Pelophylax mongolicus ( Schmidt, 1925 ) Zhou & He & Ma & Xu & Zhai & Guan & Wang & Shi, 2022

Zhou, Shengbo, He, Li, Ma, Siyu, Xu, Shujun, Zhai, Qiang, Guan, Ping, Wang, Hui & Shi, Jingsong, 2022, Taxonomic status of Rana nigromaculata mongolia and the validity of Pelophylax tenggerensis (Anura, Ranidae), Zootaxa 5165 (4), pp. 486-500 : 495-497

Pelophylax mongolicus ( Schmidt, 1925) comb. nov.

Rana nigromaculata mongolia Schmidt, 1925

Rana tenggerensis Zhao, Macey & Papenfuss, 1988

Pelophylax nigromaculatus nigromaculatus — Fei et al. 1990; Matsui et al. 1995

Hylarana tenggerensis —Chen et al. 2005

Pelophylax tenggerensis — Frost et al. 2006

Type materials. Holotype. AMNH 18149 , adult male, collected from “ Mai Tai Chao , northern Shansi [= currently Meidaizhao Town , Tumed Right Banner, Baotou City, Inner Mongolia], China ” ( Schmidt, 1925).

Specimens examined. The holotype of Rana tenggerensis , adult male CIB 80001 shared with California Academic of Science museum label CAS 166936 ( Figure 4 ), from “along the north shore of the Yellow River [Huang He], at Shapatou Desert Research Station, Shapotou (37°30’N, 104°58’E), Yinnan Prefecture [= currently Shapotou District, Zhongwei City], Ningxia, China ”, and 11 newly collected specimens (five adult males, five adult females, and one subadult): adult female SYAU BAA000030, from Shapotou Park , Shapotou District , Zhongwei City , Ningxia (37.4709°N, 105.0043°E, 1180 m a.s.l.); adult female SYAU BAA000031 and subadult SYAU BAA000032, from Salaqi Ecological Park , Tumed Right Banner , Baotou City , Inner Mongolia; adult male CIB 118075 , from Fenghuang Park , Yinchuan City , Ningxia (40.5788°N, 110.5195°E, 1003 m a.s.l.); adult male SYAU BAA000021, from Yongchenghu Park , Fengxiang County, Baoji City , Shaanxi (34.5089°N, 107.4281°E, 782 m a.s.l.); adult males SYAU BAA000001–02, IVPP OV2728 , and adult females SYS a008905, IVPP OV2729 , SYAU BAA000003 from Liupan Mountain Nature Reserve , Jingyuan County , Guyuan City , Ningxia (35.4139°N, 106.3861°E, 1673 m a.s.l.) .

Diagnosis. (1) large body size, SVL 53.6–65.7 mm adult males (n = 6), SVL 61.8–65.5 mm in adult females (n = 5); (2) head width slightly larger than head length, maxillary gland pronounced; (3) tympanum diameter slightly smaller than the eye diameter; (4) loreal region oblique, slightly concave; (5) nostril located dorsally, closer to the eye than to the tip of snout; (6) vomerine teeth two short rows, away from the maxillary teeth; (7) tongue ovoid, free-margin notched; (8) fingers with rudimentary webs; toes with entire webs, webbing formula I 0 - -1 II ⅓-1⅓ III ⅔-2 - IV 2-⅔ V; (9) hind limb shorter, TL/SVL 0.39–0.45 (n = 11); heels not meeting.

Etymology. The specific name refers to the type locality, Inner Mongolia Autonomous Region.

Common names. “Mongolia Pond Frog” in English / “ žflḛü (meng ce zhe wa)” in Chinese.

Re-description. The measurements of the examined adult specimens (n = 11) are given in Table 3 .

Body robust and large-sized, SVL 53.6–65.7 mm (n = 6) in adult males and 61.8–65.5 mm (n = 5) in adult females. Head flat in lateral view, width slightly larger than length (HW/HL 1.07–1.22, n = 11); snout blunt triangularshaped, distinctly protruding beyond lower jaw, obtuse in lateral view and rounded in dorsal view; canthus rostralis inconspicuous, loreal region oblique, slightly concave; nostril rounded, located dorsally, slightly raised, closer to the eye than to the tip of snout; eye orientation vertically, horizontal ellipse-shaped; interorbital space narrower than internarial distance; tympanum large, nearly round and clear, edge visible; maxillary glands thin and prominent; vomerine teeth two short rows, away from the maxillary teeth; tongue oval, free-margin notched.

Forelimbs moderate, lower arm 25–30% (n = 11) of SVL and hand 29–35% (n = 11) of SVL; fingers distinctly thin and long, relative finger lengths II <IV <I <III; fingers pointed bald, not dilated, and without disks; narrow lateral fringes on inner and outer sides of each finger, fingers with rudimentary webs, more distinct between fingers II and III; subarticular tubercles present at the bases of each finger but inconspicuous; without palmar tubercles prominent.

Hindlimbs short and robust, tibia 39–45% (n = 11) of SVL and foot 72–81% (n = 11) of SVL; heels not meeting when hindlimbs flexed at right angles to the axis of the body; tibiotarsal articulation reaching the tympanum when hindlimb is stretched along the side of the body; toes distinctly long and thin, relative lengths I <II <III <V <IV; toes I and V approximately equal; tips of toes pointed, dilated into pear-shaped disks; toes with entire webs, webbing formula I 0 - -1 II ⅓-1⅓ III ⅔-2 - IV 2-⅔ V, only toe IV tips lateral fringes, distinct lateral fringes on lateral edges of toes I and V; subarticular tubercles rounded, prominent; inner metatarsal tubercle large and long-elliptic, slightly raised, length twice the width; outer metatarsal tubercle quite smaller than the inner metatarsal tubercle, prominent, length slightly larger than width; inner tarsal fold relatively flat, in contact with the inner metatarsal tubercle; tarsal tubercle raised, close to the tibiotarsal articulation.

Dorsal surface relatively smooth, longitudinal wrinkles and dense tubercles on the dorsum, head, flanks, and limbs; small granules on the dorsal rears of hands and tarsi; not bearing spinules on the dorsal skin; supratympanic fold distinct, raised and gracile, extending from the posterior corner of the eye, curved on the temporal region, to the previous shoulder; dorsolateral fold distinct, extending from the upward side of the tympanum, nearly in a straight line to the crotch, the widest part is equal to the upper eyelid. Ventral surface smooth, with little denser tubercles on the thighs; dense granules on the ventral feet and tarsi.

Coloration. The living specimens exhibit varying degrees of green, light brown, or dark brown body color variation, with some individuals exhibiting black spots on their backs that were absent on other individuals, a tympanic membrane that was golden yellow with a green center, and yellow eyelids. A thin light green line was evident running down the middle of the back, extending from the head to the tail end. The dorsolateral fold ranged from green to light brown or golden yellow, with yellow at the ends and some irregular light brown spots. The legs were slightly lighter than the body, with very pale black markings. The throat, chest, and belly were creamy white. The backs of the elbows were black, with black cloud spots behind the thighs. The ventral surface of the forelimbs and hindlimbs were flesh-colored. The nuptial pads were light brown, with yellowish tubercles around the vent ( Figure 5 ).

In preservative, the dorsal surface turned grey with black spots and light grey patches, while the dorsolateral fold and backline were light grey, the limbs were brown with black spots, the ventral surface was white, the ventral surface of the limb was beige, and the hand and toe webs were dark grey ( Figure 6 ).

Sexual dimorphism. Male with a pair of external lateral vocal sacs; in the breeding season, a single, light brown nuptial pad on the dorsal surface of finger I, nuptial spinules tiny. Males slightly smaller than females.

Comparison. Pelophylax mongolicus comb. nov. can be differentiated from other species in the Pelophylax plancyi species group ( P. plancyi , P. fukienensis , P. hubeiensis and P. chosenicus ) based on the external lateral vocal sacs in males ( Fei et al., 2009). Pelophylax mongolicus comb. nov. additionally differs from P. nigromaculatus based on head width is slightly larger than head length, nostrils closer to the eyes than the tip of the snout, hind limb shorter and toes entire webbing without distinct notches (see Morphological Comparisons in the Results above). P. mongolicus comb. nov. further differs from P. terentievi based on dorsal surface relatively smooth with strip wrinkles (vs. dorsal surface rough with round wrinkles in P. terentievi ).

Distribution and ecology. At present, specimens of Pelophylax mongolicus comb. nov. have been identified in central and western Inner Mongolia, Ningxia and southwestern Shaanxi ( Figure 1 ), indicating that this species is distributed from the Ningxia Plain to the Hetao Plain, and can be expected from Loess Plateau. Specimens were collected from near slow-flowing rivers ( Figure 7 ), where they perch along the river bank during the daytime although when startled they jump into the water.

Figures

FIGURE 1. The collection localities of Pelophylax mongolicus comb. nov. (marked with the green circles) and P. nigromaculatus (marked with the blue circles) in this study. (1) Tumed Right Banner, Baotou, Inner mongolia (type locality of P. mongolicus comb. nov.); (2) Shapotou District, Zhongwei, Ningxia (type locality of “P. tenggerensis”); (3) Fenghuang Park, Yinchuan, Ningxia; (4) Liupan Mountain Nature Reserve, Guyuan, Ningxia; (5) Yongchenghu Park, Baoji, Shaanxi; (6) Gaotai Town, Hanzhong, Shaanxi; (7) Wuhou District, Chengdu, Sichuan; (8) Yuehu Park, Changsha, Hunan; (9) Hanxue Park, Shangrao, Jiangxi; (10) Santaishan Park, Suqian, Jiangsu; (11) Mashan Park, Qingdao, Shandong; (12) Dongling Park, Shenyang, Liaoning.

FIGURE 4. The holotype (CIB 80001/CAS166936) of Rana tenggerensis. (A) Dorsal view, (B) ventral view, (C) ventral view of left hand, (D) ventral view of left foot. Photographed by Jin-Long Ren.

FIGURE 5. Coloration of Pelophylax mongolicus comb. nov. (A) male CIB 118075, (B) male SYAU BAA000001, (C) female IVPP OV2729, (D) male SYAU BAA000021. Photographed by Jin-Long Ren and Shengbo Zhou.

FIGURE 6. Preservative coloration of specimen SYAU BAA000001 of Pelophylax mongolicus comb. nov. (A) Dorsal view, (B) ventral view, (C) lateral view, (D) ventral view of the hand, (E) ventral view of the foot.

FIGURE 7. The habitat of Pelophylax mongolicus comb. nov. in Liupan Mountain Nature Reserve.