Megophrys (Panophrys) rubrimera, Tapley & Cutajar & Mahony & Nguyen & Dau & Nguyen & Luong & Rowley, 2017

Tapley, Benjamin, Cutajar, Timothy, Mahony, Stephen, Nguyen, Chung Thanh, Dau, Vinh Quang, Nguyen, Tao Thien, Luong, Hao Van & Rowley, Jodi J. L., 2017, The Vietnamese population of Megophrys kuatunensis (Amphibia: Megophryidae) represents a new species of Asian horned frog from Vietnam and southern China, Zootaxa 4344 (3), pp. 465-492 : 473-481

Megophrys (Panophrys) rubrimera sp. nov.

Figs. 2 , 3 , 4 , 5 & 6 ; Table 3.

–– Megophrys kuatunensis Orlov et al. 2000:10 (partim: Megophrys cf. kuatunensis “Mount Fan Si Pan, Hoang Lien Range (Sa Pa District, Lao Cai Province)”; Orlov et al. 2002:83 (partim: “northern Vietnam”); Nguyen et al. 2009:88 (partim: Sa Pa District, Lao Cai Province, Vietnam).

Holotype: VNMN 2017.002 adult male calling beside a 1 m wide rocky stream (stream bed 5–6 m wide) in heavily disturbed evergreen forest, Sa Pa District, Lao Cai Province, Vietnam (22.38205°N, 103.78745°E, 1708 m asl; Fig. 1 ). Collected at 22:15 h on 18 June 2012 by Jodi J. L. Rowley, Dau Quang Vinh, Pham Van Sang, Tran Van Tu, Hang A Su, Hoang A Di and Dinh Van Xuan.

Paratypes: Two male specimens ( VNMN 2017.003, AMS R177676) collected from a 3.5 m wide rocky stream in slightly disturbed evergreen forest, Sa Pa District, Lao Cai Province, Vietnam (22.39829°N, 103.78545°E, 1400 m asl; Fig. 1 ) on 17 June 2012 by Jodi J. L. Rowley, Dau Quang Vinh, Pham Van Sang, Tran Van Tu, Hang A Su, Hoang A Di and Dinh Van Xuan. One adult male specimen (AMS R177675) collected from disturbed habitat; a 2 m wide rocky stream in slightly disturbed evergreen forest, Sa Pa District, Lao Cai Province, Vietnam (22.38208°N, 103.78699°E, 1722 m asl) between 22:00 and 22:30 h on 22 June 2016 by Jodi J. L. Rowley, Benjamin Tapley and Nguyen Thanh Chung. Three adult male specimens (AMS R177677, AMS R177678 and AMS R177679) collected from disturbed habitat; a steep north-easterly facing road side bank with seepages and a small stream, with evergreen forest nearby, Sa Pa District, Lao Cai Province, Vietnam (22.3809°N, 103.78798°E, 1714 m asl; Figs 1 & 7 C–E) between 22:00 and 22:30 h on 23 June 2016 by Jodi J. L. Rowley, Benjamin Tapley and Nguyen Thanh Chung.

Referred specimens: One adult male specimen (field tag JJLR03813 - HNLP2016062200001 ) collected from disturbed habitat; a 2 m wide rocky stream in slightly disturbed evergreen forest, Sa Pa District, Lao Cai Province, Vietnam (22.38208°N, 103.78699°E, 1722 m asl) between 22:00 and 22:30 h on 22 June 2016 by Jodi J. L. Rowley, Benjamin Tapley and Nguyen Thanh Chung. Specimen deposited at Hoang Lien National Park Headquarters, Vietnam . Tadpole specimen (AMS R177680) collected from a pool in a 2 m wide rocky stream in slightly disturbed evergreen forest, Sa Pa District, Lao Cai Province, Vietnam (22.38208°N, 103.78699°E, 1722 m asl) between 22:00 and 22:30 h on 22 June 2016 by Jodi J. L. Rowley, Benjamin Tapley and Nguyen Thanh Chung. The pH of the water body was 7.7, alkalinity 0.1 ppm and the water temperature was 17.6 °C.

Etymology: The specific name “ rubrimera ”, an invariable noun in apposition, derived from the Latin word ruber (prefix rubri-) meaning red, and the Latinised version of the Greek noun mera, meaning thigh, in reference to the bright red-orange colouration of the groin, and the inner and outer thighs of the new species.

Suggested vernacular name: Red-thighed horned frog (English), Cóc sừng đùi đỏ (Vietnamese)

Diagnosis: Assigned to the genus Megophrys on the basis of tadpole morphology; tadpoles have dorsally orientated umbelliform oral discs (Dubois & Ohler 1998; Li et al. 2011), which is diagnostic for the genus within Megophryidae ; and to the subgenus Panophrys on the basis of molecular data.

Megophrys rubrimera sp. nov. differs from its congeners by a combination of the following morphological characters (based on eight adult males): (1) small size (SVL 26.7–30.5 mm); (2) very small palpebral horn on upper eyelid; (3) toes lacking interdigital webbing but possessing narrow lateral fringes; (4) tympanum diameter: eye diameter 58.0–76.0 mm; (5) shank length: snout vent length 48.0–56.0%; (6) groin, inner surface of thighs and outer surface of shanks red-orange; (7) absence of subarticular tubercles on fingers and toes; (8) red-orange inner metatarsal tubercle; (9) head width greater than head length; (10) head width: snout vent length 38.0–42.0%; (11) weakly defined vomerine ridges with teeth; and (12) an advertisement call with a dominant frequency of 3.23 kHz.

Description of holotype: Sexually mature male ( Figs. 2 & 3 ). Head small, wider than long; the snout rounded in dorsal view and obtusely protruding in lateral view, rostral appendage absent ( Figs. 3A & 4G ); loreal region vertical and concave; canthus rostralis angular; dorsal region of the snout is slightly concave; eye diameter nearly twice the maximum tympanum diameter and subequal to snout length; eye-tympanum distance is smaller than the maximum tympanum diameter; tympanum round and orientated vertically. Pupil in life oval, vertically orientated when dilated; nostril orientated laterally, closer to eye than snout; internarial distance exceeds eyelid width, and subequal to narrowest point between upper eyelids; weakly defined vomerine ridges present, oblique and barely separated anteriorly with small vomerine teeth; maxillary teeth present. Tongue moderately large and not clearly notched posteriorly.

Forelimbs short and stocky, forearm length shorter than hand length; fingers short and wide without lateral fringes ( Fig. 3B ), finger length formula I <II <IV <III; interdigital webbing absent, subarticular tubercles absent, palmar tubercles absent; supernumerary tubercles absent, but skin raised on articulations of Fingers III, IV; thenar tubercle absent; finger tips slightly expanded and flattened to oval pads; terminal grooves absent. Hind limbs relatively short and stocky; thigh longer than shank, and longer than foot; toes relatively short and wide, lateral fringes present ( Fig. 3C ); toe tips very slightly dilated, terminal groves absent; toes not webbed; outer metatarsal tubercle, subarticular and supernumerary tubercles absent; inner metatarsal tubercle prominent.

Skin of dorsal surfaces of body, limbs, and dorsal and lateral surfaces of head weakly granular; tympanum granular with its borders slightly raised; very small pointed tubercle present on outer edge of upper eyelid; supratympanic fold narrows as it passes above the tympanum, terminating above axilla, supratympanic fold with many dark asperities along its crest ( Fig. 4A ); flanks with small scattered tubercles, some of which terminate in darkened asperities; thin dorsolateral fold extending from behind supratympanic fold to approximately threequarters distance to groin; a weak, “V”-shaped parietoscapular ridge present, its two sides extending posteriorly from above tympanum and meeting medially beyond level of axilla; a second inverted “U”-shaped ridge present on mid-dorsum which joins laterally with dorsolateral folds ( Figs. 2A & 4A ); ridges with some dark asperities; small tubercles tipped with dark asperities on dorsal surface of shanks, and arranged into distinct transverse rows on the thighs and forearms. Large distinct tubercles present in the inguinal region; gular region, chest and ventral surfaces of limbs smooth; pectoral glands obvious, small, slightly raised, positioned on level with axilla ( Figs. 2B & Fig. 4D ); femoral glands small, slightly raised, one positioned equidistant from knee and cloaca on the posterior surface of each thigh.

Colour of holotype in life ( Figs. 4A–B, D & F ): Dorsally light tan; darker “Y”-shaped marking on dorsum between the eyes, border of marking beige; vertical dark brown bar below eyes; lateral surface of the eyelid dark with a single medial light bar; tympanum dark brown; hind and forelimbs possess dark tan bars, darker on the forelimbs than the hind limbs; tubercles on flanks encircled by darker tan; groin red-orange; gular and pectoral region grey-brown; abdomen light grey with dark grey blotches and white speckling; ventral surface of thighs pinkish grey with darker blotches; inner thighs and outer surface of shanks red-orange; underside of Fingers III, IV orange; thenar tubercles red-orange; inner metatarsal tubercle on feet red-orange; iris metallic brown.

Colour of holotype in preservative: ( Figs. 2 & 3 ): Majority of dorsal and lateral surfaces of the head, body, forelimbs and hind limbs brown; darker brown “Y”-shaped marking between eyes; darker brown “X”-shaped marking over opposing “V”-shaped and “U”-shaped ridges; dorsolateral folds and flank tubercles bordered by darker margin; front of snout and lateral canthus rostralis dark brown; narrow vertical dark brown bar below eyes and dark brown blotch covering tympanum; upper jaw with darker blotches; two dark brown blotches on the dorsal surface of forearms; dorsal surface of Fingers II, III and IV with dark brown blotches. Gular region, chest and anterior part of abdomen primarily creamy-grey, with grey brown speckling on gular region; abdomen blotched with dark brown; ventral surfaces of thighs with grey brown mottling, and shanks with grey brown speckling; ventral surfaces of feet grey brown; area surrounding vent with dark brown blotches; forelimbs ventrally mottled and blotched with light and dark brown; extending to the ventral surface of hands; inner metatarsal tubercles unmarked and beige, tips of fingers unmarked and beige; tips of toes only lightly speckled with grey brown, if at all; lateral fringe on toes, beige, unmarked; pectoral and femoral glands beige.

Measurements (in mm): Holotype. SVL 29.8, HW 11.2, HL 9.4, SL 3.9, SN 2.0, EN 1.6, EL 3.3, IUE 4.0, UEW 3.1, IFE 3.5, IBE 3.8, TYD 2.0, TYE 1.9, FAL 6.5, HAL 7.5, FIL 2.4, FIIL 2.8, FIIIL 4.1, FIVL 2.9, TL 14.6, SHL 14.4, FOL 13.5, IMT 2.7, weight in life 2.4 g.

Variation: Measurements of the type series are shown in Table 3. Paratypes and referred specimens generally agree with the holotype morphologically, but with the following exceptions: in VNMN 2017.003, AMS R177676 the middorsal “U”-shaped ridge (on the holotype) is replaced by an inverted “V”-shaped ridge. AMS R177676 with distinct dark grey blotches on ventral surface of thighs, this is lacking in VNMN 2017.003 and the holotype specimen. In life, AMS R177676 has a vivid red-orange flash on the axillary region ( Fig. 4G ). Gular region of VNMN 2017.002 and AMS R177678 lack dark blotches, present in all other specimens. Ventral surface of thighs (on AMS R177679 and AMS R177676) are covered in dark blotches, which are not present on any of the other specimens. Tongue weakly notched in one specimen (HNLP2016062200001).

Secondary sexual characters: Females of Megophrys rubrimera sp. nov. are currently unknown. Two male specimens (AMS R177678 and AMS R177679) possessed raised oval nuptial pads covered in microspinules on the base of Finger II; protruding fleshy projection (secondary sexual characteristic of some male Megophrys e.g. M. caudoprocta , M. koui and M. pachyproctus ) above the cloaca absent from all specimens. After fixation it was very difficult to open the mouths of the specimens without damaging them due to the small head size. It was therefore not possible to determine the position, presence or absence of internal vocal slits which are a secondary sexual characteristic used as a diagnostic character to the species level (e.g. Mahony et al. 2013).

Tadpole: ( Fig. 5 ): The following tadpole description is based on a single specimen (AMS R177680) at Stage 37, the tadpole was confirmed as that of M. rubrimera sp. nov. by molecular analysis. Body elongated and slender; nares oval and are closer to the eye than to the snout; internarial distance is subequal to the interorbital distance; eyes positioned dorsolaterally, the pupils are round; the spiracle is sinistral and the spiracular tube protrudes from midway along the body wall just posterior to maximal trunk width and opens laterally; the tail makes up 68% of the total body length; the dorsal tail fin is low, particularly at the proximal half of the tail length; the basal tail width is 60% of the maximal trunk width; the oral disk is subterminal and antero-dorsal; the width of the umbelliform oral disc makes up ~80% of the maximal width of the trunk; the upper and lower lips each have deep medial emarginations; submarginal papillae are present on both sides between the oral orifice and the emarginations of the upper and lower lip, concentrated in a row around the margins; keratodonts are absent.

Colour in life: Dorsally, the head and body are brown with darker speckles; obvious pale neuromasts; the oral disk is translucent yellowish brown with dark brown submarginal papillae; the dorsal and ventral fins opaque, pale yellowish brown with speckles; the venter is speckled white and brown; iris orange, speckled with black dots.

Colour in preservative: Body brown with darker speckles; oral disc translucent grey brown with dark brown submarginal papillae; the dorsal and ventral fins opaque, pale grey brown with darker speckles; the venter is speckled grey and brown.

Tadpole body measurements (in mm): BL 10.5, BH 4.4, BS 4.3, ES 1.7, IND 1.7, IOD 4.1, BW 5.4, ED 1.2, LFH 1.3, MTH 5.9, NE 1.9, ODW 4.5, SN 0.6, SS 5.7, TAL 22.8, TTL 33.3, TMH 3.1, TMW 5.4, UFH 1.3).

Advertisement call: Call descriptions are based on the calls of one paratype (AMS R177677) and two unvouchered individuals. Advertisement calls were recorded at 21.0–22.9 °C ambient temperature. Calls were an average of 73.3 ms (62–85 ms) in duration ( Table 4; Fig. 6 ). Calls of unvouchered individual (b) contained an average of 23.05 pulses (19–25), whereas the calls of AMS R177677 and another unvouchered individual (a) were not distinctly pulsed. The average dominant frequency of calls was 3.3 kHz (3.2–3.4 kHz). Calls were repeated at a rate of approximately 3.25 (3.05–3.37) calls per second, and had an average intercall interval of 221.3 ms (190–261 ms). The number of calls within each call group ranged from 16–51, with an average of 38.7. Most call groups began at a relatively low amplitude, increasing with each call up to approximately a quarter to a third of the duration, after which amplitude remained relatively constant ( Fig. 6A i –ii & B i–ii). Individual calls either began with a medium relative amplitude and peaked near the middle before declining towards the end ( Fig. 6A iii), or peaked at the beginning, steadily declining throughout ( Fig. 6B iii).

Natural history: All specimens of Megophrys rubrimera sp. nov. were found in disturbed evergreen secondary forest. Males were calling during June 2012 and 2016, and tadpoles (Stage 37) were collected in June 2016, suggesting a prolonged breeding season or that the species has a long larval period. Males were observed calling on stream-side vegetation (Fig. 7A–B) and a steep north-eastern facing roadside bank with seepages and a small stream (Fig. 7C–E). Females were not observed.

Distribution and conservation status: This species is known from between 1400 m asl and 1722 m asl at two localities, 2 km apart in Sa Pa District, Lao Cai Province, Vietnam and 50 km north-west at Maandi, Jinping County, Ailao Mountain Range, Yunnan Province, China ( Fig. 1 ; Chen et al. 2017). The species' area of occupancy (AOO) and extent of occurrence (EOO) are currently predicted to be 385 km 2 and 2298 km 2, respectively. The Vietnamese and Chinese portions of this species’ range comprise two threat-defined locations; land use likely differs between the two countries, and habitat loss probably affects the species independently in each. Ongoing disturbance to the species’ habitat due to forest clearance for agriculture has been observed in Sa Pa District. We recommend that Megophrys rubrimera sp. nov. is listed as Endangered in accordance with the IUCN Red List of Threatened Species categories and criteria B1ab(iii).

Comparisons: Megophrys (Panophrys) rubrimera sp. nov. can be distinguished from all other congeners found in mainland southeast Asia, north of the Isthmus of Kra and neighbouring provinces of China on the basis of morphology, and from all congeners for which comparable data is available on the basis of molecular and acoustic data. Comparisons with each subgenus are discussed separately below.

Subgenus Brachytarsophrys : Megophrys rubrimera sp. nov. can be distinguished from the species in the subgenus Brachytarsophrys ( M. carinense , M. feae and M. intermedia ) in mainland southeast Asia and neighbouring provinces of China by the absence of a transverse fold at the base of the head (versus presence), and having a smaller adult male size, SVL 26.7–30.5 mm (versus SVL> 79.1 mm; examined material).

Subgenus Ophryophryne : Megophrys rubrimera sp. nov. can be distinguished from M. elfina by the presence of lateral fringes on the toes (versus absence; Poyarkov et al. 2017) and by the presence of vomerine teeth (versus absence Poyarkov et al. 2017); from M. gerti by having a smaller adult male size, SVL 26.7–30.5 mm (versus 31.7–42.2 mm; Poyarkov et al. 2017; material examined); from M. hansi by having a smaller adult male size, SVL 33.4–43.1 mm; Ohler 2003; Poyarkov et al. 2017; material examined); from M. microstoma by having a smaller adult male size, SVL 26.7–30.5 mm (versus 34.3–44.4 mm; Poyarkov et al. 2017; material examined; from M. koui by the absence of a protruding fleshy projection above the cloaca in sexually mature males (secondary sexual characteristic of sexually mature M. koui ); from M. synoria by having a smaller adult male size, SVL 26.7–30.5 mm (versus 38.2–53.7 mm; Stuart et al. 2006b; Poyarkov et al. 2017; material examined) and further from all species in the subgenus Ophryophryne due to the presence (versus absence) of maxillary teeth.

FFIGURE 7. Megophrys rubrimera sp. nov. in situ, and habitat at collection localities. (A) Adult male paratype AMS R177675 and (B) unvouchered calling male. (C–E) Habitat at type locality in Sa Pa District, Lao Cai Province, Vietnam.

Subgenus Xenophrys : Megophrys rubrimera sp. nov. differs from M. auralensis by having a smaller adult male size, SVL 26.7–30.5 mm (versus 60.1–76.7 mm; Ohler et al. 2002; Neang et al. 2013), and a lack of interdigital toe webbing (versus rudimentary webbing); from M. damrei by having a smaller adult male size, SVL 26.7–30.5 mm (versus 47.5–57.1 mm: Mahony 2011; Neang et al. 2013; material examined), a lack of interdigital toe webbing (versus rudimentary), and the presence of lateral fringes on the toes (versus absence); from M. glandulosa by having a smaller adult male size, SVL 26.7–30.5 mm (versus 76.7–81.6 mm: Fei et al. 2009; material examined), and a lack of interdigital webbing between the toes (versus basal webbing); from M. lekaguli by having a smaller adult male size, SVL 26.7–30.5 mm (versus 55.6–68.1 mm; Stuart et al. 2006a; material examined), a lack of webbing between the toes (versus rudimentary webbing), and the presence of lateral fringes on the toes (versus absence); from M. major by having a smaller adult male size, SVL 26.7–30.5 mm (versus 72.4– 79.4 mm; material examined), a lack of toe webbing (versus at least one quarter webbed), and the absence of a light-coloured upper lip stripe (versus presence); from M. maosonensis by having a smaller adult male size, SVL 26.7–30.5 mm (versus 58.0–76.0 mm; Bourret 1937), the absence of toe webbing (versus toes up to one quarter webbed), and the absence of a light-coloured upper lip stripe (versus presence); from M. pachyproctus by having a larger tympanum to eye ratio, TYM: EYE 58.0–76.0% (versus 29.0%; Huang et al. 1981), and the absence of a protruding projection posterior to cloaca on male specimens (versus presence); from M. parva by having a smaller adult male size, SVL 26.7–30.5 mm (versus 33.9–36.0 mm; material examined), a relatively larger tympanum to eye ratio, TYM: EYE 58.0–76.0% (versus 43.6–55.0%; material examined), and the presence of lateral fringes on the toes (versus absence); from M. takensis by having a smaller adult male size, SVL 26.7–30.5 mm (versus 47.3– 53.0 mm; Mahony 2011), a lack of toe webbing (versus rudimentary webbing), and the presence of lateral fringes on the toes (versus absence)

Subgenus Panophrys: Phylogenentic analysis places Megophrys rubrimera sp. nov. in the subgenus Panophrys . Megophrys rubrimera sp. nov. is most similar, in terms of morphology, to M. kuatunensis with whom it has been confused with in the past, but differs from this species by typically having relatively longer shanks, SHL: SVL 48.0–56.0% (versus 42.7–48.6%; examined material), possessing narrow lateral fringes on the toes (versus absent), the presence of vomerine teeth (versus absence), and advertisement call (see bioacoustic comparison). It could also be mistaken for other small sized (minimum SVL <35.0 mm) species within the subgenus Panophrys but differs from M. acuta by the presence (versus absence) of vomerine teeth, and absence (versus presence) of subarticular tubercles on the base of each finger; from M. binchuanensis by having a smaller adult male size, SVL 26.7–30.5 mm (versus 32.0–36.0 mm; Li et al. 2014) and the presence of vomerine teeth (versus absence); from M. boettgeri by having a smaller adult male size, SVL 26.7–30.5 mm (versus 34.5–38.3 mm; Boulenger 1899; material examined), a lack of toe webbing (versus rudimentary webbing), and advertisement call (see bioacoustic comparison); from M. brachykolos by having a smaller adult male size, SVL 26.7–30.5 mm (versus 33.9–40.5 mm; material examined), possessing narrow lateral fringes on the toes (versus absent), and the presence of vomerine teeth (versus absence); from M. daweimontis by having a smaller adult male size, SVL 26.7–30.5 mm (versus 34.0–37.0 mm; Rao & Yang 1997), the presence of lateral fringes on the toes (versus absence), and Finger I being shorter than the Finger II (versus Finger I being longer than Finger II); from M. minor by having a smaller adult male size, SVL 26.7–30.5 mm (versus 32.2–40.5 mm; Li et al. 2014; examined material), a lack of toe webbing (versus rudimentary webbing), the presence of vomerine teeth (versus absence), and advertisement call (see bioacoustic comparison); from M. wuliangshanensis by the presence of vomerine teeth (versus absence), and the presence of lateral fringes on the toes (versus absence). Megophrys rubrimera sp. nov. differs from larger bodied (SVL> 35.0 mm) species within the subgenus Panophrys , all of which possess interdigital webbing to some degree. Megophrys rubrimera sp. nov. differs from M. jingdongensis by having a smaller adult male size, SVL 26.7–30.5 mm (versus 53.0–57.0 mm; Fei et al. 2012; Li et al. 2014), and a lack of interdigital webbing (versus at least one quarter webbed); from M. latidactyla by having a smaller adult male size, SVL 26.7–30.5 mm (versus 38.9 mm; Orlov et al. 2015), possessing narrow lateral fringes on the toes (versus wide), and the absence of interdigital webbing (versus at least one quarter webbed); from M. omeimontis by having a smaller adult male size, SVL 26.7–30.5 mm (versus 56.0– 60.9 mm; Li et al. 2014; examined material), and a lack of toe webbing (versus rudimentary webbing); from M. palpebralespinosa by having a smaller adult male size, SVL 26.7–30.5 mm (versus 36.2–39.1 mm; Li et al. 2014; examined material), the presence of vomerine teeth (versus absence), and a lack of interdigital webbing between the toes (versus approximately half webbed); from M. spinata by having a smaller adult male size, SVL 26.7–30.5 mm (versus 47.2–54.4 mm; Li et al. 2014), the presence of vomerine teeth (versus absence), the lack of interdigital webbing between toes (versus at least one quarter webbed), and the absence of large keratinised spines on nuptial pads of sexually mature males (versus presence).

Bioacoustic comparison: The male advertisement call of Megophrys rubrimera sp. nov. differs from those of its seven congeners (subgenus Panophrys ) for which calls have been described. The male advertisement call of Megophrys rubrimera sp. nov. differs from M. acuta by having a call duration of 62–85 ms (versus 106–172 ms), 16–51 calls per call group (versus 7–9), an intercall interval of 190–261 ms (versus 335–747 ms), a call repetition rate of 3.05–3.37 calls/s (versus 1.87–2.04 calls/s), and relatively high amplitude variation within calls (versus relatively constant amplitude within calls) at 21.0–22.9 °C (versus 26.9 °C); from M. boettgeri by having an average call duration of 73.3 (62–85) ms (versus average 54 ms), an average call repetition rate of 3.25 (3.05–3.37) calls/s (versus an average of 4.99 calls/s) at 21.0–22.9 °C (versus 15.0–18.0 °C); from M. jinggangensis by having an average call repetition rate of 3.25 (3.05–3.37) calls/s (versus average 5.70) at 21.0–22.9 °C (versus 15.0–18.0 °C); from M. huangshanensis by having an average call duration of 73.3 (62–85) ms (versus average 86.0 ms), an average intercall interval of 221.3 (190–261) ms (versus average 165.0 ms), and an average call repetition rate of 3.25 (3.05–3.37) calls/s (versus average 4.10) at 21.0–22.9 °C (versus 15.0–18.0 °C); from M. kuatunensis by having an average call duration of 73.3 (62–85) ms (versus average 208.0 ms), an average intercall interval of 221.3 (190–261) ms (versus average 970.0 ms), an average call repetition rate of 3.25 (3.05–3.37) calls/s (versus average 0.97), and an average of 38.7 (16–51) calls per call group (versus average 11.3) at 21.0–22.9 °C (versus 15.0–18.0 °C); from M. lini by having an average call duration of 73.3 (62–85) ms (versus average 106 ms), and an average of 38.7 (16–51) calls per call group (versus average 10.2) at 21.0–22.9 °C (versus 15.0–18.0 °C); from M. minor by having a dominant frequency of 3.2–3.4 kHz (versus 3.4–3.5 kHz), a call duration of 62–85 ms (versus 75–110 ms), an intercall interval of 190–261 ms (versus 213–363 ms), an average call repetition rate of 3.25 (3.05– 3.37) calls/s (versus average 4), and an average of 38.7 (16–51) calls per call group (versus 8–16) at at 21.0–22.9 °C (versus 14.0 °C).

Figures

FIGURE 1. Distribution of Megophrys rubrimera sp. nov. in the Hoang Lien Range, northern Vietnam and Ailao Mountain Range in Yunnan Province, China.

FIGURE 2. Megophrys rubrimera sp. nov. in preservative (holotype VNMN 2017.002). (A) Dorsal view, and (B) ventral view. Scale bar 10.0 mm.

FIGURE 3. Megophrys rubrimera sp. nov. in preservative (holotype VNMN 2017.002). (A) lateral view of head, (B) palmar surface of left hand, and (C) plantar surface of right foot. Scale bar 5.0 mm.

FIGURE 4. Megophrys rubrimera sp. nov. in life. (A) Dorsal view of holotype VNMN 2017.002, (B) dorsolateral view of paratype AMS R 177679, (C) lateral view of referred specimen HNLP 2016062200001, (D) ventral view of holotype VNMN 2017.002, (E) ventral view of paratype AMS R 177679, (F) ventral view of referred specimen HNLP 2016062200001, and (G) lateral view showing groin coloration of holotype VNMN 2017.002 and (H) lateral view showing groin coloration of paratype AMS R 177676.

FIGURE 5. Megophrys rubrimera sp. nov. tadpole AMS R 177680. (A) Lateral view in life, (B) lateral view in preservative, (C) dorsal view in preservative, (D) ventral view of in preservative, (E) dorsal view of mouthparts in preservative, and (F) lateral view of mouthparts in preservative.

FIGURE 6. Advertisement call of Megophrys rubrimera sp. nov.: 60 s waveform of relative amplitude (Rel. amp.) over time for several call groups of AMS R 177677 (Ai) and unvouchered individual (b) (Bi); 20 s waveform of Rel. amp. over time for one call group of AMS R 177677 (Aii) and unvouchered individual (b) (Bii); 1 s waveform and spectrogram of Rel. amp. and frequency for three and four calls of AMS R 177677 (Aiii) and unvouchered individual (b) (Biii), respectively.