Megophrys (Panophrys) nankunensis J. Wang, Zeng & Y.Y. Wang

Wang, Jian, Lyu, Zhi-Tong, Liu, Zu-Yao, Liao, Cheng-Kai, Zeng, Zhao-Chi, Zhao, Jian, Li, Yu-Long & Wang, Ying-Yong, 2019, Description of six new species of the subgenus Panophrys within the genus Megophrys (Anura, Megophryidae) from southeastern China based on molecular and morphological data, ZooKeys 851, pp. 113-164 : 123-130

Megophrys (Panophrys) nankunensis J. Wang, Zeng & Y.Y. Wang sp. nov. Fig. 4, Table 4

Holotype.

SYS a004498, adult male, collected by Jian Wang and Hai-Long He on 20 October 2015 from Mt. Nankun (23°38'19"N, 113°53'24"E; 400 m a.s.l.), Longmen County, Huizhou City, Guangdong Province, China.

Paratypes (10 males & two females).

Adult females, SYS a004506-4507, collected by Jian Wang and Hai-Long He on 20 October 2015; adult males, SYS a002023, 2032-2033, collected by Run-Lin Li on 20 March 2013, SYS a004499-4504, SYS a004505/CIB110007, collected by Jian Wang and Hai-Long He on 20 October 2015, all from Mt. Nankun at elevations between 300-650 m.

Diagnosis.

(1) Body size small, SVL 29.9-34.9 mm in 11 adult males, 39.4-41.9 mm in two adult females; (2) head width slightly larger than head length, HDW/HDL ratio 1.00-1.20; (3) snout rounded in dorsal view, tip of snout slightly sharpened; (4) tympanum distinct, moderate-sized, TD/ED ratio 0.43-0.61; (5) strong vomerine ridge bearing vomerine teeth; (6) margin of tongue not notched behind; (7) shanks short, heels not meeting when the flexed hindlimbs are held at right angles to the body axis; tibia-tarsal articulation reaching forward to the region between tympanum and eye when hindlimb is stretched along the side of the body; (8) TIB/SVL ratio 0.35-0.42, FTL/SVL ratio 0.53-0.62; (9) absence of lateral fringes on fingers, presence of an indistinct subarticular tubercle on the bases of each finger, relative finger lengths II <I <IV <III; (10) toes with rudimentary webbing at their bases and without lateral fringes, subarticular tubercles only present on the bases of each toes; (11) dorsal surface with dense granules, surface of flanks and dorsal surface of limbs with large tubercles; (12) edge of eye lid with a small reddish horn-like tubercle; (13) supratympanic fold distinct, forming a depressed supraaxillary gland above insertion of arm; (14) dorsum beige to dark brown, with indistinct light brown patches, with an incomplete dark triangular marking between eyes; (15) males with a single subgular vocal sac, and dense dark villiform nuptial spines present on dorsal surface of first and second fingers during breeding season, respectively; (16) gravid females bear creamy yellow oocytes.

Comparisons.

Comparative data of Megophrys nankunensis sp. nov. with M. dongduanensis sp. nov., M. feii and the 33 recognized members of Megophrys s.l. allocated to the subgenus Panophrys are listed in Table 5.

In the ML and BI phylogenetic trees (Fig. 2), Megophrys nankunensis sp. nov. is a sister taxon to M. dongguanensis sp. nov. (p=4.6-5.0%) with high node-supporting value (0.1 in BI, 100% in ML%), and differs from the later by the snout rounded in dorsal view, tip of snout slightly sharpened (vs. snout pointed in dorsal view, tip of snout not sharpened), supratympanic fold forming a depressed supraaxillary gland above insertion of arm (vs. supraaxillary gland absent).

With significantly smaller body size, SVL 29.9-34.9 mm in males and 39.4-41.9 mm in females, Megophrys nankunensis sp. nov. differs from the 12 members with larger SVL values: M. baolongensis (42.0-45.0 mm in males), M. binlingensis (45.1-51.0 mm in males), M. caudoprocta (81.3 mm in single male), M. hoanglienensis (37.4-47.6 mm in males), M. jingdongensis (53.0-56.5 mm in males, 63.5 mm in single female), M. latidactyla (38.9 mm in single male), M. omeimontis (56.0-59.5 mm in males, 68.0-72.5 mm in females), M. palpebralespinosa (36.2-38.0 mm in males), M. sangzhiensis (54.7 mm in single male), M. shuichengensis (102.0-118.3 mm in males, 99.8-115.6 mm in females), M. spinata (47.2-54.4 mm in males, 54.0-55.0 mm in females) and M. tuberogranulatus (50.5 in single female).

Megophrys nankunensis sp. nov. differs from 12 species occurring in eastern and southern China ( M. acuta , M. brachykolos , M. boettgeri , M. cheni , M. huangshanensis , M. insularis , M. jinggangensis , M. kuatunensis , M. lini , M. lishuiensis , M. obesa and M. ombrophila ) by the following combination of characters: presence of vomerine teeth (vs. absent in M. acuta , M. boettgeri , M. brachykolos , M. cheni , M. huangshanensis , M. kuatunensis , M. lini , M. lishuiensis , M. obesa and M. ombrophila ), absence of lateral fringes on toes (vs. presence of narrow lateral fringes on toes in M. acuta , M. jinggangensis and M. kuatunensis ; presence of wide lateral fringes on toes in M. boettgeri , M. cheni and M. lini ), toes with rudimentary webbing (vs. toes without webbing in M. lishuiensis , M. kuatunensis and M. ombrophila ), hindlimbs short, with heels not meeting when the flexed hindlimbs are held at right angles to the body axis (vs. hindlimbs comparatively longer, with heels meeting or overlapping in M. cheni , M. boettgeri , M. kuatunensis , M. jinggangensis and M. lini ), tibio-tarsal articulation reaching forward to the region between tympanum and eye when hindlimb is stretched along the side of the body (vs. reaching forward to the shoulder in M. brachykolos and to the posterior edge of tympanum in M. insularis ), relative finger lengths II <I <IV <III (vs. IV <I <II <III in M. brachykolos and I <II <IV <III in M. obesa and M. ombrophila ); supratympanic fold forming a depressed supraaxillary gland above insertion of arm (vs. supraaxillary gland swollen in M. insularis ; absent in other 11 species).

Megophrys nankunensis sp. nov. differs from the remaining nine members of the Megophrys s.l. allocated to the subgenus Panophrys which share a moderate or small body size, by the by the small horn-like tubercle at edge of upper eyelid (vs. horn-like tubercle indistinct or absent in M. binchuanensis , M. minor , M. wuliangshanensis and M. wushanensis ; long point in M. liboensis ), presence of vomerine teeth (vs. absent in M. binchuanensis , M. leishanensis , M. minor , M. wuliangshanensis and M. wushanensis ), absence of lateral fringes on toes (vs. wide in M. binchuanensis , M. liboensis , M. wushanensis (wide in males); narrow in M. rubrimera ), toes with rudimentary webbing (vs. toes without webbing in M. daweimontis , M. rubrimera , M. wuliangshanensis and M. wushanensis (in females); webbing indistinct or absent in M. fansipanensis ), tibio-tarsal articulation reaching forward to the region between tympanum and eye when hindlimb is stretched along the side of the body (vs. reaching forward to the tip of snout in M. daweimontis ), finger II shortest (vs. finger I shortest in M. liboensis ), presence of an indistinct subarticular tubercle on the bases of each finger (vs. subarticular tubercle absent in M. fansipanensis ), heels not meeting when the flexed hindlimbs are held at right angles to the body axis (heels meeting in M. binchuanensis ; heels meeting or overlapping in M. minor and M. wushanensis ; heels overlapping in M. leishanensis , M. liboensis and M. wuliangshanensis ).

Megophrys nankunensis sp. nov. further differs from M. feii , for which molecular data are lacking and cannot be allocated to any subgenus base on morphology only ( Yang et al. 2018) by the larger body size, SVL 29.9-34.9 mm in males and 39.4-41.9 mm in females (VS. 24.3-25.1 mm in males, 28.2-28.9 mm in females), presence of nuptial pad with nuptial spines in males during breeding season (vs. absent), presence of vomerine teeth (vs. absent), absence of lateral fringes on toes (vs. moderate or wide), heels not meeting when the flexed hindlimbs are held at right angles to the body axis (vs. heels overlapping).

Description of holotype.

Adult male. Habitus small, SVL 31.3 mm; head width slightly larger than head length, HDW/HDL 1.12; snout rounded in dorsal view, tip of snout slightly sharpened, sloping backward to mouth in profile, protruding well beyond margin of lower jaw; top of head flat; eye large, ED/HDL 0.38; nostril oblique ovoid; pupil vertical; canthus rostralis well developed, forming the beginning of a fleshy, protruding ridge, that continues over the upper eyelid, and transitions into a supratympanic fold that terminates in the scapular region; loreal region vertical; internasal distance slightly larger than interorbital distance; tympanum distinct, moderate-sized, TD/ED 0.44; large ovoid choanae at the base of the maxilla; strong vomerine ridge bearing vomerine teeth; margin of tongue weakly notched posteriorly; internal vocal slits present near the rear of the lower mandible.

RAD/SVL 0.22, HND/SVL 0.22; absence of lateral fringes and webbing on fingers, relative finger lengths II <I <IV <III; tip of finger rounded, slightly swollen; presence of a distinct subarticular tubercle on the base of each finger; outer metacarpal tubercles indistinct, inner metacarpal tubercles distinct and observably enlarged. Hindlimbs short, tibio-tarsal articulation reaching forward the anterior margin of tympanum when hindlimb is stretched along the side of the body; heels not meeting when the flexed hindlimbs are held at right angles to the body axis; TIB/SVL 0.37 and FTL/SVL 0.55; relative toe lengths I <II <V <III <IV; tips of toes round and slightly dilated; presence of rudimentary webbing on toes but absence of lateral fringes and tarsal folds; presence of a subarticular tubercle only at the bases of each toes; presence of a long ovoid inner metatarsal tubercle and absence of outer metatarsal tubercle.

Dorsal skin texture smooth with dense granules, some of which forming a weak X-shaped skin ridge on center of trunk; surface of flanks with large tubercles; presence of a small horn-like tubercle at the edge of eyelid; distinct supratympanic fold curving posteroventrally from posterior corner of eye to a level above insertion of arm, forming a swollen supraaxillary gland above insertion of arm; ventral skin texture smooth with granules on the surface of abdomen; pectoral gland large, equal size to tip of fingers, closer to axilla; single large femoral gland on rear of thigh.

Measurements of holotype (in mm).

SVL 31.3, HDL 9.6, HDW 10.8, SNT 3.4, IND 3.4, IOD 2.4, ED 3.7, TD 1.6, TED 1.0, HND 6.9, RAD 7.0, FTL 17.3, TIB 11.6.

Coloration of holotype in life.

(Fig. 4 A–D) Dorsal surface beige with obscure darker patches, with a distinct and incomplete dark triangular marking between eyes, unconnected with an incomplete X-shaped marking on center of trunk. Forearm with dark bands dorsally; hindlimb with broad black transverse bands. Tip of snout dark brown. A dark brown vertical band below the eye. Supratympanic fold white. Horn-like tubercle at the edge of the upper eyelid orange. Surface of throat and chest dark brown, with scarlet spots. Posterior region of abdomen white, with dark brown and scarlet spots. Ventral surface of limbs white with brown patches. Ventral surface of hand and foot light brown, subarticular tubercle at the base of each fingers and toes, outer metacarpal tubercle, inner metatarsal tubercle and inner metacarpal tubercle pink. Pectoral and femoral glands white. Iris white.

Coloration of holotype in preservative.

On dorsal surface the beige fades to dark grey. Dark interorbital triangular marking becomes more indistinct. Ventral surface pale in color, grey-brownish grounding, markings and mottling more distinct, all scarlet spots absent.

Variation.

Measurements and body proportions of type series are given in Table 4.

All paratype specimens were very similar in morphology and color pattern. However, the holotype has the dorsal surface beige (vs. reddish brown in paratypes SYS a002033, 4501, and dark brown in paratypes SYS a004502-4506, 4507 (Fig. 4 E–F)), dorsal skin texture smooth, granules and tubercles weak (vs. dorsal skin texture relatively rough with more distinct granules and tubercles in paratypes SYS a004502, 4504 -4507), and ventral surface of hand and foot light brown (vs. ventral surface of hand and foot grey white in paratypes SYS a004502-4504).

Etymology.

The specific epithet “nankunensis” is in reference to the type locality of the new species: Mt. Nankun. We propose the common English name "Nankunshan Horned Toad" and Chinese name "Nan Kun Shan Jiao Chan ( 南昆山角蟾)”.

Distribution and habits.

Currently, Megophrys nankunensis sp. nov. is known only from the type locality, Mt. Nankun in Longmen County, Guangdong Province, China. It inhabits forest floor, leaf litter and the nearby undergrowth rocky mountainous streams (2-3 m wide) surrounded by moist subtropical evergreen broadleaved forests at elevations between 300-600 m. Breeding season of M. nankunensis sp. nov. is from October to the following March, males were found calling under the leaf litter or rocks (Fig. 5A) on the ground in the flowing streams, besides, a pair were observed exposed on the floor in a flowing stream, about 2.5 m wide, prior to amplexus (Fig. 5B) at 20:09 P. M. on 20 October 2015. Tadpoles were not observed in this period.