Megophrys (Panophrys) rubrimera Tapley, Cutajar, Mahony, Nguyen, Dau, Nguyen, Luong, and Rowley 2017
- Dataset
- The Vietnamese population of Megophrys kuatunensis (Amphibia: Megophryidae) represents a new species of Asian horned frog from Vietnam and southern China
- Rank
- SPECIES
- Published in
- 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): 465-492, DOI: 10.11646/zootaxa.4344.3.3
Classification
- kingdom
- Animalia
- phylum
- Chordata
- class
- Amphibia
- order
- Anura
- family
- Megophryidae
- genus
- Megophrys
- species
- Megophrys rubrimera
description
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. 3 A & 4 G); 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. 3 B), 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. 3 C); 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. 4 A); 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. 2 A & 4 A); 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. 2 B & Fig. 4 D); 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. 4 A – 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 R 177676 the middorsal “ U ” - shaped ridge (on the holotype) is replaced by an inverted “ V ” - shaped ridge. AMS R 177676 with distinct dark grey blotches on ventral surface of thighs, this is lacking in VNMN 2017.003 and the holotype specimen. In life, AMS R 177676 has a vivid red-orange flash on the axillary region (Fig. 4 G). Gular region of VNMN 2017.002 and AMS R 177678 lack dark blotches, present in all other specimens. Ventral surface of thighs (on AMS R 177679 and AMS R 177676) are covered in dark blotches, which are not present on any of the other specimens. Tongue weakly notched in one specimen (HNLP 2016062200001). Secondary sexual characters: Females of Megophrys rubrimera sp. nov. are currently unknown. Two male specimens (AMS R 177678 and AMS R 177679) 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 R 177680) 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 R 177677) 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 R 177677 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. 6 A 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. 6 A iii), or peaked at the beginning, steadily declining throughout (Fig. 6 B 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. 7 A – B) and a steep north-eastern facing roadside bank with seepages and a small stream (Fig. 7 C – E). Females were not observed.
diagnosis
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.
distribution
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 B 1 ab (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.
etymology
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 s ừng đùi đ ỏ (Vietnamese)
materials_examined
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 R 177676) 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 R 177675) 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 R 177677, AMS R 177678 and AMS R 177679) 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 JJLR 03813 - HNLP 2016062200001) 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 R 177680) 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.
materials_examined
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).