Karstsinnectes daxinensis Luo, Zhou & Zhou, 2024

Luo, Tao, Luo, Fang-Wei, Lan, Chang-Ting, Xiao, Ming-Yuan, Zhou, Jia-Jun, Liao, Mei, Xiao, Ning & Zhou, Jiang, 2024, Evolutionary history of Chinese karst loaches (Nemacheilidae, Karstsinnectes): new insights from mitochondrial-based genomes and description of a new species from Guangxi, China, Zoosystematics and Evolution 100 (4), pp. 1473-1486 : 1473-1486

publication ID	https://doi.org/ 10.3897/zse.100.133964
publication LSID	lsid:zoobank.org:pub:326B6F9E-E524-422A-8389-570E82341BBD
DOI	https://doi.org/10.5281/zenodo.14042785
persistent identifier	https://treatment.plazi.org/id/BA75B4CD-0B3E-4EC6-AD2A-CB8556244BA7
taxon LSID	lsid:zoobank.org:act:BA75B4CD-0B3E-4EC6-AD2A-CB8556244BA7
treatment provided by	Zoosystematics and Evolution by Pensoft
scientific name	Karstsinnectes daxinensis Luo, Zhou & Zhou
status	sp. nov.

Treatment

Karstsinnectes daxinensis Luo, Zhou & Zhou sp. nov.

Suppl. material 5, Figs 4 View Figure 4 , 5 View Figure 5

Chresonymy.

Oreonectes anophthalmus : Wang, 2022 (Leiping Town, Daxin County, Guangxi, China). Karstsinnectes anophthalmus : Luo et al. 2023, 2024; Yu et al. 2023; Ge et al. 2024; Zhao et al. 2024 (Leiping Town, Daxin County, Guangxi, China).

Holotype.

GZNU 20200427002 , 30.8 mm total length, 27.5 mm standard length (SL), collected by Tao Luo on April 27, 2020, in Leiping Town , Daxin County, Chongzuo City, Guangxi Zhuang Autonomous Region, China (22.64141996°N, 107.1030802°E; ca. 155 m a. s. l.). GoogleMaps

Paratypes.

Five specimens from the same locality as the holotype: GZNU 20200427001 , GZNU 20200427006 , GZNU 20200427003 –427005, collected by Tao Luo on April 27, 2020 GoogleMaps .

Etymology.

The specific epithet “ daxinensis ” refers to the type locality of the new species: Leiping Town, Daxin County, Chongzuo City, Guangxi, China. We propose the English common name “ Daxin Chinese Karst Loach ” and Chinese common name “ Dà Xīn Zhōng Huá Kā Qiū (大新中华喀鳅). ”

Diagnosis.

Karstsinnectes daxinensis sp. nov. can be distinguished from all of the other congeners by the following combination of characters: (1) body naked and without pigmentation; (2) eyes absent; (3) dorsal-fin rays iii- 7, pectoral-fin rays i- 10–11, pelvic-fin rays i- 5, anal-fin rays iii- 5, caudal fin truncated with 13–14 branched caudal-fin rays; (4) pelvic fins slightly long, length 9.5–13.2 % of SL, tip reaching the anus; (5) high and wide head (depth 6.3–9.8 % of SL; wide 10.0–14.8 % of SL), narrow mouth (width 6.2–7.9 % of SL), long inrostral barbel length (length 7.2–12.7 % of SL), and long maxillary barbel length (length 11.3–13.1 % of SL).

Description.

Morphological data of all of the specimens of Karstsinnectes daxinensis sp. nov. were collected in this study are provided in Table 6 View Table 6 and Suppl. material 5.

Body elongated and cylindrical, anterior portion gradually raised from upper eye to dorsal-fin base, posterior portion gradually compressed from dorsal fin to caudal-fin base, with deepest body depth anterior to dorsal-fin origin, deepest body depth 9.1–10.4 % of SL. Dorsal profile of forehead and predorsal profile convex, concave from dorsal-fin origin to anterior margin of upper caudal adipose keel. Ventral profile flat. Head short, length 18.9–23.6 % of SL, slightly depressed and flattened, width greater than depth (head depth / head length = 29.2–42.6 %). Snout short and lightly blunt. Mouth inferior, snout tip truncated, upper and lower lips smooth, lower lip with a V-shaped median notch.

Three pairs of barbels: inrostral barbels short, length 7.2–12.7 % of SL, tip not reaching to corner of the mouth; outrostral barbel long, length 9.4–12.7 % of SL, tip reaching to posterior margin of the eye. Maxillary barbel slightly developed, length 11.3–13.1 % of SL, tip not reaching to anterior margin of operculum. Anterior and posterior nostrils adjacent. Anterior nostril tube long, truncated, without elongated long barbel-like tip. Eyes absent. Gill rakers not developed, 9–10 gill rakers on first gill arch (n = 2).

Dorsal-fin rays iii- 7, pectoral-fin rays i- 10–11, pelvic-fin rays i- 5, anal-fin rays iii- 5, and with 13–14 branched caudal-fin rays. Dorsal fin short, length 12.7–17.2 % of SL, distally margin truncated, origin slightly posterior to pelvic-fin insertion, first branched ray longest, tip of dorsal fin slight beyond to vertical of anus. Pectoral fin slightly developed, length 12.8–14.8 % of SL, tip not beyond midpoint between origins of pectoral and pelvic fins. Pelvic fin slightly long, length 9.5–13.2 % of SL, distally margin oval, vertically aligned with first unbranched ray of dorsal fin, tip of pelvic fin reaching the anus. Anal fin slightly long, length 11.7–16.8 % of SL, tip not reaching to caudal-fin base. Caudal fin truncated, upper lobe is equal in length to lower one, tip pointed, caudal peduncle length 13.2–16.8 % of SL, caudal peduncle depth 7.4–10.4 % of body depth, with not developed adipose crests along both dorsal and ventral sides. Total vertebrae: 4 + 31 (n = 1) (Fig. 4 D View Figure 4 ).

Body naked, smooth, and scaleless. Cephalic lateral line system developed. Lateral line and head sensory pores absent. Two chambers of air-bladder, anterior chamber dumbbell-shaped and membranous, open on both sides and posteriorly (Fig. 4 E View Figure 4 ), and posterior chamber slight developed, slightly filling body cavity, connected with anterior chamber by short tube.

Coloration.

In cave water bodies when living, body semi-translucent and pale pink, without skin pigment, and all of the fins hyaline (Fig. 5 View Figure 5 ). After fixation in 7 % formalin solution, the body color was yellowish white, thorax and gills light brown color, transparent on all of the fins (Fig. 4 A – C View Figure 4 ).

Comparisons.

Morphological data of K. daxinensis sp. nov. with the six known species within genus Karstsinnectes are given in Table 7 View Table 7 .

Karstsinnectes daxinensis sp. nov. can be distinguished from K. cehengensis , K. acridorsalis , K. parvus , K. hyalinus, and K. longzhouensis by caudal fin truncated (vs. forked). The new species can be further distinguished from K. cehengensis by eye absent (vs. reduced); and from K. cehengensis , K. parvus , and K. longzhouensis by lateral line absent (vs. present).

Morphologically and genetically, K. daxinensis sp. nov. is closest to K. anophthalmus , but can still be distinguished by some morphological characters. Karstsinnectes daxinensis sp. nov. different from K. anophthalmus by tip of pelvic fin reaching the anus (vs. not reaching the anus) (Fig. 6 View Figure 6 ), three unbranched pelvic-fin rays (vs. two), narrow mouth (6.2–7.9 % of SL vs. 8.7–8.8 % of SL), long inrostral barbel length (7.2–12.7 % of SL vs. 3.4–5.3 % of SL), and long maxillary barbel length (11.3–13.1 % of SL vs. 7.1–10.0 % of SL).

Distribution.

At present, this new species K. daxinensis sp. nov. has only been discovered in the type locality and nearby caves within the Zuojiang River basin (Fig. 1 View Figure 1 ).