Oreolalax longmenmontis, Hou & Shi & Hu & Deng & Jiang & Xie & Wang, 2020

Hou, Yinmeng, Shi, Shengchao, Hu, Daming, Deng, Yue, Jiang, Jianping, Xie, Feng & Wang, Bin, 2020, A new species of the toothed toad Oreolalax (Anura, Megophryidae) from Sichuan Province, China, ZooKeys 929, pp. 93-115 : 93

Oreolalax longmenmontis sp. nov. Figures 3 , 4A, B , 5 , 6 ; Tables 1, 2, Suppl. materials 1, 2

Holotype.

CIB20180522001, adult male (Fig. 3 ), from Xia Jia Gou (31.293360N, 103.866190E, ca. 1335 m a. s. l.), White River National Nature Reserve, Pengzhou City, Sichuan Province, China, collected by SC Shi on 26 May 2018.

Paratype.

Two adult males collected from the same place of the holotype. Specimen CIB20180526001 collected by SC Shi on 26 May 2018; CIB20180527002 collected by B Wang on 27 May 2018.

Diagnosis.

Oreolalax longmenmontis sp. nov. is assigned to the genus Oreolalax by its molecular phylogenetic position and the following morphological characters: the maxillary teeth prominent; back rough scattered with large warts, covered with oval black spots; pupil vertical; tongue oval, notched posteriorly; femoral glands prominent; pectoral and axillary gland present in males in breeding season; inner two fingers with black nuptial spines in males in breeding season.

Oreolalax longmenmontis could be distinguished from its congeners by a combination of the following characters: body size moderate (SVL 51.2-64.2 mm in males); head broad; tympanum hidden; interorbital region with dark triangular pattern; belly with marbling; male lacking spines on lip margin; spiny patches on chest small with thick and sparse spines in male; nuptial spines thick and sparse; tibio-tarsal articulation reaching beyond nostril when leg stretched forward; toe webbing at base.

Description of holotype.

Measurements in mm. Body size medium, SVL 64.2; body relatively slender and flat; head wider than long (HDW/HDL ratio 1.14); snout rounded in dorsal and lateral views, slightly projecting beyond lower jaw; maxillary teeth present; vomerine range absent; eye large (ED 6.3), shorter than snout length (SL 9.5); pupil vertical; interorbital region flat; tympanum hidden; vocal sac absent; supratympanic fold significant; tongue longer than wide, free at the back, notched posteriorly; nostril oval, internarial distance (IND 4.5) shorter than upper eyelid (UEW 5.6), shorter than interorbital distance (IOD 6.2); nostril slightly closer to eye (EN 4.3) than to tip of the snout (NS 4.6).

Forelimbs moderately long and strong, length (LAL 31.2) approximately half of SVL; relative finger lengths: II <I <IV <III; fingers slender, distinct longitudinal ridges under fingers III and IV; finger tips rounded, two metacarpal tubercles oval, inner larger than outer; nuptial spines large and sparse on dorsal surface of fingers I and II.

Hindlimbs flat; toe webbing rudimentary, with narrow dermal fringes, distinct dermal ridges present under five toes; tibiotarsal articulation reaching beyond nostril when leg stretched forward; thigh length (THL 31.7) slightly shorter than tibia length (TL 32.8); foot length (FL 31.9) almost equal with thigh; relative toe lengths: I <II <V <III <IV; tips of toes rounded; subarticular tubercles distinct; inner metatarsal tubercle elliptical and narrow (IML 2.7), no outer metatarsal tubercle.

Rough skin on the back, lateral limb surfaces, large scattered tubercles with oval black spot; forehead and upper lip with scatted small tubercles; upper jaw protrudes slightly from lower jaw; supratympanic fold distinct, from posterior canthus above base of upper arm, mostly covered with dark spots. A pair of spinal patches small, present on chest, with relatively large and sparse spines; axillary glands small; posterior femoral gland small present. The backs of limbs with scatted differently sized tubercles; the forelimbs and hindlimbs have black longitudinal stripes, the hindlimbs are covered with medium-sized wart granules, the forelimbs are covered with many small white warty granules. Skin smooth on throat, belly, and ventral sides of the limbs.

Colouration of the holotype in life.

In life, body dark brown dorsally, with large tubercles, tubercular region with scattered black, oval-shaped markings, tongue orange-yellow, limb surfaces dark brown, scattered with different sizes of white tubercles; five or six faint transverse black stripes on the dorsal surface of the forearm; most parts of supratympanic line covered with black spots; belly interlaced with two colours: flesh red and greyish-white with some black speckles, throat and anterior chest are darker than belly. Back of posterior limbs with nine or ten black stripes; finger and toe tips flesh-pink. Arms and fingers covered in many scattered small white tubercles. Dorsal surfaces of head and hind limbs scattered with black medium-sized tubercles; upper lip barred with yellowish brown and black spots; iris bicolored; slightly beige above, silver below, with black reticulations throughout. Posterior femoral glands yellow-brown. Nuptial spines light grey, chest spiny patches flesh-pink. Outer metacarpals grey-pink, inner metatarsals brown.

Preserved holotype colouration.

In preservative (75% ethanol), the dorsal and lateral surfaces are dark brown; throat and anterior chest brown, belly grey, dark markings are evident on the abdomen and throat; the forelimbs and ventral surface of the thigh are brown, Inner and outer metacarpals brown; tongue creamy white; the colour of dorsal spots and stripes on limbs and posterior femoral glands become more conspicuous; the spiny patches become flat and indistinct (Fig. 4A, B ).

Variations.

The two paratypes CIB20180526001 (Fig. 5A, B ) and CIB20180527002 (Fig. 5C, D ) are smaller than holotype on body size (Table 2 , Suppl. material 1). The colour of paratypes is brown, lighter than holotype. The arrangement and shape of the large tubercles on the dorsal surface are more irregular than of the holotype. The paratype CIB20180526001 has fewer abdominal streaks than the holotype. The paratype CIB20180527002 has fewer markings at the meeting of thighs to abdomen and more markings in the posterior abdomen than holotype. Iris colour also varies between individuals: the holotype is light blue-green, CIB20180526001 is yellowish orange, and CIB20180527002 is orange.

Secondary sexual characteristics.

In breeding males, a pair of small spiny patches on chest, nuptial spines thick and sparse on dorsal surface of fingers I and II (Fig. 3D, H ).

Tadpoles.

Measurements in mm. Differences in measurements are shown in Suppl. material 2. Character description is based on the preserved tadpole specimen CIB2018041501 (Fig. 6 ). Stage 37. Labial tooth row formula: 1:5+5/5+5:1; body dark brown in the back and lateral view, creamy white in the ventral; tail light brown; snout rounded; eye positioned dorsolateral; the opening of the spiracle single in the lateral, without a free distal tube; tail end blunt; caudal fin light and broad.

Comparisons.

By having a relatively larger body (SVL 51.2-64.2 mm in males; N = 3), Oreolalax longmenmontis sp. nov. differs from O. pingii (N = 20), O. puxiongensis (N = 20), O. schmidti (N = 30), O. sterlingae (N = 1), O. multipunctatus (N = 4), and O. xiangchengensis (N = 10) (vs. SVL <51.0 mm in the latter).

By head wider than long, O. longmenmontis differs from O. multipunctatus , O. rhodostigmatus , and O. schmidti (vs. head longer than wide in the latter).

By the hidden tympanum, Oreolalax longmenmontis differs from O. granulosus , O. jingdongensis , O. xiangchengensis , and O. rugosus (tympanum absent in the latter) and differs from O. rhodostigmatus (tympanum rather visible).

By lacking spines on lip margin in male, Oreolalax longmenmontis sp. nov. differs from O. sterlingae , O. granulosus , O. jingdongensis , O. liangbeiensis , O. lichuanensis , O. major , O. multipunctatus , O. omeimontis , O. pingii , O. puxiongensis , O. rugosus , O. schmidti , O. weigoldi , and O. xiangchengensis (vs. spines on lip margin visible in male in the latter).

By vocal sac absent, Oreolalax longmenmontis differs from O. omeimontis (vs. vocal sac present in male in the latter).

By interorbital region with dark triangular pattern, Oreolalax longmenmontis differs from O. multipunctatus , O. granulosus , O. major , O. liangbeiensis , O. lichuanensis , O. pingii , O. rhodostigmatus , O. rugosus , O. weigoldi , O. sterlingae , and O. xiangchengensis (vs. without in the latter).

By spiny patches on chest small in male, Oreolalax longmenmontis differs from O. granulosus , O. liangbeiensis , O. major , O. omeimontis , O. pingii , O. rhodostigmatus , O. jingdongensis , O. weigoldi , and O. xiangchengensis (vs. large in the latter).

By spines on spiny patches on chest thick and sparse in male, Oreolalax longmenmontis differs from O. omeimontis , O. granulosus , O. major , O. liangbeiensis , O. pingii , O. puxiongensis , O. rugosus , O. schmidti , O. sterlingae , and O. xiangchengensis (vs. spines thin and fine in the latter).

By nuptial spines on fingers thick and sparse, Oreolalax longmenmontis differs from O. sterlingae , O. omeimontis , O. granulosus , O. liangbeiensis , O. major , O. rugosus , O. schmidti , O. pingii , O. puxiongensis , and O. xiangchengensis (vs. thin and fine in the latter).

By tibio-tarsal articulation reaching beyond nostril when leg stretched forward, Oreolalax longmenmontis differs from O. omeimontis , O. multipunctatus , O. granulosus , O. major , O. liangbeiensis , O. lichuanensis , O. pingii , O. puxiongensis , O. rhodostigmatus , and O. rugosus (vs. reaching up to the posterior corner of eye in the latter).

By toe webbing at base, Oreolalax longmenmontis sp. nov. differs from O. granulosus , O. jingdongensis , O. liangbeiensis , O. major , O. rugosus , O. weigoldi , and O. xiangchengensis (vs. toe IV at least 1/4 webbed in the latter).

By belly with marble spots, Oreolalax longmenmontis differs from O. omeimontis , O. liangbeiensis , O. pingii , O. rhodostigmatus , O. schmidti , and O. xiangchengensis (vs. without spot in the latter).

Oreolalax longmenmontis sp. nov. most resembles O. popei in morphology and is also potentially sympatric with it. The new species could be distinguished from O. popei by a combination of following characters: comparatively small body size (mean male SVL 56.8 mm vs. 64.4 mm in O. popei ), head wider than long (vs. head longer than wide in O. popei ), tibio-tarsal articulation reaching beyond nostril when leg stretched forward (vs. just reaching the anterior angle of eye in O. popei ), forelimb long (mean male LAL/SVL ratio 51.89% vs. 46.87% in O. popei ), hindlimb long (mean male HLL/SVL ratio 182.05% vs. 172.02% in O. popei , and mean male TFL/SVL ratio 77.64% vs. 73.21% in O. popei ), and short IML (4.46% of SVL vs. 5.03% O. popei ).

Oreolalax longmenmontis is genetically closer to O. nanjiangensis and O. chuanbeiensis . The new species distinctly differs from O. chuanbeiensis by the following characters: broader head (vs. head wide almost equal to long in the latter), lacking spines on lip margin in male (vs. visible in male in the latter), spiny patches on chest small with thick sparse spines in male (vs. large with fine spines in the latter), nuptial spines thick sparse on fingers (vs. thin and fine in the latter), toe webbing at base (vs. toe IV 1/3 webbed in the latter), tibio-tarsal articulation reaching beyond nostril when leg stretched forward (vs. just reaching the level of eye in the latter), and having significant differences on HDL, HDW, SL,NS, IND, UEW, LW (p <0.05 when comparing with the latter; Table 3 ). The new species differs from O. nanjiangensis by the following characters: broader head (vs. head wide almost equal to long in the latter), belly with marble spots (vs. without spot in the latter), tibio-tarsal articulation reaching beyond nostril when leg stretched forward (vs. just reaching the level of eye in the latter), interorbital region with dark triangular pattern (vs. without in the latter), comparatively long body size (mean male SVL 56.8 vs. 53.7 in the latter), forelimb long (mean male LAL/SVL ratio 51.9% vs. 48.9% in the latter), and hindlimb long (mean male HLL/SVL ratio 182% vs. 172% in the latter, and mean male TFL/SVL ratio 77.6% vs. 72.7% in the latter; Table 3 ).

Distribution and ecology.

Oreolalax longmenmontis sp. nov., is currently known only from the type locality, the White River National Nature Reserve, Pengzhou City, Sichuan Prov., China at elevations of 1300-1450 m. The new species inhabits subtropical evergreen broad-leaved forests and is frequently found near the ponds in the montane streams (Fig. 7 ). The breeding season is currently uncertain. Three sympatric amphibian species, i.e., Amolops chunganensis (Pope, 1929), Odorrana margaratae (Liu, 1950), and Quasipaa boulengeri ( Günther, 1889), were found in the same habitat.

Etymology.

The specific epithet longmenmontis refer to the type locality of the species, the central part of the Longmen Mountains, Pengzhou City of Sichuan Prov., China. We propose the common name "Longmen Mountains toothed toad" (English) and "long men shan chi chan" (Chinese).

Figures

Figure 3. Photos of the holotype CIB 20180522001 of Oreolalax longmenmontis sp. nov. in life A dorsal view B ventral view C lateral view D view of chest E view of oral cavity E dorsal view of fingers G view of femoris posterior H ventral view of foot I ventral view of hand. Key: 1 indicates tympanum hidden; 2 denotes a pair of spinal patches with large and sparse spines on chest; 3 denotes nuptial spines on the dorsal surface of fingers I and II; 4 denotes two small posterior femoral glands.

Figure 4. Specimen photos of Oreolalax longmenmontis sp. nov. and its relative species A, B dorsal and ventral view of the holotype CIB 20180522001 of Oreolalax longmenmontis sp. nov. C, D dorsal and ventral view of the topotype CIB 25142 of O. popei E, F dorsal and ventral view of the topotype CIB 89700 of O. nanjiangensis G, H dorsal and ventral view of the topotype CIB 89682 of O. chuanbeiensis. Scale bar: equal to 10 mm.

Figure 5. Colour variations in Oreolalax longmenmontis sp. nov. A, B dorsal and ventral view of the paratype CIB 20180527002 C, D dorsal and ventral view of the paratype CIB 20180526001.

Figure 6. The tadpole specimen CIB 2018041501 of Oreolalax longmenmontis sp. nov. A dorsal view B lateral view C ventral view D mouth structure. Key: 1 spiracle; 2 upper keratodonts; 3 lower keratodonts; 4 additional tubercles at the angles of mouth; 5 labial papillae on upper lips; 6 labial papillae on lower lips.

Figure 7. Habitats of Oreolalax longmenmontis sp. nov. in the type locality, Sichuan White River National Nature Reserve in Pengzhou City, Sichuan Province, China A landscape of montane forests B a montane stream with a small pond occupied by toad (insert: the holotype CIB 20180522001 in life).