Yunnanilus niulanensis, Chen, Ziming, Yang, Jian & Yang, Junxing, 2012

Chen, Ziming, Yang, Jian & Yang, Junxing, 2012, Description of a new species of the genus Yunnanilus Nichols, 1925 (Teleostei: Nemacheilidae) from Yunnan, China, Zootaxa 3269, pp. 57-64 : 58-61

Yunnanilus niulanensis , sp. nov.

( Fig. 1 , 2 )

Holotype. KIZ 20060285, 55.3 mm SL; Yanglinhe River, 25°14ʹ34.0ʺ N; 103°03ʹ53.3ʺE (altitude: 1909 m), upper reaches of the Niulanjiang River, in Yanglin Town, Songming County, Yunnan Province, China.

Paratypes. KIZ 20060281, KIZ 20060287, KIZ 20060291–20060293, 20060297, six specimens, 41.7–52.5 mm SL; collected with the holotype.

Diagnosis. The new species can be distinguished from its congers by the following combination of characters: dorsal-fin rays iii, 9; anal-fin rays iii, 5; pectoral-fin rays i, 11; pelvic-fin rays i, 7–8; branched caudal-fin rays 14; mouth subterminal; 9–11 gillrakers in the inner side of the first gill arch, outer row of gill rakers absent; upper twothirds of body and head covered by large brown spots; fins hyaline; body covered with scales; no lateral line; no cephalic sensory pores; caudal peduncle length less than caudal peduncle depth; caudal peduncle length 9.2–11.1% SL; body depth 21.0–25.8 % SL; eye diameter 5.4–6.0 % SL; interorbital width 9.9–12.1 % SL.

Description. Proportional measurements and counts are given in Table 1. Body elongate, compressed. Body depth at dorsal-fin origin 21.0–25.8 % SL. Dorsal profile convex, ventral profile slightly convex. Dorsal midline with a concavity between nape and dorsal-fin origin. Pectoral fin reaching beyond halfway to pelvic-fin bases, 54.0–78.4 % of length between pectoral and pelvic-fin bases. Axillary pelvic lobe absent or vestigial. Pelvic fin reaching mid-point of distance between pelvic-fin origin and anus. Anus separated from anal-fin origin by a distance less than eye diameter. Anal fin not reaching caudal-fin base. Caudal-peduncle depth 107.1–142.3 % caudal-peduncle length. Predorsal length 54.0–57.5 % SL; dorsal-fin origin anterior to vertical line from pelvic-fin origin.

Characters Holotype Paratypes (Range) Mean SD Total length (mm) 69.2 54.4–68.1 62.1 Standard length (mm) 55.3 41.7–52.5 48.8 Percent standard length

Head length 26.8 26.6–29.0 27.6 1.0 Body depth at DO 23.3 21.0–25.8 24.0 1.6 Predorsal length 55.0 54.0–57.5 55.7 1.2 Prepelvic length 56.8 57.0–58.7 57.5 0.7 Caudal-peduncle length 9.2 9.4–11.1 10.3 0.9 Caudal-peduncle depth 13.1 11.4–13.3 12.7 0.7 Head compressed, its height greater than width at nape; head length greater than body depth at dorsal-fin origin, head length 26.6–29.0 % of SL. Snout obtuse, rounded, its length far less than postorbital length of head, 32.4–36.3 % of HL. Nostrils widely separated; anterior nostril at tip of a short tube, not reaching halfway to posterior one when adpressed. Interorbital space flat or a little convex, 36.9–41.7 % HL. Mouth subterminal, arched. Lips thick, almost smooth; upper lip without median groove, lower one with a median notch and 2 shallow furrows on each side. Processus dentiformes present on upper jaw; no notch or only a very shallow concavity on lower jaw. Eye invisible in ventral view, eye diameter 19.5–21.4 % of HL. Inner rostral barbel almost reaching vertical from anterior nostril, not reaching base of maxillary barbel; outer rostral barbel reaching beyond vertical of anterior nostril, not reaching posterior nostril or base of maxillary barbel. Maxillary barbel extending beyond vertical line through posterior margin of eye. Free posterior chamber of air bladder voluminous, 11.6× 4.4 mm, with an additional 3.3 mm duct connecting the anterior capsule (KIZ200627007, 48.7 mm SL), extending beyond vertical through dorsal-fin origin, extending beyond pelvic-fin base. Gillrakers 9–11 on the inner side of first gill arch, absent on outer one. Intestine simple, with almost no coil from stomach to anus. Peritoneum gray ventrally, black-gray dorsally.

Distal margin of dorsal-fin slightly convex. Caudal fin truncate or slightly emarginate, its tips rounded. Body entirely covered by embedded scales except for abdomen. Lateral line absent; cephalic lateral line and pores on head absent.

No sexual dimorphism observed.

Coloration. In alcohol, upper two-thirds of body and head covered by large brown spots, some spots more or less interconnected to form irregular vertical bars along the flank. Fins hyaline. A vertical black line present on caudal-fin base ( Fig. 1 ).

Habitat. The type specimens were collected from the Yanglinhe River (altitude: 1909m), one of the upper tributaries of the Niulanjiang River in Yanglin town, Songming County, Yunnan Province. The water was slowflowing and clear, pH: 7.0. The stream at the type locality is about 2 m in width, and about 0.4–0.5m in depth (the width and depth may be greater during the rainy season). The substrate was sandy or a little muddy. The landform, which the river flows through, is plain, with wheat fields, but becomes mountainous not far away from the stream. Distribution. This species is thus far known only from type locality ( Fig. 3 ).

Etymology. The specific name, niulanensis alludes to the type locality, the Niulanjiang River.

Figures

FIGURE 1. Lateral, dorsal and ventral views of Yunnanilus niulanensis, sp. nov., holotype, KIZ 20060285, 55.3 mm SL; Yanglinhe River, 25 ° 14 ′ 34.0 ″ N; 103 ° 03 ′ 53.3 ″ E (altitude: 1909 m), which belongs to one of the upper reaches of the Niulanjiang River, in Yanglin Town, Songming County, Yunnan Province, China.

FIGURE 2. Lateral and ventral views of head of Yunnanilus niulanensis, sp. nov., holotype, KIZ 20060285, 55.3 mm SL. an, anterior nostril; irb, inner rostral barbel; ll, lower lip; mb, maxillary barbel; pn, posterior nostril; orb, outer rostral barbel; up, upper lip.

FIGURE 3. Map of partial Yunnan, Guizhou and Sichuan, China. Triangle (˔) indicating the distribution of Yunnanilus niulanensis, sp. nov. in Songming County, Yunnan Province, China.