Gracixalus jinggangensis, Zeng, Zhao-Chi, Zhao, Jian, Chen, Chun-Quan, Chen, Guo-Ling, Zhang, Zhong & Wang, Ying-Yong, 2017

Zeng, Zhao-Chi, Zhao, Jian, Chen, Chun-Quan, Chen, Guo-Ling, Zhang, Zhong & Wang, Ying-Yong, 2017, A new species of the genus Gracixalus (Amphibia: Anura: Rhacophoridae) from Mount Jinggang, southeastern China, Zootaxa 4250 (2), pp. 171-185 : 175-183

Gracixalus jinggangensis sp. nov.

Figs. 3 , 4 A

Holotype. SYS a004811, adult male, collected on 24 May 2016 by Ying-Yong Wang and Zhi-Tong Lyu from the Jingzhushan Area (26°29′28.53″ N, 114°04′32.94″ E; 1208 m a.s.l.), Mt. Jinggang, Jiangxi Province, China.

Paratypes. Ten specimens were collected by Ying-Yong Wang, Zhi-Tong Lyu, Jian Wang and Hai-Long He from the same locality as the holotype at elevations between 1100 and 1340 m a.s.l.: SYS a004096, adult female, and two male subadults , SYS a004095 and 4806 were collected on 5 July 2015; seven adult males: SYS a003170, collected on 27 July 2014; SYS a003223, collected on 6 August 2014; SYS a004805, 4807, 4809, 4810 and 4812, collected on 24 May 2016.

Other material examined. Two juveniles from the same locality as the holotype: SYS a003186, collected on 28 July 2014 and SYS a004806, collected on 24 May 2016 .

Etymology. The specific epithet “ jinggangensis ” refers to the locality of the holotype, Mount Jinggang, Jiangxi Province, China. We propose the common English name “Jinggang Tree Frog” for this species.

Diagnosis. Gracixalus jinggangensis sp. nov. is assigned to genus Gracixalus based upon our molecular phylogenetic analyses and the following morphological characters: the presence of an intercalary cartilage between the terminal and penultimate phalanges of digits, tips of digits expanded into large discs bearing circum marginal grooves, vomerine teeth absents, horizontal pupil, tibia length greater than four times width, distance between nostrils less than between eyes, rictal gland connected to the mouth ( Delorme et al. 2005; Rowley et al. 2014), and the back bearing dark X-or inverted V-shape ( Fei et al. 2009)

Gracixalus jinggangensis sp. nov. can be distinguished from its congeners by the following morphological characters: (1) size relatively small, SVL 27.9–33.8 mm in 9 adult males, 31.6 mm in single adult female; (2) head slightly wider than long; (3) vomerine teeth absent; (4) upper eyelid and dorsum lacking spines; (5) supratympanic fold distinct; (6) tympanum distinct; (7) skin of dorsal and lateral surface of head, body and limbs rough, sparsely scattered with tubercles; (8) ventral skin granular; (9) tibiotarsal projection absent; (10) toes with moderately developed webbings, finger webbing rudimentary; (11) brown to beige above, with an inverse Y-shaped dark brown marking extended from interorbital region to central region of dorsum; (12) males with a single subgular vocal sac; (13) males with nuptial pads with barely visible minute granules on dorsal surface of the bases of first and second finger.

Description of holotype. Adult male, dorsoventrally compressed; head width slightly greater than head length (HW: HL = 1.04 mm); snout triangularly pointed in dorsal view, rounded in profile, projecting beyond margin of the lower jaw; canthus rostralis distinct and rounded; loreal region oblique and concave; nostrils oval, significantly protuberant, closer to tip of snout than to the eye; interorbital region flat, interorbital distance slightly broader than internasal distance (IOD: IND = 1.03 mm); eye large, horizontal diameter slightly smaller than snout length (ED: SL = 1.02); pupil horizontal; tympanum distinct, rim weakly developed; tympanum diameter smaller than half of eye diameter (TYD 39% of ED); tympanum very close to the eye; supratympanic fold distinct, extending from posterior corner of eye to a level above insertion of arm; vomerine teeth absent; tongue deeply notched behind; a single subgular vocal sac present.

Forelimb moderately robust; forearm and hand relative long, FAHL 48% of SVL, hand significantly longer than forearm, HAL 31% of SVL; fingers dorsoventrally compressed, webbing rudimentary, with narrow lateral fringes on outer edge of all fingers; relative finger length I <II <IV <III; tips of all fingers with well expanded discs with distinct transverse circum-marginal grooves; disc of third finger large, its width significantly broader than width of distal phalanx of finger III (FDW III:FPW III = 2.04), and slightly larger than tympanum diameter (FDW III: TYD = 1.10); subarticular tubercles markedly elevated and prominent, rounded, one on finger I and II, two on finger III and IV; supernumerary tubercles present; prepollex distinct, oval; two nuptial pads with barely visible minute granules present on the first two fingers; nuptial pad on dorsolateral surface of first finger strongly dilated, extending from hand base to level of subarticular tubercle; nuptial pad on dorsal surface of base of second finger relatively small and slightly dilated; several tubercles on palmar, the outer palmar tubercle largest.

Hindlimb long, TIB 46% of SVL, FTL 66% of SVL; tibio-tarsal articulation reaching the middle eye when hindlimb adpressed along the side of the body; heels just meeting when the flexed hindlimbs are held at right angles to the body axis; toes moderately long, relative toe lengths I <II <III <V <IV; tips of toes with expanded discs with distinct transvers circum-marginal grooves; discs of toes smaller than those of fingers; subarticular tubercles distinct, rounded, one on finger I and II, two on finger III and V, three on finger IV; webbing formula I (2), (2½) II (1¾), (3) III (2), (3) IV (3), (2) V; sole smooth with small tubercles; inner metatarsal tubercle elongated, ellipsoid; outer metatarsal tubercle absent; inner tarsal fold absent.

Skin of dorsal surface of head, body and limbs rough, sparsely scattered with tubercles; temporal region and corner of the mouth densely covered with large tubercles; pectoral and subgular skin smooth with barely visible granules; belly granular; anterior surface of hindlimbs smooth, posterior and ventral surface of hindlimbs with tubercles, slightly smooth; tarsal fold absent.

Measurements of holotype (in mm). SVL 33.8, HL 11.6, HW 12.1, SL 4.9, IND 3.8, IOD 3.8, ED 5.0, TYD 2.0, TED 0.3, HAL 10.5, FAHL 16.2, TIBL 15.5, FTL 22.4, FDW III 2.2, FPW III 1.1, TDW IV 1.4, TPW IV 1.0.

Coloration of holotype in life. Brown above, with an inverse Y-shaped dark brown marking, starting at the interorbital region, bifurcating into two branches on the shoulder, extending posteriorly; dorsal surface of arm without dark bands, dorsal surface of limbs with dark brown transverse bands; several faint, large dark blotches on ventrolateral region of flanks arranged in a longitudinal row; ventral surface of throat, chest and forelimbs dirty white with small dark specks; belly white anteriorly with large dark blotches, translucent posteriorly and yellowish; ventral surface of hindlimbs brown; iris golden; pupil black.

TABLE ³. Measurements (minimumDmaximum (mean ± SD); in mm), anđ bođy proportions of Gracixalus jinggangensis sp. nov. anđ G. jinxiuensis .

Gracixalus jinggangensis sp. nov. Gracixalus jinxiuensis

SEX males, n= 9 female, n= 1 males, n= 4 females, n=3

SVL 27.9D33.8 (30.9 ± 2.0) 31.6 24.2D26.3 (25.5 ± 1.0) 28.0D29.2 (28.6 ± 0.6)

9.8D11.6 (10.6 ± 0.6) 10.4 8.9D10.0 (9.5 ± 0.5) 9.8D10.2 (10.0 ± 0.2)

10.5D12.1 (11.3 ± 0.7) 11.2 9.4D10.5 (10.1 ± 0.5) 10.1D10.5 (10.3 ± 0.2)

4.2D5.0 (4.4 ± 0.3) 4.4 3.4D3.8 (3.6 ± 0.1) 3.8D3.9 (3.8 ± 0.1) IND 3.1D3.8 (3.4 ± 0.2) 3.6 2.7D3.0 (2.8 ± 0.1) 2.9D3.1 (3.0 ± 0.1) IOD 3.6D3.9 (3.8 ± 0.1) 3.9 3.2D3.5 (3.4 ± 0.1) 3.3D3.7 (3.5 ± 0.2)

4.0D5.0 (4.3 ± 0.3) 4.1 3.4D3.6 (3.4 ± 0.1) 3.5D3.6 (3.5 ± 0.1) TYD 1.8D2.1 (1.9 ± 0.1) 2.1 1.5D1.9 (1.7 ± 0.2) 1.6D1.7 (1.6 ± 0.1) TED 0.3D0.7 (0.4 ± 0.1) 0.3 0.4D0.6 (0.5 ± 0.1) 0.4D0.6 (0.5 ± 0.1) FAHL 13.8D16.2 (15.4 ± 0.8) 15.5 12.3D14.3 (13.2 ± 0.8) 12.2D13.2 (12.8 ± 0.5) HAL 8.7D10.6 (9.9 ± 0.6) 10.2 7.6D8.3 (8.0 ± 0.3) 7.6D8.2 (8.0 ± 0.3) TIBL 13.9D15.5 (14.9 ± 0.5) 15.3 12.5D14.31 (13.2 ± 0.8) 13.4D14.5 (13.8 ± 0.6) FTL 20.0D22.4 (21.0 ± 0.8) 21.0 17.0D20.0 (18.3 ± 1.3) 18.08D18.72 (18.34 ± 0.33) FDW III 1.5D2.2 (1.9 ± 0.2) 1.9 1.0D1.4 (1.3 ± 0.20) 1.2D1.3 (1.3 ± 0.1) FPW III 0.8D1.1 (1.0± 0.1) 0.9 0.4D0.72 (0.6 ± 0.2) 0.5D0.6 (0.5 ± 0.1) TDW IV 1.3D1.8 (1.5 ± 0.2) 1.9 0.7D1.3(1.0 ± 0.2) 1.0D1.1 (1.1 ± 0.1) TPW IV 0.9D1.1 (1.0 ± 0.1) 0.8 0.5D0.7 (0.6 ± 0.1) 0.6

:SVL 0.33D0.35 (0.34 ± 0.01) 0.33 0.37D0.38 (0.37 ± 0.01) 0.33D0.36 (0.35 ± 0.02) HW:SVL 0.36D0.38 (0.36 ± 0.01) 0.36 0.38D0.41 (0.40 ± 0.01) 0.34D0.37 (0.36 ± 0.01) HW:HL 1.03D1.09 (1.06 ± 0.02) 1.08 1.04D1.08 (1.06 ± 0.02) 1.01D1.03 (1.02 ± 0.01):HL 0.40D0.43 (0.42 ± 0.01) 0.42 0.36D0.39 (0.38 ± 0.02) 0.37D0.40 (0.38 ± 0.02) IND:HW 0.29D0.32 (0.31 ± 0.01) 0.32 0.26D0.29 (0.28 ± 0.01) 0.28D0.30 (0.29 ± 0.01) IOD:HW 0.31D0.36 (0.34 ± 0.02) 0.35 0.32D0.35 (0.33 ± 0.01) 0.32D0.36 (0.34 ± 0.02):SL 0.95D0.99 (0.97 ± 0.01) 0.94 0.94D0.99 (0.96 ± 0.02) 0.90D0.95 (0.92 ± 0.03):HL 0.39D0.43 (0.40 ± 0.01) 0.40 0.34D0.38 (0.36 ± 0.02) 0.34D0.36 (0.35 ± 0.01) TYD:HL 0.17D0.21 (0.18 ± 0.01) 0.20 0.16D0.19 (0.18 ± 0.02) 0.15D0.17 (0.16 ± 0.01) FAHL:SVL 0.48D0.53 (0.50 ± 0.02) 0.49 0.51D0.54 (0.52 ± 0.02) 0.42D0.47 (0.45 ± 0.03) HAL:SVL 0.31D0.34 (0.32 ± 0.01) 0.32 0.31D0.32 (0.31 ± 0.01) 0.26D0.29 (0.28 ± 0.02) TIBL:SVL 0.46D0.50 (0.48 ± 0.02) 0.49 0.51D0.55 (0.52 ± 0.02) 0.46D0.51 (0.48 ± 0.02) Coloration of holotype in preservative. Dark reddish brown above; ventral surface of head and body yellowish white; all spots, Y-shaped marking and transverse bands black, and are more distinct than in life.

Variation. The external morphology and color pattern of all paratypes corresponds to that of the holotype, except for the following exceptions: toe webbing in the female, I (2), (2½) II (1½), (3) III (1½), (3) IV (3), (1¾) V, is more developed than in males; the toe discs in the female are relatively larger than those in males (TDW IV:TPW IV 2.26 in female, 1.32–1.79 in males); adult males collected in the breeding season (SYS a004805, 4807–4812, 4808) possess nuptial pads on the dorsal surface of first and second fingers, but specimens collected in the non-breading season (SYS a003170, 3223) have barely visible nuptial pads; tibio-tarsal articulation reaches the region between the eye and nostril when the hindlimbs are adepressed along the side of the body in subadult SYS a004095. Measurement and body proportions of the type series of G. jinggangensis sp.nov. are given in Table 3.

Distribution, ecology and behavior. Currently, Gracixalus jinggangensis sp. nov. is only known from the Jingzhushan area, located in Mt. Jinggang, Jiangxi Province, China. It appears to be restricted to bamboo forest at elevations between 1100–1340 m a.s.l. Seven specimens were found in bamboo, about 1.0–2.0 m above the ground, six on the leaves of plants in the genera Reynoutria , Camellia and Urtica ., ca. 0.4–1.2 m above the ground. Eggs and tadpoles were not found. Breeding sites were not detected. The breeding season of the new species includes May and June, all adult males, collected in May 2016 (SYS a004805, 4807–4812), possessed nuptial pads and well-developed testes; and males at this time were frequently heard calling. In addition, two juveniles were found, one (SYS a003186 with SVL 16.6 mm) was found on a leaf at a height of 0.2 m above the stream; another was found on a leaf at a height of 0.3 m at a distance of 2.5 m away from the stream on 19 October 2010. Specimens collected later in the year did not appear reproductively active; two adult males, collected from late July to early August (SYS a003170 and SYS a003223) had fat bodies and atrophied testis and barely visible nuptial pads, and the single adult female collected in early July had fat bodies, visible fallopian tubes, and barely visible ovaries. In addition, only a few males occasionally emitted erratic advertisement calls at this time.

Advertisement calls. We recorded the calls of the male holotype SYS a004811 in bamboo forest at an ambient air temperature of 17.6 °C. The call of G. jinggangensis sp. nov. is composed of an introductory note followed by two uniform ‘click’ notes, together being 447–0.511 ms duration (mean 496 ± 21 ms, N = 10; Fig. 6 ). The introductory note has a duration of 158–219 ms (mean 196 ± 20 ms, N = 10), and the two click notes each have a duration of 47–67 ms (mean 57 ± 6 ms, N = 20). The interval between the introductory note and the first click note has a duration of 81–92 ms (mean 85 ± 6 ms, N = 10), and the interval between two click notes is of 100–111 ms duration (mean 105 ± 4 ms, N = 10). Occasionally, the call of G. jinggangensis sp. nov. has three click notes (about 35%) of 597–620 ms duration (mean 609 ± 9 ms, N = 10). In these calls, the introductory note has a duration of 147–181 ms (mean 162 ± 11 ms, N = 10), and the three click notes each have a duration of 42–57 ms (mean 48 ± 5 ms, N = 30). The interval between the introductory note and the click note is 69–110 ms (mean 84 ± 13 ms, N = 10), and the interval between first and second and the second and third click notes respectively is 88–108 s (mean 100 ± 8 ms, N = 10) and 94–126 ms (mean 109 ± 12 ms, N = 10). Note-intervals gradually increase in duration from the beginning to the end of each call. The call contains multiple harmonics. Both types of call have a broad frequency range of 2.0–3.1 kHz ( Fig. 6 ), with a dominant frequency of 2.6 kHz.

Comparisons. Gracixalus jinggangensis sp. nov. appears to be most closely related to G. jinxiuensis , but differs from the species ( Fig. 4 B and Table 3) by having a relatively larger size, SVL 27.9–33.8 mm in adult males, 31.6 mm in single adult female (vs. 24.2–26.3 mm in males, 28.0– 29.2 mm in females in G. jinxiuensis ); formula of webbing of the fourth toe is (3) IV (3), more developed than those in G. jinxiuensis ((3½) IV (3½) in the latter); nuptial pads on first and second fingers of the males (vs. only on first finger in G. jinxiuensis ); sole of foot and palmar smooth with sparse small tubercles (vs. rough with dense large tubercles in G. jinxiuensis ). The new species differs from G. carinensis by having a relatively smaller size, maximum SVL 33.8 mm (vs. 38 mm in G. carinensis ), snout slightly longer than diameter of eye (vs. shorter in G. carinensis ), and ventral surface of body with dark marbling (vs. immaculate white in G. carinensis ). The new species differs from G. nonggangensis by having a tibio-tarsal articulation reaching the middle eye or the region between the eye and nostril (vs. reaching the tip of snout in G. nonggangensis ), background color of dorsal surface of head, body and limbs brown to beige in life (vs. yellowish-olive in G. nonggangensis ), webbing on both sides of fourth toe formula (3) IV (3), more developed than those in G. nonggangensis (vs. (3½) IV (3+) in the latter); the presence of nuptial pads on first and second finger in adult males (vs. absent in G. nonggangensi s). The new species differs from G. waza by having a relatively smaller size of female, SVL 31.6 mm (vs. 37.6 mm in G. waza ), heels just meeting when the flexed hindlimbs held at right angles to the body axis (vs. overlapping in G. waza ), background color of dorsal surface of head, body and limbs brown to beige in life (vs. greyish green to moss-green in G. waza ), the presence of nuptial pads on first and second fingers in adult males (vs. only on first finger in G. waza ); presence of a single subgular vocal sac in males (vs. a pair of vocal sac openings in G. waza ).

Gracixalus jinggangensis sp. nov. can be easily distinguish from the five members of Clade I ( Fig. 2 ). It differs from G. seesom by having a relatively larger size, SVL 27.9–33.8 mm in adult males, 31.6 mm in the adult female (vs. 21.6–23.0 mm in males, 23.2–25.4 mm in females in G. seesom ), a single subgular vocal sac in males (vs. a pair of vocal slits in G. seesom ), first and second fingers with nuptial pads (vs. absent in G. seesom ), dorsal skin rough with tubercles (vs. nearly smooth in G. seesom ); from G. quangi by having relatively large size, SVL 27.9– 33.8 mm in adult males, 31.6 mm in the adult female (vs. 21.4–22.9 mm in males, 26.8–27.3 mm in females in G. quangi ), spines on upper eyelid absent (vs. present in G. quangi ), tibiotarsal projection absent (vs. present a tibiotarsal projection in G. quangi ), background color of dorsal surface of head, body and limbs brown to beige in life (vs. greenish to brownish green in G. quangi ); from G. gracilipes by having background color of dorsal surface of head, body and limbs brown to beige, with inverse Y-shaped dark brown marking on back in life (vs. transparent green with X-shaped brown marking in G. gracilipes ), the absence of white patch under the eye to the tympanum (present in G. gracilipes ), spines on upper eyelid absent (vs. present in G. gracilipes ); from G. supercornutus by having background color of dorsal surface brown to beige (vs. yellowish green in G. supercornutus ), the absence of white patch under the eye to the tympanum (present in G. supercornutus ), spines on upper eyelid absent (vs. present in G. supercornutus ), tibiotarsal projection absent (vs. present a tibiotarsal projection in G. supercornutus ); from G. quyeti by having head broader than long (vs. head longer than wide in G. quyeti ), heels just meeting when the flexed hindlimbs held at right angles to the body axis (vs. overlapping in G. quyeti ), background color of dorsal surface of head, body and limbs brown to beige (vs. brownish to moss-green in G. quyeti ).

Gracixalus jinggangensis sp. nov. differs from G. lumarius , which formed Clade III in our phylogenetic tree, by having a relatively smaller size, SVL 27.9–33.8 mm in 9 adult males, 31.6 mm in single adult female (vs. 38.9– 41.6 mm in males, 36.3 mm in females in G. lumarius ), skin on dorsal surface of head, body rough, sparsely scattered with brown tubercles (vs. with dense network of conical tubercles in adult males in G. lumarius ), venter with white to yellowish with dark colored specks and blotches (vs. pink in G. lumarius ), nuptial pads on first and second fingers in males present (vs. absent in G. lumarius ), and the presence of a single subgular vocal sac in males (vs. a pair of vocal sacs in G. lumarius ).

Gracixalus jinggangensis sp. nov. differs from G. medogensis , the only species not included in our phylogenetic tree, by having a background color of brown to beige on the dorsal surface (vs. green in G. medogensis ), dorsal skin rough (vs. smooth in G. medogensis ), heels just meeting when the flexed hindlimbs held at right angles to the body axis (vs. significantly overlapping in G. medogensis ), nuptial pads on the first and second fingers in males present (vs. only on first finger in G. medogensis ).

Figures

FIGURE 2. Bayesian inference tree derived from partial DNA sequences of the mitochondrial 16 S rRNA gene with Bayesian posterior probabilities (BPP> 70 % retained) and maximum-likelihood bootstrap values (1000 replicates; BS> 60 retained), respectively.

FIGURE 3. The adult male holotype SYS a 004811 of Gracixalus jinggangensis sp. nov. in life. A: showing a single subgular vocal sac; B: the general aspect; C: ventral view; D: showing nuptial pads with barely visible minute granules on dorsal surface of first and second fingers; E: ventral view of the hand; D: ventral view of the foot.

FIGURE 4. Comparison of morphological characters of adult females in life between A: Gracixalus jinggangensis sp. nov. and B: G. jinxiuensis. A 1: the general aspect, A 2: ventral view, A 3 and A 4: the ventral view of the fore- and hind limb of paratype SYS a 004096. B 1 and B 2: the general aspect and ventral view of the specimen SYS a 002184; B 3 and B 4: ventral views of fore- and hind limb of the specimen SYS a 002182.

FIGURE 6. Two types of advertisement call of a male Gracixalus jinggangensis sp. nov (the holotype SYS a 004811) recorded at ambient air temperature of 17.6 ° C. A: The advertisement call composed of an introductory note followed by two ‘ click’ notes. B: The advertisement call composed of an introductory note followed by three click notes.