Megophrys chishuiensis, Xu & Li & Liu & Wei & Wang, 2020

Xu, Ning, Li, Shi-Ze, Liu, Jing, Wei, Gang & Wang, Bin, 2020, A new species of the horned toad Megophrys Kuhl & Van Hasselt, 1822 (Anura, Megophryidae) from southwest China, ZooKeys 943, pp. 119-144 : 119

Megophrys chishuiensis sp. nov. Figures 4 , 5 , 6 , 7 , 8

Type material.

Holotype. CIBCS20190518031 (Figs 4 , 5 ), adult male, from Chishui National Nature Reserve, Chishui City, Guizhou Province, China (28.436708N, 105.997794E, ca. 460 m a. s. l.), collected by Shi-Ze Li on 18 May 2019.

Paratype. Two adult males and five adult females from the same place as holotype, collected by Shi-Ze Li and Jing Liu. Two females CIBCS20190518022 and CIBCS20190518023 collected by Jing LIU on 18 May 2019, two adult males CIBCS20190518019 and CIBCS20190518021 and three adult females CIBCS20190518025, CIBCS20190518027 and CIBCS20190518030 collected by Shi-Ze Li on 18 May 2019.

Diagnosis.

Megophrys chishuiensis sp. nov. is assigned to the genus Megophrys based on molecular phylogenetic analyses and the following generic diagnostic characters: snout shield-like; projecting beyond the lower jaw; canthus rostralis distinct; chest glands small and round, closer to the axilla than to midventral line; femoral glands on rear part of thigh; vertical pupils ( Fei et al. 2009).

Megophrys chishuiensis sp. nov. could be distinguished from its congeners by a combination of the following morphological characters: (1) body size moderate (SVL 43.4-44.1 mm in males, and 44.8-49.8 mm in females; (2) vomerine teeth absent; (3) tongue not notched behind; (4) a small horn-like tubercle at the edge of each upper eyelid; (5) tympanum distinctly visible, rounded; (6) two metacarpal tubercles on palm; (7) relative finger lengths II <I <V <III; (8) toes without webbing; (9) heels overlapping when thighs are positioned at right angles to the body; (10) tibiotarsal articulation reaching the level between tympanum and eye when leg stretched forward. In breeding male, (11) an internal single subgular vocal sac; (12) nuptial pads with black spines on dorsal surface of bases of the first two fingers.

Description of holotype.

(Figs 4 , 5 ). SVL 43.4 mm; head width larger than head length (HDW/HDL ratio about 1.2); snout obtusely pointed, protruding well beyond the margin of the lower jaw in ventral view; loreal region vertical and concave; canthus rostralis well-developed; top of head flat in dorsal view; a small horn-like tubercle at the edge of the upper eyelid; eye large, eye diameter 43.9% of head length; pupils vertical; nostril orientated laterally, closer to snout than eye; tympanum distinct, TYP/EYE ratio 0.64; vomerine ridges and vomerine teeth absent; margin of tongue smooth, not notched behind.

Forelimbs slender, the length of lower arm and hand 42.4% of SVL; fingers slender, relative finger lengths: II <I <V <III; tips of digits globular, without lateral fringes; subarticular tubercle distinct at the base of each finger; two metacarpal tubercles, prominent, the outer one long and thin, the inner one oval-shaped.

Hindlimbs slender, 1.48 times SVL; heels overlapping when thighs are positioned at right angles to the body, tibiotarsal articulation reaching tympanum to eye when leg stretched forward; tibia length longer than thigh length; relative toe lengths I <II <V <III <IV; tips of toes round, slightly dilated; subarticular tubercles absent; toes without webbing; no lateral fringe; inner metatarsal tubercle oval-shaped; outer metatarsal tubercle absent.

Dorsal skin rough, with numerous granules; several large warts scattered on flanks; a small horn-like tubercle at the edge of each upper eyelid; tubercles on the dorsum forming a weak X-shaped ridge, the V-shaped ridges disconnect; two discontinuous dorsolateral parallel ridges on either side of the X-shaped ridges; an inverted triangular brown speckle between two upper eyelids; several tubercles on the flanks and dorsal surface of thighs and tibias and forming four transverse tubercle rows; supratympanic fold distinct.

Ventral surface smooth; chest with small and round glands, closer to the axilla than to midventral line; femoral glands on rear of thighs, numerous white granules on outer thighs; posterior end of the body distinctly protruding and forming an arc-shaped swelling above the anal region.

Coloration of holotype in life.

(Fig. 4 ). An inverted triangular brown speckle between the eyes; X-shaped ridges on the dorsum, four transverse bands on the dorsal surface of the thigh and shank; several dark brown and white vertical bars on the lower and upper lip; venter purple grey, some white spots on the ventral surface of body and limbs; palms and soles uniform purple grey, tip of digits pinkish; pectoral and femoral glands white.

Coloration of holotype in preservation.

(Fig. 5 ). Color of dorsal surface fades to olive; the inverted triangular brown speckle between the eyes, X-shaped ridges on dorsum and transverse bands on limbs and digits distinct; ventral surface greyish white; creamy-white substitutes the pinkish on tip of digits; the posterior of ventral surface of body, inner of thigh and upper of tibia light red.

Variations.

In CIBCS20190518027, the back is brown with some brick-red granules (Fig. 6A ); in CIBCS20190518030, the X-shaped marking on back of trunk consists of a ridge with brown spots (Fig. 6B ), and the throat and anterior belly are purplish, with grey spots on the posterior belly and black spots on the flank belly (Fig. 6E ); in CIBCS20190518025, the marking on the back consists of a V-shaped ridge (Fig. 6C ), and the anterior belly is brownish with some black spots on flank and belly, and posterior belly is beige (Fig. 6F ); in CIBCS20190518019, the whole ventrum is purplish except the posterior belly that shows white blotches (Fig. 6D ).

Advertisement call.

The call description is based on recordings of the holotype CIBCS20190518031 (Fig. 7 ) from the shrub leaf near the streamlet, and the ambient air temperature was 24.5 °C. Each call consists of 14-20 (mean 16.14 ± 1.95, N = 10) notes. Call duration was 2.10-3.18 second (mean 2.51 ± 0.33, N = 7). Call interval was 0.92-1.32 seconds (mean 1.13 ± 0.15, N = 6). Each note had a duration of 0.07- 0.12 seconds (mean 0.98 ± 0.01, N = 113) and the intervals between notes 0.038-0.085 seconds (mean 0.056 ± 0.011, N = 106). Amplitude modulation within note was apparent, beginning with moderately high energy pulses, increasing slightly to a maximum by approximately mid note, and then decreasing towards the end of each note. The average dominant frequency was 5859 ± 118.02.61 (5733-6064 Hz, N = 7).

Secondary sexual characters.

Adult females with SVL 44.8-49.8 mm, larger than adult males with 43.4-44.1 mm. Adult males have a single subgular vocal sac. In breeding males, brownish red nuptial pads are present on dorsal surface of the bases of the first and second fingers with black spines obvious under microscope.

Comparisons.

By having medium body size, Megophrys chishuiensis sp. nov. differs from M. aceras Boulenger, 1903, M. auralensis Ohler, Swan & Daltry, 2002, M. carinense Boulenger, 1889, M. caudoprocta Shen, 1994, M. chuannanensis (Fei, Ye & Huang, 2001), M. damrei Mahony, 2011, M. edwardinae Inger, 1989, M. feae Boulenger, 1887, M. flavipunctata Mahony, Kamei, Teeling & Biju, 2018, M. gigantica Liu, Hu & Yang, 1960, M. glandulosa Fei, Ye & Huang, 1990, M. himalayana Mahony, Kamei, Teeling & Biju, 2018, M. intermedia Smith, 1921, M. jingdongensis Fei & Ye, 1983, M. kalimantanensis Munir, Hamidy, Matsui, Iskandar, Sidik & Shimada, 2019, M. lekaguli Stuart, Chuaynkern, Chan-ard & Inger, 2006, M. liboensis (Zhang, Li, Xiao, Li, Pan, Wang, Zhang & Zhou, 2017), M. major Boulenger, 1908, M. mangshanensis Fei & Ye, 1990, M. maosonensis Bourret, 1937, M. medogensis Fei, Ye & Huang, 1983, M. omeimontis Liu, 1950, M. oreocrypta Mahony, Kamei, Teeling & Biju, 2018, M. orientalis (Li, Lyu, Wang & Wang, 2020), M. periosa Mahony, Kamei, Teeling & Biju, 2018, M. popei (Zhao, Yang, Chen, Chen & Wang, 2014), M. sangzhiensis Jiang, Ye & Fei, 2008, M. shapingensis Liu, 1950, M. shuichengensis Tian & Sun, 1995, and M. takensis Mahony, 2011 (maximum SVL <49.8 mm in the new species vs. minimum SVL> 53 mm in the latter), and differs from M. acuta Wang, Li & Jin, 2014, M. angka (Wu, Suwannapoom, Poyarkov, Chen, Pawangkhanant, Xu, Jin, Murphy & Che, 2019), M. caobangensis Nguyen, Pham, Nguyen, Luong & Ziegler, 2020, M. damrei Mahony, 2011, M. dongguanensis Wang & Wang, 2019, M. cheni , M. jiangi , M. jinggangensis (Wang, 2012), M. jiulianensis Wang, Zeng, Lyu & Wang, 2019, M. kuatunensis Pope, 1929, M. lini (Wang & Yang, 2014), M. lishuiensis (Wang, Liu & Jiang, 2017), M. mufumontana (Wang, Lyu & Wang, 2019), M. minor , M. nanlingensis (Lyu, Wang, Liu & Wang, 2019), M. obesa Wang, Li & Zhao, 2014, M. pachyproctus Huang, 1981, M. palpebralespinosa Bourret, 1937, M. serchhipii Mathew & Sen, 2007, M. shunhuangensis Wang, Deng, Liu, Wu & Liu, 2019, M. vegrandis Mahony, Teeling & Biju, 2013, M. wuliangshanensis Ye & Fei, 1995, M. wushanensis Ye & Fei, 1995, M. zunhebotoensis Mathew & Sen, 2007, M. xianjuensis Wang, Wu, Peng, Shi, Lu & Wu, 2020, and M. zhangi Ye & Fei, 1992 (vs. maximum SVL <42 mm in the latter).

By the absence of vomerine teeth, Megophrys chishuiensis sp. nov. differs from M. aceras , M. ancrae Mahony, Teeling & Biju, 2013, M. carinense , M. baluensis (Boulenger, 1899), M. caudoprocta , M. chuannanensis , M. damrei , M. daweimontis Rao & Yang, 1997, M. dongguanensis , M. fansipanensis Tapley, Cutajar, Mahony, Nguyen, Dau, Luong, Le, Nguyen, Nguyen, Portway, Luong & Rowley, 2018, M. flavipunctata , M. glandulosa , M. hoanglienensis Tapley, Cutajar, Mahony, Nguyen, Dau, Luong, Le, Nguyen, Nguyen, Portway, Luong & Rowley, 2018, M. himalayana , M. insularis (Wang, Liu, Lyu, Zeng & Wang, 2017), M. intermedia , M. jingdongensis , M. jinggangensis , M. jiulianensis . M. kalimantanensis , M. kobayashii Malkmus & Matsui, 1997, M. lancip Munir, Hamidy, Farajallah & Smith, 2018, M. lekaguli , M. liboensis , M. ligayae Taylor, 1920, M. longipes Boulenger, 1886, M. major , M. mangshanensis , M. maosonensis , M. medogensis , M. megacephala Mahony, Sengupta, Kamei & Biju, 2011, M. montana Kuhl & Van Hasselt, 1822, M. nasuta (Schlegel, 1858), M. nankunensis , M. nanlingensis , M. omeimontis , M. oropedion Mahony, Teeling & Biju, 2013, M. oreocrypta , M. palpebralespinosa , M. parallela Inger & Iskandar, 2005, M. parva (Boulenger, 1893), M. periosa , M. popei , M. robusta Boulenger, 1908, M. rubrimera Tapley, Cutajar, Mahony, Chung, Dau, Nguyen, Luong & Rowley, 2017, M. sangzhiensis , M. stejnegeri Taylor, 1920, M. takensis , M. zhangi , and M. zunhebotoensis (vs. present in the latter).

By having a small horn-like tubercle at the edge of each upper eyelid, Megophrys chishuiensis sp. nov. differs from M. binchuanensis Ye & Fei, 1995, M. binlingensis , M. damrei , M. gigantica , M. minor , M. monticola ( Günther, 1864), M. nasuta , M. nankiangensis Liu & Hu, 1966, M. oropedion , M. pachyproctus , M. spinata , M. stejnegeri , M. takensis , M. wuliangshanensis , M. wushanensis , M. zhangi , and M. zunhebotoensis (vs. lacking tubercle in the latter), and differs from M. carinense , M. feae , M. gerti (Ohler, 2003), M. hansi (Ohler, 2003), M. intermedia , M. kalimantanensis , M. koui Mahony, Foley, Biju & Teeling, 2017, M. latidactyla , M. liboensis , M. microstoma (Boulenger, 1903), M. palpebralespinosa , M. popei , M. shuichengensis , and M. synoria (Stuart, Sok & Neang, 2006) (vs. having a prominent and elongated tubercle in the latter).

By having a tongue not notched behind, Megophrys chishuiensis sp. nov. differs from M. ancrae , M. baolongensis Ye, Fei & Xie, 2007, M. binlingensis , M. boettgeri (Boulenger, 1899), M. carinense , M. cheni , M. chuannanensis , M. damrei , M. dringi Inger, Stuebing & Tan, 1995, M. fansipanensis , M. feae , M. feii Yang, Wang & Wang, 2018, M. flavipunctata , M. gerti , M. glandulosa , M. hoanglienensis , M. huangshanensis Fei & Ye, 2005, M. insularis , M. jiulianensis . M. jingdongensis , M. kalimantanensis , M. kuatunensis , M. liboensis , M. mangshanensis , M. maosonensis , M. medogensis , M. minor , M. nankiangensis , M. nanlingensis , M. omeimontis , M. oropedion , M. pachyproctus , M. parallela , M. popei , M. robusta , M. sangzhiensis , M. shapingensis , M. shuichengensis , M. spinata , M. vegrandis , M. wawuensis Fei, Jiang & Zheng, 2001, M. zhangi , and M. zunhebotoensis (vs. tongue notched behind in the latter).

By lacking lateral fringes on the toes, Megophrys chishuiensis sp. nov. differs from M. acuta , M. auralensis , M. baolongensis , M. binchuanensis , M. boettgeri , M. carinense , M. cheni , M. chuannanensis , M. elfina Poyarkov, Duong, Orlov, Gogoleva, Vassilieva, Nguyen, Nguyen, Nguyen, Che & Mahony, 2017, M. feae , M. feii , M. flavipunctata , M. gigantica , M. glandulosa , M. hansi , M. intermedia , M. jingdongensis , M. jinggangensis , M. kuatunensis , M. latidactyla , M. lini , M. major , M. maosonensis , M. nankiangensis , M. omeimontis , M. palpebralespinosa , M. popei , M. rubrimera , M. sangzhiensis , M. serchhipii , M. shapingensis , M. shuichengensis , M. spinata , M. vegrandis , M. xianjuensis , M. zhangi , and M. zunhebotoensis (vs. present in these species).

By having toes without webs at bases, Megophrys chishuiensis sp. nov. differs from M. brachykolos Inger & Romer, 1961, M. carinense , M. flavipunctata , M. jingdongensis , M. jinggangensis , M. lini , M. major , M. palpebralespinosa , M. popei , M. shuichengensis , M. spinata (vs. at least one-fourth webbed).

By heels overlapping when thighs are positioned at right angles to the body, Megophrys chishuiensis sp. nov. differs from M. acuta , M. brachykolos , M. dongguanensis , M. huangshanensis , M. kuatunensis , M. nankunensis , M. obesa , M. ombrophila Messenger & Dahn, 2019, and M. wugongensis Wang, Lyu & Wang, 2019 (vs. not meeting).

With tibiotarsal articulation reaching to the level between tympanum and eye when leg is stretched forward, Megophrys chishuiensis sp. nov. differs from M. baolongensis , M. nankiangensis , M. pachyproctus , M. shuichengensis and M. tuberogranulata Shen, Mo & Li, 2010 (vs. just reaching posterior corner of the eye in the latter); differs from M. daweimontis , M. glandulosa , M. lini , M. major , M. medongensis , M. obesa , and M. sangzhiensis (vs. reaching the anterior corner of the eye or beyond eye or nostril and tip of snout in the latter); differs from M. leishanensis Li, Xu, Liu, Jiang, Wei & Wang, 2018 (vs. reaching middle part of eye in this group of species); and differs from M. mufumontana (vs. reaching tympanum in males and to the eye in females).

By having an internal single subgular vocal sac in male, Megophrys chishuiensis sp. nov. differs from M. caudoprocta , M. shapingensis , and M. shuichengensis (vs. vocal sac absent).

By having nuptial pads and nuptial spines on dorsal surface of the base of the first two fingers in breeding males, Megophrys chishuiensis sp. nov. differs from M. acuta , M. feii , M. shapingensis , and M. shuichengensis (vs. lacking in these species).

The congeners M. carinense , M. jiangi , M. leishanensis , M. liboensis , M. shuichengensis , and M. spinata have sympatric distribution with Megophrys chishuiensis sp. nov. ( Fei et al. 2012; Zhang et al. 2017; Li et al. 2018; Liu et al. 2020). The new species can be distinguished from these species by a series of morphological characters as follows. The new species vs. M. carinense : body size smaller (adult males with 43.4-44.1 mm and adult females with SVL 44.8-49.8 mm vs. adult males with 92-123 mm and adult females with SVL 137mm), vomerine teeth absent (vs. present), horn-like tubercle at the edge of each upper eyelid small (vs. prominent), tongue not notched behind (vs. notched behind), lacking lateral fringe in toes (vs. present), and toes without webs at bases (vs. one-fourth webbed). The new species vs. M. jiangi : body size bigger (adult males with 43.4-44.1 mm and adult females with SVL 44.8-49.8 mm vs. adult males with 34.4-39.2 mm and adult females with SVL 39.5-40.4 mm), and relative finger lengths II <I <V <III vs. I <II <V <III. The new species vs. M. leishanensis : body size bigger (adult males with 43.4-44.1 mm and adult females with SVL 44.8-49.8 mm vs. adult males with 30.4-38.7 mm and adult females with SVL 42.3 mm), and tibiotarsal articulation reaching forward to the region between tympanum and eye when hindlimb is stretched along the side of the body vs. reaching middle part of eye. The new species vs. M. liboensis : body size smaller in adult females (adult females with SVL 44.8-49.8 mm vs. adult females with SVL 60.8-70.6 mm), vomerine teeth absent vs. vomerine teeth present, and horn-like tubercle at the edge of each upper eyelid is small vs. prominent. The new species vs. M. shuichengensis : body size smaller (adult males with 43.4-44.1 mm and adult females with SVL 44.8-49.8 mm vs. adult males with 102.0-118.3 mm and adult females with SVL 99.8-115.6 mm), horn-like tubercle at the edge of each upper eyelid is small vs. prominent, tongue not notched behind vs. tongue notched behind, lacking lateral fringe in toes vs. present, toes without webs at bases vs. one-fourth webbed, having an internal single subgular vocal sac in male vs. absent, and having nuptial pads and nuptial spines on the dorsal base of the first two fingers in breeding male vs. lacking. The new species vs. M. spinata : body size is smaller (adult males with 43.4-44.1 mm and adult females with SVL 44.8-49.8 mm vs. adult males with 47.2-54.4 mm and adult females with SVL 54.0-55.0 mm), horn-like tubercle at the edge of each upper eyelid is small vs. lacking tubercle, tongue not notched behind vs. notched behind, lacking lateral fringe in toes vs. present, and toes without webs at bases vs. one-fourth webbed.

Megophrys chishuiensis sp. nov. is phylogenetically closest to M. minor , and this new species could be identified from the latter distinctly by having larger body size (SVL 43.4-44.1 mm in males vs. 34.5-41.2 mm in males of M. minor ), having a small horn-like tubercle at the edge of each upper eyelid (vs. absent in the latter), tongue not notched behind (vs. notched in the latter), tibiotarsal articulation reaching the level between tympanum to eye when leg stretched forward (vs. reaching the level between eye and tip of snout in the latter), and having two metatarsal tubercles in each hand (vs. absent in the latter).

Distribution and habitats.

Megophrys chishuiensis sp. nov. is known from the type locality, Chishui National Nature Reserve (28.38-28.45N, 106.05-109.75E), Chishui City, Guizhou Province, China at elevations between 270-604 m. The individuals of the new species were frequently found in bamboo forest nearby the streams (Fig. 8 ), and five sympatric amphibian species were also found: Megophrys omeimontis , Odorrana margaratae (Liu, 1950), Zhangixalus omeimontis (Stejneger, 1924), and Rana omeimontis Ye & Fei, 1993.

Etymology.

The specific name chishuiensis refers to the distribution of this species, Chishui City, Guizhou Province, China. We propose the common name "Chishui horned toad" and its Chinese name as Chi Shui Jiao Chan (赤水角蟾).

Figures

Figure 4. Photos of the holotype CIBCS 20190518031 of Megophrys chishuiensis sp. nov. in life A dorsal view B ventral view C dorsal view of hand D ventral view of hand E ventral view of foot.

Figure 5. The holotype specimen CIBCS 20190518031 of Megophrys chishuiensis sp. nov. A dorsal view B ventral view C lateral view D ventral view of hand E ventral view of foot.

Figure 6. Color variation in Megophrys chishuiensis sp. nov. A dorsolateral view of the female specimen CIBCS 20190518027 B dorsolateral view of the female specimen CIBCS 20190518030 C dorsal view of the female specimen CIBCS 20190518025 D ventral view of the male specimen CIBCS 20190518019 E ventral view of the female specimen CIBCS 20190518030 F ventral view of the female specimen CIBCS 20190518025.

Figure 7. Visualization of advertisement calls of Megophrys chishuiensis sp. nov. A waveform showing one note B sonogram showing one notes C waveform showing 16 notes of one call D sonogram showing 16 notes of one call.

Figure 8. Habitats of Megophrys chishuiensis sp. nov. in the type locality, Chishui National Nature Reserve, Chishui City, Guizhou Province, China A landscape of montane forests B a mountain stream (the inset illustrates the holotype on stone).