Hemiphyllodactylus ywanganensis, Grismer & Wood & Zug & Thura & Grismer & Murdoch & Quah & Lin, 2018

Grismer, L. Lee, Wood, Perry L., Zug, George R., Thura, Myint Kyaw, Grismer, Marta S., Murdoch, Matthew L., Quah, Evan S. H. & Lin, Aung, 2018, Two more new species of Hemiphyllodactylus Bleeker (Squamata: Gekkonidae) from the Shan Hills of eastern Myanmar (Burma), Zootaxa 4483 (2), pp. 295-316 : 303-310

Hemiphyllodactylus ywanganensis sp. nov.

Ywangan Slender Gecko

( Figs 4 , 5 )

Holotype. Adult male ( LSUHC 13139 ) collected on 28 March 2017 at 1600 hrs by L. Lee Grismer, Matthew L. Murdoch, and Toby Smith from 2.7 km southwest of Ywangan , Ywangan Township, Taunggyi District, Shan State, Myanmar (21.14643°N, 96.42178°E; 1157 m in elevation).

Paratype. Adult female ( LSUHC 13138) bears the same collection data as the holotype.

Diagnosis. Hemiphyllodactylus ywanganensis sp. nov. can be separated from all other species of Hemiphyllodactylus by possessing the unique combination of having a maximum SVL of 38.0 mm; 10 chin scales; enlarged postmentals; five circumnasals; two or three intersupranasals (=postrostrals); nine or 10 supralabials; 10 infralabials; 13–15 longitudinally arranged dorsal scales at midbody and seven or eight ventral scales contained within one eye diameter; varied digital formulae ( Tables 5, 6, & 7); three subdigital lamellae on the first finger; two or three subdigital lamellae on the first toe; 26 continuous pore-bearing femoroprecloacal scales in the male; no plate-like subcaudal scales; adult females not being yellow; a dark postorbital stripe not extending onto trunk; no pairs of paravertebral light spots on trunk; no dark, diffuse, dorsolateral stripe; dark paravertebral markings on trunk; dorsal body pattern not unicolor; postsacral marking bearing light-colored anteriorly projecting arms; and unpigmented ceacum and gonads. These characters are scored across all species of the eastern Myanmar clade in Tables 5 and 6 and from all other species of Hemiphyllodactylus from southern China and western Thailand (clades 3 and 4 in Grismer et al. [2017b: Table 3]).

Description of holotype. Adult male; head triangular in dorsal profile, depressed, distinct from neck; lores and interorbital regions flat; rostrum moderate in length (NarEye/HeadL 0.29); prefrontal region flat to weakly concave; canthus rostralis smoothly rounded, barely discernable; snout moderate, rounded in dorsal profile; eye large; ear opening elliptical, small; eye to ear distance greater than diameter of eye; rostral wider than high, bordered posteriorly by small supranasals; two intersupranasals (=postnasals); external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by two postnasals, ventrally by first supralabial (=circumnasals); 10 (R,L) rectangular supralabials tapering to below posterior margin of orbit; 10 (R,L) rectangular infralabials tapering to below posterior margin of orbit; scales of rostrum, lores, top of head, and occiput small, granular, those of rostrum largest and slightly raised; dorsal superciliaries flat, mostly square, subimbricate, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by two large postmentals; each postmental bordered laterally by a single slightly enlarged sublabial; 10 chin scales; gular scales small, subimbricate, grading posteriorly into slightly larger, subimbricate throat and even larger pectoral scales which grade into slightly larger, subimbricate ventrals.

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Body somewhat elongate (Trunk/SVL 0.48), dorsoventrally compressed; ventrolateral folds absent; dorsal scales small, granular, 15 dorsal scales at midbody contained within one eye diameter; ventral scales flat, subimbricate much larger than dorsal scales, seven ventral scales contained within one eye diameter; precloacal scales slightly larger than abdominal scales; pore-bearing precloacal scales continuous with pore-bearing femoral scales, totaling 26 femoroprecloacal pore-bearing scales; single enlarged tubercle on anterior margin of hemipenial swelling; forelimbs short, robust in stature, covered with flat, subimbricate scales dorsally and ventrally; palmar scales flat, subimbricate; all digits except digit I well-developed; digit I vestigial, clawless; distal subdigital lamellae of digits II–V undivided, angular and U-shaped, lamellae proximal to these transversely expanded; lamellar formula of digits II–V 3-3 -4-3 (R,L); three transversely expanded lamellae on digit I; claws on digits II–V well developed, unsheathed; distal portions of digits strongly curved, terminal joint free, arising from central portion of lamellar pad; hind limbs short, more robust than forelimbs, covered with flat, juxtaposed scales dorsally and by larger, flat subimbricate scales ventrally; plantar scales low, flat, subimbricate; all digits except digit I welldeveloped; digit I vestigial, clawless; distal subdigital lamellae of digits II–V undivided, angular and U-shaped, lamellae proximal to these transversely expanded; lamellar formula of digits II–V 3-3 -3-3 (R,L); two transversely expanded lamellae on digit I; claws on digits II–V well developed, unsheathed; distal portions of digits strongly curved, terminal joint free, arising from central portion of lamellar pad; dorsal and subcaudal scales of regenerated tail small, subcycloid, subimbricate, subcaudals slightly larger than dorsals, not plate-like. Morphometric data are presented in Table 6.

Coloration in life ( Fig. 4 ). All Hemiphyllodactylus are capable of considerable change in the intensity and boldness of their coloration and pattern. The description below is of that at the time the specimens were photographed the next morning approximately 12 hours after the time of collection. Ground color of top of head, body, limbs, and tail densely mottled in dark-gray; top of head overlain with small white, diffuse specking; broad, dark, diffuse postorbital stripe extends to neck; pairs of indistinct, dark, paravertebral markings extend from forelimb insertions to base of tail transforming into a distinct post-sacral marking; postsacral marking bears faint, light-colored, anteriorly projecting arms; dorsum and flanks faintly mottled with light-colored speckling lacking distinct pairs of paravertebral light spots; limbs bearing irregularly shaped dark markings; regenerated tail generally gray, patternless; gular region generally immaculate, except for darker lateral areas and faint stippling in scales; and pigmentation density increases posteriorly with the abdomen being generally gray.

Variation ( Figs. 4 , 5 ). The color pattern of the paratype (LSUHC 13138) generally matches that of the holotype. LSUHC 13138 is slightly darker overall and has an original tail bearing 10 indistinct, wide, dark bands countershaded posteriorly with more narrow, cream-colored bands. Slightly enlarged, dull-orange colored ventrolateral caudal scales occur at the base of each cream-colored band. The dorsal caudal scales of original tail are subimbricate, larger than the dorsal body scales, and grad laterally into larger, slightly flared scales along the side of the tail bearing elevated posterior margins. The subcaudal scales are larger than the dorsal caudals, flat, imbricate, and not plate-like. Differences in scales counts are presented in Table 6.

Distribution. Hemiphyllodactylus ywanganensis sp. nov. is known only from the type locality of 2.7 km southwest of Ywangan, Ywangan Township, Taunggyi District, Shan State, Myanmar ( Fig. 1 ).

Natural History. The area surrounding the collection site at the type locality is a generally flat, open and disturbed landscape with low, short, vegetated karstic ridges and small, isolated, scattered karst outcrops ( Fig. 6 ). The holotype was found 1 m above the ground on the trunk of a small tree and the paratype—a gravid female carrying two eggs—was found approximately 10 m away 1 m above the ground on a karst boulder. The fact that the female was gravid indicates that March falls within the reproductive season of this species.

Etymology. The specific epithet, ywanganensis , is a noun in apposition in reference to the type locality being near the town of Ywangan, Shan State.

Comparisons. The molecular analyses indicate that Hemiphyllodactylus ywanganensis sp. nov. is embedded within eastern Myanmar clade and forms a monophyletic group with H. linnwayensis and H. uga sp. nov. Although not statistically significant due to small sample sizes, it is separated from H. uga sp. nov. by having 26 (n = 1) as opposed to 18–22 (n = 2) femoroprecloacal pores in males. Additional samples of each will bear out the significance or further insignificance of this difference. It does differ from H. uga sp. nov. in having, as opposed to lacking dark, paravertebral markings on the dorsum and light-colored, anteriorly projecting arms of the postsacral marking and lacking, as opposed to variably having, pairs of paravertebral light spots on trunk. From H. linnwayensis , H. ywanganensis sp. nov. it differs further in lacking distinct pairs of light-colored paravertebral spots on the dorsum and having a significantly higher mean number of chin scales (10.0 vs 5.0, p = 0.003; Table 7). Similarly, it differs from H. tonywhitteni and H. montawaensis in having a significantly higher mean number of chin scales (10.0 vs 6.6, p = 0.04 and 10.0 vs 6.3, p = 0.03, respectively) and from H. montawaensis it differs even further in having more femoroprecloacal pores in males (26, n = 1 vs 19–21, n = 2) and a non-reticulated dorsal pattern.

Figures

FIGURE 1. Distribution of the species of the eastern Myanmar clade of Hemiphyllodactylus in Shan State (H. linnwayensis, H. montawaensis, H. tonywitteni, and H. ywnaganensis sp. nov.) and Mandalay Region, Myanmar (H. uga sp. nov.). The green square in the inset delimits the study area.

FIGURE 4. A. Adult female paratype (LSUHC 13138) of Hemiphyllodactyus ywanganensis sp. nov. from 2.7 km southwest of Ywangan, Ywangan Township, Taunggyi District, Shan State, Myanmar (Photo by L. L. Grismer). B and C: Adult male holotype (USNM 570733) and adult female paratype (USNM 570734) of H. uga sp. nov., respectively, from the Pyin Oo Lwin, Kandawgyi National Gardens, Pyin Oo Lwin, Mandalay Region, Myanmar (Photos by G. R. Zug). D. Adult female (LSUDPC 10666) of H. montawaensis from the new locality of Ruby Cave, 5.1 km northeast of the type locality of Montawa Cave, 3.7 km southwest of Taunggyi, Taunggyi District, Shan State, Myanmar (Photo by L. L. Grismer).

FIGURE 5. Upper row: Type series of Hemiphyllodactyus ywanganensis sp. nov. from 2.7 km southwest of Ywangan, Ywangan Township, Taunggyi District, Shan State, Myanmar. Lower row: Type series of H. uga sp. nov. from the Pyin Oo Lwin, Kandawgyi National Gardens, Pyin Oo Lwin, Mandalay Region, Myanmar. Photos by L. L. Grismer.

FIGURE 6. Habitat of Hemiphyllodactyus ywanganensis sp. nov. from 2.7 km southwest of Ywangan, Ywangan Township, Taunggyi District, Shan State, Myanmar. Photo by L. L. Grismer.