Raorchestes hekouensis, Du & Xu & Liu & Yu, 2024

Du, Lingyun, Xu, Yuhan, Liu, Shuo & Yu, Guohua, 2024, A new species of Raorchestes (Anura, Rhacophoridae) from Yunnan Province, China, ZooKeys 1192, pp. 213-235 : 213

publication ID	https://dx.doi.org/10.3897/zookeys.1192.106013
publication LSID	lsid:zoobank.org:pub:0A4E2531-A55E-4F94-A479-D051D8A84256
persistent identifier	https://treatment.plazi.org/id/4175879C-5620-49B0-B016-8489657C6069
taxon LSID	lsid:zoobank.org:act:4175879C-5620-49B0-B016-8489657C6069
treatment provided by	ZooKeys by Pensoft
scientific name	Raorchestes hekouensis
status	sp. nov.

Treatment

Raorchestes hekouensis sp. nov.

, Figs 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8

Chresonymy.

Raorchestes gryllus ( Li et al. 2013).

Type material.

Holotype. GXNU YU000159, adult male, collected on 25 March 2019 by Shuo Liu from Liangzi, Hekou, Yunnan, China (22°49'N, 103°44′E, 1200 m a.s.l.; Fig. 1 View Figure 1 ).

Paratypes. Adult female (GXNU YU000160), three sub-adults (GXNU YU000153, GXNU YU000154, and GXNU YU000156) with the same collection information as the holotype, and three adult males (GXNU YU000536, GXNU YU000537 and GXNU YU000538) collected at the same locality as the holotype on 4 April 2023 by Lingyun Du and Shuo Liu.

Etymology.

The specific epithet hekouensis is named after the type locality, Hekou County, Yunnan, China. We suggest "Hekou bush frog" as its English common name, and “Hé Kǒu Guàn Shù Wā ( 河口灌树蛙)” as its Chinese common name.

Diagnosis.

Raorchestes hekouensis sp. nov. is distinguished from all other relevant congeners by a combination of the following characters: (1) small body size (male SLV 16.1-17.5 mm, n = 4; female 21.1 mm, n = 1); (2) tympanum distinct; (3) tips of all fingers and toes expanded into discs with circummarginal grooves; (4) rudimentary webbing on toes; (5) all fingers and toes with lateral dermal fringes; (6) inner metacarpal tubercle present and outer metacarpal tubercle indistinct; (7) heels meeting when limbs held at right angles to body; (8) discs of fingers and toes yellow; (9) male with external single subgular vocal sac; (10) distinct X-shaped dark brown marking on back; (11) inner metatarsal tubercle oval, outer metatarsal tubercle absent.

Description of holotype.

GXNU YU000159, adult male, body size small (SVL 17.5 mm); head wider than long (HW = 6.9 mm, HL = 6.1 mm); snout rounded in profile, projecting beyond lower jaw, snout length almost equal to diameter of eye (SL = 2.4 mm; ED = 2.5 mm); canthus rostralis rounded, loreal region slightly concave; internarial distance slightly less than interorbital distance, and wider than maximum width of upper eyelid (INS = 2.2 mm; IOS = 2.4 mm; UEW = 1.9 mm); tympanum distinct (TD = 1.3 mm); tongue pyriform, with deep notch at posterior tip; vomerine teeth absent; temporal fold distinct; dorsolateral fold absent. Length of forelimb and hand slightly shorter than half of snout-vent length (LAHL = 8.5 mm, SVL = 17.5); relative fingers lengths: I <II <IV <III; tips of all four fingers expanded into discs with circummarginal grooves; lateral dermal fringes on all fingers; subarticular tubercles distinct, rounded; supernumerary tubercles absent; no webbing between fingers; inner metacarpal tubercle present, outer metacarpal tubercle indistinct; nuptial pads present on first and second fingers in male. Hindlimbs relatively slender, thigh length (TIL = 9.2) shorter than tibia length (TL = 11.4), but greater than foot length (FL = 6.6); tibiotarsal articulation reaching anterior of eye when hindlimb stretched alongside body; heels meeting when limbs held at right angles to body; relative toe lengths: I <II <III <V <IV; tips of toes with well-developed discs with circummarginal grooves; all toes with lateral dermal fringes; subarticular tubercles distinct, rounded; supernumerary tubercles absent; rudimentary webbing between toes; inner metatarsal tubercle rounded, outer metatarsal tubercle absent. Dorsal surfaces rough, dorsum, dorsal surface of limbs, snout, between eyes, and upper eyelid shagreened with numerous tubercles; flank of body, dorsal part of forelimbs, thighs, and tibia relatively smooth, scattered with sparse granules; throat, chest, and ventral surfaces of forelimbs smooth; abdomen, underside of thigh, and around vent with granules; dorsolateral folds absent; dorsal, dorsal surface of limbs and around vent with several beige patches.

Coloration of holotype in life.

Dorsal surface yellowish brown, with distinct dark brown X-shaped marking on back; blackish line between eyes; tea-brown spots on both sides of lower jaw; dorsal side of limbs with several brown bands; flank near crotch with distinct black region between two creamy white patches, thighs with similar black patch near groin, next to another creamy white patch; ventral surface of throat, chest, ventral side of limbs, and belly opaque creamy white with small black spots and white tubercles; finger and toe discs yellow (Fig. 4 View Figure 4 ).

Coloration of holotype in preservative.

Dorsal color changed to grayish brown; forelimbs and hindlimbs with black-brown bands; patches or spots blackish brown; abdomen and ventral sides of limbs still milky white with several small black spots (Fig. 5 View Figure 5 ).

Male secondary sexual characteristics.

Adult male with nuptial pads on dorsal surface of first and second fingers and external single subgular vocal sac with slit-like opening at posterior of jaw. White lineae masculinae visible on ventral body.

Variation.

Specimen GXNU YU000160 significantly has more black spots on the abdomen and near the cloaca (Fig. 6 View Figure 6 ), specimen GXNU YU000156 differs from the other seven type specimens (GXNU YU000159, GXNU YU000160, GXNU YU000153, GXNU YU000154, GXNU YU000536, GXNU YU000537, and GXNU YU000538) by pale yellow mid-dorsal vertebral stripe from snout to vent, pale yellow stripe along hindlimbs crossing at vent region, mid-ventral stripe from snout to vent and stripe along forelimbs crossing at breast region (Fig. 7 View Figure 7 ), and the specimen GXNU YU000537 has distinctly darker ground color on the dorsal side, especially on the head (Fig. 8 View Figure 8 ).

Distribution.

Currently known from the type locality, Hekou County, Yunnan Province, China, and Bac Pan, Tuyen Quang, Vietnam.

Habitat.

In Yunnan, Raorchestes hekouensis sp. nov. was found in shrubs and herbs on the edge of a small stream near the road at an elevation of ca 1200 m a.s.l. (Fig. 9 View Figure 9 ) on the nights of 25 March 2019 and 4 April 2023. There were many herbaceous plants near the stream, such as Ageratina adenophora . No male was heard calling and no eggs were observed during our surveys in late March, but there were males calling during our surveys in April. Therefore, the breeding season for this species starts in April.

Remarks.

Raorchestes hekouensis sp. nov. is assigned to the genus Raorchestes based on its molecular phylogenetic position and the following morphological characters: relatively small body size (SVL 15.0-45.0 mm); absence of vomerine teeth; large transparent/translucent vocal sac. Due to the close phylogenetic relationship and distribution (Figs 1 View Figure 1 , 2 View Figure 2 ), we compared the new species with 16 recognized congeners distributed in Southeast Asia, southwestern China, the Himalayas, and northeastern India, as mentioned above. Raorchestes hekouensis sp. nov. is distinguished from all other 16 congeners by a unique combination of characters. A detailed morphological comparison table of currently known Raorchestes species from China is provided (Table 4 View Table 4 ).

Raorchestes gryllus is still considered a member of Raorchestes in Frost (2023), although Poyarkov et al. (2021) suggested that it should be transferred to the genus Kurixalus . Raorchestes hekouensis sp. nov. can be distinguished from K. gryllus based on the following characters: no webbing between fingers (vs rudimentary webbing between fingers), rudimentary webbing between toes (vs little more than half webbed), heel with no pointed appendage (vs heel with small, pointed appendage), snout rounded (vs snout pointed with dermal tip), and series of tubercles along outer side of forearm and foot absent (vs present). Raorchestes hekouensis sp. nov. differs from R. malipoensis by inner metacarpal tubercle present, outer metacarpal tubercle indistinct (vs inner and outer metacarpal tubercle indistinct), heels meeting when limbs held at right angles to body (vs heels not meeting when limbs held at right angles to body); and relative toe lengths: I <II <III <V <IV (vs I <II <V <III <IV). Raorchestes hekouensis sp. nov. is distinguishable from R. huanglianshan by supernumerary tubercles absent (vs present) and lateral dermal fringes on all fingers and toes present (vs absent). Raorchestes hekouensis sp. nov. differs from R. parvulus by length of lower arm and hand slightly shorter than half of body size (vs longer than half of body size) and supernumerary tubercles absent (vs present on third finger). Raorchestes hekouensis sp. nov. differs from R. menglaensis by external single subgular vocal sac in adult male (vs internal single subgular vocal sac), tympanum distinct in male (vs indistinct), and lateral dermal fringes on all fingers and toes present (vs absent). Raorchestes hekouensis sp. nov. differs from R. cangyuanensis by tympanum distinct in male (vs indistinct) and relative toe lengths: I <II <III <V <IV (vs I <II <V <III <IV). Raorchestes hekouensis sp. nov. differs from R. hillisi by head wider than long (vs head longer than wide) and lateral dermal fringes on all fingers and toes present (vs fingers lacking lateral dermal fringes and toes with weak lateral dermal fringes, except outside of toe I and both sides of toe II). Raorchestes hekouensis sp. nov. differs from R. dulongensis by head wider than long (vs head longer than wide), snout rounded (vs pointed), relative toe lengths: I <II <III <V <IV (vs I <II <V <III <IV), and nuptial pad present (vs absent). Raorchestes hekouensis sp. nov. differs from R. longchuanensis by head wider than long (vs head length almost equal to width) and lateral dermal fringes on all fingers and toes (vs lateral dermal fringes only on fingers I and II and no lateral dermal fringes on toes). Raorchestes hekouensis sp. nov. differs from R. andersoni by tibiotarsal articulation reaching anterior of eye (vs tibiotarsal articulation reaching tip of snout), ventral surface of throat, chest, and belly opaque creamy white, with small black spots (vs chest and belly yellowish, with brown punctuations), and flank near crotch with distinct black region between two creamy white patches (vs irregular large black patch on groin, extending to half of side, with two yellow patches). Raorchestes hekouensis sp. nov. differs from R. yadongensis by lacking webbing between fingers (vs fingers with rudimentary webbing) and tibiotarsal articulation reaching anterior of eye when adpressed (vs tibiotarsal articulation reaching tip of snout when adpressed).

Raorchestes hekouensis sp. nov. differs from R. rezakhani by nuptial pad present (vs absent), dermal fringes present on fingers (vs absent), rudimentary webbing between toes (vs webbing moderate, formula: I2-2+II 1¾-2+III1½-3IV2¾ -2-V), and inner metacarpal and inner metatarsal tubercles present (vs absent). Raorchestes hekouensis sp. nov. differs from R. annandalii by snout rounded (vs pointed), supernumerary tubercles in toes absent (vs present), and inner metatarsal tubercle present (vs absent). Raorchestes hekouensis sp. nov. differs from R. shillongensis by inner metatarsal tubercles distinct, outer metatarsal tubercle absent (vs inner metatarsal tubercle indistinct, outer metatarsal tubercle present), and relative toe lengths: I <II <III <V <IV (vs I ≤ II <V ≤ III <IV). Raorchestes hekouensis sp. nov. differs from R. sahai by rudimentary webbing between toes (vs nearly half-webbed in toes) and mid-dorsal line absent (vs dark narrow line originating from interorbital region and extending posteriorly to hindmost part of body). Raorchestes hekouensis sp. nov. differs from R. manipurensis by rudimentary webbing between toes (vs almost 2/3 webbing in toes) and webbing between fingers absent (vs present).