Leptobrachella murphyi, Chen & Suwannapoom & Wu & Poyarkov & Xu & Pawangkhanant & Che, 2021

Chen, Jin-Min, Suwannapoom, Chatmongkon, Wu, Yun-He, Poyarkov, Nikolay A., Xu, Kai, Pawangkhanant, Parinya & Che, Jing, 2021, Integrative taxonomy reveals a new species of Leptobrachella (Anura: Megophryidae) from the mountains of northern Thailand, Zootaxa 5052 (2), pp. 191-214 : 200-210

Leptobrachella murphyi sp. nov. Chen, Suwannapoom, Wu, Poyarkov, Xu, Pawangkhanant & Che

( Figures 4–6 )

Chresonymy: Leptolalax sp. — Ohler et al. 2011: 9; Leptolalax sp. 3 — Chen et al. 2018: 165; Leptolalax pelodytoides — Taylor 1962.

Holotype. KIZ034039 , adult male, collected from Ban Huai Wok in Doi Inthanon , Chiang Mai Province, Thailand (98.5348°N, 18.4662°E, 587m a.s.l.; Fig. 1 ), on 17 January 2018 by Chatmongkon Suwannapoom.

Paratype. KIZ034038 , KIZ034165–66 , KIZ034158 , four adult females and KIZ034159 , one adult male from the same locality as the holotype, collected by Chatmongkon Suwannapoom and Yunhe Wu on 17 January 2018 ; KIZ034182–83 , two adult males, from Ban Khun Klang in Doi Inthanon , Chiang Mai Province, Thailand (98.5140°N, 18.6670°E, 1090 m a.s.l.; Fig. 1 ) collected by Yunhe Wu on 19 January 2018 ; KIZ031168 , KIZ031198 – KIZ031200 , four adult males, from Mae Ya Noi in Doi Inthanon , Chiang Mai Province, Thailand (98.5337°N, 18.4939°E, 956 m a.s.l.) collected by Chatmongkon Suwannapoom on 6 August 2018 ; KIZ034225 , one adult male from Ban Khun Wang in Doi Inthanon , Chiang Mai Province, Thailand (98.5049°N, 18.6045°E) collected by Chatmongkon Suwannapoom on 19 January 2018 ; KIZ034173 , one adult male from Pha Dok Siaw Waterfall in Doi Inthanon , Chiang Mai Province, Thailand (98.5305°N, 18.5410°E, 1200 m a.s.l.) collected by Yunhe Wu on 20 January 2018 .

Diagnosis. Leptobrachella murphyi sp. nov. can be distinguished from its congeners by the following combination of morphological characters: (1) body size small (SVL 23.2–24.9 mm in 10 adult males, 29.3–32.1 mm in 4 adult females); (2) tympanum distinct, almost entirely black; (3) skin on dorsum shagreened with reddish tubercles and folds; (4) creamy white belly with small black spots on the margin; (5) distinct reverse-triangle marking between eyes, close to a black W-shaped marking between axillae on the dorsum; (6) distinct black blotches on flanks; (7) white ventrolateral glands forming a distinct line; (8) finger webbing and fringes absent; (9) toe webbing rudimentary and lateral fringes wide; (10) longitudinal ridges distinct under toes and uninterrupted at the articulations; (11) iris distinctly bicolored, typically orange in upper half and silver white in lower half; (12) small pectoral gland embellished on the flesh-colored oval marking; and (13) supratympanic line distinct with reddish pigmentation.

Description of the holotype. Adult male, SVL 24.60 mm; head length almost equal with width (HDL/ HDW=1.03), head triangular in dorsal view; snout rounded in both ventral view and lateral view, protruding slightly beyond lower jaw ( Fig. 4 ); oval-shaped nostril closer to tip of snout than to anterior margin of eye; loreal region oblique; canthus rostralis indistinct; eyes large (EYE/HDL=0.37), eye diameter slightly shorter than snout length (EYE/SNT=0.97), eyes notably protuberant in both dorsal and lateral views, pupil vertical; tympanum distinct, rounded, tympanum diameter smaller than eye (TMP/EYE = 0.57); tympanic annulus notably elevated; vomerine teeth absent; vocal sac openings small, slit-like, located postero-laterally on mouth floor; supratympanic ridge distinct with reddish pigmentation, running from posterior corner of eye towards axilla, posterior end of supratympanic ridge not expanded ( Fig. 4 ).

Forelimb relatively long (FAL/SVL=0.26), fingers long and slender (ML/SVL=0.28), without webbing and lateral fringes ( Fig. 4 ); relative length of fingers: II<I<IV<III; tips of fingers rounded and slightly swollen; subarticular tubercles absent on fingers, inner metacarpal tubercle large and rounded, separated from much smaller outer metacarpal; supra-axillary glands oval. Hindlimb relatively long, tibio-tarsal articulation of adpressed limb reaching beyond eye, but not reaching snout; heels meeting when the tibias perpendicular to the body axis; tibia length less than half of snout-vent length (TIB/SVL=0.46); relative toe length: I<II<V<III<IV; toe tips rounded and slightly swollen; rudimentary webbing present between all five toes; wide lateral fringes present on all toes; subarticular tubercles indistinct under the base of I, II and III toe; distinct dermal ridges present under toes and uninterrupted at the articulations; moderate, oval inner metatarsal tubercle distinct, outer metatarsal tubercle absent ( Fig. 4 ). Dorsal skin relatively rough with small tubercles and short folds with reddish tips; ventral skin smooth; supra-axillary gland distinct and yellowish, located in axillary region dorsally from insertion of forelimb; pectoral gland small and indistinct; round femoral glands present and protuberant on rear of thigh, closer to knee than to vent; ventrolateral glands forming a distinct white line on flanks ( Fig. 4 ).

Coloration of holotype. In life, dorsal surface of head and trunk olive brown, with a distinct reverse-triangle dark markings between eyes connecting to a thick dark W-shaped marking between axillae; elbow to upper arm and tibio-tarsal articulation distinctly yellowish orange in color on the dorsum; transverse black bars present on dorsal surface of fingers and toes, lower arms, tarsus, thighs and tibia ( Fig. 4 ); one dark blotch between nostril and eyes on loreal region; upper lip barred with black and white; supratympanic ridge reddish; a large black marking under supratympanic ridge covers most of tympanum; distinct, irregularly-shaped black blotches present on flanks from the groin to axilla; fine, distinct reddish tubercles scattered on upper eyelids, snout, dorsal surfaces of head, body and limbs. Ventral surface of throat pale with some dusting; ventral surface of belly creamy white with small spots on the margin; ventral surfaces of limbs pinkish, scattered with small white speckles. Ventrolateral glands, pectoral glands and femoral glands yellowish white. Iris distinctly bicolored, typically orange in upper half, silver white in lower half, with black reticulations throughout ( Fig. 4 ). In preservation, dorsal surface of head and trunk dark brown with light tawny limbs. Ventral surface of throat, chest, belly and limbs creamy white; brown dusting present on ventral surfaces of throat. The patterns of dark markings, spots and bars all over the body are same as when in life. Bars and blotches on dorsum and limbs became more distinct. Pectoral glands indistinct; femoral glands distinct and white ( Fig. 5 ).

Morphological variation. All paratypes match the overall characters of the holotype ( Table 3 ). Representative photographs of paratypes in life are shown in Fig. 6 and in preservation are shown in Fig. 5 . Females larger than males (SVL 23.2–24.9 mm in 10 adult males and 29.3–32.1 mm in 4 adult females). All males have small slit-like vocal sac openings, as well as a comparatively large single subgular vocal sac when inflated during calling. Dusting pattern on throat and margin of belly varies individually ( Fig. 6 ). Males have more distinct white flecks dorsum than females ( Fig. 6 ).

Etymology. The specific epithet “ murphyi ” is a patronymic noun in the genitive singular; derived from the name of Prof. Robert W. Murphy from the Royal Ontario Museum, Canada, the co-founder of ColdCode, the international effort to DNA barcode species of amphibians and reptiles. We acknowledge his continuous support and inspiration of our study across the country border from China to Southeast Asia. For the common name, we recommend “Chiang Mai Leaf Litter Toad”.

Distribution and ecology. Leptobrachella murphyi sp. nov. is currently known from two isolated montane areas: Doi Inthanon and Doi Chiang Dao, both belonging to the Thanon Thong Chai Range in Chiang Mai Province, Thailand ( Fig. 1 ). These two sites are separated by a straight-line distance of about 110 kilometers. The known localities in Doi Inthanon for this new species includes Mae Ya Noi, Ban Huai Wok, Ban Khun Klang, Khun Wang 1, Pha Dok Siaw Waterfall and Mae Ya at elevations ranging from 587 to 1477 m a.s.l. During our field surveys, males were usually located at night by their calling while sitting on the litter and leaves of bushes along the streams and waterfalls surrounded by moist evergreen broadleaved forests ( Fig. 7 ). A tadpole of Leptobrachella , which was previously regarded as Leptobrachella sp. (GenBank No. JN848455 ; Ohler et al., 2011) and collected from Doi Chiang Dao, belongs to the new species we describe ( Fig. 2 ). The ecological information on L. murphyi in Doi Chiang Dao is currently insufficient. Advertisement calls of the new species, resembling calling of orthopterans, could be heard along the streams from November to February in Doi Inthanon; a gravid female (KIZ034165) collected in January was swollen with pure white eggs.

Comparisons. Compared with the 26 known congeners occurring south of the Isthmus of Kra, Leptobrachella murphyi sp. nov. can be easily distinguished from L. arayai , L. dringi , L. fritinniens , L. gracilis , L. hamidi , L. heteropus , L. kajangensis , L. kecil , L. marmorata , L. melanoleuca , L. maura , L. picta , L. platycephala , L. sabahmontana and L. sola by the presence of supra-axillary and ventrolateral glands (vs. absence); and from the following miniaturized species it can be distinguished by presence of rounded digit tips (vs. pointed digit tips in all species listed below) and by having an obviously larger body size (SVL 23.2–24.9 mm in males of L. murphyi sp. nov.): L. baluensis (14.9–15.9 mm in males), L. brevicrus (17.1–17.8 mm in males), L. bondangensis (17.8 mm in males), L. fusca (16.3 mm in males), L. itiokai (15.2–16.7 mm in males), L. juliandringi (17.0– 17.2 mm in males), L. mjobergi (15.7–19.0 mm in males), L. natunae (17.6 mm in males), L. parva (15.0– 16.9 mm in males), L. palmata (14.4–16.8 mm in males) and L. serasanae (16.9 mm in female).

Leptobrachella murphyi sp. nov. differs from all other species of Leptobrachella occurring north of the Isthmus of Kra by a combination of small body size, distinct black tympanum, reddish supratympanic line, skin texture and markings on dorsum, ventral coloration, white ventrolateral glands forming a distinct line, degree of webbing and lateral fringes on the toes, distinct black blotches on flanks, longitudinal ridges distinct under toes and uninterrupted at the articulations, small pectoral gland and a bicolored iris ( Table 4 ).

In particular, L. murphyi sp. nov. can be easily distinguished from its phylogenetically close congeners. It differs from L. oshanensis , by having relatively smaller body size in males (SVL 23.2–24.9 mm vs. 26.6–30.7 mm), femoral glands located closer to the knee than to the vent (vs. closer to the vent than to the knee), skin on dorsum shagreened with reddish tubercles and folds (vs. smooth with few glandular ridges), as well as the presence of webbing and dermal fringes on toes (vs. absence). Leptobrachella murphyi sp. nov. differs from L. tengchongensis by having a bicolored iris (vs. uniform), relatively larger body size in females (SVL 29.3–32.1 vs. 28.8–28.9), wide dermal fringes on toes (vs. narrow), ventrolateral glands distinct (vs. indistinct) and ventral side creamy white with small black spots on the margin (vs. ventral surfaces white with dark brown blotches). The new species differs from L. purpurus by having olive brown dorsum coloration in life (vs. purplish brown), creamy white belly with small black spots on the margin (vs. ventral side dull white with indistinct grey dusting), pectoral gland indistinct (vs. distinct), as well as the absence of black marking/spots on dorsum and flanks mottled with distinct yellow pigmentation al. 2017; Yuan et al. 2017; Yang et al. 2018; Chen et al. 2020).

(vs. presence). Leptobrachella murphyi sp. nov. differs from L. purpuraventra by having relatively smaller body size (SVL 23.2–24.9 mm in males, 29.3–32.1 mm in females vs. 27.3–29.8 mm in males, 33.0– 35.3 mm in females), toes with wide lateral fringes (vs. narrow), ventral surface creamy white (vs. grey purple with distinct nebulous greyish speckling on chest and ventrolateral flanks), as well as the absence of dense, tiny conical spines on surface of chest extending to anterior region of abdomen in males (vs. presence). The new species can be distinguished from L. alpina by dorsum olive brown in life (vs. grey brown), indistinct pectoral gland (vs. distinct) and supra-axillary gland yellowish (vs. white). The new species differs from L. bijie by having smaller body size in males (SVL 23.2–24.9 mm vs. 29.0– 30.4 mm), toes with wide lateral fringes (vs. narrow), as well as the absence of distinct nebulous greyish speckling on chest and ventrolateral flanks (vs. presence) and the absence of dense tiny conical spines present on surface of chest in males during breeding season (vs. presence). Leptobrachella murphyi sp. nov. differs from L. eos by having a smaller body size in males (SVL 23.2–24.9 mm vs. 33.1–34.7 mm), olive brown dorsum with black markings and spots in life (vs. almost uniformly brown dorsal coloration), as well as the presence of distinct black spots on flanks (vs. absence) and the presence of distinct supratympanic fold (vs. absence). The new species differs from L. bourreti by having a relatively smaller body size in males (SVL 23.2–24.9 mm vs. 28.0– 36.2 mm), wide dermal fringes on toes (vs. narrow), skin on dorsum shagreened with reddish tubercles and folds (vs. relatively smooth, some with small warts). The new species differs from L. chishuiensis by having smaller body size in males (SVL 23.2–24.9 mm vs. 30.8–33.4 mm). The new species differs from L. dorsospina by having smaller body size in males (SVL 23.2–24.9 mm vs. 28.7–30.5 mm), toes with wide lateral fringes (vs. narrow), as well as the absence of dense conical spines on dorsum (vs. presence). The new species differs from L. jinshaensis by having smaller body size in males (SVL 23.2–24.9 mm vs. 29.7–31.2 mm) and toes with wide lateral fringes (vs. narrow). The new species differs from L. niveimontis by having toes with wide lateral fringes (vs. narrow) and belly creamy white (vs. belly marbled with black speckling). The new species differs from L. suiyangensis by having dermal ridges under toes not interrupted at articulations (vs. interrupted) and smaller body size in males (SVL 23.2–24.9 mm vs. 28.7–29.7 mm). The new species differs from L. wulingensis by having toes with wide lateral fringes (vs. narrow) and dermal ridges under toes not interrupted at articulations (vs. interrupted). The new species differs from L. yeae by having dermal ridges under toes not interrupted at articulations (vs. interrupted) and toes with wide lateral fringes (vs. narrow).

For the remaining known species of Thai Leptobrachella , L. murphyi sp. nov. differs from L. fuliginosa by having a relatively smaller body size in males (SVL 23.2–24.9 mm vs. 28.2–30.0 mm), wide dermal fringes on toes (vs. narrow), distinct femoral glands (vs. narrow), skin on dorsum shagreened with reddish tubercles and folds (vs. skin nearly smooth, with a few tubercles), as well as the absence of dusty ventral side (vs. presence). The new species differs from L. melanoleuca by a relatively smaller body size (SVL 23.2–24.9 mm in males, 29.3–32.1 mm in females vs. 26.6–28.8 mm in males, 32.7 mm in females), creamy white belly with small black spots on the margin (vs. ventral coloration with large black markings on a white background), distinct femoral gland (vs. indistinct) and distinct ventrolateral glandular ridges (vs. indistinct). The new species differs from L. sola by having iris with orange in upper half and silver white in lower half (vs. iris with dark red in upper half and dark brown in lower half), as well as the presence of supra-axillary and ventrolateral (vs. absence). Leptobrachella murphyi sp. nov. differ from L. minima by having a relatively smaller body size in males (SVL 23.2–24.9 mm vs. 25.7–31.4 mm), wide lateral fringes on toes (vs. absent), dorsal skin shagreened with reddish tubercles and folds (vs. mostly smooth) and iris that is orange above and silver white below (vs. dark gold above and grey below). The new species differs from L. zhangyapingi by having a smaller body size in males (SVL 23.2–24.9 mm vs. 45.8−52.5 mm) and creamy white belly with small black spots on the margin (vs. throat, chest, and belly nearly immaculate white).

In addition, L. murphyi sp. nov. further differs from L. pelodytoides , the notoriously “widespread” species of Leptobrachella in Indochina, by having a relatively smaller body size (SVL 23.2–24.9 mm in males, 29.3–32.1 mm in females vs. 27.5–32.3 mm, 35.5–37.8 mm), small pectoral glands (vs. large), distinct dermal ridges under toes (vs. indistinct), ventral surface creamy white with small black spots on the margin (vs. whitish), wide lateral fringes on toes (vs. narrow).

During the final revisions of our paper, two new species of Leptobrachella ( L. shiwandashanensis and L. graminicola ) were described. Morphologically, L. murphyi sp. nov. can be easily distinguished from L. shiwandashanensis and L. graminicola . Leptobrachella murphyi sp. nov. differs from L. shiwandashanensis by having a relatively smaller body size (SVL 23.2–24.9 mm in males, 29.3–32.1 mm in females vs. 26.8–29.7 mm, 33.7–35.9 mm), toe webbing rudimentary and lateral fringes wide (vs without webbing and lateral fringes on toes), heels meeting when the tibias perpendicular to the body axis (vs. not meeting). Leptobrachella murphyi sp. nov. differs from L. graminicola by having dermal ridges on the dorsal surface (vs. dorsal surface lacking dermal ridges), as well as the absence of a dark brown throat with light grey-brown flecks and spots (vs. presence), the absence of a row of large white spots on the outer edge of the tarsus extending from the heel to the inner metatarsal tubercle (vs. presence).

Advertisement call comparisons. The advertisement call of L. murphyi sp. nov. (Results and Fig. 3 ) differs from all other congeners occurring north of the Isthmus of Kra for which comparable acoustic data are available in consisting of uniform and continuous calls with four to five pulses in each note on average and a peak frequency of 4.5–4.7 kHz. Of the congeners in the region with known calls, the new species can be separated from L. purpurus , L. tuberosus , L. puhoatensis and L. yingjiangensis by not having an invariably single-note call with irregular intervals. In addition, the dominant frequency of 4.5–4.7 kHz (at 15.0 °C) further distinguishes the call of L. murphyi sp. nov. from that of the higher frequency calls of L. aereus (6.2–7.9 kHz at 22.4–25.7 °C), L. yingjiangensis (5.7–5.9 kHz at 19 °C), L. bijie (4.8–5.1 kHz at 18.6–19.3 °C), L. shangsiensis (5.5–6.5 kHz at 21.5 °C), L. isos (5.9–6.2 kHz at 22.4–22.8 °C), L. puhoatensis (4.9–5.6 kHz at 22.3–25.8 °C) and L. ventripunctatus (6.1–6.4 kHz at 15 °C), and the lower frequency calls of L. applebyi (4.0–4.3 kHz at 21.5 °C), L. ardens (3.1–3.4 kHz at 21.4–24.7 °C), L. bidoupensis (1.9–3.8 kHz at 19–21 °C), L. botsfordi (2.6–3.2 kHz at 14 °C), L. croceus (2.6–3.0 kHz at 21.6–25.1 °C), L. fuliginosus (2.1–2.8 kHz at 19.3–19.6 °C), L. kalonensis (2.8 kHz at 26.4 °C), L. maculosus (2.7–2.8 kHz at 23.3–24.1 °C), L. melicus (2.6–4.0 kHz at 26.1–26.2 °C), L. pallidus (2.4–2.7 kHz at 14.0–21.4 °C), L. purpurus (4.3–4.5 kHz at 15 °C), L. pyrrhops (1.91–2.2 kHz at 25 °C), L. rowleyae (3.3–3.5 kHz at 21.5 °C), L. tadungensis (2.6–3.1 kHz at 12.9–22.3 °C) and L. tuberosus (2.6–2.8 kHz at 22.5–24.5 °C).

Figures

FIGURE 1. Distribution of Leptobrachella murphyi sp. nov. The known distribution of L. murphyi sp. nov. indicated by the purple dots (1: Type Locality Doi Inthanon, Thailand; 2: Doi Chiang Dao, Thailand).

FIGURE 2. Bayesian phylogram of Leptobrachella inferred from 16S mtDNA gene fragment. “*” denotes high support by Bayesian posterior probabilities (BPP> 0.95), and bootstrap support values (BS> 70%); Nodes without any numbers or symbols represent low support values. Outgroup taxa not shown. Inserted photo showing Leptobrachella murphyi sp. nov. Scale bars represent the number of substitutions per site. New samples for the present study are indicated by the blue font.

FIGURE 3. Advertisement call of Leptobrachella murphyi sp. nov. (A) A 15 s waveform of relative amplitude (Rel. amp.) of male KIZ034159 (recorded at ambient air temperature of 15.0 °C); (B) power spectrum (relative amplitude vs. frequency) and (C) the corresponding spectrogram of the same call; (D) expanded 1.2 s waveform of relative amplitude, (E) corresponding power spectrum and (F) spectrogram of the same call.

FIGURE 4. Holotype of Leptobrachella murphyi sp. nov. (KIZ034039) in life. (A) General dorso-lateral view, (B) dorsal view, (C) ventral view, (D) thenar view of the right hand, (E) plantar view of the right foot, (F) close-up of the iris. Photos by Chatmongkon Suwannapoom.

FIGURE 5. Type series of Leptobrachella murphyi sp. nov. in preservation in dorsal and ventral aspects. Photos by Jin-Min Chen.

FIGURE 6. Paratypes of Leptobrachella murphyi sp. nov. in life in dorso-lateral (upper row) and ventral (lower row) aspects. A: KIZ034038; B: KIZ034158. Photos by Chatmongkon Suwannapoom.

FIGURE 7. Breeding habitat of Leptobrachella murphyi sp. nov. at the type locality in Doi Inthanon, Chiang Mai Province, Thailand. Photo by Chatmongkon Suwannapoom.