Karstsinnectes acridorsalis ( Lan, 2013 )

Ge, Jia-Yue, Nong, Zheng-Quan, Yang, Jian, Du, Li-Na & Zhou, Jia-Jun, 2024, Taxonomic revision of the cavefish genus Karstsinnectes (Cypriniformes, Nemacheilidae), with a description of a new species from Guangxi Province, China, Zoosystematics and Evolution 100 (2), pp. 663-673 : 663-673

Karstsinnectes acridorsalis ( Lan, 2013)

Figs 1 A , 2 ; Table 1

Oreonectes acridorsalis Lan, 2013: 68, fig. 50 (Bamu Town, Tian’e County, Hechi City, Guangxi).

Troglonectes acridorsalis Xiao & Lan, 2023: 33 (Bamu Town, Tian’e County, Hechi City, Guangxi).

Karstsinnectes acridorsalis Luo et al., 2023 , 696 (Bamu Town, Tian’e County, Guangxi).

Material examined.

Paratypes. 2 ex. China; Guangxi, Hechi City, Tian’e County, Bamu Town , 22.8754 ° N, 107.1947 ° E, 284 m a. s. l. CLJH 1202001 , CLJH 04100607 , 37.9–38.1 mm SL, deposited in the Fishery and Animal Husbandry Bureau of Du’an, Guangxi, China .

Diagnosis.

Karstsinnectes acridorsalis differs from K. anophthalmus by caudal fin forked (vs. truncated), 14 branched caudal-fin rays (vs. 12), longer and lower head (length 29.9 % – 32.7 % of SL vs. 22.7 % – 24.6 %, height 34.6 % – 39.6 % of head length vs. 41.0 % – 44.0 %), longer pectoral fin (61.6 % – 67.7 % of distance between pectoral-fin origin and pelvic-fin origin vs. 35.9 % – 48.9 %); from K. hyalinus by scaleless (vs. scaled), five branched anal-fin rays (vs. four), 14 branched caudal-fin rays (vs. 11 or 12); from K. parvus and K. longzhouensis sp. nov. by lateral line absent (vs. present), lower body (body depth 13.9 % – 15.5 % of SL vs. 17.1 % – 18.4 % and 16.1 % – 19.4 %, respectively), shorter caudal peduncle (length 15.7 % – 15.9 % of SL vs. 18.4 % – 22.3 % and 17.3 % – 19.5 %, respectively).

Description.

Body elongated, head depressed, snout depressed, forehead raised, head height at nostril 46.1 % – 67.9 % of maximum head height. Body trunk compressed, with maximum body depth anterior to dorsal-fin origin, deepest body depth 13.9 % – 15.5 % of SL. Dorsal profile of head and predorsal profile slightly convex, clearly concave from dorsal-fin origin to tip of dorsal fin, and gradually convex from tip of dorsal fin to anterior quarter of caudal fin due to caudal adipose keel on upper edge of caudal peduncle. Ventral profile of head straight, nearly straight from pectoral-fin insertion to anal-fin origin, convex from posterior margin of anal-fin base to anterior quarter of caudal fin due to caudal adipose keel on lower edge of caudal peduncle.

Anterior and posterior nostrils adjacent, distance less than posterior nostril diameter, base of anterior nostril tube-shaped and tip not elongated to barbel-like. Eyes absent. Mouth inferior, snout rounded, upper and lower lips smooth, lower lip with V-shaped median notch. Three pairs of barbels, inner and outer rostral barbels reaching mouth corner, and maxillary barbel reaching anterior margin of interopercle. Inner gill rakers on first gill arch nine (one specimen).

Dorsal fin with three unbranched and eight branched rays, distal margin straight, origin posterior to pelvic-fin origin, predorsal length 54.3 % – 55.5 % of SL. Pectoral fin with one unbranched and 10 branched rays, pectoral-fin length 61.6 % – 67.7 % of distance between pectoral-fin origin and pelvic-fin origin. Pelvic fin with one unbranched and five branched rays, tip of pelvic fin not reaching anus. Anal fin with two unbranched and five branched rays, distal margin straight. Anus abutting anal-fin base. Caudal fin forked. High caudal adipose keels on upper and lower edges of caudal peduncle, height at most of upper adipose keel nearly 1 / 2 caudal peduncle depth. Caudal peduncle depth 46.1 % – 51.9 % of its length (containing adipose keels). Lateral line and cephalic sensory pores absent. Body scaleless.

Coloration.

Whole body translucent, without color pattern. Fin membrane hyaline.

Distribution and habitat.

Only known from the type locality. Karstsinnectes acridorsalis inhabits a subterranean river, 22.8754 ° N, 107.1947 ° E, 284 m a. s. l. Co-inhabitants of the stream include Triplophysa tianeensis Chen, Cui & Yang, 2004 , Sinocyclocheilus furcodorsalis Chen, Yang & Lan, 1997 , and Hongshuia megalophthalmus (Chen, Yang & Cui, 2006) .

Remarks.

The population of K. acridorsalis is small. Initially described by Lan et al. (2013) based on three specimens, subsequent collections yielded only one specimen, collected in 2019 by J. J. Zhou.

Figures

Figure 1. Collection sites (A), K. anophthalmus (red round), K. acridorsalis (green triangle), K. hyalinus (purple rhombus), K. longzhouensis sp. nov. (blue square), K. parvus (black star), and habitat of Karstsinnectes longzhouensis sp. nov. (B) and K. parvus (C).

Figure 2. Lateral, dorsal, and ventral views of Karstsinnectes acridorsalis, holotype, CLJH 04100608 (photograph from J. H. Lan). Scale bar: 1 cm.