Homatula xiangzhi Cao, Liu, Zeng & Zhang, 2025

Cao, Liang, Liu, Yi, Zeng, Zhixuan, Yi, Wenjing & Zhang, E, 2025, Two new species of the loach genus Homatula Nichols, 1925 (Pisces, Nemacheilidae) from the upper Chang-Jiang Basin in China, Zoosystematics and Evolution 101 (2), pp. 697-710 : 697-710

Homatula xiangzhi Cao, Liu, Zeng & Zhang sp. nov.

Figs 1 , 2 .

Nemachelius variegatus : Wu, 1987: 27 (Nanming-He of Wu-Jiang).

Paracobitis variegatus : Ding, 1994: 51 (Wulong County, Wu-Jiang).

Holotype.

IHB 202006048865 , 98.0 mm SL; China: Guizhou Province: Guiyang City: Wudang District: Baishui-He, a tributary of Qingshui-He discharging into Wu-Jiang, at Shanglongjiao Village (26°46'21"N, 106°55'02"E) of Xiangzhi-Gou; collected by Z. X. Zeng in June 2020.

Paratypes.

IHB 202006048864 , 202006049211–9212, three specimens, 53.7–133.4 mm SL; other date same as holotype . IHB 20180055996 –5997, two specimens, 61.0– 76.6 mm SL and IHB 202006048866 –8867, two specimens, 60.5–73.1 mm SL; China: Guizhou Province: Guiyang City: Wudang District: Pudu-He, a stream tributary to Qingshui-He of Wu-Jiang, at Duzhai Village (26°41'52"N, 113°12'39"E); collected by L. Cao, C. T. An and Z. T. Wang in October 2018 and by D. M. Guo and W. H. Shao in June 2020 .

Diagnosis.

A member of the scaleless group of Homatula , defined by having no scales on the body or a small number of scales sparsely scattering over the caudal peduncle. It is distinct from other six species of the group in having a complete (vs. incomplete in H. wujiangensis ) lateral line, an elongate (vs. stout) body with a uniform depth (vs. non-uniform, gradually decreasing towards the caudal-fin base in H. wujiangensis and H. robusta ), an adipose crest along the dorsal mid-line of the caudal peduncle anteriorly terminating vertically away from the anal-fin origin, but beyond the posterior end of the anal-fin base (vs. above vertical of the posterior end of the anal-fin base in H. wenshanensis ; above or beyond the anal-fin origin in H. nanpanjiangensis , H. oligolepis , H. disparizona and H. robusta ), a slender (vs. stout) caudal peduncle with (depth 42.0–53.8 % of its length vs. 70.5–78.5 % in H. robusta and 100.0–120.0 % in H. wujiangensis ) of its length, vertebrae 4 + 42-43 (vs. 4 + 47–48 in H. wenshanensis and 4 + 35–41 in remaining species), more branched dorsal-fin rays (9 vs. 7–8 in H. disparizona , H. robusta , H. wenshanensis and H. wujiangensis ), a truncate (vs. emarginate in H. disparizona , H. nanpanjiangensis and H. robusta and forked in H. wenshanensis ) and no median notch on the lower jaw (vs. present in H. nanpanjiangensis , H. oligolepis , H. robusta , H. wenshanensis and H. wujiangensis ).

Description.

Morphometric measurements for type specimens given in Table 2 and general appearance of holotype shown in Fig. 1 .

Body elongated, anteriorly cylindrical and posteriorly compressed laterally, with uniform depth from behind head to caudal peduncle. Ventral profile of head straight or slightly concave; ventral profile of body straight or slightly concaved from pectoral-fin insertion to anal-fin origin and slightly convex from anal-fin origin to caudal-fin base. Body nearly scaleless; only a few tiny scales scattered over caudal peduncle. Lateral line complete, with 80–90 pored scales, extending along mid-lateral body to caudal-fin base. Adipose crests along dorsal and ventral mid-lines of caudal peduncle supported by rudimentary rays; dorsal adipose crest anteriorly terminating vertically away from the anal-fin origin, but beyond the posterior end of the anal-fin base and ventral adipose crest anteriorly extending close to posterior end of anal-fin base. Head relatively long and slightly depressed, wider than deep. Snout blunt when viewed laterally, shorter than postorbital head and slightly pointed in dorsal view. Eye oval or elliptical with slightly convex interorbital space, placed dorsolaterally in upper half of head, not reaching dorsal profile, when viewed laterally; eye diameter less than interorbital width. Anterior and posterior nostrils set closely; anterior nostril situated at end of small and oblique tube. Mouth inferior; lips thick, slightly folded, smooth with small median incision in upper lip and marked median longitudinal groove on lower lip. Upper jaw with shallow processus dentiformis; lower jaw spoon-like, without median notch. Two pairs of rostral barbels; inner barbels extending close to rictus and outer barbels reaching rictus. Maxillary barbels rooted in corners of mouth, extending close to vertical through middle of eye. Cephalic lateralis system with 8 supraorbital, 4 + 10 infraorbital, 9 pre-operculo-mandibular and 3 supratemporal pores. Gill opening large, with its upper extremity aligned with centre of orbit.

Fin rays flexible. Dorsal fin with 3 unbranched and 9 branched rays; longest ray shorter than dorsal-fin base; distal margin slightly convex; origin closer to snout tip than to caudal-fin base. Pectoral fin with one unbranched and 9–11 branched rays, tip of depressed fin not reaching mid-way between pectoral- and pelvic-fin insertion. Pelvic fin with one unbranched and 7–8 branched rays, reaching about half the distance between pelvic-fin insertion and anus; origin of pelvic fin at vertical of 1 st or 2 nd branched dorsal fin ray. Axillary lobe present on pelvic-fin base. Anus set closer to anal-fin origin than to pelvic-fin insertion; separated from anal-fin origin by distance 1.2–1.5 times greater than eye diameter. Anal fin with 3 unbranched and 5 branched rays, tip of depressed fin not reaching caudal-fin base; distal margin slightly convex. Caudal fin with 9 + 8 branched rays and truncate with slightly concave outer margin.

Vertebrae 4 + 42–43 (n = 5), including 20–21 abdominal and 22 caudal vertebrae. Gas bladder bipartite; anterior chamber invisible, fully enclosed in capsule; posterior chamber degenerative. Intestine with a distinct transverse bend not reaching posterior end of U-shaped stomach.

Colouration.

In formalin-stored specimens (Fig. 1 ), ground colour of body yellowish, with light yellowish ventral surface. Head yellowish with vermiform marks; snout, lips and anterior nostril light white. Thirteen to fourteen brown vertical bars on flank; anterior six or seven bars oval and closely set, but six post-dorsal bars nearly oblong and deep. Four or five brown rounded bars along dorsal mid-line of predorsal body; last three bars merged into a brown band in some individuals; some brown bars of irregular shape inserted between rounded bars along dorsal mid-line and vertical bars on flank, less or more touched with these bars and sometimes merged to form discontinuous brown band. Some irregular brown bars present on dorsum from behind dorsal-fin origin to anterior end of adipose crest amongst dorsal mid-line of caudal peduncle. A brown lateral stripe extending along base of dorsal adipose crest. Melanin pigments on branched rays forming proximal and subdistal brownish bands across dorsal fin. Pectoral, pelvic and anal fins translucent white yellowish. Caudal fin greyish with some dark black spots and blackish distal edge. Caudal-fin base with dark brown vertical bar. In freshly-collected individuals (Fig. 2 ), overall body colouration very similar to that of formalin-preserved specimens, but a little bright. Caudal fins and dorsal adipose crest red, particularly in spawning season.

Distribution.

The type specimens were collected from Qingshui-He, tributary to Wu-Jiang of upper Chang-Jiang Basin in Guizhou Province, China. The species is also known from upstream of Mengjiang, tributary to Zhu-Jiang Basin in Huaxi District of Guiyang City and Changshun County of Qiannan Prefecture, Guizhou Province, China (Fig. 3 ).

Etymology.

The specific epithet, used as a noun, is named after ‘ Xiangzhi’. This Chinese word means fragrant paper. The type locality (Xiangzhi-Gou) is named after the local intangible cultural heritage, the fragrant paper manufacturing technique. A corresponding common Chinese name “ 香纸荷马条鳅 ” is proposed here for the new species.

Figures

Figure 1. Homatula xiangzhi sp. nov, IHB 202006048865, holotype, 98.0 mm SL; China: Guizhou Province: Guiyang City: Wudang District: Baishui-He. Lateral (upper), dorsal (middle) and ventral (lower) view.

Figure 2. Freshly-captured individual of H. xiangzhi sp. nov., collected from China: Guizhou Province: Guiyang City: Wudang District: Baishui-He, a tributary of Qingshui-He discharging into Wu-Jiang, at Shanglongjiao Village.

Figure 3. Distribution of the partially scaled and the scaleless group of Homatula in China.