Xenophrys insularis, Wang, 2017

Wang, Ying-Yong, 2017, A new species of the genus Xenophrys (Amphibia: Anura: Megophryidae) from an offshore island in Guangdong Province, southeastern China, Zootaxa 4324 (3), pp. 541-556 : 547-554

Xenophrys insularis sp. nov.

Figure 3 & 4 .

Chresonymy: Megophrys minor Stejneger, 1926 : Li et al. 2011.

Holotype. SYS a002169, adult male ( Figure 3 : A to D, Figure 4 ), collected on 29 June 2013 by Yu-Long Li (YLL hereafter), Jian Zhao (JZ hereafter) and Run-Lin Li ( RLL hereafter) from Nan’ao Island (23°26'0.09" N, 117°4'45.61" E; 425 m a.s.l.), Shantou City, Guangdong Province, China ( Figure 1 ).

Paratypes. Five specimens (four adult males, one adult female), from Nan’ao Island at elevations between 50– 500 m a.s.l., SYSa002168 ( Figure 3 : E and F), adult female, SYS a002167, 2170–71, adult males, collected on 29 June 2013 by YLL, JZ, and RLL, SYS a003666 / CIB 106881, adult male, collected on 29 April 2015 by Jian Wang (JW hereafter) and Can-Rong Lin ( CRL hereafter).

Diagnosis. Xenophrys insularis sp. nov. is characterized by the combination of following characters: (1) Body stout and moderate-sized, SVL 36.8–41.2 mm in four adult males, 47.1 mm in the single adult female specimen; (2) head width slightly larger than head length; (3) snout obtusely rounded in dorsal view; (4) tympanum distinct and small, TD/ED ratio 0.46–0.57; (5) vomerine ridge strong with vomerine teeth; (6) margin of tongue weakly notched behind; (7) hindlimbs short, heels not meeting, tibio-tarsal articulation reaches the posterior edge of tympanum on each side; (8) fingers and toes without lateral fringes; (9) toes with rudiment of webs at their bases; (10) subarticular tubercle only present at the base of each finger and toe; (11) dorsal skin rough with several large warts scattered on flanks, usually short skin ridges occurred on dorsal body; (12) presence of a barely visible hornlike tubercle at the edge of the eyelid; (13) supratympanic fold narrow, forming a swollen supraaxillary gland above insertion of arm; (14) greyish brown or dark olive dorsally, dorsal coloration uniform with only a barely visible incomplete dark triangle present between eyes and several dark brown cross-bars on dorsal limbs; (15) presence of a single vocal sac in males; (16) presence of two darker brown nuptial spines on dorsal surface of the first and second fingers during breeding season, respectively.

Comparisons. Comparative data of Xenophrys insularis sp. nov. with 48 recognized species of the genus Xenophrys were obtained from the literature ( Boulenger 1908; Inger & Romer 1961; Taylor 1962; Fei et al. 1992; Tian et al. 2000; Ohler et al. 2002; Mathew & Sen 2007; Fei et al. 2009; Mahony et al. 2010; Mahony 2011; Mahony et al. 2011; Stejneger 1926; Wang et al. 2012; Mahony et al. 2013; Li et al. 2014; Wang et al. 2014; Orlov et al. 2015; Wang et al. 2017) or from own examination of individuals of X. acuta , X. boettgeri , X. brachykolos , X. cheni , X. jinggangensis , X. kuatunensis , X. mangshanensis , X. maosonensis (Bourret) , X. minor , X. lini and X. obesa , as listed in Appendix 1. All comparative morphological data are shown in Tables 3 and 4.

Xenophrys insularis sp. nov., was previously reported as X. minor ( Li et al. 2011) , and differs from true X. minor from type locality by having obtusely rounded snout (vs. pointed snout); presence of the horn-like tubercles above the eye (vs. absent); comparative tympanum size, TD/ED ratio 0.46–0.57 (vs. enlarged tympanum, TD/ED ratio 0.8–0.83), tympanum diameter being almost equidistant with tympanum–eye distance, TED/TD ratio 0.92– 1.00 (vs. TD greater than TED, TED/TD ratio 0.61–0.62); shank short, TIB/SVL ratio 0.38–0.43 (vs. TIB/SVL ratio 0.46–0.48); tibio-tarsal articulation reaching the posterior edge of tympanum (vs. reaching the region between eye and tip of snout); the heels not meeting when thighs are positioned at right angles to the body in the new species (vs. heels meeting or overlapping).

Xenohprys insularis sp. nov. significantly differs from ten species occurring in eastern and southern China by the following combination of characters: presence of vomerine teeth (vs. absence in X. brachykolos , X. boettgeri , X. kuatunensis , X. huangshanensis , X. lini , X. cheni , X. acuta , X. obesa , X. lishuiensis ); margin of tongue notched behind (vs. not notched in X. brachykolos , X. jinggangensis , X.lini , X. acuta , X. obesa , X. lishiuensis ); toes without lateral fringes (vs. with lateral fringes in X. boettgeri , X. kuatunensis , X. jinggangensis , X. lini , X. cheni , X. acuta ); hindlimbs comparatively short, with heels not meeting when thighs are positioned at right angles with respect to body (vs. hindlimbs comparatively longer, with heels meeting or overlapping in X. boettgeri , X. kuatunensis , X. jinggangensis , X. lini , X. cheni ).

Body size of the new species is smaller than that of the following 20, additional species of Xenophrys , with no overlap of values: X. aceras (Boulenger) , X. auralensis (Ohler, Swan & Daltry) , X. binglingensis (Jiang, Fei & Ye) , X. caudoprocta (Shen) , X. damrei (Mahony) , X. glandulosa (Fei, Ye & Huang) , X. jingdongensis (Fei & Ye) , X. lekaguli (Stuart, Chuaynkern, Chan-ard & Inger) X. longipes (Boulenger) , X. major (Boulenger) , X. mangshanensis , X. maosonensis , X. medogensis (Fei, Ye & Huang) , X. megacephala (Mahony, Sengupta, Kamei & Biju) , X. omeimontis (Liu) , X. robusta (Boulenger) , X. sangzhiensis (Jiang, Ye & Fei) , X. shuichengensis (Tian & Sun) , X. spinata (Liu & Hu) , X. takensis (Mahony) . Body size of the new species is larger than in the following eight additional species with no overlap values: X. acuta , X. cheni , X. kuatunensis , X. lishuiensis , X. pachyproctus (Huang) , X. vegrandis (Mahony, Teeling & Biju) , X. wuliangshanensis (Ye & Fei) , X. wushanensis (Ye & Fei) . Comparative data see Table 3.

From the remaining 13 species of the genus which share a moderate body size with the new species, X. insularis sp. nov. can be steadily distinguished by the following combination of characters: hindlimbs short, heels not meeting each other when thighs are adpressed at right angles with respect to body (vs. relatively long hindlimbs, heels meeting or overlapping in X. palpebralespinosa (Bourret) , X. parva (Boulenger) , X. tuberogranulatus (Shen, Mo & Li) , X. zhangi (Ye & Fei) , X. daweimontis (Rao & Yang) , X. binchuanensis (Ye & Fei) , X. ancrae (Mahony, Teeling & Biju) , X. oropedion (Mahony, Teeling & Biju) ; tibio-tarsal articulation reaches the posterior edge of tympanum (vs. reaches the anterior region of eye in X. serchhipii , reaches the middle of eye in X. zunhebotoensis Mathew & Sen ); vomerine teeth present (vs. absent in X. baolongensis (Ye, Fei & Xie)) ; margin of tongue notched behind (vs. not notched in X. oropedion , X. parallela (Inger & Iskandar) , X. palpebralespinosa , X. parva , X. tuberogranulatus and X. latidactyla (Orlov, Poyarkov & Nguyen)) ; toes with rudiment of webs (vs. at least one-fourth webbed in X. ancrae and X. serchhipii ).

Description of holotype. Adult male. Habitus stout, body size moderate, SVL 39.7 mm; head length slightly shorter than head width, HDW/HDL ratio 1.09; snout rounded nearly to truncate in dorsal view, slightly projecting, sloping backward to mouth in profile, protruding beyond margin of lower jaw; top of head flat; eye large, EYE 41% of HDL, pupil vertical; canthus rostralis well developed; loreal region slightly sloping, not concave; internasal distance slightly larger than interorbital distance; tympanum large, rounded, distinctly visible, TMP/EYE ratio 0.57; choanae large, ovoid at the bases of the maxilla; strong vomerine ridges with vomerine teeth; margin of tongue weakly notched behind.

Radioulna length 25% of SVL, hands without webbing, hand length 25% of SVL; no lateral fringes, relative finger lengths: II <I ± III <IV; tips of digits rounded, slightly dilated; a large subarticular tubercle at the base of each finger; hindlimbs of moderate length, slightly robust; tibio-tarsal articulation reaches forward to the posterior edge of tympanum when hindlimb is stretched along the side of the body; heels not meeting when thighs are held at right angles to the body axis; tibia length 42% of SVL; foot length 60% of SVL; relative toe lengths: I <II <V <III <IV; tips of toes rounded, slightly dilated; toes with rudiment of webs at their bases; subarticular tubercles absent; no lateral fringes; external tarsal fold present; inner metatarsal tubercle long ellipsoid; outer metatarsal tubercle absent.

Dorsal skin rough, with numerous granules and tubercles; several large warts scattered on flanks; an indistinct horn-like tubercle at the edge of the eyelid, barely visible in ethanol; supratympanic fold distinct, curving posteroventrally from posterior corner of eye to a level above insertion of arm and forming a raised supraaxillary gland on each side; ventral surface smooth, with small granules on throat and chest, posteriorly densly covered with pustules and small granules on belly, ventral side and rear of thighs; pectoral gland closer to axilla than to midventral line; single femoral gland on rear of thigh.

TABLE ³. Diagnostic characters separating X. insularis sp. nov. from all known 48 recognizeđ species of Xenophrys occurring from the Inđia, Inđo-China Peninsula to China. Comparative đata were obtaineđ from the literature ( Boulenger 1908; Inger & Romer 1961; Inger 1995; Inger et al. 2005; Taylor 1962; Fei et al. 1992; Tian et al. 2000; Orlov et al. 2015; Ohler et al. 2002; Mathew & Sen

; Fei et al. 2009; Mo et al. 2010; Mahony 2011; Mahony et al. 2011; Wang et al. 2012; Mahony et al. 2013; Wang et al. 2014) anđ examineđ specimens of X. boettgeri , X. brachylokos , X. cheni , X. huangshanensis , X. jinggangensis , X. kuatunensis , X. lini , X. mangshanensis , X. maosonensis , X. minor , X. omeimontis anđ X. spinata .

……continued on the next page TABLE 3. (Continued) Measurements of holotype (in mm). SVL 39.7, HDL 10.5, HDW 11.2, SNT 4.4, IND 3.5, IOD 3.3, EYE 3.7, TMP 2.5, TEY 1.6, HND 7.8, RAD 8.2, FTL 17.8, TIB 13.4.

Coloration of holotype in life. Dark-olive above; an incomplete dark interorbital triangle between the eyes; forearm with a distinct, black oblique band; hindlimbs with black transverse bands; tip of snout dark brown; a dark brown vertical band under the eye; supratympanic fold light-colored. Ventral surface of throat, chest and anterior abdomen greyish-brown, scattered with white spots; ventral surface of limbs greyish-white; palms, soles, inner metatarsal tubercle and outer metacarpal tubercle greyish-white; pectoral glands and femoral glands white. Pupil black; iris brown. See Figure 3 .

Coloration of holotype in preservative. Dark-olive fades to greyish-brown on dorsal surface; incomplete dark triangle between the eyes and transverse bands on dorsal limbs becomes indistinct; color of ventral surface fades: ventral ground color of throat and chest light orange and covered with blackish-gray spots, belly light yellow with black spots on both flanks. See Figure 4 .

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

All paratypes are very similar in morphology and color pattern but exhibit noticeable sexual dimorphism. Female paratype SYS a002168 ( Figure 3 : E and F) with greater body size (SVL 47.1 mm vs. 36.8–41.2 mm in all male paratypes and the holotype); all males with a single subgular vocal sac, and two patches of dark brown nuptial spines on the dorsal surfaces first and second fingers, respectively. In addition, in female paratype SYS a002168, dorsal skin with short skin ridges, supraaxillary gland well developed; brownish-yellow above; throat and chest brownish-red, belly greyish-white. In male paratype SYS a002167, dorsal body with an indistinct V-shaped ridge and short ridge on dorsolateral trunk of body. In male paratype SYS a002170, dorsal coloration olive. In male paratype SYS a003666 / CIB 106881, dorsum greyish-brown with numerous scattered black spots.

Etymology. The specific epithet “ insularis ” is a Latin adjective “of or belonging to an island”, referring to the new species as an endemic dweller to the Nan’ao Island. We propose the common English name “ Nan’ao Island Horned Toad ”, Chinese name “ Nan Ao Dao Jiao Chan ”.

Distribution and habits. Xenophrys insularis sp. nov. is known only from the type locality, Nan’ao Island, Shantou City, Guangdong Province, China. It inhabits forest floor, leaf litter, and the nearby undergrowth along slow montane streams surrounded by moist subtropical evergreen broadleaved forests at elevations between 50– 500 m ( Figure 1 ). It appears to be an endemic species to the Nan’ao Island, with an area of occurrence estimated to be less than 10 km 2.

Figures

FIGURE 1. Sampling localities of Xenophrys toads in this study. 1: Nan’ao Island, Guangdong; 2: Hong Kong; 3: Heishiding Nature Reserve, Guangdong; 4: Mt. Longtou, Guangdong; 5: Nanfengmian Nature Reserve, Hunan; 6: Mt. Jinggang, Jiangxi; 7: Taoyuandong Nature Reserve, Hunan; 8: Guadun Village (= Kuatun), Fujian; 9: Mt. huangshan, Anhui; 10: Dujiangyan City, Sichuan.

FIGURE 3. A and B: Dorsolateral and ventral views of the adult male holotype SYS a 002169 of Xenophrys insularis sp. nov. in life; C and D: Ventral views of hand and foot of the holotype in life; E and F: Dorsolateral and ventral views of the adult female paratype SYS a 002168 in life.

FIGURE 4. A, B and C: Dorsal, ventral and lateral views of the adult male holotype SYS a 002169 of Xenophrys insularis sp. nov. in preservative; D: Front view of head the holotype in preservative; E and F: Ventral views of hand and foot of the holotype in preservative.