning fin, referring to the well-developed tubercles on pectoral fins; the term is in the nominative masculine singular. We propose the Chinese common specific name “ 珠鳍爬岩鳅 ”.

Figures

Figure 2. Lateral (top), dorsal (middle), and ventral (bottom) views of Beaufortia granulopinna sp. nov., holotype, adult, SHOU 20240103001, 57.17 mm SL; from Lizhou River, a stream tributary of Bo′ai River of the Pearl River basin, at Tianlin County, Guangxi Province, China.

Figure 3. Lateral (top), dorsal (middle), and ventral (bottom) views of Beaufortia granulopinna sp. nov. during early juvenile and sub-adult stages. A. Early juvenile stage, SHOU 20240103658, from type locality, 16.09 mm SL, pelvic fins completely separated; B. Sub-adult stage, SHOU 20240103005, paratype, 24.21 mm SL.

Figure 4. Lateral (top), dorsal (middle), and ventral (bottom) views of one common phenotypic variation of Beaufortia granulopinna sp. nov. and other regional phenotypes. A. Phenotype with persistent vertical stripe on lateral body, paratype, SHOU 20240103003, 40.77 mm SL, from Tianlin County, Guangxi; B. Regional phenotype from Qingshui River, Guangnan County, Yunnan Province, paratype, SHOU 20240115001, 39.01 mm SL.

Figure 5. Collection site of the holotype (SHOU 20240103001) of Beaufortia granulopinna sp. nov., from Lizhou River, a stream tributary of Bo′ai River of the Pearl River basin, Tianlin County, Guangxi Province, China. Photographed by Qian-Yu Liang on 24 December 2023.

Figure 6. Pinnate-type lower lip of the Beaufortia pingi species group, elongated, with the lower lip on both sides being multilobed, typically comprising more than three lobes, with deep divisions; the extremities of the lower lip extend to the corners of the mouth, with several wart-like protrusions present on the extended parts. The red line outlines the left side of the lower lip contour; the red arrow indicates the position of the ventral head sensory canal-pores located anterior to the origin of the pectoral fins. А. B. pingi, from the type locality; B. B. zebroida, from Napo County, Guangxi Province; C. B. viridis, from the type locality; D. B. granulopinna, from the type locality.

Figure 7. Dicot-type lower lip of species outside the Beaufortia pingi group, shorter, with the sides of the lower lip being smooth or featuring 1–2 shallow notches; the ends of the lower lip do not extend to the corners of the mouth, or the extension is poor-developed and lacks protrusions. The red line outlines the left side of the lower lip contour; the red arrow indicates the position of the ventral head sensory canal-pores, with the second pair of canal-pores located posterior to the origin of the pectoral fins in all species except B. liui. А. B. leveretti, from the type locality; B. B. kweichowensis, from Congjiang County, Guizhou Province, downstream near the type locality; C. B. cyclica, holotype; D. B. intermedia, paratype; E. B. polylepis, syntype; F. B. huangguoshuensis, syntype; G. B. szechuanensis, from Neijiang City, Sichuan Province; H. B. niulanensis, from the type locality; I. B. liui, syntype. (C-F and I were photographed by Yi-Yang Xu, Institute of Hydrobiology, Chinese Academy of Sciences.)

Figure 8. Sexual dimorphism within the Beaufortia pingi species group, with males exhibiting well-developed and numerous nuptial tubercles on the head compared to females. A, B. B. viridis sp. nov.; C, D. B. pingi; and E, F. B. granulopinna sp. nov.

Figure 9. Distribution map of species within the Beaufortia pingi species group. Light red: B. granulopinna sp. nov.; light green: B. viridis sp. nov.; light blue: B. pingi; light yellow: B. zebroida. Rivers are labeled with their names in Chinese: Qingshui River (清水江), Nanpan River (南盘江), Beipan River (北盘江), Hongshui River (红水河), Tuoniang (驮娘江), Xiyang River (西洋江), Leli River (乐里河), Chengbi River (澄碧河), Bo’ai River (剥隘河), Jian River (鉴河), You River (右江), Wuming River (武鸣河), Yu River (郁江), Shuikou River (水口河, known as Sông B ằng in Vietnamese), and Red River (红河).