Nidirana guangdongensis Lyu, Wan, & YY Wang, 2020

Lyu, Zhi-Tong, Dai, Ke-Yuan, Li, Yao, Wan, Han, Liu, Zhe-Yi, Qi, Shuo, Lin, Si-Min, Wang, Jian, Li, Yu-Long, Zeng, Yang-Jin, Li, Pi-Peng, Pang, Hong & Wang, Ying-Yong, 2020, Comprehensive approaches reveal three cryptic species of genus Nidirana (Anura, Ranidae) from China, ZooKeys 914, pp. 127-159 : 127

Nidirana guangdongensis Lyu, Wan, & YY Wang sp. nov. Figures 5 , 6 , 7

Chresonymy.

Nidirana adenopleura : Fei et al. 2009, 2012; Li et al. 2011

Holotype.

SYS a005767 (Figs 5 , 6 ), adult male, collected by Zhi-Tong Lyu on 24 April 2017 from Shimentai Nature Reserve (24.4450°N, 113.1617°E; ca. 320 m a.s.l.), Yingde City, Guangdong Province, China.

Paratypes.

Seven adult specimens from the same locality as the holotype. Male SYS a005765 and female SYS a005766, collected by Zhi-Tong Lyu and Yuan-Qiu Li at the same time as the holotype; male SYS a005995 and females SYS a005997-98, collected by Zhi-Tong Lyu, Yong-You Zhao and Chao-Yu Lin on 20 June 2017; male SYS a006879/ CIB 107273 collected by Zhi-Tong Lyu, Yong-You Zhao and Yuan-Qiu Li on 20 April 2018; male SYS a007688 collected by Yu-Long Li, Can-Zhong Rong and Yuan-Qiu Li on 23 April 2019.

Etymology.

The species name guangdongensis refers to Guangdong (广东), also known as Yue (粤), which is the province where the type locality, Shimentai Nature Reserve, belongs to.

Differential diagnosis.

Nidirana guangdongensis sp. nov. is distinguished from its congeners by the following combination of the morphological characteristics: (1) body large and elongated, with SVL 50.0-58.4 (53.9 ± 3.3, N = 5) mm in adult males, and SVL 55.3-59.3 (57.0 ± 2.1, N = 3) mm in adult females; (2) disks of digits dilated, rounded; (3) lateroventral grooves present on every digit except finger I; (4) heels overlapping; (5) tibio-tarsal articulation reaching the nostril; (6) mid-dorsal stripe present on posterior dorsum; (7) week supernumerary tubercles below the base of each finger, palmar tubercles prominent and distinct; (8) supratympanic fold absent; (9) white horny spinules on the entirely dorsum, dorsolateral folds, flanks and dorsal hindlimbs, while absent on temporal regions in males; (10) a pair of subgular vocal sacs present; (11) one single nuptial pad present on the finger I, nuptial spinules invisible; (12) suprabrachial gland large and smooth, prominent; (13) calling: 2-4 identical regular notes.

Comparison.

Morphologically, Nidirana guangdongensis sp. nov. is unique when compared with all known congeners by the combination of the following characteristics: (1) large body size, SVL 50.0-58.4 mm in males and 55.3-59.3 mm in females vs. <48.0 mm in males or <53.0 mm in females in N. nankunensis , N. okinavana , N. daunchina , N. yaoica , N. chapaensis and N. hainanensis ; (2) relative finger lengths II <I <IV <III vs. II <I = IV <III in N. chapaensis ; vs. II <IV <I <III in N. leishanensis ; (3) presence of lateroventral groove on every digit except finger I vs. absent on fingers and toes in N. pleuraden ; vs. absent or barely visible on fingers in N. daunchina ; vs. present on finger I in N. yaoica , N. leishanensis and N. hainanensis ; (4) tibio-tarsal articulation reaches at the nostril vs. beyond the snout tip in N. lini ; (5) white horny spinules on the entirely dorsum and flanks in males vs. absent on dorsum and flanks or few above vent in N. nankunensis , N. okinavana , N. daunchina , N. yaoica , N. chapaensis , N. leishanensis and N. hainanensis ; vs. present on dorsum while absent on flanks in N. adenopleura , N. lini and N. pleuraden ; (6) the presence of a single nuptial pad on finger I vs. absent in N. hainanensis ; vs. divided into two parts in N. chapaensis ; vs. two nuptial pads on fingers I and II respectively; (7) the presence of a pair of subgular vocal sacs vs. absent in N. okinavana .

Description of holotype.

SYS a005767 (Figs 5 , 6 ), adult male. Body large and elongated, SVL 55.2 mm; head longer than wide (HDW/HDL 0.90), flat above; snout rounded in dorsal and lateral views, slightly protruding beyond lower jaw, longer than horizontal diameter of eye (SNT/ED 1.30); canthus rostralis distinct, loreal region concave; nostril round, directed laterally, closer to the snout than to the eye; a longitudinal swollen mandibular ridge extending from below nostril through lower edges of eye and tympanum to above insertion of arm, where the ridge is intermittent, forming a maxillary gland and shoulder gland; supratympanic fold absent; interorbital space flat, narrower than internasal distance (IND/IOD 1.24); pupil elliptical, horizontal; tympanum distinct, round, TD/ED 0.86, and close to eye, TED/TD 0.32; pineal ocellus slightly visible; vomerine ridge present, bearing small teeth; tongue large, cordiform, notched behind; a pair of subgular vocal sacs present.

Forelimbs moderately robust, lower arm 0.17 of SVL and hand 0.27 of SVL; fingers thin, relative finger lengths II <I <IV <III; tip of each finger slightly dilated, forming rounded disks; lateroventral grooves on all fingers except finger I, not meeting at the tip of disks; fingers free of webbing; presence of distinct lateral fringes on inner and outer sides of fingers II, III and IV, and on outer side of finger I; subarticular tubercles prominent and rounded; week supernumerary tubercles below the base of each finger; three elliptic, large, prominent and very distinct palmar tubercles; a single nuptial pad on the dorsal surface of first finger, nuptial spinules invisible.

Hindlimbs relatively robust, tibia 0.54 of SVL and foot 0.77 of SVL; heels overlapping when hindlimbs flexed at right angles to axis of body; tibio-tarsal articulation reaching the nostril when hindlimb is stretched along the side of the body; toes relatively long and thin, relative lengths I <II <V <III <IV; tip of each toe slightly dilated with remarkable elongated ventral callous pad, forming long and pointed disk; well-developed lateroventral grooves on toes, not meeting at the tip of disks; webbing moderate, webbing formula: I 1⅓ - 2 II 1⅓ - 2⅓ III 1⅔ - 3 IV 3⅓ - 1⅓ V; presence of lateral fringes on inner and outer sides of each toes, forming distinct dermal flap on the lateral edges of toes I and V; subarticular tubercles rounded, prominent; inner metatarsal tubercle elliptic, length triple the width; outer metatarsal tubercle indistinct, small and rounded; tarsal folds and tarsal tubercle absent.

Dorsal surface rough with dense horny spinules; developed dorsolateral fold with sparse horny spinules from posterior margin of upper eyelid to above groin but intermittent posteriorly; flank rough with dense tubercles and dense horny spinules; a large and smooth suprabrachial gland behind base of forelimb, prominent; dorsal surface of forelimb relatively smooth without horny spinules, weak longitudinal ridges on upper arms and slightly extending to lower arm; the dorsal surfaces of thigh and tibia rough with dese tubercles and dense horny spinules, forming several longitudinal ridges. Ventral surface of throat, body, and limbs smooth; large flattened tubercles densely arranged on the rear of thigh and around vent.

Coloration of holotype.

In life (Fig. 5 ), dorsal surface reddish brown; horny spinules on the skin white; pineal ocellus yellowish; a yellowish mid-dorsal stripe on the posterior dorsum; dorsolateral fold dark brown; upper flank dark brown; lower flank light brown; suprabrachial gland light brown. Dorsal forelimbs light brown; a longitudinal black stripe on the anterior surface of the forelimb; dorsal hindlimbs dark brown, four dark crossbars on the thigh, three on the tibia and three on the tarsus. Loreal and temporal regions dark brown, tympanum light brown; upper ⅓ iris brownish white and lower ⅔ iris reddish brown; maxillary gland and shoulder gland white. Throat dark purplish brown; ventral surface of body and limbs creamy white; rear thigh tinged with pink; ventral hand white with large purplish brown patches; ventral foot purplish brown.

In preservative (Fig. 6 ), dorsal surface faded with the pineal ocellus and mid-dorsal stripe clearer; white spinules more distinct; dorsal limbs faded with the crossbars more distinct; ventral surface faded, throat grey.

Variations.

Measurements of type series are given in Table 6 . All specimens were similar in morphology. Females (57.0 ± 2.1 mm, N = 3) (Fig. 7A ) are not significantly larger than males (53.9 ± 3.3 mm, N = 5), but relatively smooth than males, not bearing white horny spinules on the dorsum, dorsolateral folds, and flanks. Pineal ocellus invisible in SYS a005765 (Fig. 7B ); numerous black spots on flanks in SYS a005766.

Distribution and ecology.

Currently, Nidirana guangdongensis sp. nov. is known from northern Guangdong, southern Jiangxi and southeastern Hunan, indicating that this frog is distributed in the Nanling Mountains and southern Luoxiao Mountains of southern China. The frog inhabits in natural ponds. The adult males call at the water surface and the females oviposit directly into the water (Fig. 7C ) from April to June. The tadpoles of this species remain unknown. In Mt Nankun, N. guangdongensis sp. nov. is sympatric with N. nankunensis in the same pond and is more abundant.

Vocalization.

The advertisement call (N = 54) of Nidirana guangdongensis sp. nov. contains 2-4 repeated, identical, regular notes. The two-note call has a duration of 445.0-559.0 (520.6 ± 27.4, N = 19) ms; the three-note call has a duration of 681.5-875.8 (794.6 ± 46.4, N = 28) ms; the four-note call has a duration of 1117.6-1198.1 (1152.9 ± 29.8, N = 7) ms. The notes last 134.0-226.7 (164.3 ± 16.2, N = 150) ms with the rise time 0.0-138.5 (28.7 ± 32.4, N = 150) ms, and the intervals last 79.9-262.6 (162.1 ± 26.4, N = 96) ms.

Figures

Figure 5. Morphological features of the adult male holotype SYS a 005767 of Nidirana guangdongensis sp. nov. in life. (A) dorsolateral view; (B) ventral view; (C) left hand; (D) nuptial pad; (E) right foot; (F) close-up of head showing the dense white horny spinules on dorsum, upper eyelid, while absent on temporal regions.

Figure 6. Morphological features of the adult male holotype SYS a 005767 of Nidirana guangdongensis sp. nov. in preservative. (A) dorsal view; (B) ventral view; (C) lateral view; (D) right hand; (E) right foot.

Figure 7. (A) adult female paratype SYS a 005766 of Nidirana guangdongensis sp. nov.; (B) adult male paratype SYS a 005765; (C) eggs in the water surface found in Mt Bamian.