Rhacophorus yinggelingensis, Chou & Lau & Chan, 2007

Chou, Wen-hao, Lau, Michael Wai-neng & Chan, Bosco P. L., 2007, A New Treefrog Of The Genus Rhacophorus (Anura: Rhacophoridae) From Hainan Island, China, Raffles Bulletin of Zoology 55 (1), pp. 157-165 : 158-162

publication ID	https://doi.org/ 10.5281/zenodo.5332218
persistent identifier	https://treatment.plazi.org/id/0385878A-FF87-B13D-FCCD-F8200D35C2B3
treatment provided by	Diego
scientific name	Rhacophorus yinggelingensis
status	sp. nov.

Treatment

Rhacophorus yinggelingensis , new species

( Figs. 2–4 View Fig View Fig View Fig )

Material examined. – Holotype: NMNS 4091 View Materials , an adult male, SVL 43.4 mm; CHINA: Hainan Island: Yinggeling: Mahuoling :

18 ° 57'23.4"N 109 ° 23'02.1"E, at an elevation of 1,300 m ( Fig. 1 View Fig ). Coll. at 2000 hours on 21 Mar.2003 by Bosco Chan.

Paratype: KFBG 0004, an adult male, SVL 43.0 mm; CHINA: Hainan Island, Yinggeling, Yinggezui , 19 ° 03'55.6"N 109 ° 32'41.6"E, at an elevation of 1,550 m ( Fig. 1 View Fig ). Coll. at 1230 hours on 31 May.2005 by Bosco Chan GoogleMaps .

Diagnosis. – Rhacophorus yinggelingensis ( Fig. 2 View Fig ) is a medium-sized treefrog possessing the following combination of characteristics: (1) snout rounded, without protruding process; (2) green dorsum with few fine white spots, dorsolateral folds absent; (3) skin on dorsum smooth, flanks and venter granulate; (4) metatarsal skinfolds faint; (5) fingers and toes webbed; (6) front of thigh yellow and red-tinged, rear of thigh and inner side of tibia red; (7) white-tipped tuberculous dermal ridge on cloaca present, not well developped; (8) iris silvery, partly light golden in upper half.

Description of holotype. – Body slender, snout-vent length (SVL) 43.4 mm ( Fig. 3 View Fig ). Head medium, wider than long (head width 17.2 mm; head length 15.5 mm), concave above. Snout rounded in lateral profile, not protruding, its length (SL 7.8 mm) longer than horizontal diameter of eye (5.8 mm). Canthus rostralis rounded, loreal region concave. Interorbital space slightly convex, interorbital distance (5.2 mm) larger than upper eyelid width (3.6 mm), equal to internarial distance (5.2 mm). Intercanthal distance (9.1 mm) 0.65 times in distance between posterior ends of eyes (13.9 mm). Nostrils oval, flap of skin not obvious, closer to eye (N-EL 2.9 mm) than to tip of snout (SNL 3.9 mm). Tympanum distinct, rounded, horizontal diameter (4.5 mm) 0.78 of eye diameter (5.8 mm); tympanum-eye distance (0.3 mm) 0.07 of tympanum diameter. Vomerine ridge present, bearing small teeth, between choanae, with an angle of ca. 30º relative to body axis, closer to choanae than to each other, length about the distance between them. Tongue somewhat elongate, width ca. half of length, not laterally emarginated, posteriorly 1/8 notched. Supratympanic fold distinct, from posterior canthus to above base of upper arm.

Arm short, moderately strong, forearm (8.8 mm) shorter than hand (13.3 mm), not distinctly enlarged. Relative length of fingers I <II <IV <III. Finger I (length 3.8 mm) thinnest; finger II length 4.6 mm; finger III length 7.1 mm ( Fig. 4 View Fig ). Tip of fingers enlarged; discs present with distinct circummarginal grooves. Fingers with thin dermal fringes; webbing present; web only a rudiment between I and II, beyond subarticular tubercle on postaxial side of II, to proximal subarticular tubercle for preaxial side of finger III, between proximal and distal subarticular tubercle for postaxial side of finger III, reaching disc as fringe of both sides of finger III, to level of distal subarticular tubercles on IV, reaching discs as a fringe on postaxial side of II, III, and preaxial side of IV, lateral fringes on preaxial side of I and postaxial side of IV to terminal phalanges. Subarticular tubercules prominent oval. Prepollex elongate, prominent; palmar tubercles not prominent.

Hind limbs long. Tibia (length 18.4 mm) almost as long as thigh (length 18.2 mm), longer than foot (length 17.8 mm). Toes long, toe IV (10.8 mm) longer than tarsus (9.6 mm)( Fig. 4 View Fig ). Relative length of toes: I <II <III <V <IV. Tips of toes enlarged; discs present on all toes with distinct circummarginal grooves. Webbing present; web full to base of toe discs, except preaxial side of II, III and both sides of IV; webbing on preaxial side of II full to proximal edge of subarticular tubercle, continuing to disc as a fringe; web on preaxial side of III full to between proximal and distal subarticular tubercles, reaches close to disc as a fringe; web on IV full to level between proximal and distal subarticular tubercles, reaching disc as a fringe; lateral fringes on preaxial side of I and postaxial side of V to disc. Subarticular tubercles prominent, rounded, simple; single tubercle: I(1)-II(1)-III(2)- IV(3)-V(2) (formula = digital numbers with tubercle counts in parentheses). Inner metatarsal tubercle distinct, elongate, length (2.7 mm) 0.7 times in length of toe I (3.5 mm). Tarsal fold or ridge weak. Outer metatarsal tubercle, supernumerary tubercles, and tarsal tubercle absent.

Skin on dorsum of body smooth; dorsolateral folds absent; belly grossly granulate. Dorsal surface of limbs smooth; ventral surface of forelimbs smooth, grossly granulate beneath cloaca and posterior surface of thighs, smooth in the rest of hind limbs. Faint dermal fringe or fold running along outer edges of fourth finger, forearm, elbow, fifth toe, tarsus and ankle. White-tipped supracloacal ridge not well developed.

Colour in life of holotype. – Dorsal surfaces of head, body and limbs green with a small number of very fine white spots. Throat , chest, and ventral surfaces of body and limbs yellow. Flanks white, lacking clear white lines that divide dorsal and ventral portions. Axillary and inguinal regions yellow with some poorly defined black spots. White lines present on outer edges of fourth finger, forearm, and elbow. Front of thigh yellow and red-tinged; rear of thigh and inner side of tibia red. White lines on inner and outer sides of tibia forming clear border lines between the green dorsal surface and reddish or yellow underside. White lines present on outer edges of fifth toe, tarsus and ankle. Supracloacal region green, dermal ridge white. Fingers I, II, III and webbing yellow; discs of III and IV reddish yellow; finger IV light green dorsally. Toes I, II, III, and inner half of toe IV red; all toe discs yellow or reddish yellow; toe webbing red; a green, thickened dermal stripe present on web between toes IV and V. Iris silvery, light golden in upper half .

Colour in preservative of holotype. - Ground colour of dorsum becomes greyish-blue with white spots. Tympanum reddish brown. White lines along faint dermal fringe or fold at outer edges of fourth finger, forearm, elbow, fifth toe, tarsus and ankle prominent. No clear flank white lines observed. Ventral region, webbing, concealed and non-green portions of limbs creamy white. Iris greyish-blue.

Measurements of holotype (mm). – SVL 43.4, HL 15.5, HW 17.2, EL 5.8, TD 4.5, ICD 9.1, IND 5.2, IOD 5.2, EW 3.6, ETD 0.3, HLAL 20.6, TFL 7.1, TTL 2.7, OPTL 1.6; ThL 18.2, TiL 18.4, FL 17.8, TaL 9.6, FTL 10.8, and IMTL 2.6.

Variation. – The throat and chest in the paratype is creamy in colour rather than yellow. Measurements of paratype (mm): SVL 43.0, HL 15.2, HW 17.1, EL 5.7, TD 4.5, ICD 9.0, IND 5.5, IOD 5.5, EW 3.4, ETD 0.4, HLAL 21.1 , TFL 7.3, TTL 2.8, OPTL 1.5 ; ThL 18.5, TiL 18.5, FL 18.3, TaL 9.6, FTL 11.0, and IMTL 2.7 .

Etymology. – The specific name is to mark the discovery of this distinctive treefrog from the Yinggeling mountain range of Hainan Island, emphasizing the importance of protecting primary forests in biodiversity conversation. The word “Yinggeling” means “mountain of parrots” in Chinese.

Eggs, Tadpoles, and Call. – Eggs and tadpoles unknown. At the site where the paratype was collected, a frog called at about 2045 hrs. on 1 June.2005. The call was a long series of repeated deep “Auuu” notes, each note lasted about 0.8 second followed by 0.2 second inter-note duration. Two recorded calls lasted four seconds and 14 seconds, respectively. While being held captive in the base camp in the forest, the paratype emitted similar calls during the day and at night in rainy weather.

Distribution and Ecology. – This species is currently known only from high-altitude (at or above 1,300 m) primary rainforest in the Yinggeling mountain range which has the largest remaining primary tropical forest on Hainan Island. The type locality at Mahuoling is a small, flat, well-forested catchment basin at 1,300 m, bisected by a 2 m-wide lowgradient stream. The holotype was collected on leaves of a Pinanga discolor (Palmae) 30 cm above a dried rain pool by the stream. Another individual was also present approximately 15 m upstream from the holotype, also on a shrub with large leaves. Sympatric amphibians include Leptobrachium hainanensis , Limnonectes fragilis , Huia nasuta , Sylvirana spinulosa , Amolops torrentis , Philautus odontotarsus and Microhyla heymonsi .

At the time of the survey, in early spring 2003, the type locality had a daytime temperature of around 20– 240 C, and a night time temperature of 14– 160 C; the basin was always misty and humid. The paratype was found during the day hiding among sedges in a small, dried rain pool along a mountain ridge at 1,550 m. Its dorsum was dull green when collected but changed to bright green at night. The paratype was collected in late spring-early summer, when it rained almost daily; daytime temperature was around 28– 320 C, and night time temperature ca. 24– 260 C. Sympatric amphibians include Philautus odontotarsus , Rhacophorus rodopus and Micryletta sp.

Remarks. – The following treefrogs that have brown, reddish brown, orange red, or grayish brown background colour on dorsum (with additional distinguishing characters in parentheses), can be distinguished from the new species: R. annamensis (outer fingers fully webbed, webbing dark grayish brown dorsally, a pointed projection on heels, usually with two to three long tubercles at infra-cloacal region; Inger et al., 1999), R. appendiculatus (forearm and tarsus with crenulated dermal ridge, white-tipped infra-cloacal fringe present; Inger, 1954), R. baliogaster (ventral surfaces of head and body with conspicuous black spots, females with a rostral cone; Inger et al., 1999), R. bimaculatus (two round black spots at axillary region; outer fingers webbed reaching distal subarticular tubercles; Inger, 1954; Fei, 1999), R. bipunctatus (a pointed projection on heels, axillary spots present; Wilkinson et al., 2005), R. bisacculus (fingers with web remnants, a row of tubercles on underside of arm and another on tarsus; Taylor, 1962; Das & Haas, 2005); R. calcaneus (snout sloping and sharply pointed, heels with a pointed projection, a glandular supratympanic fold; Inger et al., 1999; Das & Haas, 2005), R. colletti (fingers not webbed; Taylor, 1962), R. exechopygus (outer fingers fully webbed, forearm and tarsus with crenulated dermal ridge; Inger et al., 1999), R. hoanglienensis (loreal region dark brown, a pointed projection on heels, dorsum with irregular black and brown spotting, brown line running between the eyes, white lines running from the supratympanic fold to tip of snout through eyelid and canthal ridge; Orlov et al., 2001; Bain & Truong, 2004), R. leucomystax (fingers not webbed), R. megacephalus (fingers not webbed), R. mutus (fingers not webbed), R. naso (a pointed knob at snout, forearm and tarsus with crenulated dermal ridge; Fei, 1999), R. orlovi (dark brown bar between eyes, loreal region and supratympanic fold dark brown with irregular yellow patches; Ziegler & Köhler, 2001), R. rhodopus (a round black spot at axillary region, a squarish supra-cloacal flap and a squarish dermal projection on heels; Fei, 1999), R. translineatus (a pointed knob at snout, outer fingers fully webbed, a pointed projection on heels; Fei, 1999), R. tuberculatus (head and back with large, irregular grey markings; toe webs black; Fei, 1999), R. verrucopus (forearm and tarsus with tuberculous crenulated dermal ridge, a pointed projection on heels, basally fused tubercles transversally arrayed above cloacal opening; Fei et al., 2005), R. verrucosus (forearm and tarsus with crenulated dermal ridge, two to six long whitish tubercles at infra-cloacal region; Inger et al., 1999; Orlov et al., 2001; Ziegler & Köhler, 2001; Fei et al., 2005). Among the other Rhacophorus frogs that have green ground colour on dorsum, the reduced webbing between the outer fingers ( Fig. 4 View Fig ) distinguishes the mediumsized R. yinggelingensis (SVLs 43.0– 43.4 mm) from the large-sized R. dennysi , R. feae , R. kio (Ohler & Delorme, 2006) , R. maximus , and R. reinwardtii (SVLs of these species 68–116 mm; Fei, 1999) that have fully webbed outer fingers. The new species is distinguished from R. omeimontis , R. pingbianensis ( Kou et al., 2001; probably a synonym of P. duboisi according to Orlov et al. [2002]), R. gongshanensis , R. duboisi ( Ohler et al., 2000) and R. dugritei (probably a complex containing R. puerensis [ He, 1999] and R. zhaojuensis [Wu & Zheng, 1994]; see Orlov et al., 2001; Fei et al., 2005) by lack of black or brown spots or patches on dorsum.

The new species seems closely related to R. arvalis , R. aurantiventris , R. chenfui , R. dorsoviridis , R. hungfuensis , R. moltrechti , R. nigropunctatus (probably a synonyum of R. dorsoviridis ; Orlov et al., 2001), R. prasinatus , R. taipeianus , and R. yaoshanensis on the basis of adult morphology. Male R. yinggelingensis has the relatively largest tympanum of which the diameter is 0.78-–0.79 of the eye (vs. 0.41–0.58 in males of listed species based on examined specimens). Orlov et al. (2001), however, found sexual tympanum size dimorphism present in several Vietnamese frogs. A male R. cf. hungfuensis has a large tympanum (about 79% of eye diameter). Rhacophorus arvalis , R. aurantiventris , and R. chenfui have white flank lines that clearly divide dorsal and ventral portions [note: this character is stable in these species according to WHC’s observation but is variable in R. dugritei noted by Bain & Truong (2004)]. In addition, R. arvalis has slightly granulate dorsum and pale purple belly in life; R. aurantiventris has golden yellow iris and orange red belly in life; R. chenfui has purple flanks in life (Liu & Hu, 1961; Fei, 1999) and creamy white belly with brown flecks in preservative, dorsum with fine granules; R. prasinatus has shagreened dorsum and a golden brown stripe extending from midway of canthal ridge to margin of eyelid and supratympanic folds; R. hungfuensis has dark brown iris ( Orlov et al., 2001), yellow flanks, ventral surfaces of limbs and venter in life (Liu & Hu, 1961; Fei, 1999), more granulate dorsal skin, and lacks supra-cloacal white line; R. taipeianus has more granulate skin, relatively indistinct tympanum that is obscured by a layer of skin, and yellow colouration on anterior and posterior margins of thigh; R. nigropunctatus and R. yaoshanensis have weak tuberculous dermal ridge along outer sides of forearm and tarsus; R. dorsoviridis has weak tuberculous dermal ridge along outer sides of forearm and tarsus, variable black spotting at flanks, and orange or reddish brown iris in life ( Orlov et al., 2001); R. moltrechti has red or reddish brown iris and black spots or patches posterior flanks, anterior and posterior margins of thigh, and in some cases, variable spotting on belly, tibia, tarsus, foot and webbing.