Boulenophrys yunkaiensis, Qi & Lyu & Wang & Mo & Zeng & Zeng & Dai & Li & Grismer & Wang, 2021

Qi, Shuo, Lyu, Zhi-Tong, Wang, Jian, Mo, Yun-Ming, Zeng, Zhao-Chi, Zeng, Yang-Jin, Dai, Ke-Yuan, Li, Yuan-Qiu, Grismer, L. Lee & Wang, Ying-Yong, 2021, Three new species of the genus Boulenophrys (Anura, Megophryidae) from southern China, Zootaxa 5072 (5), pp. 401-438 : 421-424

Boulenophrys yunkaiensis sp. nov. Qi, Wang, Lyu & Wang

Yunkai Horned Toad / yun kai jiao chan (云开fflDz)

Figures 6 , 7C

Chresonymy. Megophrys sp 32 (SYS a004637–4638, 4694)— Liu et al. 2018

Holotype. SYS a004637 ( Figs. 6A , 7C ), adult male, collected on 14 April 2016 by Jian Wang , Zhi-Tong Lyu and Ying-Yong Wang from the Yunkaishan Nature Reserve (22.2758°N, 111.1952°E; ca 950 m a.s.l.), Xinyi City, Guangdong Province, China.

Paratypes. Eight adult specimens from the same locality as the holotype: males SYS a004636 and SYS a004638 collected on 14 April 2016 by Jian Wang, Zhi-Tong Lyu and Ying-Yong Wang; male SYS a004662/ CIB 116085 and females SYS a004659 ( Figs. 6B ) and SYS a004660 collected on 15 April 2016 by Jian Wang, Zhi-Tong Lyu and Ying-Yong Wang; female SYS a004691 collected on 16 April 2016 by Jian Wang, Zhi-Tong Lyu and Ying-Yong Wang; males SYS a004986 and SYS a004987 collected on 28 June 2016 by Jian Wang .

Etymology: The specific epithet yunkaiensis refers to its type locality, the Yunkaishan Nature Reserve, western Guangdong, China.

Diagnosis. (1) Small body size, SVL 35.3–40.0 mm (37.6 ± 1.7, N = 6) in adult males and SVL 45.3–46.1 mm (45.8 ± 0.4, N = 3) in adult females; (2) snout rounded in dorsal view; (3) tympanum boundary clear, ED/TD 1.68–1.91 in males, 1.47–1.80 in females; (4) presence of vomerine ridge and absence of vomerine teeth; (5) margin of tongue rounded, not notched behind; (6) hindlimbs slender, heels overlapping or just meeting and tibio-tarsal articulation reaching forward between tympanum to posterior corner of eye when leg stretched forward; (7) tibia 0.40–0.48 of SVL and foot 0.60–0.68 of SVL in males, while tibia 0.42–0.46 of SVL and foot 0.59–0.66 of SVL in female; (8) a subarticular tubercle present at the base of each fingers; (9) toes without lateral fringes and with only rudimentary webbing; (10) presence of small horn-like tubercle at the edge of upper eyelid; (11) surface around cloaca with large tubercles bearing tiny spines; (12) dorsal skin rough with small granules, a discontinuous “X” or “Y”-shaped ridge with two discontinuous dorsolateral ridges on two side of dorsum; (13) sparse distinct enlarged tubercles on the flanks; (14) single subgular vocal sac in males; (15) presence of villiform black nuptial spines on the dorsal surface of the first and second fingers in adult males; (16) dense tubercles on skin of upper lip, upper eyelid, mandibular articulation, loreal and temporal regions; (17) dense tubercles on skin of ventral surface of thigh, spiny tubercles surrounding the cloaca.

Comparisons. Comparative data of Boulenophrys yunkaiensis sp. nov. from B. yaoshanensis sp. nov., B. yingdeensis sp. nov., and the other recognized members of the genus Boulenophrys are listed in Table 3 .

Having a smaller body size with SVL 35.3–40.0 mm in males, Boulenophrys yunkaiensis sp. nov. is significantly different from congeners whose SVL> 50 mm in males, including B. caudoprocta (81.3 mm in single male), B. jingdongensis (53.0– 56.5 mm in males), B. liboensis (60.5–67.7 mm in males), B. mirabilis (55.8–61.4 mm in males), B. omeimontis (56.0– 59.5 mm in males), B. sangzhiensis (54.7 mm in single male), and B. shuichengensis (102.0– 118.3 mm in males).

Having relatively longer shanks with the heels overlapping or meeting when the flexed hindlimbs are held at right angles to the body axis, Boulenophrys yunkaiensis sp. nov. can be easily distinguished from the following nine congeners, B. acuta , B. brachykolos , B. daoji , B. dongguanensis , B. insularis , B. nankunensis , B. obesa , B. ombrophila , and B. wugongensis (vs. all of which have relatively shorter shanks with the heels not meeting).

Lacking vomerine teeth, Boulenophrys yunkaiensis sp. nov. differs from B. caudoprocta , B. daiyunensis , B. daweimontis , B. dongguanensis , B. fansipanensis , B. frigida , B. hoanglienensis , B. insularis , B. jingdongensis , B. jinggangensis , B. jiulianensis , B. liboensis , B. nankunensis , B. nanlingensis , B. omeimontis , B. palpebralespinosa , B. qianbeiensis , B. rubrimera , B. sangzhiensis , B. shimentaina , B. tongboensis , and B. yingdeensis sp. nov. (vs. presence of vomerine teeth in these species).

Having an unnotched tongue, Boulenophrys yunkaiensis sp. nov. can be distinguished from B. baolongensis , B. binlingensis , B. boettgeri , B. cheni , B. hoanglienensis , B. huangshanensis , B. insularis , B. jingdongensis , B. jiulianensis , B. kuatunensis , B. liboensis , B. lushuiensis , B. minor , B. nanlingensis , B. ombrophila , B. qianbeiensis , B. sangzhiensis , B. sanmingensis , B. shuichengensis B. spinata , and B. tongboensis (vs. tongue notched posteriorly in these species).

Lacking lateral fringes on toes, Boulenophrys yunkaiensis sp. nov. differs from B. acuta , B. anlongensis , B. baishanzuensis , B. binchuanensis , B. boettgeri , B. congjiangensis , B. cheni , B. daiyunensis , B. daoji , B. jingdongensis , B. jinggangensis , B. liboensis , B. lini , B. lushuiensis , B. mirabilis , B. mufumontana , B. nanlingensis , B. omeimontis , B. palpebralespinosa , B. qianbeiensis , B. rubrimera , B. sangzhiensis , B. sanmingensis , B. shimentaina , B. shuichengensis , B. spinata , B. xiangnanensis , B. xianjuensis , and B. yangmingensis (vs. presence of lateral fringes on toes in these species); and from B. wushanensis (vs. presence of wide lateral fringes on toes in males while lacking in females).

Having rudimentary webbing on toes, Boulenophrys yunkaiensis sp. nov. differs from B. baishanzuensis , B. baolongensis , B. daweimontis , B. fansipanensis , B. frigida , B. huangshanensis , B. kuatunensis , B. lishuiensis , B. ombrophila , B. rubrimera , B. tongboensis , and B. wuliangshanensis (vs. absence of webbing on toes in these species); and from B. jingdongensis , B. palpebralespinosa , B. qianbeiensis , B. shuichengensis , and B. spinata (vs. presence of well-developed webbing on toes in these species).

For the remaining eight species, Boulenophrys yunkaiensis sp. nov. can be further distinguished by body size with SVL 45.3–46.1 mm in females (vs. 37.5–39.2 mm in B. angka , 39.5–40.4 mm in B. jiangi , 42.3 mm in B. leishanensis , 37.6 mm in B. shunhuangensis , and 50.5 mm in B. tuberogranulatus ), the relative finger lengths II <I = IV <III (vs. I <II <IV <III in B. angka, IV <I <II <III in B. caobangensis ), and the presence of tiny spines on skin of upper lip, upper eyelid, loreal and temporal regions excluding the tympanum in adult males (vs. absence of such tiny spines in B. angka , B. chishuiensis , B. jiangi , B. leishanensis , B. shunhuangensis , B. tuberogranulatus , and B. yaoshanensis sp. nov.).

Description of holotype. Adult male. small body size, SVL 37.0 mm; head width slightly larger than head length, HWD/HDL 1.15; snout rounded in dorsal view, projecting, sloping backward to mouth in profile, protruding well beyond the margin of lower jaw; top of head flat; eyes moderate in size, ED 0.36 of HDL, pupil vertical, near diamond-shaped; nostril oblique-ovoid; canthus rostralis well developed; loreal region slightly oblique; internasal distance slightly larger than interorbital distance; tympanum boundary clear, TD/ED 1.84; large ovoid choanae at the base of the maxilla; vomerine ridge weak, vomerine teeth absent, maxillary teeth present; margin of tongue rounded, not notched behind; presence of a single subgular vocal sac, a pair of slit-like openings at posterior of jaw.

Radio-ulnar length 0.22 of SVL and hand 0.27 of SVL; hand without webbing, fingers without lateral fringes, relative finger length II <I = IV <III; tips of fingers slightly dilated, round; subarticular tubercles present and distinct; inner metacarpal tubercle observably enlarged and the outer one smaller; a single nuptial pad on the dorsal surface of the first and second fingers. Hindlimbs slender, tibio-tarsal articulation reaching forward between eye and tympanum when hindlimb is stretched along the side of the body; heels just meeting when the flexed hindlimbs are held at right angles to the body axis; tibia length 0.46 of SVL and foot length 0.65 of SVL; relative toe length I <II <V <III <IV; tips of toes round and slightly dilated; toes without lateral fringes and with only rudimentary webbing; subarticular tubercles indistinct but recognizable; inner metatarsal tubercle long ovoid and the outer one absent.

Skin of doesum rough with sparse granules; sparse large tubercles on the flanks; a small, horn-like prominent tubercle on the edge of upper eyelid; clear supratympanic fold curving posteroventrally from posterior corner of eye to a level above insertion of arm; dense tubercles on skin of upper lip, upper eyelid, mandibular articulation, loreal and temporal regions, excluding the tympanum and surface around cloaca, some of them bearing tiny spines; a discontinuous “X” shaped ridge and a few elongated warts arranged in longitudinal rows on two sides at the middorsum; sparse tubercles on the dorsal shank and thigh; ventral surface smooth; small pectoral gland close to axilla; a single femoral gland positioned subequally distant from knees and cloaca on posterior surface of each thigh.

Coloration of holotype in life. Dorsal surface of body yellowish brown with an inverted brown triangular marking between eyes; an “X” shaped marking on the mid-dorsum. Forearms and hindlimbs with dark brown transverse bands. Supratympanic fold with a discontinuous white line; a dark vertical band below the eye, from the inferior margin of the eye to the upper lip. Numerous brown patches scattered on lateroventral surface of flanks; groin red-orange. Ventral surface of throat and chest light salmon in color with brown patches, an indistinct longitudinal stripe on throat; ventral surface of body light salmon in color with brown patches and white spots; ventral surface of limbs light salmon in color with dark brown spots and blotches; ventral surfaces of hands and ventral surfaces of feet brown, tips of digits pale brown; metacarpal tubercle and metatarsal tubercle reddish. Pectoral glands and femoral glands white. Iris yellowish brown.

Coloration of holotype in preservative. Yellowish brown faded to greyish brown dorsally. Triangular marking between eyes, “X”-shaped marking on the mid-dorsum, transverse bands on dorsal forearms and hind limbs became indistinct. Color of ventral surface faded to greyish white, all bands and spots became indistinct.

Variation and sexual dimorphism. Measurement data of type series are listed in Table 6 . Females ( SVL 45.3–46.1 mm) are distinctly larger than males ( SVL 35.3 –40.0 mm). In adult males, skin of upper lip, upper eyelid, mandibular articulation, loreal and temporal regions excluding the tympanum and surface around cloaca with dense tubercles, some of them bearing tiny spine. Tubercles present in females but without tiny spines. Presence of villiform black nuptial spines on the dorsal surface of the first and second fingers in adult males .

Distribution and ecology. Currently, Boulenophrys yunkaiensis sp. nov. is known only from Yunkaishan Nature Reserve, Guangdong, China.All individuals were found in evergreen secondary forest, near montane streams and in the nearby leaf litter on the forest floor at elevations between 900–1400 m. Males call on the rocks by the flowing streams from April to June, suggesting their breeding season corresponds to this period. Females were found on the forest floor, and one female was observed feeding on an earthworm. Tadpoles could be found all year-round.

Figures

FIGURE 6. Boulenophrys yunkaiensis sp. nov. in life. A: holotype (SYS a004637), male; B: paratype (SYS a004659), female; 1: dorsolateral view; 2: ventral view; 3: hand; 4: foot.

FIGURE 7. Comparisons of lateral position of the head with three new Boulenophrys species in preservative. The white arrows marking tubercles bearing tiny spine in Boulenophrys yunkaiensis sp. nov.. A: Boulenophrys yaoshanensis sp. nov. (SYS a002189); B: Boulenophrys yingdeensis sp. nov. (SYS a002099); C: Boulenophrys yunkaiensis sp. nov. (SYS a004637).