Rhacophorus qiongica, Tang & Xiao & Liu & Wang & Yu & Du, 2024

Tang, Shangjing, Xiao, Fanrong, Liu, Shuo, Wang, Lijun, Yu, Guohua & Du, Lina, 2024, Underestimated species diversity within the Rhacophorus rhodopus and Rhacophorus bipunctatus complexes (Anura, Rhacophoridae), with a description of a new species from Hainan, China, Zoosystematics and Evolution 100 (2), pp. 625-643 : 625-643

Rhacophorus qiongica sp. nov.

Figs 6 , 7 , 8 , 9

Rhacophorus rhodopus — Fei 1999; Fei et al. 2004, 2009, 2010, 2012; Shi 2011; Nguyen et al. 2014.

Rhacophorus bipunctatus — Orlov et al. 2002.

Type material.

Holotype. GXNU YU 000691 , adult male, collected on 14 July 2023 by Lingyun Du from Diaoluo Mt. , Lingshui, Hainan, China (18 ° 43 ' 28 " N, 109 ° 52 ' 12 " E, ca 914 m a. s. l.).

Paratypes. GXNU YU 000690, an adult male, collected at the same time as the holotype from the type locality by Lingyun Du and Jiaqi Luo; GXNU HN 110501 ‒ HN 110503, three adult males, collected on 20 July 2021 by Fanrong Xiao from the type locality; and three adult males ( GXNU YU 000693, GXNU YU 000696, GXNU YU 000697) and an adult female ( GXNU YU 000698) collected on 11 July 2023 by Qiumei Mo and Chunyi Pang from Yinggeling, Hainan, China (19 ° 2 ' 24 " N, 109 ° 34 ' 12 " E, ca 670 m a. s. l.).

Etymology.

The specific name qiongica is derived from Qiong (琼), referring to Hainan, China, and meaning good and beautiful in Chinese. The specific name means that this species is very beautiful, and in China, it is distributed in Hainan. We suggest the English common name “ Hainan flying frog ” and the Chinese common name “ 琼树蛙 (Qióng Shù Wā) ”.

Diagnosis.

The new species is assigned to Rhacophorus by the presence of intercalary cartilage between terminal and penultimate phalanges of digits, terminal phalanges of fingers and toes Y-shaped, the tip of the digits expanded into disks with circummarginal grooves, fingers webbed, tarsal projections present, dermal folds along the forearm and tarsus present, and a horizontal pupil ( Jiang et al. 2019). Rhacophorus qiongica sp. nov. differs from its congeners by a combination of the following characters: 1) medium body size (adult males SVL 35.1‒38.2 mm); 2) dorsal surface red brown; 3) entire web between fingers and toes; 4) webbing between toes purely scarlet; 5) small black blotches on flank; 6) bands on limbs distinct; 7) throat smooth; 8) absence of dermal appendage on snout tip; 9) absence of small black spots on head sides; 10) palm smooth without small tubercles; and 11) tibiotarsal articulation reaching beyond eye.

Description of holotype.

Adult male, body size medium ( SVL 37.8 mm); head width ( HW 13.2 mm) longer than head length (HL 12.0 mm); snout blunt pointed, sloping in profile, protruding beyond the margin of lower jaw in ventral view; snout length (SL 5.5 mm) longer than diameter of eye ( ED 4.4 mm); canthus rostralis distinct, curved; loreal region oblique, concave; nostril oval, lateral, slightly protuberant, slightly closer to tip of snout than to eye; internarial space ( IND 3.8 mm slightly smaller than interorbital distance ( IOD 4.2 mm), nearly equal to the width of the upper eyelid ( UEW 3.6 mm); pupil horizontal; pineal ocellus absent; tympanum distinct ( TD 2.3 mm), rounded, about half eye diameter ( ED 4.4 mm); supratympanic fold narrow, flat; tongue cordiform, attached anteriorly, notably notched posteriorly; choanae oval; vomerine teeth present in two series, touching the inner front edges of the choanae; an internal single subgular vocal sac; a vocal sac opening on the floor of the mouth at each corner.

Forelimbs thin, length of forearm and hand ( FHL 18.2 mm) is about half snout-vent length; relative length of fingers I <II <IV <III; tips of all fingers expand into discs with circummarginal and transverse ventral grooves, disc of finger I smaller than discs of other fingers; entire web between fingers, webbing formula: I 2‒2 II 1 ‒ 1.5 III 1 ‒ 1 IV; subarticular tubercles rounded and prominent, formula 1, 1, 2, 2, proximal one smaller than distal one on the third and fourth fingers; supernumerary tubercles below the base of finger absent; metacarpal tubercle single, inner, oval and prominent (Fig. 7 ).

Hindlimbs slender and long, heels overlapping when legs at right angle to body, tibiotarsal articulation reaching beyond eye; tibia length (TL 18.6 mm) nearly equal to length of forearm and hand ( FHL 18.2 mm), longer than foot length ( FL 16.7 mm), and shorter than length of tarsus and foot ( TFL 25.6 mm); relative length of toes I <II <III < V <IV; tips of all toes expanded into discs with circummarginal and transverse ventral grooves; entire web between toes, webbing formula I 1‒1 II 1 ‒ 1 III 1 ‒ 1 IV 1 ‒ 1 V; subarticular tubercles rounded and prominent, formula 1, 1, 2, 3, 2; supernumerary tubercles absent; single inner metatarsal tubercle, oval (Fig. 7 ).

Dorsal skin smooth with very fine granules; throat and ventral surface of forelimbs smooth; chest, belly, and ventral surface of thighs granular (Figs 6 , 7 ); dermal folds on forearm, tarsus, heels, and vent present.

Coloration in life.

Iris light brown; dorsal surface red brown, mottled with two discontinued rows of dark patches and scattered with small black spots on dorsum; dark brown bands and small black spots on dorsal surface of limbs; upper part of flank orange red and lower part of flank orange yellow, scattered with a few small black blotches; skin of ventral surface semi-transparent, mottled with orange yellow on throat and belly; ventral, anterior, and posterior surfaces of limbs orange yellow; discs of fingers and dorsal surface of fingers I ‒ III orange yellow; discs of toes and toes I ‒ IV red; web between fingers yellow, mottled with red; web between toes completely red.

Color of holotype in preservative.

The color faded, but the pattern remained the same as in life. Dorsal surface brown, with dark patches and spots; dorsal side of limbs barred with dark brown; throat, chest, belly, webbing, ventral surface of limbs, and anterior and posterior parts of thighs faded to yellowish; a few small black blotches on flank.

Sexual dimorphism.

The body size of males is smaller than that of female; adult males have an internal single subgular vocal sac with a pair of slit-like openings on the floor of the mouth at each corner. Additionally, adult males have a milk-white nuptial pad on the inner side of the base of finger I.

Morphological variation.

The number of small black spots on the flank varied among specimens. The holotype GXNU YU 000691 and two paratypes ( GXNU YU 000698 and GXNU HN 110502) have multiple small black spots on flank; paratypes GXNU YU 000690 and GXNU YU 000697 have no black spots on flank; and paratypes GXNU YU 000693 and GXNU YU 000696 have two small black spots on flank (Fig. 8 ). Additionally, dorsal color pattern also varied among specimens, as the two paratypes GXNU YU 000696 and GXNU YU 000698 have yellowish-brown blotches on dorsal surfaces of the body and limbs (Fig. 9 ).

Distribution and ecology.

The species is distributed in Hainan, China and Gia Lai, Vietnam. In Hainan, the species was found usually in shrubs and small arbors at elevations ranging from 600 to 850 m ( Shi 2011; as R. rhodopus ) and called from 19: 00 to 03: 00 every night during the breeding season (from May to July), with a peak at about 22: 00 ( Sun et al. 2017; as R. rhodopus ). The types in this study were found in roadside bushes ca. 1‒2 m above the ground (Fig. 10 ). There were temporary puddles under the bushes, and there is a lake (Tianchi) and a stream nearby the road in the type locality. Chirixalus doriae Boulenger, 1893 , Kurixalus hainanus ( Zhao, Wang & Shi, 2005) , and Polypedates megacephalus Hallowell, 1861 were also found in sympatry at the type locality.

Comparisons.

Currently, there are three known species in the R. rhodopus and R. bipunctatus complexes, namely R. bipunctatus , R. napoensis , and R. rhodopus . The new species differs from R. bipunctatus by smaller body size (male SVL 35.1‒38.2 mm, n = 8 vs. 37.8‒50.4 mm, n = 28; Table 7 ), dorsal surface red brown (vs. green; Fig. 11 ), spots on flanks small (vs. large; Fig. 11 b ), bands on limbs distinct (vs. indistinct), and throat smooth (vs. granular; Bordoloi et al. 2007); from R. napoensis by smaller body size (male SVL 35.1‒38.2 mm [37.1 ± 1.3, n = 8] vs. 39.7‒44.2 mm [41.3 ± 1.8, n = 5]), snout pointed without dermal appendage on tip (vs. snout pointed with a dermal appendage on tip; Fig. 11 ), black spots on flanks small (vs. large; Fig. 11 ), and throat smooth (vs. granular; Fig. 11 ); and from R. rhodopus (Clade C) by black spots on axillar and flanks small (vs. usually large), absence of small black spots on head sides (vs. present; Fig. 12 ), palm smooth without small tubercles (vs. palm rough with rows of small tubercles; Fig. 12 ), smaller tympanum, wider upper eyelid, larger distance between nostril and eye (Table 4 ), and tibiotarsal articulation reaching beyond eye (vs. tibiotarsal articulation reaching eye).

Both the present and previous phylogenetic analyses revealed that R. norhayatiae , R. reinwardtii , R. kio , R. borneensis , and R. helenae are imbedded in the R. rhodopus and R. bipunctatus complexes. The new species can be easily distinguished from these five species by the dorsal surface being red brown (vs. green) and the web between toes being red with no black pigmentation (vs. black pigmentation present).

Figures

Figure 6. Lateral, dorsal, and ventral views of the holotype of R. qiongica sp. nov. (GXNU YU 000691) in life.

Figure 7. Dorsal, ventral, and lateral views of the holotype of R. qiongica sp. nov. (a ‒ c) in preservative and ventral views of its hand (d) and foot (e).

Figure 8. Variation of black spots on flank among paratypes of R. qiongica sp. nov. from Hainan, China.

Figure 9. Dorsal view of paratypes GXNU YU 000696 (a) and GXNU YU 000698 (b) in life.

Figure 10. Habitat of R. qiongica sp. nov. at the type locality.

Figure 11. Dorsal (a. BMNH 1872.4. 17.127, lectophoront from Khasi Hills, India) and lateral (b. CAS 229893, collected from Putao, Kachin State, Myanmar) views of R. bipunctatus, throat (c) and lateral view (d) of R. napoensis (GXNU YU 000170), and throat (e) and lateral view (f) of R. qiongica sp. nov. (GXNU YU 000693). The images of a and b were reproduced from Bordoloi et al. (2007) and Wilkinson et al. (2005), respectively.

Figure 12. Head side and ventral surface of the hand of R. rhodopus (a, b. GXNU YU 090186) and R. qiongica sp. nov. (c, d. GXNU YU 000693).