Gobiobotia lii, Chen & Wang & Cao & Zhang, 2022

Chen, Xiao, Wang, Man, Cao, Liang & Zhang, E, 2022, Gobiobotia lii, a new species of gudgeon (Teleostei, Gobionidae) from the middle Chang-Jiang Basin, central China, with notes on the validity of G. nicholsi Bănărescu & Nalbant, 1966, Zoosystematics and Evolution 98 (1), pp. 93-107 : 93

Gobiobotia lii sp. nov.

Figs 1 , 2

Gobiobotia pappenheimi Chen & Cao, 1977: 556 (Lake Dongting), Synonym

Holotype.

IHB 202103051401, 48.6 mm SL. P. R. China: Hubei Province: Qichun County: Xiangqiao Town: Chang-Jiang Basin, Qi-Shui stream, 30°20'31"N, 115°43'43"E; D. M. Guo, X. Gong and Y. Liu; 5 March 2021.

Paratypes.

IHB 202103051399-1400, 202103050858-0859, 4 specimens, 45.1-48.0 mm SL, other data same as holotype. IHB 2014070560439-0447, 9 specimens, 42.1-51.2 mm SL. P. R. China: Hunan Province: Hanshou City: Potou Town: Chang-Jiang Basin, Lake Dongting, 29°00'05"N, 111°58'31"E; L. Cao, Z. G. Jiang, S. J. Ren, R. X. Xie and X. Wang; 5 July 2014. IHB 2017101929, 201711015435, 201801015997; 6012-6015; 6143-6146, 11 specimens, 35.0-40.1 mm SL. P. R. China: Hunan Province: Yuanjiang City: Liaodaokou: Chang-Jiang Basin, Lake Dongting, 28°51'39.02"N, 112°33'37.87"E; X. Chen, C. T. An, W. H. Shao and Z. T. Wang; 19 October 2017 and 1 January 2018.

Diagnosis.

Gobiobotia lii is distinct from all other congeneric species, except G. brevirostris Chen & Cao, 1977, G. homalopteroidea Rendahl, 1933, G. jiangxiensis Zhang & Liu, 1995 and G. pappenheimi Kreyenberg, 1911, in having a naked region of the abdomen adjacent to the ventral mid-line extending to or beyond the vent (vs. to or away from the pelvic-fin base) (Figs 2c , 3 ). It differs from these four species in having 4+31-32 (vs. 4+33-37) vertebrae. The new species shares with G. homalopteroidea and G. pappenheimi the presence of smaller eyes (diameter less than the interorbital width), maxillary barbels longer than the eye diameter and the third pair of longer mental barbels extending to the pectoral-fin insertion, these three characters separating them from G. brevirostris and G. jiangxiensis . The new species further differs from G. homalopteroidea in possessing a smaller (vs. larger) naked region of the abdomen adjacent to the ventral mid-line extending to the anus (vs. to the anal-fin origin) and the eye diameter 20.0-25.8% of HL (vs. 10.8-13.9%); and from G. pappenheimi in having pectoral fins extending away from (vs. beyond) the pelvic-fin insertion, the second branched pectoral-fin ray not prolonged (vs. prolonged) and a longer (vs. shorter) snout than the post-orbital length.

Description.

Morphometric data for type specimens given in Table 1 . General body appearance of holotype shown in Figs 1 and 2 . Body small and slender, with maximum depth at dorsal-fin origin. Pre-dorsal body profile depressed. Ventral profile slightly compressed. Abdomen flat or slightly convex from pectoral-fin insertion to anal-fin origin and slightly concave from anal-fin origin to caudal-fin base.

Head depressed and broad. Snout pointed in lateral view and slightly bluntly rounded in dorsal view, longer than post-orbital head. Eyes small and dorsolateral; diameter less than interorbital width. Interorbital space flattened. Some irregular papillae present on the mental region.

Mouth inferior, with opening laterally extending to the vertical line of front edge of nostril. Four pairs of barbels: one pair of maxillary barbels and three pairs of mental barbels. Maxillary barbels extending closely to a vertical line through middle of eye; first pair of mental barbels short, inserted at the same level passing through maxillary-barbel roots and anterior to roots of second mental barbels and reaching anterior margin of eye; second pair of mental barbels extending beyond bases of third pair of mental barbels to hind margin of pre-opercula; third pair of mental barbels long, reaching pectoral-fin insertion.

Fins rays flexible, dorsal fin with 3 simple and 7 (14 specimens examined) branched rays; pectoral fin with 1 simple and 12 (6) or 13 (8) branched rays, extending about two-thirds of the distance to pelvic-fin insertion. Pelvic fin with 1 simple and 7 (14) branched rays, reaching beyond the midway to anal-fin origin and surpassing anus; inserted closer to anal-fin origin than to anterior end of pectoral-fin base; located opposite to that of dorsal-fin base. Anal fin with 3 simple and 6 (14) branched rays; origin equidistant from pelvic-fin insertion and caudal-fin base. Anus positioned closer to the pelvic-fin insertion than to anal-fin origin. Caudal fin moderately forked; lower lobes are longer than upper lobes.

Lateral line complete and almost straight, extending along mid-lateral of body, with 37 (7) or 38 (7) pored scales; scale rows above and below lateral lines 5 and 3; circumpeduncular scales 11 (7) or 12 (7) and pre-dorsal mid-line scales 13 (14). Body covered with moderately-sized scales; no scales on breast and belly in front of vent. Vertebral counts 4+31-32 (modally 4+32, see Fig. 4 ).

Colouration.

In freshly-collected specimens, head and dorsum of body golden yellow, underside and abdomen golden grey; back and lateral head peppered with dark flecks. Back darker and belly lighter, with a dark spot back of the head, 12-13 dorsal dark brown spots extending along mid-line of dorsum from nape to caudal-fin base and 9-10 large dark brown spots along middle of side from gill opening to caudal-fin base. Fin golden yellow, distal margin hyaline.

In formalin-stored specimens, ground colour slightly faded; body dorsally greyish and ventrally greyish-white; dorsal and lateral dark brown spots not clear and the back of the head becoming yellowish-brown. Dorsal, pectoral, pelvic and anal fins light greyish; caudal fin with numerous narrow dark crossbars (Fig. 2 ).

Sexual dimorphism.

No sexual dimorphism was observed in the specimens examined.

Distribution and habitat.

Gobiobotia lii is known from the Qi-Shui, a stream tributary to the middle Chang-Jiang mainstem at Qichun County, Hubei (Fig. 5 ). The new species was found in turbid, slow-running water with mixed substrates including sand and gravel (Fig. 6 ); and Lake Dongting in Hunan, where it was collected in lotic habitats or estuaries of effluents. Co-existing species included Misgurnus anguillicaudatus , Opsariichthys bidens and Parabotia fasciata .

Etymology.

The specific epithet is named after Shi-Zhen Li, a native of Qichun County where the holotype and partial paratypes were caught. Li was a well-known medical scientist in the Ming Dynasty, who compiled "Compendium of Materia Medica" ( ‘本草纲目’ in Chinese) - one of the most valuable pieces of literature of traditional Chinese medicine. He had a typical image as an old man with a long white dense beard, just like the eight-barbel gudgeon. The common Chinese name ‘李氏鳅鮀’ in here proposed for Gobiobotia lii .

Sequence variation and molecular phylogeny.

A total of 37 cyt b gene sequences from five Chinese species of Gobiobotia : G. filifer (one sequence), G. guilingensis (one), G. lii (10), G. meridionalis (23) and G. tungi (two) were amplified in this study. These sequences were used for phylogenetic analysis along with another 11 GenBank-retrieved sequences from six congeneric species and two out-groups ( Microphysogobio fukiensis and M. xianyouensis ) (Table 3 ). A total length of 1038 bp gene sequence was obtained after sequence alignment and trimming, including 643 conserved sites, 396 variable sites, 349 parsimony informative sites and 47 singleton sites. The mean frequency of four nucleotides of the new species was A = 30.7%, T = 27.5%, C = 15.5% and G = 26.4%; the base composition was A-T rich (58.2%). The Bayesian Inference tree, based on the cyt b gene for G. lii and other 10 congeners, is shown in Fig. 7 , with node support values displayed. Intraspecific genetic distance values for here-recognised species of the Gobionidae ranged from 0.0% to 1.8%. The interspecific genetic distance of G. lii with all other sampled congeneric species varied from 2.6% to 22.1% (mean 16.8%) and the intraspecific genetic distance value of this species was 0.8% (Table 5 ). In the Bayesian 50% majority-rule consensus tree, samples of G. lii constituted a robustly-supported (100% Bayesian posterior probability, bpp) lineage, strongly supported by 100% bpp to be sister of G. naktongensis Mori, 1935.

Figures

Figure 1. Gobiobotia lii, holotype, IHB 202103051401, 48.6 mm SL, photographed alive immediately upon capture. P. R. China: Hubei Province: Qichun County: Xiangqiao Town: Chang-Jiang Basin, Qi-Shui.

Figure 2. Dorsal (a), lateral (b) and ventral (c) views of Gobiobotia lii, holotype, IHB 202103051401, 48.6 mm SL. P. R. China: Hubei Province: Qichun County: Xiangqiao Town: Chang-Jiang Basin, Qi-Shui.

Figure 3. Ventral view of body in: (a) G. guilingensis IHB 202104053183, 86.7 mm SL. P. R. China: Guangxi Province: Rongshui County: Zhu-Jiang Basin, Rong-Jiang; and (b) G. meridionalis, IHB 201609021174, 84.8 mm SL. P. R. China: Hunan Province: Chenxi County: Chang-Jiang Basin: Yuan-Jiang.

Figure 4. Micro-CT images of lateral body in: (a) G. lii, IHB 202103051401, holotype and (b) G. jiangxiensis, IHB 90 IV 1256, holotype. X-rayed photographs of lateral body in: (c) G. pappenheimi, ZMB 18466, holotype and (d) G. nicholsi, AMNH 20523, holotype.

Figure 5. Map showing the distribution of type series of Gobiobotia lii in the middle Chang-Jiang Basin.

Figure 6. Sampling locality of the holotype (IHB 202103051401) of Gobiobotia lii in the Qi-Shui stream, tributary to the middle Chang-Jiang mainstem in Xiangqiao Town, Qichun County, 5 March 2021.

Figure 7. Bayesian Inference tree inferred from the cyt b gene for 11 putative species of eight-barbel gudgeons. Nodal numbers are posterior probability values greater than 50 %.