Diploderma panchi Wang, Zheng, Xie, Che, Siler, 2020

Dong, Wenjie, Li, Ling, Xun, Hao, Gao, Wei, Wang, Kai & Che, Jing, 2024, Extended Descriptions and Revised Diagnoses of Three Recently Described, Little-Known Mountain Dragons (Reptilia: Agamidae: Diploderma) from the Yalong River Valley in Southwest China, Zootaxa 5463 (4), pp. 479-500 : 483-485

Diploderma panchi Wang, Zheng, Xie, Che, Siler, 2020

Newly collected materials. KIZ 038776 , 038777 , 52442 , adult males, and KIZ 51010 , adult females, from the vicinity of Yajiang Township , Ganzi Zangzu Autonomous Prefecture, Sichuan Province, China, collected in August 2021 and May 2023 .

Revised diagnosis. Diploderma panchi can be diagnosed from congeners by a combination of the following morphological characters: (1) body size moderate (relatively small for male), SVL 49.6–55.5 mm in adult males, 59.6–67.7 mm in adult females; (2) tail short, TAL 149.6%–169.5% SVL in adult males, 141.8%–155.6% in adult females; (3) hind limbs short, HLL 64%–77.2% SVL in adult males, 60.2%–68.5% in adult females; (4) head width moderate, HW 61.6%–74.2% HL in adult males, 65.8%–73.6% in adult females; (5) MD 39–41 in adult males, 38–46 in adult females; (6) F4S 15 or 16 in adult males, 14–18 in females; (7) T4S 18–22 in adult males, 20–24 in adult females; (8) conical post-rictal scale moderately developed, 3 or 4 in adult males, 2–7 in adult females; (9) tympanum concealed for both sexes; (10) nuchal crest poor developed in males, feebly developed with no skin folds in females; (11) transverse gular fold present, distinct for both sexes; (12) ventral scales of head and body distinctively keeled for both genders; (13) ventral head scales and ventrolateral body scales homogeneous in size for both sexes; (14) distinct Light Pink (Color 242) lateral scales of head in males, lighter in females; (15) distinct, scattered black or grey gular spots in males, against a Dark Spectrum Yellow (Color 78) to Medium Chrome Orange (Color 75) background coloration, nearly absent in females, in which mosaic Light Sulphur Yellow (Color 93) patterns present; (16) dorsolateral stripes moderately jagged, Pale Greenish Yellow (Color 86) in males, strongly jagged, White, Light Buff (Color 2), or Light Sulphur Yellow (Color 91) in females; (17) ventral body uniform Pale Buff (Color 1) for both sexes; and (18) inner lips, oral cavity, and tongue uniform flesh color for both genders.

Expanded comparison. Diploderma panchi is morphologically similar to D. xinlongense , D. brevicauda , D. drukdaypo , and D. flavilabre , in which all five species showed a dwarf appearance (i.e. small body size and disproportionally shorter limbs and tails). However, males D. panchi differ from D. brevicauda by having a different gular pattern (entire ventral surface of head dark Spectrum Yellow vs. pale yellow gular spot limited to posterior center of gular pouch) and a different shape of dorsolateral stripes (prominently jagged vs. moderately jagged); from D. drukdaypo by having distinctively keeled ventral scales (vs. smooth or feebly keeled), longer hind limb lengths (HLL 64%–77.2% SVL and 60.2%–68.5% in males and females, respectively vs. 58.2%–63.8% and 58.3%–62.8% in males and females, respectively), and a distinct ventral head coloration (Dark Spectrum Yellow [Color 78] to Medium Chrome Orange [Color 75] vs. white); and from D. flavilabre by having feebly developed nuchal crest in males (vs. well-developed with strong skin folds), a distinctly different coloration of inner lips (Light Flesh Color [Color 250] vs. Dark Spectrum Yellow [Color 78]), and a distinct coloration of ventral surface of head (Dark Spectrum Yellow [Color 78] to Medium Chrome Orange [Color 75] vs. Pale Emerald Green [Color 141]).

Comparing to D. xinlongense , a newly described sister species to D. panchi , D. panchi differs from D. xinlongense by having a larger body size (SVL 49.6–55.5 mm and 59.6–67.7 mm in males and females, respectively vs. 44–48 mm and 41–58 mm in males and females, respectively), more suborbital scale rows (SOR 4 or 5 vs. 2 or 3), and a distinct gular coloration (Dark Spectrum Yellow [Color 78] to Medium Chrome Orange [Color 75] vs. Sky Blue [Color 167]).

Sexual dimorphism and dichromatism. Morphometrically, males of D. panchi differ from the females by having a smaller body size (SVL 49.6–55.5 mm vs. 59.6–67.7 mm), a shorter body (TRL 41.5%–47.4% SVL vs. 44.4%–55.3%), a tendency toward a shorter snout (SEL 36.4%–39.4% HL vs. 36.7%–41.1%), and a tendency toward a longer tail (TAL 149.6%–169.5% SVL vs. 130.9%–155.6%).

Sexual dichromatism is particularly evident. In males, the dorsal head is Amber (Color 51) in background, with darker Burnt Umber (Color 48) transverse stripes between orbits. The lateral head is Light Flesh Color (Color 250), and the region above the corner of the mouth is light Pink (Color 242). Ventral surface of head is entirely vibrant Dark Spectrum Yellow (Color 78) to Medium Chrome Orange (Color 75), adorned with black or gray punctate or short vermiculate lines, with no clear “gular spot”. Notably, the background color of the ventral surface of head varies among individuals: in voucher KIZ 038776, the overall color is Dark Spectrum Yellow (Color 78), but the base of some gular scales is Medium Chrome Orange (Color 75). In contrast, specimen KIZ 038777 showcases a substantial area of Medium Chrome Orange (Color 75) background color, and the color of some gular scales is Chrome Orange (Color 74). The dorsal background coloration of the males is Amber (Color 51), which gradually changes to Burnt Umber (Color 48) on the lateral sides. Two strongly jagged, dorsolateral stripes are present on the dorsum in males: the initial two-thirds of the stripes are Pale Greenish Yellow (Color 86), which gradually transitions to Pale Buff (Color 1) towards the posterior end. Irregularly scattered Pale Greenish Yellow (Color 86) spots are present inferior to the dorsolateral stripes. In contrast, the gular region of females is much duller and the coloration is far less saturated; the dorsal background of females is Cinnamon–Drab (Color 50), with Light Yellow Ocher (Color 13) dorsolateral stripes and Pale Buff (Color 1) spots inferiorly.

Natural history and conservation. Individuals were observed to inhabit shrublands along the warm-dry Yalong River Valley. Large, mossy-covered rocks are the main basking sites for this species. Males and females show distinct preferences on the temperature/climatic conditions: males are more frequently observed during sunny, hot days, whereas females are more commonly observed during overcast days. At night, individuals rest on branches of low shrubs, with females being more commonly observed than males.

Our two-year survey revealed that the vital shrubland habitat of D. panchi is highly fragmented near the type locality, caused by the ongoing road construction projects ( Fig. 4 ). Consequently , the population at the type locality has been nearly extirpated, and no individuals were observed several kilometers upstream and downstream of the Yalong River from the type locality. Although our surveys were limited to one side of the river valley due to limitations in accessibility, our results showed that the species has been affected largely by habitat destructions, and its sharp population decline warrant conservation attention, as suggested by Wang et al. (2020). Following IUCN criteria B1b (iii, v): geographic range less than 20,000 km 2, and continuing decline observed in area, extent and quality of habitat, and in number of mature individuals, we recommend listing the species as Endangered ( EN) and call for its conservation attention.

Figures

FIGURE 4. Habitat destruction at the type locality of D. panchi, showing the site before destruction in 2021 (A) and after destruction in 2023 (B). Photos by Wenjie Dong.