Diploderma bifluviale, Liu & Wu & Zhang & Yang & Liu & Chen & Chang & Xie & Cai, 2025

Diploderma bifluviale sp. nov.

Figs 4 View Figure 4 , 5 View Figure 5

Japalura flaviceps View in CoL authority, date: Zhao 2003: 84, partim in the Aba Tibetan and Qiang Autonomous Prefecture

Type material.

Holotype: • CIB 119368 (field number CB 23 JC 04), adult male, collected from Baiwan Town ( 31.809249°N, 101.88182°E, 2306 m a. s. l.), Barkam City, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China (Fig. 4 View Figure 4 ) GoogleMaps . Allotype: • CIB 119369 (field number CB 23 JC 08), adult female, also collected from Baiwan Town ( 31.803494°N, 101.91378°E, 2525 m a. s. l.) (Fig. 5 B View Figure 5 ) GoogleMaps . Paratypes: • subadult CIB -CB 23 JC 02 and female CIB -CB 23 JC 03 are collected from Baiwan Town ( 31.807989°N, 101.886555°E, 2314 m) GoogleMaps ; • juvenile CIB -CB 23 JC 05 , male CIB -CB 23 JC 06 and female CIB -CB 23 JC 07 are collected from the same location as holotype GoogleMaps ; male CIB -CB 23 JC 19 and female CIB -CB 23 JC 20 are collected from Baiwan Town ( 31.809273°N, 101.881811°E, 2304 m a. s. l.) GoogleMaps , and juvenile CIB - 201808022 was collected from Baiwan Town ( 31.808662°N 101.883118°E, 2290 m a. s. l.) GoogleMaps , • female YBU 23081 ( GP 10410 ) was collected from Lewu Town ( 31.466004°N, 102.091464°E, 2252 m a. s. l.), Jinchuan County Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China GoogleMaps , and subadult YBU 22294 was collected from Xinsha village ( 31.59322°N, 102.06453°E, 2187 m a. s. l.), Jichuan County GoogleMaps .

Diagnosis.

Diploderma bifluviale sp. nov. can be diagnosed from other Diploderma species by a combination of the following morphological characteristics: (1) body size short, SVL 62.51 ~ 64.47 mm, mean 63.62 mm (sample standard deviation 1.01) in adult males, 63.13 ~ 72.55 mm, mean 68.41 mm (3.53) in adult females; (2) tail short, TAL / SVL 1.41 ~ 1.53, mean 1.48 (0.06) in adult males, 1.37 ~ 1.56, mean 1.46 (0.08) in adult female; (3) head relatively long, HW / HL 0.71 ~ 0.78, mean 0.75 (0.03) in adult males, 0.68 ~ 0.74, mean 0.72 (0.02) in adult females; (4) limbs moderately long, FLL / SVL 0.42 ~ 0.44, mean 0.43 (0.01) in adult males, 0.41 ~ 0.42, mean 0.41 (0.01) in adult females, HLL / SVL 0.64 ~ 0.69, mean 0.66 (0.03) in adult males, 0.64 ~ 0.69, mean 0.65 (0.02) in adult females; (5) MD 49 ~ 54; (6) F 4 S 15 ~ 17, T 4 S 20 ~ 23; (7) tympanum concealed; (8) nuchal and dorsal crests almost continuous, scales of nuchal and dorsal crests enlarged, moderately erected skin fold under nuchal in males in life, weakly erected skin fold under nuchal crest and no skin fold under dorsal crest in females in life; (9) distinct transverse gular fold present; (10) ventral scales of head almost uniform in size, posterior and side ones smaller, all strongly keeled; (11) ventral scales of body strongly keeled; (12) gular spot absent in both sexes; (13) dorsolateral stripes distinct in males, strongly jagged and the upper and lower edges are almost touching each other, pale yellow in life; (14) a series of dark spots or a dark stripe like large wavy between dorsolateral stripes on dorsum; (15) a distinct wide black stripe on shoulder fold region on each side; (16) stripes around eye absent or very indistinct; (17) tongue wheat color in life; (18) fourth toe with claw reaching either the tympanum or the area between shoulder and tympanum when hind limbs adpressed forward (Table 2 View Table 2 ).

Description of holotype.

Adult male, body relatively small-sized, SVL 62.5 mm; tail short, TAL 88.2 mm; head longer ( 19.9 mm) than wide ( 15.6 mm); head depth 12.3 mm; length of tallest nuchal crest 0.5 mm; snout – eye length 8.6 mm; foreleg length 26.2 mm; hindleg length 40.4 mm; toe IV length 10.5 mm; trunk length 28.5 mm; snout moderately long, SEL / HL 0.43. Rostral flat, bordered by six small postrostral scales; dorsal head scales heterogeneous in size, most of them keeled. Number of scales between supraoculars 16; nasal scale approximately oval; internasals 9; loreals 7 / 6, small, unkeeled; mental pentagonal; supralabials 10 / 10, infralabial scales 11 / 13, supratemporals 4 / 3, and middorsal crest scales 54, keeled; gular scales 30 and ventralscales 64; finger IV subdigital lamellae 16 / 17; toe IV subdigital lamellae 21 / 22; nasal supralabial scale rows 1 / 1; suborbital scale rows 3 / 4. Transverse gular fold present; gular pouch present in life; tympanum concealed, covered with small keeled scales; well-developed skin fold under nuchal crest present, vertebral crest continuous between nuchal and dorsal sections; axillary scales much smaller than remaining dorsals; dorsal and ventral scales distinctively keeled exclude scales around eyes and lips; dorsal scales of head, trunk, limbs, and tail heterogeneous in size, ventral scales of head almost ventral scales of head almost uniform in size with few larger scales, posterior and side ones smaller, all strongly keeled; fold present in front of shoulder; fourth toe with claw reaching at tympanum when hindlimbs adpressed forward. Upper and lower edges of dorsolateral stripes are strongly serrated and separated only by a lemon-chiffon dorsal scale at the serrated tip; tail scales all strongly keeled, ventral tail scales slightly larger than dorsal tail scales; fourth toe with claw reaching tympanum when hind limbs adpressed forward (Table 2 View Table 2 ).

Coloration in life.

The dorsal head is mainly dark khaki (189, 183, 107), with an olive (128, 128, 0) transverse stripe at the front and a blurred olive stripe at the back connecting the left and right supraoculars, and olive markings on the anterodorsal edge. Olive dots walking on the rest of dorsal head. Lateral surfaces of head grey (128, 128, 128) to dark khaki. There are seven stripes around the upper eye except the subocular regions on each side, with a thick black and dark khaki stripe extending from the posterior nasal through the lower palpebral to the temporal region. The subocular scale rows are white-smoke (245, 245, 245) with few dark grey (169, 169, 169) scales. The supralabials and infralabials are white smoke with dark grey, make the eye area appear inconspicuous radial lines. The inner-lip coloration is smoky white, and the coloration of the tongue wheat (245, 222, 179).

The dorsal surface is predominantly dark khaki. A lemon-chiffon (255, 250, 205) strongly jagged dorsolateral stripe from neck to pelvis on each side of body. At the serrated tip, the upper and lower edges of these stripes are separated only by a lemon-chiffon dorsal scale. Between the dorsolateral stripes there is an almost continuous black to olive almost wavy pattern. A distinct wide black stripe on shoulder fold region on each side. Some reticular markings below dorsolateral stripe on each side of body, with dark-khaki patches wrapped around a larger white (255, 255, 255) dorsal scale on each side of body. Dorsal surfaces of limbs dark khaki with black to olive trans verse bands. Dorsal surface of tail wheat with olive transverse bands.

Ventral surface of head white-smoke with dim grey (105, 105, 105) reticulated pattern. No gular spot. Ventral surfaces of body and limbs white-smoke with dim grey with smoke pattern, ventral surface of tail white-smoke with indistinct dark khaki transverse bands (Fig. 4 View Figure 4 ).

Variations.

Diploderma bifluviale sp. nov. is sexually dimorphic: (1) males are smaller than females, SVL 62.51 ~ 64.47 (mean 63.62) mm vs 63.13 ~ 72.55 (mean 68.41) mm; (2) trunk relatively shorter, TRL / SVL 0.45 ~ 0.46 (mean 0.46) vs 0.48 ~ 0.52 (mean 0.50); (3) fore-limb relatively longer, FLL / SVL 0.42 ~ 0.44 (mean 0.43) vs 0.41 ~ 0.42 (mean 0.41); (4) skin folds under nuchal and dorsal crest obviously present in adult males only; (5) dorsolateral stripes prominent present in adult males, absent or not noticeable in females.

Comparisons.

Diploderma bifluviale sp. nov. differs from D. flaviceps by having the following combined characteristics: (1) relatively shorter body ( SVL 62.51 ~ 64.47 [mean 63.62] mm vs 60.5 ~ 75.6 [mean 68.42] mm in males; (2) relatively shorter tail ( TAL / SVL 1.41 ~ 1.53 vs 1.88 ~ 2.09 in males, 1.37 ~ 1.56 vs 1.72 ~ 2.17 in females); (3) relatively shorter fore-limbs ( FLL / SVL 0.42 ~ 0.44 [mean 0.43] vs 0.44 ~ 0.49 [mean 0.47] in males; (4) relatively shorter hind limbs ( HLL / SVL 0.64 ~ 0.69 [mean 0.66] vs 0.72–0.80 [mean 0.76] in males, 0.64 ~ 0.69 [mean 0.65] vs 0.7 ~ 0.81 [mean 0.74] in females; (5) relatively longer snout – eye length ( SEL / HL 0.42 ~ 0.44 [mean 0.43] vs 0.30 ~ 0.34 [mean 0.33] in females (Table 2 View Table 2 ); (6) moderately erected skin fold under dorsal crest in males in life (vs strongly erected) and the absence of a skin fold under dorsal crest in females in life (vs presence); (7) upper and lower edges of dorsolateral stripes are separated only by a lemon-chiffon dorsal scale at the serrated tip in males (vs relatively smooth or wavy and separated by more than 3 dorsal scales), dorsolateral stripes absent or not noticeable in females (vs distinct); (8) tongue wheat color in life (vs ‘ pale flesh’ [240, 208, 202]); (9) fourth toe with claw reaching either the tympanum or the area between shoulder and tympanum when hind limbs adpressed forward (vs reaching the posterior edge of the eye).

Diploderma bifluviale sp. nov. differs from D. danbaense by having the following combined characteristics: (1) relatively shorter body ( SVL 62.51 ~ 64.47 [mean 63.62] mm vs 64.72 ~ 77 [mean 70.05] mm in males; (2) relatively shorter tail ( TAL / SVL 1.41 ~ 1.53 vs 1.61 ~ 1.89 in males, 1.37 ~ 1.56 vs 1.55 ~ 1.59 in females); (3) relatively shorter head ( HL 19.63 ~ 20.51 [mean 20.01] mm vs 21.38 ~ 26.6 [mean 22.88]) in males; (4) relatively shorter hind limbs ( HLL / SVL 0.64 ~ 0.69 [mean 0.66] vs 0.66 ~ 0.71 [mean 0.70] in males; (5) relatively longer trunk length ( TRL / SVL 0.48 ~ 0.52 [mean 0.50] vs 0.45 ~ 0.47 [mean 0.46]) in adult females (Table 2 View Table 2 ); (6) upper and lower edges of dorsolateral stripes are separated only by a lemon-chiffon dorsal scale at the serrated tip in males (vs relatively smooth or wavy and separated by 3 [fewer 1] dorsal scales); (7) tongue wheat color in life (vs ‘ pale flesh’); (8) fourth toe with claw reaching either the tympanum or the area between shoulder and tympanum when hind limbs adpressed forward (vs the area between eyes and ears).

Diploderma bifluviale sp. nov. differs from D. daduense ( Cai, Liu & Chang, 2024) by having the following combined characteristics: (1) relatively shorter body ( SVL 62.51 ~ 64.47 [mean 63.62] mm vs 74.7–95.0 [mean 86.5] mm in males; (2) relatively shorter tail ( TAL / SVL 1.41 ~ 1.53 vs 2.04 ~ 2.62 in males; (3) dorsolateral stripes are lemon-chiffon (vs green-yellow anteriorly, cyan in the center, and blurry off-white posteriorly); (4) tongue wheat color in life (vs ‘ pale flesh’).

Diploderma bifluviale sp. nov. differs from D. brevipes (Gressitt, 1936) , D. chapaense (Bourret, 1937) , D. fasciatum (Mertens, 1926) , D. hamptoni (Smith, 1935) , D. luei (Ota, Chen & Shang, 1998) , D. makii (Ota, 1989) , D. menghaiense Liu, Hou, Wang, Ananjeva & Rao, 2020 , D. micangshanense (Song, 1987), D. nangunhe Liu, Li , (Yang, Hou, Rao & Ananjeva, 2024), D. ngoclinense (Ananjeva, Orlov & Nguyen, 2017) , D. polygonatum Hallowell, 1861 , D. swinhonis (Günther, 1864) , and D. yunnanense (Anderson, 1878) by the presence of a transverse gular fold (vs absence).

Diploderma bifluviale sp. nov. differs from D. dymondi (Boulenger, 1906) , D. panlong Wang, Che & Siler, 2020 , D. slowinskii (Rao, Vindum, Ma, Fu & Wilkinson, 2017) , D. swild Wang, Wu, Jiang, Chen, Miao, Siler & Che, 2019 , and D. varcoae (Boulenger, 1918) by having concealed tympana (vs exposed).

Diploderma bifluviale sp. nov. differs from D. angustelinea Wang, Ren, Wu, Che & Siler, 2020 , D. aorun Wang, Jiang, Zheng, Xie, Che & Siler, 2020 , D. batangense (Li, Deng, Wu & Wang, 2001) , D. bowoense Wang, Gao, Wu, Siler & Che, 2021 , D. brevicauda (Manthey, Denzer, Hou & Wang, 2012) , D. chapaense (Bourret, 1937) , D. daochengense Cai, Zhang, Li, Du, Xie, Hou, Zhou & Jiang, 2022 , D. donglangense Liu, Hou, Ananjeva & Rao, 2023 , D. flavilabre Wang, Che & Siler, 2020 , D. formosgulae Wang, Gao, Wu, Dong, Shi, Qi, Siler & Che, 2021 , D. iadinum (Wang, Jiang, Siler & Che, 2016) , D. jiulongense Liu, Hou, Ananjeva & Rao, 2023 , D. kangdingense Cai, Zhang, Li, Du, Xie, Hou, Zhou & Jiang, 2022 , D. laeviventre (Wang, Jiang, Siler & Che, 2016) , D. limingense Liu, Hou, Rao & Ananjeva, 2022 , D. nangunhe Liu, Li, Yang, Hou, Rao & Ananjeva, 2024 , D. panchi Wang, Zheng, Xie, Che & Siler, 2020 , D. qilin Wang, Ren, Che & Siler, 2020 , D. splendidum (Barbour & Dunn, 1919) , D. tachengense Liu, Hou, Ananjeva & Rao, 2023 , D. xinlongense Cai, Zhang, Li, Du, Xie, Hou, Zhou & Jiang, 2022 , D. yangi Wang, Zhang & Li, 2022 , D. yongshengense , D. yulongense , and D. zhaoermii (Gao & Hou, 2002) by the absence of a gular spot in males in life (vs presence of a colourful gular spot).

Diploderma bifluviale sp. nov. differs from D. drukdaypo (Wang, Ren, Jiang, Zou, Wu, Che & Siler, 2019) by having strongly keeled ventral scales of body (vs smooth or weakly keeled); from D. qiaojiaense ( Liu, Hou & Rao, 2024) by having lemon-chiffon dorsolateral stripes in males in life (vs light green); from D. grahami (Stejneger, 1924) due to having relatively longer hind limbs ( HLL / SVL 0.64 ~ 0.69 vs 0.61), and the presence of dorsolateral stripes (vs absence) in males; from D. kangdingense Cai, Zhang, Li, Du, Xie, Hou, Zhou & Jiang, 2022 by having dim grey ventrolateral surface of body in males in life (vs yellow); from D. shuoquense Liu, Hou, Rao & Ananjeva, 2022 by having strongly keeled ventral head scales and from D. vela (Wang, Jiang & Che, 2015) by having inconspicuous radial lines around the eyes (vs distinct radial stripes), and having moderately erected skin fold under nuchal (vs a pronounced, sail-like, and continuous vertebral crest) in males.

Distribution and natural history.

Diploderma bifluviale sp. nov. is currently known to inhabit the semi-arid region of warm-dry valley in the upper reaches of the Dadu River. It is primarily concentrated around Shuangjiangkou, located at the confluence of the Chuosijia River and the Jiaomuzu River, spanning Jinchuan County and Barkam City (Ma’erkang City) within the Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China (Fig. 1 View Figure 1 ). This area is characterized by long hours of sunlight, frequent clear days, distinct wet and dry seasons, and significant diurnal temperature variations ( Zhang 1992). The known distribution range of Diploderma bifluviale sp. nov. exhibits higher humidity and greater vegetation coverage compared to that of D. danbaense .

The species is known to inhabit altitudes ranging from 2187 to 2314 meters, residing in arid shrublands with small leaves and scattered rock piles, where the shrubs can reach heights of 0.5–2 meters (Fig. 5 View Figure 5 ). All specimens were collected between 09: 00 and 18: 00 hr from June to August. During the investigation, it was observed that this species preys on valley insects, this species represents one of the few secondary consumers inhabiting this arid river valley ecosystem.

This species is oviparous. Specimens CB 23 JC 16, CIB 119369 , CB 23 JC 07, CB 23 JC 03, and CB 23 JC 20 were found to contain 3, 5, 6, 6, and 7 eggs, respectively.

Etymology.

The specific epithet bifluviale is derived from the Latin words bi - meaning two, and fluviale, relating to rivers. This name refers to the species’ discovery location near Shuangjiangkou (双江口), which denotes the area around the confluence of the Chuosijia River (绰斯甲河, Chuosi River) and the Jiaomuzu River (脚木足河, Kyom-kyo River) of Sichuan Province, China. We suggest Upper Dadu Mountain Lizard as its English common name and 双江口攀蜥 (Chinese phonetic alphabet: Shuāng jiāng kǒu Pānxī) as its Chinese common name.