Japalura drukdaypo, Wang & Jiang & Ren & Zou & Wu & Che & Siler, 2019

Wang, Kai, Jiang, Ke, Ren, Jinlong, Zou, Dahu, Wu, Jiawei, Che, Jing & Siler, Cameron D., 2019, A new species of Dwarf Japalura sensu lato (Reptilia: Squamata: Agamidae) from the upper Mekong River in Eastern Tibet, China, with notes on morphological variation, distribution, and conservation of two congeners along the same river, Zootaxa 4544 (4), pp. 505-522 : 508-516

Japalura drukdaypo sp. nov. Wang, Ren, Jiang, Zou, Wu, Che, Siler, 2016

( Fig. 2–6 )

Synonyms:

Japalura flaviceps Hu et al. 1987 ; Zhao & Yang 1997; Li et al. 2010

Japalura cf. flaviceps Wang et al. 2015, 2016

Holotype. KIZ 0 27616, adult male from Chaya County, Chamdo , Tibet, China (30.7294˚ N, 97.3808˚ E, elevation 3,310 m; WGS 84), collected by Kai WANG on 19 June 2016 ( Figs. 1 , 2 ).

Paratypes. KIZ 027617–19 , 027629–30 , adult females collected by Kai WANG and Gadeng NIMA on 19 June 2016 ; KIZ 0 27628, adult male collected by Kai WANG and Gadeng NIMA on 21 June 2016 . KIZ 0 16486, adult female from Kanuo , Chamdo, Tibet, China (31.0433˚ N, 97.2239˚ E, elevation 3,245 m; WGS 84), collected by Dahu ZOU and Fang YAN on 13 May 2015 .

Diagnosis. Japalura drukdaypo sp. nov. can be distinguished from all congeners by a combination of the following morphological characteristics: (1) adult body size small, SVL 49.85–58.93 mm; (2) head moderate, HW 65.94–75.16% HL; (3) limbs relatively short, FLL 37.52–45.40% SVL, HLL 58.18–63.75% SVL; (4) tail relatively short, TAL 153.01–154.40% SVL in males, 132.84–143.95% SVL in females; (5) transverse gular fold present, well developed; (6) tympanum concealed; (7) MD 43–56; (8) T4S 18–25; (9) ventral head and body scales feebly keeled or smooth; (10) nuchal and dorsal crest scales feebly developed, not distinctively erected or raised on skin folds; (11) dorsal enlarged scales relatively flat; (12) gular spots absent in both sexes; and (13) dorsolateral stripes present in both sexes, jagged, bright sulphur yellow in males, medium chrome orange in females.

Description of holotype. Adult male. Body size small, SVL 49.85 mm, moderately compressed dorsally, dwarf looking; tail relatively short, TAL 154.40% SVL; hind limbs short, HLL 63.75% SVL. Head moderate in length and width, HL 33.16% SVL, HW 65.94% HL. Rostral rectangular, four times wider than long; nasal oval in shape, separated from rostral and first supralabial by single small scale; supralabials 9/10 (Left/Right), weakly keeled; suborbital scale rows 4/4, scales roughly equal in size, keeled; infralabials 10/9, smooth; post-rictal scales roughly homogeneous in size, except single moderately enlarged, keeled, post-rictal scale present on each side of head; enlarged scales scattered between posterior orbit and dorsal anterior tympanum, 6/7; tympanum concealed beneath small scales; single enlarged, conical scale post-superior to tympanum. Supraciliaries 6/6, overlapping more than one third of lengths with succeeding ones posteriorly. Dorsal head scales heterogeneous in size, distinctively keeled; dorsal snout surface with raised, keeled ridge, Y-shaped, running from snout tip to point in line with anterior edge of orbit on dorsal side; interparietal sub-rectangular, with distinct pineal eyespot; enlarged, conical scales present on occipital region, 4/4.

Ground scales of dorsal body small, keeled, intermixed with enlarged, keeled scales; enlarged, keeled scales mostly flat, not protruding or giving spiky appearance; two paravertebral ridges present on each side of vertebral crest dorsolaterally, composed of enlarged scales, spanning distance from neck to pelvis; scales of medial dorsolateral ridge smaller than distal ridge, more widely spaced longitudinally along ridge, less regularly aligned; nuchal and dorsal crest feebly developed, nuchal crest scales slightly raised compared to dorsals, not erect; skin folds along crest absent; antehumeral fold present, distinct; axillary fold present. Scales of dorsal limbs keeled, generally homogeneous in size on fore-limbs, heterogeneous in size on hind limbs, with enlarged scales scattered on posterior femoral surface; ventral scales of fore-limbs and lower hind limbs distinctively keeled, ventral femoral scales feebly keeled. Tail slender and short, covered with keeled scales.

Ventral head scales smooth or feebly keeled, largely homogeneous in size, except chin shields and scales near transverse gular fold, which enlarged and lessened; mental triangular, in contact with single pair of enlarged chin shields; gular pouch present in life, well developed, indistinct after preservation; transverse gular fold present, distinct; scales under gular fold smaller than other ventral scales. Ventral body scales smooth or weakly keeled, mostly homogeneous in size and shape.

Coloration of holotype in life. Color name and code conventions follow Köhler (2012). The dorsal surface of the head is Smoke Gray (Code 264), with a single, distinct Raw Umber (Code 280) transverse band present between the eyes. The band forms a “V-shaped” point medially, with the tip pointing posteriorly. Lateral surface of head is Pale Buff (Code 1). Distinct, Sepia (Code 286) radial stripes are present around the eyes, with the posterior stripes on each side of the head the broadest. These broad posterior stripes extend posteriorly to about two scales above the corner of the mouth. Oral cavity is uniform Light Flesh Color (Code 250).

Background coloration of the dorsal surface of the body is Raw Umber (Code 280) to Jet Black (Code 300). A Sulphur Yellow (Code 80) dorsolateral longitudinal stripe is present on each side of the vertebral crest from the occipital region of the head to the pelvis, both of which are strongly jagged. Nine Sulphur Yellow (Code 80), narrow transverse bands are distributed evenly between the two dorsolateral stripes from the neck to the base of the tail, separating the background coloration of the dorsal surfaces of the body into nine rectangular-shaped patches of pigmentation. Irregularly scattered, enlarged, Sulphur Yellow (Code 80) scales are distributed along the lateral surface of the body, ventral to the dorsolateral stripes. The background coloration of the dorsal surfaces of the forelimbs is Jet Black (Code 300), where it is Drab (Color 19) to Olive Brown (Code 278) on the hind limbs. Numerous narrow, Pale Buff (Code 1), transverse bands are present on the dorsal surfaces of the limbs, with forelimb bands more distinct than hind limb bands. Coloration and ornamentation patterns gradually fade posteriorly towards the base of the tail, and the coloration of the tail eventually becomes Beige (Code 254).

Background coloration of the ventral surface of head is Pale Buff (Code 1). Distinct Jet Black (Code 300) vermiculate stripes are present, but they do not reach the center of the gular pouch, resulting in a triangular empty space in background coloration. The anterior and medial part of the ventral surface of the body is Pale Sulphur Yellow (Code 92), with no distinct ornamentation patterns. The posterior part of the ventral body is white ( Figs. 2 ).

Coloration of holotype in preservative. In preservation, most color, pigmentation, and ornamentation patterns remain consistent with those in life, with only a few exceptions. First, Sulphur Yellow (Code 80) coloration of dorsolateral stripes, transverse bands across dorsal body, and irregular spots of lateral surfaces of body fade into Pale Buff (Code 1) or white in preservation. Second, the Pale Sulphur Yellow (Code 92) of ventral surfaces of the body fade to Pale Buff (Code 1) ( Fig. 3 ).

Variation. Morphological variation among the type series is summarized in Table 1. Even though our sample size is small, sexual dimorphism is evident in the new species, with males possessing a smaller adult body size (SVL 49.85–51.48 mm in males vs. 51.05–58.01 mm in females), relatively longer tails (TAL 153.01–154.40% SVL in males vs. 132.84–143.95% in females), and relatively shorter trunk length (TRL 40.4–45.3% SVL in males vs. 51.7–52.4% in females). Furthermore, males have distinct coloration patterns from females, including the background body coloration (Raw Umber [Code 280] to Jet Black [Code 300] in males vs. Olive Horn Color [Code 16] or Drab [Code 19] in females), dorsal ornamentation patterns (solid, Jet Black [Code 300] rectangular patches separated by Sulphur Yellow [Code 80] bands along body midline in males vs. triangular, Olive Horn Color [Code 16] or Drab [Code 19] patches or zigzag stripes separated by Pale Buff [Code 1] transverse bands in females), throat patterns (conspicuous vermiculate stripes in males vs. more faded stripes in females), and shapes and coloration of dorsolateral stripes (distinct, Sulphur Yellow [Code 80] stripes in males vs. somewhat faded, Medium Chrome Orange [Code 75] stripes in females) ( Figs. 2–5 ). In one male individual (KIZ 016486), the center of the throat is Pale Sulphur Yellow (Code 92), but nevertheless the coloration has faded edges and does not form a clear gular spot.

Comparisons. Previous phylogenetic study found that the Himalayan species of the genus Japalura are paraphyletic with respect to the East Asian species ( Macey et al. 2000). In addition to the different zoogeography between the Himalaya region and the HMR ( Zhang 1999), we exclude the comparisons between the new species and Himalayan species (including J. andersoniana , J. dasi , J. kumaonensis , J. major , J. otai , J. planidorsata , J. sagittifera , J. tricarinata , and J. variegata ).

Although populations of Japalura drukdaypo sp. nov. have been confused historically with J. flaviceps , the new species can be distinguished readily from the latter by having a smaller adult body size (SVL 49.85–58.93 mm vs. 64.35–75.35 mm), shorter hind limbs (HLL 58.18–63.75% SVL in males, 59.69–62.82% in females vs. 64.93– 70.86% SVL in males, 61.61–74.09% in females), shorter tails (TAL 153.01–154.40% SVL in males, 132.84– 143.95% SVL in females vs. 170.08–191.26% SVL in males, 167.18–181.98% SVL in females), less distinctive crests in males (slightly raised nuchal crest scales, flat dorsal crest scales, with no skin fold underneath vs. distinctively erected crest scales along skin fold), distinct gular pigmentation patterns (vermiculated stripes not reaching the center of the throat vs. highly reticulated, mosaic patterns occupying the center of the throat), as well as by the absence of strongly differentiated conical, post-rictal scales (vs. presence), absence of dark rhomboid- shaped patterns with yellow centers along the midline of the body (vs. presence), and presence of distinct radial stripes around the eyes (vs. absence or faded and indistinct) ( Fig. 5 ; Table 2).

The new species is phenotypically most similar to Japalura laeviventris and J. brevicauda , from the upper Salween and middle Jinsha River Valleys, respectfully. However, Japalura drukdaypo sp. nov. can be differentiated from J. laeviventris by having a smaller adult body size (SVL 49.85–58.93 mm vs. 64.00– 71.60 mm), shorter hind limbs (HLL 58.18–63.75% SVL in males, 59.69–62.82% in females vs. 70.42%–74.33% SVL in males, 64.43%–74.06% in females), shorter tails (TAL 153.01–154.40% SVL in males, 132.84–143.95% SVL in females vs. 197.22–198.51% SVL in males, 168.57–184.38% SVL in females), fewer MD (43–56 vs. 57–59), feebly developed nuchal crest in males without strongly erected crest scales or skin fold (vs. distinctively erected crest scales on skin fold), and by the absence of distinct gular spots in both sexes (vs. presence), absence of Mshaped pigmentation patterns along body midline in males (vs. presence), and absence of distinct, dense dark speckles on all surfaces of head and dorsal and lateral surfaces of body (vs. presence) ( Fig. 5 ); and from J. brevicauda by having relatively longer tails in males (TAL 153.01–154.40% SVL in males, 132.84–143.95% SVL in females vs. 140% in males, 125–145% in females), a greater number of MD (43–56 vs. 34–40), and smooth or weakly keeled ventral scales (vs. distinctively keeled) ( Fig. 4 ).

Japalura drukdaypo sp. nov. can be differentiated from J. vela by having shorter hind limbs (HLL 58.18– 63.75% SVL vs. 65.67–85.64% SVL), shorter tails (TAL 153.01–154.40% SVL in males, 132.84–143.95% SVL in females vs. 174.58–238.11% SVL in males, 159.8–202.17% SVL in females), feebly developed crests in males without strongly erected crest scales or skin fold (vs. distinctively erected crest scales on continuous, well developed skin fold), weakly keeled or smooth ventral scales of head and body (vs. strongly keeled), flat and relatively less enlarged scales on dorsal body (vs. distinctly keeled, raised, and relatively large), and faint yellowish ventral coloration in live males (vs. uniform white) ( Figs. 3–5 ).

The new species differs from all remaining congeners in Tibet and adjacent areas ( J. batangensis , J. dymondi , J. iadina , J. micangshanensis , J. splendida , J. yulongensis , J. varcoae , and J. zhaoermii ) by having a shorter tail (TAL 153.01–154.40% SVL in males, 132.84–143.95% SVL in females vs.>160.00% SVL in males,>150.00% SVL in females), shorter hind limbs (HLL 58.18–63.75% SVL in males, 59.69–62.82% in females vs.>64.00% SVL), and smooth or feebly keeled ventral scales (vs. distinctively keeled). Furthermore, from J. batangensis , J. iadina , and J. yulongensis , the new species differs by the absence of gular spots in both sexes (vs. presence); from J. batangensis , J. dymondi , J. iadina , J. micangshanensis , J. splendida , J. yulongensis , and J. zhaoermii by the presence of narrow, orange dorsolateral stripes in females (vs. absence); from J. batangensis , J. iadina , J. micangshanensis , J. yulongensis , and J. zhaoermii by having feebly developed crests in males without strongly erected crest scales or skin fold (vs. distinctively erected crest scales on well developed skin fold); and from J. dymondi and J. varcoae by having concealed tympana (vs. exposed). For remaining congeners from the mainland Asia, the new species differs from J. bapoensis , J. chapaensis , J. hamptoni , J. fasciata , and J. yunnanensis by feebly developed nuchal crest scales (vs. well developed in triangular shape), from J. chapaensis and J. yunnanensis by differential oral coloration (Light Flesh Color [Code 250] vs. Light Chrome Orange [Color 76] to Dark Spectrum Yellow [Color 78]); and from J. fasciata by differential dorsal ornamentation (jagged dorsolateral stripes vs. hourglass-shaped transverse bands across midbody). Lastly, the new species differ from all island congeners ( J. brevipes , J. luei , J. makii , J. polygonata , J. swinhonis ) by the presence of distinct transverse gular fold (vs. absent), feebly developed nuchal crest (vs. well developed), and by the differential ecology (terrestrial vs. arboreal).

Etymology. The species name, drukdaypo , was derived from the pronunciation of the Kham Tibetan word that means “dwarf dragon”, which describes the diagnostic dwarf-morphology of the new species. We name the new species using Kham Tibetan in honor of the local culture and people, as well as their positive impacts on wildlife conservation. Suggested English common name is: Dwarf Mountain Dragon, and the suggested Chinese common name is ẇ̿b (Pinying: Zhu Pan Xi).

Natural history. Japalura drukdaypo sp. nov. is terrestrial and inhabits high-elevation hills (> 3,130m) in warm-and-dry valleys near the headwaters of the Mekong River in Chamdo, Tibet ( Figs. 1 , 6 ). Habitat throughout the areas or observation includes mostly spiky shrubs (e.g. Caragana sp. and Selaginella sp.). The new species was observed to be most active in the morning and at dusk in the summer, and with individuals appearing to stay around the entrances to shelters (rock crevices and rodent/insect borrows) or in the shade of vegetation during hot afternoons. Currently, J. drukdaypo sp. nov. is known only from the valleys near the headwaters of the Mekong River in Karuo and Chaya Counties of Chamdo, Tibet, China. We believe the species may be a micro-endemic to this area based on our extensive field surveys of the surrounding region.

Figures

FIGURE 1. Distribution of Japalura sensu lato in the Hengduan Mountain Region in Southwest China. Numbers represent new localities for Japalura vela (1–5) and J. iadina (6), which are: (1) Tongsha, Markam, Tibet; (2) Rumei Township, Markam Prefecture, Tibet; (3) Xilu, Deqin County, Yunnan Province; (4) Foshan, Deqin County, Yunnan Province; (5) Xidang, Deqin County, Yunnan Province; and (6) Yunling, Deqin County, Yunnan Province.

FIGURE 2. Holotype male (left; KIZ 027619) and paratopotype female (right, KIZ 027617) of Japalura drukdaypo sp. nov. in life. Photos by Kai WANG.

FIGURE 3. Dorsal (1), ventral (2), and lateral close-up (3) comparisons of male Japalura drukdaypo sp. nov. (holotype KIZ 027619) and J. vela (KIZ 027670), showing the relatively shorter tail, shorter hind limbs, smoother ventral scales, and feeble and non-erecting crest of J. drukdaypo sp. nov. compared with the closely distributed population of J. vela from Tongsha, Markam Prefecture, Tibet, China. Images are not to scale. Photos by Kai WANG.

FIGURE 4. Dorsal (1) and ventral (2) comparisons of females among Japalura drukdaypo sp. nov. (paratopotype KIZ 027617), J. brevicauda (paratype ZMB 28932), and J. vela (KIZ 027671), showing the differences in relative tail length, relative limb length, and texture of ventral body scales. Individual images are not to scale. Dorsal view of J. vela (B1) was horizontally rotated 180˚ to align with other figures. Photos by Kai WANG and Frank TILLACK.

FIGURE 5. Comparisons of live males (columns 1, 2) and females (columns 3, 4) among Japalura drukdaypo sp. nov. (row A), J. batangensis (row B), J. vela (row C), J. laeviventris (row D), and J. flaviceps (row E). Photos by Kai WANG and Xu ZHANG.

FIGURE 6. Habitat at the type localities of Japalura drukdaypo sp. nov. in Kanuo (A and B) and Chaya (C and D), Chamdo, Tibet, China. Photos by Kai WANG.