Leptobotia citrauratea Nichols, 1925

Guo, Dong-Ming & Zhang, E, 2021, Re-description of the loach species Leptobotia citrauratea (Teleostei, Botiidae), with the description of L. brachycephala from southern Zhejiang Province, China, ZooKeys 1017, pp. 89-109 : 89

Leptobotia citrauratea Nichols, 1925 (Fig. 1a-c)

Botia citrauratea Nichols, 1925: 5 [Tungting [now Dongting] Lake, Hunan Province

Leptobotia elongata : Chen, 1980: 14 (no localities). Kottelat, 2004:15 (no localities); 2012:16 (no locality)

Leptobotia citrauratea : Nalbant, 2002: 316 (no localities). Bohlen & Šlechtová, 2017: 90 (Nanchang City, Jiangxi Province)

Material examined.

Leptobotia citrauratea : AMNH 8402, holotype, 50 mm SL; China: Hunan Province: Dungting Lake (photograph examined); collected by Clifford H. Pope, 29 December 1921; IHB 2017100260-65, 201801026314, 201711016295, 201711015676, 201711015673-74, 201711015715-16, 201711016204, 201707028880, 201711015718, 201707028888, topotypes, 17 specimens, 47.0-65.3 mm SL; China: Hunan Province: Nanxian County: Dongting Lake; 29°2'29"N, 112°18'22"E; collected by C.T An, November 2017; IHB 2017056850-60, 2017056862, 12 specimens, 33.3-42.7 mm SL; China: Jiangxi Province: Nanchang City: Gan-Jiang, an effluent of Poyang Lake; 28°32'12"N, 115°49'24"E; collected by D.M. Guo, November 2019.

Diagnosis.

Leptobotia citrauratea shares with L. micra and L. brachycephala the unique presence of a row of orange spots or an orange stripe along the dorsal mid-line of the body, extending from the nape to the caudal-fin base. It differs from L. micra and L. brachycephala by having a deeply forked (vs. emarginate) caudal fin (length of median rays 1.7-2.3 times in length of upper lobe vs. 1.3-1.4 in L. micra and 1.2-1.5 in L. brachycephala ), pelvic fin inserted slightly posterior or inferior (vs. slightly anterior in L. brachycephala ) to the dorsal-fin origin, a longer head (22.5-26.8% SL vs. 18.4-22.8% SL in L. brachycephala ) and a shorter predorsal distance (51.4-56.3% SL vs. 58.1-59% SL in L. micra ) (Table 2 , Fig. 2 ).

Description.

Morphometric data for specimens examined in Tables 1 , 2 . See Fig. 1 for lateral and dorsal view of body. Body slender, strongly compressed laterally, with maximum depth at dorsal-fin origin. Predorsal body profile slightly convex. Ventral profile of head slightly concave or straight; ventral profile of body almost straight or slightly concave from pectoral-fin insertion to anal-fin origin and slightly convex from anal-fin origin to caudal-fin base. Lateral line nearly complete, extending along mid-lateral of body. Cheek and trunk covered with minute scales.

Head short, compressed laterally, length greater than maximum body depth. Snout slightly concave in lateral view, slightly shorter than postorbital head. Eye small, dorsolateral, in upper half of head; diameter less than interorbital space. Mouth inferior, with opening laterally extended to vertical through anterior margin of nostril. Button-like fleshy protrusion in gular region absent. Two rostral barbels at tip of snout. Maxillary barbel in corner of mouth, reaching beyond vertical through posterior margin of nostrils, not or just approaching to level of anterior margin of eye. Simple suborbital spine ventral to anterior margin of eye, reaching posterior margin of eye.

Fin rays flexible. Dorsal fin with 4 unbranched and 8 branched rays; distal margin slightly concave; origin slightly anterior to or superior to pelvic-fin insertion and closer to caudal-fin base than to snout tip. Pectoral fin with 1 unbranched and 10-11 branched rays, tip of depressed fin extending about midway between pectoral-fin and pelvic-fin insertion. Pelvic fin with 1 unbranched and 7 branched rays, reaching about half of distance between pelvic-fin insertion and anal-fin origin and just reaching anus. Anus closer to anal-fin insertion than pelvic-fin insertion. Anal fin with 3 unbranched and 5 branched rays, tip of depressed fin not extending to caudal-fin base; distal margin slightly concave. Caudal fin strongly forked, median fin rays 1.7-2.3 times as long as lobes; upper and lower lobes broadly pointed and almost equal in length and shape.

Colouration.

In freshly-collected specimens, ground colour of head and body yellowish-brown or orange; lateral head and flank faintly peppered with dark grey flecks. Dorsal side of head and body dark with some rounded light orange spots usually fused to form an orange stripe extending along mid-line of dorsum from nape to caudal-fin base. Anterior to orange spots or light stripe, an orangish stripe present between eye and nape. Faint dark grey stripe extending from snout tip to anterior margin of eye. Grey bar, similar in width to eye diameter, present on caudal-fin base. In some specimens, caudal fin hyaline, in others with dark grey stripes. Single row of faint dark grey stripes present in dorsal fin.

In specimens preserved in formalin, ground colour slightly faded, not presenting vivid yellowish-brown or orange, but becoming whitish-grey and peppered with dark flecks. Dorsum and head darkened. Orange spots along mid-line of dorsum white. Dorsal, pectoral, pelvic and anal fins greyish-yellow at base with white distal margins. Caudal fin dusky.

Geographical distribution and habitat.

Leptobotia citrauratea is known from Dongting Lake in Hunan Province and the Gan-Jiang, discharging into Poyang Lake, in Jiangxi Province, southern China (Fig. 3 ). The specimens here described were collected in deep and slow-running water with mixed substrate. Syntopic fish species included Saurogobio dabryi Bleeker, 1871, Parabotia banarescui (Nalbant, 1965) and Hemibarbus maculatus Bleeker, 1871.

Figures

Figure 1. Lateral (upper) and dorsal (lower) view of L. citrauratea for freshly-caught specimens a IHB 2017100265, topotype, 53.0 mm SL, China, Hunan Province, Yiyang City, Nanxian County, Dongting Lake b IHB 2017056850, 38.1 mm SL, China, Jiangxi Province, Nanchang City, Gan-Jiang c AMNH 8402, holotype, 50 mm SL, China, Hunan Province, Dungting (presently Dongting) Lake (photos by Department of Ichthyology, American Museum of Natural History).

Figure 2. Relationship between body depth and SL (a), between head length and SL (b), between caudal-peduncle length and SL (c) and between pectoral-fin length and SL (d) for two closely-related species: L. brachycephala (gray triangle) and L. citrauratea (light blue diamond).

Figure 3. Collection localities of L. brachycephala (dark blue star) and L. citrauratea (light green dot).