Amolops yunkaiensis Lyu & Wu & Wang & Sung & Liu & Zeng & Wang & Li & Wang 2018, sp. nov.

Amolops yunkaiensis Lyu, Wang, Liu, Zeng and Wang sp. nov.

(Fig. 3 and 4)

Chresonymy:

Amolops torrentis (Smith, 1923): Fei et al. 2009 (Xinyi, Guangdong). Amolops torrentis: Wei et al. 2010 (Yunkaishan Nature Reserve, Xinyi, Guangdong).

Holotype: SYS a004705, adult male, collected by Zhi-Tong Lyu (ZTL), Jian Wang (JW), and Hai-Long He (HLH) on 20 April 2016 from Bajiaxianhu (21°53′35.5″N, 111°29′5.1″E; 441 m a.s.l.), Ehuangzhang Nature Reserve, Guangdong Province, China.

Paratypes: 16 adult specimens. Male SYS a000773 and female SYS a000774, collected on 29 March 2010 by Run-Lin Li from the same stream as holotype; six females, SYS a004698–4701, 4706–4707, collected on 19–20 April 2016 by ZTL, JW and HLH from the same stream as holotype. Two females SYS a003979 and 3982 collected on 14 May 2015 by ZTL, Chao Huang and Kai-Chi Huang from Liping (2148′59.9″N, 11126′57.5″E; 337 m a.s.l.), EHZ, Guangdong Province, China. Six males, SYS a004674, 4681–4684, collected on 15–16 April 2016 by ZTL, Ying-Yong Wang and HLH, and SYS a004992/ CIB 106880 collected on 29 June 2016 by JW and HLH, from Dongkeng (2214′50.3″N, 11111′23.1″E; 987 m a.s.l.), Yunkaishan Nature Reserve, Guangdong Province, China.

Etymology. The specific name, yunkaiensis, refers to the locality of the new species, the Yunkai Mountains. We suggest its English common name “Yunkai Torrent Frog” and Chinese name “Yun Kai Tuan Wa (ĀHṁü)”.

Diagnosis. The diagnostic character for the genus Amolops is the presence of an abdominal sucker in the tadpole (Rao & Wilkinson 2007). However, because the tadpole of the new species remains to be discovered, we assigned the new species to this genus based on the morphological and genetic similarity of the adult specimens to those of A. ricketti and A. wuyiensis.

Amolops yunkaiensis sp. nov. is distinguished from its congeners by a combination of the following morphological characteristics: (1) relatively small body size, SVL 31.8–34.1 mm in adult males, 35.2–39.0 mm in adult females; (2) dorsal skin of body very rough with numerous raised large warts; (3) several large raised warts on flanks, white or yellowish white; (4) dorsal body olive-brown or light brown with dark brown blotches; (5) vomerine teeth absent; (6) tongue cordiform, deeply notched posteriorly; (7) absence of the dorsolateral folds; (8) presence of a circummarginal groove on the disk of the first finger; (9) absence of outer metatarsal tubercles; (10) absence of tarsal glands; (11) sparse translucent tubercles on the lower jaw, forechest, posterior of belly and ventral thigh in males; (12) males with a pair of subgular vocal sacs; (13) nuptial pad on first finger prominent with developed white conical spines in breeding males.

Description of Holotype: Head length slightly larger than head width (HDW/HDL = 0.93); snout short (SNT/ HDL = 0.36) and rounded in profile, projecting beyond lower jaw; nostril closer to tip of snout than eye; loreal region concave; top of head flat; eye large (ED/HDL = 0.4) and convex; canthus rostralis distinct; pineal body barely visible; tympanum small, edge faintly distinct; supratympanic fold distinct, from back of eye to shoulder; choanae moderate; vomerine teeth absent; tongue cordiform, deeply notched posteriorly.

Forelimbs moderately robust; hands moderately long (HND/SVL = 0.31); relative finger lengths I <II <IV <III; finger tips dilated to wide oval disks with circummarginal grooves, relative width of finger disks I <II <III = IV; subarticular tubercles prominent, rounded; inner and outer metacarpal tubercle slightly elongated; no finger webbing or lateral fringes.

Hindlimbs long and robust (TIB/SVL = 0.54); tibio-tarsal articulation reaching loreal region when hindlimb stretched alongside of body; relative toe lengths I <II <V <III <IV; tips of all toes expanded to well-developed oval discs with circummarginal grooves; subarticular tubercles oval and distinct; inner metatarsal tubercle prominent, elongated; outer metatarsal tubercles absent; toes fully webbed; lateral fringes of toes I and V developed; tarsal glands absent; heels slightly overlapping when hindlimbs flexed at right angles to axis of body.

Dorsal skin of body very rough with raised large warts; dorsolateral fold absent; flanks very rough with numerous tubercles and large raised warts; dorsal limbs rough with numerous tubercles; several longitudinal dermal ridges on dorsal surfaces of thigh, tibia and tarsus; posterior part of upper lip swollen; rictal gland prominent and ellipsoidal, posterior to corner of mouth. Ventral surface slightly wrinkled; raised tubercles arranged on the lower jaw, forechest, posterior of belly and ventral thigh; large warts surrounding the vent.

Measurement of holotype (in mm). SVL 32.4; HDL 12.3; HDW 11.5; SNT 4.4; IND 3.9; IOD 2.8; ED 4.9; TD 1.5; TED 1.3; HND 10.1; RAD 6.3; FTL 23.2; TIB 17.5; F3W 2.3; T4W 2.1.

Color in life. Dorsal body olive-brown with dark brown blotches; large warts on flanks yellowish white; a dark brown longitudinal band on each side of lower flank of body; faint dark transverse bars on dorsal surface of limbs; dorsal discs of digits greyish-white; posterior edge of upper lip and rictal gland light maize-yellow. Throat, chest, and belly creamy white; tubercles on the lower jaw, forechest, posterior of belly and ventral thigh slightly translucent; ventral surfaces of limbs with greyish-white flecks; creamy white blotches on ventral thighs; rear of thighs mottled with dark brown; ventral hands and feet dark grey; a yellowish oval spot on each side of cloaca. Color in preservative. Dorsal surface of head, body and limbs transformed into dark olive with black blotches, transverse bars and spots; ventral surface of head and body white ventral surface of limbs light brown. Variation. Measurements of type series are given in Table 4. All paratypes are very similar in morphology and color pattern except that dorsal skin yellowish brown in SYS a003979 and 4674; throat or chest with grey flecks in SYS a000774, 3983, 3984, 4699, 4703, 4704 and 4707; pineal body distinctly visible in SYS a000773, 0 776, 0 778, 0 779, 3979, 4670, 4681, 4683, 4704, 4706 and 4992; heel just meeting in SYS a004700, 4701 and 4993; tibiotarsal articulation reaching tip of snout when hindlimb stretched alongside of body in SYS a000773, 0 778, 3983, 3984, 4674, 4681, 4682 and 4683.

Male secondary sexual characteristics. A pair of subgular vocal sacs, a pair of slit-like openings at posterior of jaw; a white nuptial pad on first finger prominent with strongly developed white conical spines.

Comparisons. Amolops yunkaiensis sp. nov. was previously reported as A. torrentis, but differs from true A. torrentis from Hainan Island by having numerous raised large warts on dorsum and flanks (vs. smooth in A. torrentis), tarsal glands absent (vs. present), having sparse translucent tubercles on the lower jaw, forechest, posterior of belly and ventral thigh in males (vs. absent), having nuptial pad prominent with developed conical spines on first finger in males (vs. nuptial pad and spines absent).

Amolops yunkaiensis sp. nov. differs from A. albispinus, A. ricketti, A. wuyiensis, A. daiyunensis, A.

hongkongensis and A. hainanensis, to which it is most closely related (Fig. 2), by having a relatively small body size, SVL 31.8–34.1 mm in adult males and SVL 35.2–39.0 mm in adult females (vs. SVL 36.7–42.4 mm in adult males and SVL 43.1–51.9 mm in adult females of A. albispinus, SVL 42.0– 60.5 mm in adult males and SVL 53.5– 67.0 mm in adult females of A. ricketti, SVL 38.0–45.0 mm in adult males and SVL 45.0–53.0 mm in adult females of A. wuyiensis, SVL 34.0–41.0 mm in adult males and SVL 31.0–48.0 mm in adult females of A. hongkongensis, SVL 36.0–58.0 mm in adult males and SVL 44.0–63.0 mm in adult females of A. daiyunensis, SVL 71.0–93.0 mm in adult males and SVL 68.0–78.0 mm in adult females in A. hainanensis); the presence of numerous raised large warts on dorsal body in A. yunkaiensis (vs. absent in A. ricketti, A. wuyiensis and A. daiyunensis); tarsal glands absent in A. yunkaiensis (vs. present in A. daiyunensis and A. hainanensis); having translucent tubercles on the lower jaw, forechest, posterior of belly and ventral thigh in males (vs. absent in A. albispinus, A. ricketti, A. daiyunensis, A. hongkongensis and A. hainanensis); nuptial pad on first finger prominent with developed white conical spines (vs. absent in A. hainanensis, black conical spines in A. wuyiensis); having a pair of vocal sacs in A. yunkaiensis (vs. absent in A. albispinus, A. ricketti and A. hainanensis).

Amolops yunkaiensis sp. nov. differs from the remaining congeners in having tubercles on the lower jaw, forechest, posterior of belly and ventral thigh in males; the absence of dorsolateral folds (vs. present in A. akhaorum, A. aniqiaoensis, A. archotaphus, A. bellulus, A. chakrataensis, A. chayuensis, A. chunganensis, A. compotrix, A. cremnobatus, A. cucae, A. gerbillus, A. iriodes, A. jaunsari, A. kohimaensis, A. longimanus, A. mengyangensis, A. minutus, A. monticola, A. nyingchiensis, and A. vitreus); the presence of a circummarginal groove on disk of first finger (vs. absent in A. formosus, A. granulosus, A. jinjiangensis, A. xinduqiao, A. liangshanensis, A. lifanensis, A. loloensis, A. mantzorum, A. nidorbellus, A. tuberodepressus, and A. viridimaculatus); the absence of vomerine teeth (vs. present in A. afghanus, A. assamensis, A. caelumnoctis, A. daorum, A. himalayanus, A. indoburmanensis, A. kaulbacki, A. larutensis, A. marmoratus, A panhai, A. spinapectoralis and A. splendissimus); having dorsal surface olive-brown with dark brown blotches (vs. dorsal color of green or bright yellow in A. medogensis).

Distribution and ecology. Amolops yunkaiensis sp. nov. inhabits rocky, fast-flowing streams (300–900 m a.s.l.) surrounded by moist subtropical secondary evergreen broadleaved forests and the frog is sympatric with a congener, A. ricketti, in the same steams. All individuals were observed from April to June, when males were found bearing mature nuptial pads. Nevertheless, the call of the frog was not heard during any of our repeated surveys, and much of its ecology and behavior remains unknown.

Currently, the Yunkai Torrent Frog is only known from the type locality, the Ehuangzhang Nature Reserve and Yunkaishan Nature Reserve in the Yunkai Mountains. Its extent of occurrence is estimated to be less than 5000 km 2, and the area of occupancy is estimated to be less than 500 km 2. Moreover, these areas are being threatened by hydropower station construction and tourism development. This frog appeared to be rare in EHZ and YKS. Surveys are urgently needed in southern China to investigate the population status and the distribution of this species. We suggest the species may be eligible for listing as Endangered (B1ab(i, ii, iii) + 2ab(i, ii, iii)) in the IUCN Red List of Threatened Species.