Amolops mengdingensis, Yu & Wu & Yang, 2019

Yu, Guohua, Wu, Zhengjun & Yang, Junxing, 2019, A new species of the Amolops monticola group (Anura: Ranidae) from southwestern Yunnan, China, Zootaxa 4577 (3), pp. 548-560 : 553-558

Amolops mengdingensis sp. nov.

Figs 3–4

urn:lsid:zoobank.org:act:25FD9445-4EA0-4776-9324-92C6B04C342E

Holotype. KIZ 20160266 , an adult male, collected at 22:10 on 20 July 2017 by Guohua Yu from Mengding Township (23°27'46.66"N, 99°9'14.11"E, 1040 m a.s.l.; Fig. 1 ), Gengma County, Lincang city, Yunnan, China.

Paratype. KIZ 20160265 , an adult female, collected at same time with the holotype from the type locality by Guohua Yu . KIZ 20160317 , KIZ 20160318 , and KIZ 20160321–20160323 , five adult males, collected from the type locality by Guohua Yu at 21:00–22:30 on 11 April 2018 .

Etymology. The specific epithet is named for the type locality, Mengding Township.

Diagnosis. Morphologically, A. mendingensis sp. nov. assigns to the A. monticola group by having the combination of smooth dorsal skin, dorsolateral fold, and the side of head dark with a light-colored upper lip stripe extending to the axilla ( Stuart et al. 2010). Amolops mengdingensis sp. nov. can be distinguished from other members in its group by having a combination of the following characters: 1) top of head and dorsum green with dark spots on dorsum; 2) loreal region dark brown and flanks brown without any coloration of green; 3) SVL 36.9– 40.2 mm in males and 64.3 mm in female; 4) dorsal surface smooth, except white spinules on posterior part of dorsolateral folds and above vent; 5) two external subgular vocal sacs in males; 6) vomerine teeth in two oblique ridges, separated by a small distance; 7) pineal body absent; 8) snout longer than eye diameter; 9) internarial space broader than interorbital space; 10) tympanum distinct, smaller than half of eye diameter; 11) all fingertips expanded; 12) two palmar tubercles; 13) outer metatarsal tubercle absent; 14) tibiotarsal articulation reaching beyond snout tip; and 15) velvety nuptial pads.

Description of holotype. Adult male (SVL 39.7 mm); head longer (HL 13.7 mm) than wide (HW 12.6 mm); snout obtusely pointed, projecting beyond margin of lower jaw in ventral view, rounded in profile; canthus rostralis distinct, nearly straight; loreal region sloping, concave; nostrils oval, lateral, slightly protuberant, slightly closer to eye than snout tip; internarial distance (IND 4.7 mm) greater than interorbital distance (IOD 3.6 mm); upper eyelid width (UEW 3.4 mm) slightly narrower than interorbital space; pineal spot absent; pupil oval, horizontal; tympanum distinct, rounded, less than half eye diameter; supratympanic fold indistinct; vomerine teeth in two oblique rows between choanae, closer to each other than choanae; choanae oval; tongue attached anteriorly, cordiform, deeply notched posteriorly; vocal sac opening on floor of mouth at each corner; two external subgular vocal sacs.

Forelimbs robust, relative length of fingers I <II <IV <III; all finger tips expanded into discs with circummarginal and transverse grooves; velvety nuptial pad present on first finger; webbing between fingers absent; subarticular tubercles prominent and rounded, formula 1, 1, 2, 2; supernumerary tubercle present; two metacarpal tubercles, oval.

Hindlimbs long, heels overlapping when legs at right angle to body, tibiotarsal articulation reaching beyond snout tip; tibia length (TL 24.1 mm) longer than thigh length (THL 22.1 mm) and foot length (FL 21.7 mm); relative length of toes I <II <III <V <IV; dermal fringe on preaxial side of toe I and postaxial side of toe V; all toe tips expanded into discs with circummarginal and transverse grooves, slightly narrower than discs of outer fingers; webbing between toes developed well, webbing formula I1 -1.5II1- 2III 1- 2IV 2- 1V; subarticular tubercles distinct, formula 1, 1, 2, 3, 2; inner metatarsal tubercle prominent, oval; outer metatarsal tubercle absent; supernumerary tubercle absent.

Dorsolateral folds distinct, extending from rear of eye to near vent; skin on dorsal and ventral surfaces of head, body, limbs and flanks smooth, with exception of small white warts on posterior part of dorsolateral folds and above vent; two rictal glands, continuous with upper lip; no humeral gland.

Coloration of holotype. In life, iris bronze with red wash and black reticulations; top of head and dorsum light green with some dark spots; narrow, brown stripe on edge of canthus from tip of snout among margin of upper eyelid, continuing along upper edge of dorsolateral fold; side of head dark brown from snout tip to axilla; white upper lip stripe extending to axilla; flanks brown; limbs dorsally grayish brown with clear dark brown bars on hindlimbs; ventral surface nearly immaculate; throat, chest, and abdomen white, mottled with light yellow, more so on throat; venter of limbs grayish; subarticular tubercles dark grayish; foot webbing yellowish-gray.

In preservative, dorsum faded to gray with dark spots; dorsal surface of limbs whitish-gray with dark bands and marbling; head side black brown; flanks gray-brown; throat, chest, abdomen, and ventral surfaces of limbs faded to white, almost immaculate.

Morphological variation. Table 4 gives measurements of holotype and paratypes. The new species is sexually dimorphic with female being obviously larger than males and having no vocal sacs and nuptial pads. THL is longer than FHL in holotype and all paratypes except paratype KIZ 20160318 . In addition, FHL is slightly longer than FL in holotype and all paratypes except paratype KIZ 20160265 .

Distribution and ecology. The new species is only known from the type locality ( Fig. 5a ). The holotype and the paratype KIZ 20160265 were found in amplexus on a rock in the stream at night on 20 July 2017 and other individuals were found on leaves or small branches less than 1 m above the ground along the stream at night on 11 April 2018, indicating that the breeding season of A. mengdingensis sp. nov. may be from April to July. The female paratype KIZ 20160265 laid eggs soon after it was caught. Eggs white ( Fig. 5b ). Neither tadpoles nor vocal recordings were collected for the new species. Xenophrys major Boulenger, 1908 , Limnoectes banaensis Ye, Fei, & Jiang, 2007, and Odorrana graminea ( Boulenger, 1899) were also encountered along the stream at the type locality.

Comparisons. Phylogenetic data assign the new species to the A. monticola group, which at present has 16 species, and suggest close relationships to with A. akhaorum and A. archotaphus ( Fig. 2 ). Genetically, the new species differs from A. akhaorum and A. archotaphus by 4.7% and 5.2%, respectively, for 16S sequences. Morphologically, A. mengdingensis sp. nov. differs from A. akhaorum by having larger males (SVL 36.9–40.2 mm versus SVL 34.9–37.2 mm), having two palmar tubercles (versus palmar tubercle absent), having velvety nuptial pad in males (versus nuptial pad absent), having white spinules on the posterior part of dorsolateral fold (versus lacking white spinules on the dorsolateral fold), and lacking large raised tubercles on dorsum, pineal body, and distinct transverse bands on dorsal surface of forelimbs (versus all present); and from A. archotaphus by top of head and dorsum green and flanks brown (versus dorsal and lateral surfaces olive green), all finger tips expanded into discs (versus outer three fingers expanded into discs), dorsolateral folds distinct (versus dorsolateral folds weak or absent), eye diameter shorter than snout (versus eye diameter equal to or longer than snout), tympanum smaller than half of eye diameter (versus tympanum about two-thirds eye diameter), outer metatarsal tubercle absent (versus present), and ventral surface of thighs smooth (versus ventral surface of thighs coarsely granular).

Three members ( A. chakrataensis , A. gerbillus , and A. monticola ) of the A. monticola species group are not included in the molecular data owing to that homologous sequences are unavailable for them. Amolops mengdingensis sp. nov. differs from A. chakrataensis by top of head and dorsum green and flanks brown (versus dorsal surface uniformly slaty brown and flanks dark green), larger female (SVL 64.3 mm versus 55 mm), pineal ocellus absent (versus present), head longer than wide (versus head wider than long), tibia longer than half of body size (versus length of tibia equal to half of body size), tympanum smaller than half of eye diameter (versus tympanum almost half the diameter of eye), supratympanic fold indistinct (versus distinct), foot shorter than tibia (versus foot length equal to tibia length), and tibiotarsal articulation reaching beyond the tip of snout (versus tibiotarsal articulation reaching only tympanum or just posterior corner of eye); from A. gerbillus by top of head and dorsum green (versus very dark grey obscurely mottled with a paler shade), lack of tooth at the tip of the lower jaw (versus present), lack of large compressed longitudinal tubercles on dorsum (versus present), ventral surface near immaculate (versus large round or oval brown spots on the chin, throat and chest), tympanum distinct (versus indistinct), and lack of webbing between fingers (versus a web rudiment between the third and fourth fingers); and from A. monticola by having two vomerine teeth in two oblique ridges separated by very small distance (versus two ridges of vomerine teeth separated by a considerable interspace), snout longer than eye (versus snout as long as eye), internarial space broader than interorbital space (versus distance between the nostrils equal to the interorbital width), top of head and dorsum green (versus dorsal surface brown or yellow), and eggs white (versus creamy yellow).

Currently, eight Amolops species that are not in the A. monticola group occur in Yunnan, including Amolops caelumnoctis Rao & Wilkinson, 2007 , Amolops jinjiangensis Su, Yang, & Li, 1986 , Amolops loloensis ( Liu, 1950) , Amolops mantzorum ( David, 1872) , Amolops marmoratus ( Blyth, 1855) , Amolops splendissimus Orlov & Ho, 2007 , Amolops tuberodepressus Liu & Yang, 2000 , and Amolops viridimaculatus ( Jiang, 1983) . Amolops mengdingensis sp. nov. differs from A. caelumnoctis and A. splendissimus by having smaller body size (SVL 36.9– 40.2 mm in males and SVL 64.3 mm in female versus SVL of males 71.3–73.7 mm and SVL of females 78.0– 90.6 mm in A. caelumnoctis and SVL of males 62.6–75.6 mm and SVL of females 69.3–96.8 mm in A. splendissimus ), dorsolateral folds distinct (versus absent), a white upper lip stripe present (versus absent), two external subgular vocal sacs (versus vocal sac absent), and dorsal surface green with no light yellow spots (versus dorsum dark purple with numerous small round light yellow spots in A. caelumnoctis and dorsum black-brown with numerous small light yellow spots of irregular shape in A. splendissimus ). Amolops mengdingensis sp. nov. can be distinguished from A. jinjiangensis , A. loloensis , A. mantzorum , A. tuberodepressus , and A. viridimaculatus by having distinct dorsolateral folds (versus absent), all finger tips expanded into discs with circummarginal and transverse grooves (versus lack of horizontal groove on tip of first finger), and two external subgular vocal sacs (versus vocal sac absent); and from A. marmoratus by dorsal surface smooth (versus dorsal surface granular), dorsolateral folds distinct (versus absent), dorsum green (versus black), and toe IV webbed incompletely (versus all toes completely webbed).

Morphologically the new species also can be distinguished from other species in the A. monticola group that are distinct genetically and not directly related to it. Amolops mengdingensis sp. nov. differs from A. aniqiaoensis , A. bellulus , and A. nyingchiensis by having smaller males (SVL 36.9–40.2 mm versus about 52 mm in A. aniqiaoensis , 45.9–50.1 mm in A. bellulus , and 52.3–58.3 mm in A. nyingchiensis ); from A. aniqiaoensis , A. bellulus , A. nyingchiensis , and A. chunganensis by top of head and dorsum green (versus olive green in A. aniqiaoensis , sandy beige clouded with olive green and brown spots in A. bellulus , brown in A. nyingchiensis , and reddish-brown in A. chunganensis ); from A. bellulus and A. nyingchiensis by having two external subgular vocal sacs (versus vocal sac absent); from A. chunganensis , A. compotrix , A. daorum , and A. wenshanensis by larger body size in female (SVL 64.3 mm versus SVL 58 mm in A. chunganensis , 55.6–56.9 mm in A. compotrix , 53.3– 57.6 mm in A. daorum , and 43.7–45.6 mm in A. wenshanensis ); from A. compotrix , A. cucae , A. mengyangensis , A. nyingchiensis , A. vitreus , and A. wenshanensis by having white spinules on posterior part of dorsolateral folds (versus absent); from A. compotrix , A. cucae , and A. vitreus by lacking outer metatarsal tubercle (versus present); from A. cucae , A. iriodes , and A. nyingchiensis by venter near immaculate (versus maculate); and from A. bellulus , A. compotrix , A. daorum , and A. iriodes by lack of pineal body (versus present).

The new species further differs from A. chunganensis by internarial space broader than interorbital space (versus distance between nostrils equal to interorbital width); from A. daorum by having vomerine teeth (versus absent); from A. iriodes by dorsolateral folds brown (versus gold or orange-red) and lack of white glandular spot on flanks (versus present); from A. mengyangensis by having velvety nuptial pads in males (versus nuptial pads with white spinules); from A. vitreus by lacking translucent venter skin (versus translucent); and from A. wenshanensis by having dark spots on dorsum (versus absent) and distinct transverse bands on dorsal surfaces of hindlimbs (versus absent).

Figures

FIGURE 1. Collection site of Amolops mengdingensis sp. nov. from southwestern Yunnan, China.

FIGURE 2. Bayesian phylograms of the Amolops monticola group inferred from the combination of 16S rRNA, ND2, and COI (a), from 16S rRNA (b), from ND2 (c), and from COI (d). Numbers above branches are Bayesian posterior probabilities (only values above 50% are shown).

FIGURE 3. Dorsal-lateral (a) and ventral (b) views of the holotype of Amolops mengdingensis (KIZ 20160266) in life and dorsal (c) and ventral (d) views of the holotype in preservative.

FIGURE 4. Ventral view of hand (a) and foot (b) of the holotype of Amolops mengdingensis sp. nov. in preservative.

FIGURE 5. Habitat at the type locality of Amolops mengdingensis sp. nov. (a) and the eggs laid by the female paratype KIZ 20160265 (b).