Xenophrys pangdaensis, Shu & Li & Wu & Liu & He & Li & Zhang & Guo, 2023

Shu, Guocheng, Li, Ke, Wu, Yayong, Liu, Qin, He, Zhongping, Li, Ling, Zhang, He & Guo, Peng, 2023, A new species of Xenophrys (Amphibia, Anura, Megophryidae) from southern Tibet, China, ZooKeys 1182, pp. 307-329 : 307

Xenophrys pangdaensis sp. nov.

Fig. 3

Type material.

Holotype. YBU21248, adult male, collected by Ke Li and He Zhang on 28 August 2021 from Pangda Village (27°17.25'N, 89°0.42'E; ca. 2000 m a.s.l.), Yadong Town, Yadong County, Tibet Autonomous Region, China.

Paratypes. Six adult specimens (males: YBU21258, YBU21259, YBU21260, YBU21261, YBU21269; female: YBU21262) were collected from two very close sites in Yadong Town by Ke Li and He Zhang on 28 August 2021.

Other specimens examined.

Thirteen tadpoles were collected by Ke Li and He Zhang on 4 September 2021. Five tadpoles were collected from Pangda Village (17 km, 27°18.18'N, 89°0.34'E), Yadong Town. The other tadpoles were collected from Pangda Village (27°17.25'N, 89°0.42'E) together with the holotype .

Etymology.

The species name pangdaensis indicates the type locality of Pangda Village, Yadong County, Tibet Autonomous Region, China.

Suggested name.

Pangda Horned Toad (English), and Pang Da Jiao Chan (庞达角蟾, Chinese).

Diagnoses.

(1) Small body size, SVL 17.9-22.2 mm (20.5 ± 1.8, n = 6) in adult males and SVL 23.4 mm (n = 1) in the adult female (Table 3 ); (2) tympanum indistinct, supratympanic fold distinct; (3) canthus rostralis well-developed, snout tip far beyond the margin of the lower lip; (5) pupil vertical; (6) vomerine teeth present, maxillary teeth present; (7) tongue notched terminally; (8) supernumerary tubercles absent, subarticular, metacarpal and metatarsal tubercles indistinct; (9) relative finger lengths I <II <IV <III, finger tips rounded, slightly expanded relative to digit widths; (10) toes with narrow lateral fringes and tarsal folds; (11) a dark triangular marking with light edge between eyes, a dark)(-shaped marking, with light edge, present on center of dorsum, pectoral glands on sides of the breast.

Holotype description.

Measurements in mm. Mature male, body slender, extremely small (SVL 21.5) (Fig. 3 ); small protuberance beyond cloaca from dorsal view, not visible from ventral view, not swollen; head moderate, longer than wide (HW 7.0, HL 7.6, IFE 2.8, IBE 3.7); snout nearly rounded in dorsal view, slightly protruding beyond lower jaw, angular in anterior and lateral view; loreal region acute, concave; canthus rostralis angular; dorsal surface of snout slightly concave; nostril oval, closer to eye than tip of snout (SN 1.5, EN 1.6); internarial distance greater than eyelid width, and shorter than narrowest point between upper eyelids (IN 2.5, UEW 1.9, IUE 2.9); eye diameter 1.5 × maximum diameter of visible portion of tympanum, and shorter than snout (EL 2.7, TYD 1.8, SL 3.3); eye-tympanum distance (TYE 1.7) shorter than diameter of visible portion of tympanum; tympanum oval-shaped, slightly oblique, upper border concealed by supratympanic ridge; pupil in life vertically elliptical; pineal ocellus not visible externally; vomerine ridges medium sized, orientated acutely, positioned between to slightly posterior to choanae, vomerine teeth small; maxillary teeth present; tongue moderately large, feebly notched posteriorly, medial lingual process absent.

Forelimbs moderately long and thin; forearm slender, shorter than hand (FAL 3.4, HAL 6.5); fingers moderately long, with narrow lateral fringes and rudimentary webbing (Fig. 2 ); finger length formula I <II <IV <III (FIL 2.6, FIIL 3.6, FIIIL 6.0, FIVL 4.4); supernumerary, thenar and metacarpal tubercles absent, with slightly visible subarticular tubercles; finger tips rounded, with subcircular pads, without terminal grooves, slightly expanded relative to digit widths (FIIIW 0.2, FIIIDW 0.3).

Hindlimbs long and thin, heels overlapping when hindlimbs held at right angles to body; thighs slightly shorter than shanks and feet (TL 9.1, SHL 10.9, FOL 10.8); toes with narrow lateral fringes, rudimentary webbing; relative toe lengths I <II <V <III <IV; toe tips rounded, with subcircular pads, terminal grooves absent; supernumerary, subarticular and outer metatarsal tubercles absent; inner metatarsal tubercles indistinct.

Skin of dorsal and ventral surfaces of head, body and limbs basically smooth; dorsal skin with very small densely-distributed granules; tympanum smooth with borders slightly raised; supratympanic ridges thin before and above departure with tympanum and gradually expanding beyond posterior edge of tympanum; skin ridges formed by small disconnected tubercles;)(-shaped skin ridge on center of dorsum, its anterior ends extending posteriorly from above tympanum; flanks with two slender skin ridges, started at the shoulder and ended on both sides of the back of the cloaca; two small pectoral glands positioned on level with axilla; femoral glands moderate, positioned posterior surface of thigh, sub-equally distant from knee and cloaca.

Coloration in life.

Dorsal surface basically saddle brown, darker on anterior and hindlimbs than on posterior; orange-red granules scattered on surface; dark brown) (-shaped marking with orange edge on central dorsum; ventrolateral trunk with white spots and orange dots; dark brown triangular pattern with orange edges presents between eyes, and dark brown rod-like pattern positioned in front of triangular pattern; supratympanic fold white mingled with orange flecks; temporal region under supratympanic ridge black; two dark brown patches present on upper lips under eye and nostril on side of head; eight relatively large white patches present on lower lip, symmetrically distributed; two white symmetrically curved lines on both sides of throat; many orange-red dots scattered on surface of throat; iris orange-red; two dark transverse bands on each forearm; finger tips orange-red; large white blotches on belly and ventral surfaces of hindlimbs; three dark transverse bands on anterior surface of thigh and shank; femoral glands white on thigh.

Coloration in preservative.

After preservation in ethanol, dorsal surface primarily brown; dark brown triangular pattern with white edges presents between eyes; brown) (-shaped marking with white edge on central dorsum; two white slender skin ridges in flanks; two dark transverse bands on each forearm; dark brown band with white dots in middle of thigh and shank; throat pale brownish grey, two white symmetrically curved lines distinct; eight distinct white patches on lower lip; chest brown with two white pectoral glands; belly pale gray-white with large black-brown blotches on sides; posterior ventral body surface, thigh, and upper part of tibia pale brown with scattered white spots; ventral surfaces of fingers and toes dark brown with white blotches.

Variations.

Paratypes generally resemble the holotype but with some differences. For example, a few specimens (YBU21258, YBU21262 and YBU21269) have the head width greater than the head length; YBU21258 had more and larger maxillary teeth, the tongue thinner; rod-like patterns on the top of head different between specimens. Coloration varied on ventral body, with some specimens being darker. The tips of the fingers in some specimens were not orange-red.

Sexual dimorphism.

Males: external vocal sac indistinct; internal vocal slit present on floor of mouth near rear of mandible, one on each side; vocal sac, vocal slits, and enlarged forearms all absent in female.

Tadpole.

Gosner stages 25-36. Body length range from 6.3-13.8 mm (Table 4 ); oral disk funnel like, positioned anterior-dorsal, large, width average 1.5 × (1.1-1.7, n = 13) maximum body width, rice-like submarginal papillae scattered on lower and upper lips and pointed towards oral cavity; nares oval and closer to eye than to snout (RN 1.0, NE 0.4); internarial distance nearly equal to interorbital distance (IND 2.8, PP 2.7); eyes dorsolateral, pupils rounded; spiracle opens left of body in dorsal view, spiracular tube positioned equidistant between tip of the snout and trunk-tail junction; the tail accounts for 0.7 of the total length (TOL 37.0, TAL 26.6); dorsal fin arise near middle of tail, upper tail fin higher than lower tail, and approximately half of tail muscle height (UF 1.5, LF 1.1, TMW 2.8)(Fig. 4 ).

Coloration in preservative. Dorsal and lateral parts of body greyish white, mixed with brown patches; lateral tail semi-transparent brown, muscle scattered with many distinct brown patches; no pigment on upper and lower fins; ventral body semi-transparent white, with tiny gray pigment scattered on it, the viscera can almost be seen; lips semi-transparent white, papillae brown. Coloration in life were not noted.

Distribution and ecology.

Xenophrys pangdaensis sp. nov. is only known from the type locality, Yadong Town, Yadong County, Tibet Autonomous Region, China at elevations of 2003-2972 m. All calling males were recorded in August and September on ferns near or on a small stream in the tropical forest (Fig. 5 ). The tadpoles collected from near the type locality were from Gosner stages 25-36. The habitat is located in the small gully, both sides covered with ferns and other vegetation. None of the adults or tadpoles were found in July, and all specimens were found in late August and early September, implying that the breeding season included August and September. The sympatric species, Raorchestes yadongensis Zhang, Shu, Liu, Dong & Guo, 2022, Nanorana blanfordii (Boulenger, 1882), Duttaphrynus himalayanus ( Günther, 1864), and Nanorana liebigii ( Günther, 1860) were also recorded.

Comparisons.

Xenophrys pangdaensis sp. nov. is here compared with all 28 recognized species of the Xenophrys (Table 5 ). The smallest recognized species of Xenophrys is X. zunhebotoensis (male 28.4-33.9, females 37-39.5). So, by having small body size (males 18.0-22.2 mm, n = 6; female 23.4 mm, n = 1), Xenophrys pangdaensis sp. nov. differs from all congeners from Xenophrys .

Xenophrys pangdaensis sp. nov. differs from X. awuh , X. damrei , X. dzukou , X. flavipunctata , X. glandulosa , X. megacephala , X. numhbumaeng , X. oropedion , X. serchhipii , X. takensis , X. truongsonensis , X. zhangi , X. zunhebotoensis , X. pava , X. dehongensis , and X. lancangica by the presence of a horn-like tubercle laterally on the upper eyelid (vs absence of horn-like tubercle at edge of upper eyelid).

Xenophrys pangdaensis sp. nov. differs from X. awuh , X. monticola , X. robusta , and X. zunhebotoensis by presence of vomerine teeth (vs absence of vomerine teeth).

Xenophrys pangdaensis sp. nov. differs from X. lekaguli , X. truongsonensis by presence of vocal sac (vs absence of vocal sac).

Xenophrys pangdaensis sp. nov. differs from X. ancrae , X. awuh , X. dzukou , X. flavipunctata , X. himalayana , X. major , X. megacephala , X. monticola , X. numhbumaeng , X. oropedion , X. periosa , X. robusta , X. serchhipii , X. takensis , X. zhangi , X. zunhebotoensis , X. pava , X. dehongensis and X. lancangica by absence of nuptial pads on fingers (vs presence of nuptial pads on fingers).

Xenophrys pangdaensis sp. nov. differs from X. ancrae , X. awuh , X. dzukou , X. glandulosa , X. major , X. mangshanensis , X. maosonensis , X. medogensis , X. monticola , X. numhbumaeng , X. oropedion , X. truongsonensis , X. zhangi , X. zunhebotoensis , X. pava , X. lancangica (vs tongue feebly notched), X. auralensis , X. lekaguli , X. megacephala , X. robusta , X. takensis , X. dehongensis by tongue distinctly notched (vs tongue not notched).

Xenophrys pangdaensis sp. nov. differs from X. ancrae , X. awuh , X. auralensis , X. damrei , X. lekaguli , X. mangshanensis , X. maosonensis , X. medogensis , X. megacephala , X. numhbumaeng , X. oreocrypta , X. oropedion , X. periosa , X. robusta , X. serchhipii , X. takensis , X. zunhebotoensis , X. pava , and X. dehongensis by having narrow lateral fringes on toes (vs lateral fringes on toes absent), and X. glandulosa (vs lateral fringes on toes wide).

Xenophrys pangdaensis sp. nov. differs from X. dzukou , X. mangshanensis , X. oropedion , X. zhangi , X. pava , and X. zunhebotoensis by toes with rudiment of webbing (vs toes without webbing), X. flavipunctata , and X. maosonensis (vs at most one-fourth webbed).

Xenophrys pangdaensis sp. nov. differs from X. ancrae , X. awuh , X. damrei , X. dzukou , X. flavipunctata , X. glandulosa , X. himalayana , X. lekaguli , X. major , X. mangshanensis , X. maosonensis , X. medogensis , X. megacephala , X. monticola , X. numhbumaeng , X. oreocrypta , X. oropedion , X. periosa , X. robusta , X. serchhipii , X. takensis , X. truongsonensis , X. zhangi , X. zunhebotoensis , X. pava , X. lancangica and X. dehongensis by presence of indistinct subarticular tubercles on toes (vs absence of subarticular tubercles on toes).

Xenophrys pangdaensis sp. nov. differs from X. awuh , X. damrei , X. dzukou , X. glandulosa , X. lekaguli , X. mangshanensis , X. maosonensis , X. numhbumaeng , X. periosa , and X. truongsonensis by dorsal skin texture smooth with small tubercles (vs dorsal skin texture smooth), X. dehongensis (vs dorsal skin rough).

Figures

Figure 2. Phylogenetic tree of the genus Xenophrys inferred from two mitochondrial gene fragments by Bayesian inference.

Figure 3. Xenophrys pangdaensis sp. nov. in life. A dorsal view of body B ventral view of body C ventral view of hand D ventral view of foot E lateral view of body F lateral view of head.

Figure 4. Tadpole of Xenophrys pangdaensis sp. nov. (Gonser stage 29) from Yadong County, Tibet Autonomous Region, China. A dorsal view of the tadpole B ventral view of the tadpole C lateral view of the tadpole. All photographs of just- preserved specimens.

Figure 5. Habitat of Xenophrys pangdaensis sp. nov. in the type locality, Pangda Village, Yadong County, Tibet Autonomous Region, China.