Hemiphyllodactylus zwegabinensis, Grismer & Wood & Quah & Thura & Oaks & Lin, 2020

Grismer, L. Lee, Wood, Perry L., Quah, Evan S. H., Thura, Myint Kyaw, Oaks, Jamie R. & Lin, Aung, 2020, Four new Burmese species of Hemiphyllodactylus Bleeker (Squamata: Gekkonidae) from distantly related parapatric clades from the Shan Plateau and Salween Basin, Zootaxa 4758 (1), pp. 45-82 : 63-67

Hemiphyllodactylus zwegabinensis sp. nov.

Zwegabin Mountain Slender Gecko

( Figs. 7A , 8 )

Holotype. Adult female ( LSUHC 14184 ) collected on 8 August 2019 at 1830 hrs by L. Lee Grismer, Evan S. H. Quah, Perry L. Wood Jr., Myint Kyaw Thura, Jamie R. Oaks , and Aung Lin at the top of Zwegabin Mountain, Kayin State, Myanmar (16.82407°N 97.66810°E WGS; 710 m in elevation).

Diagnosis. Hemiphyllodactylus zwegabinensis sp. nov. can be separated from all other species of Hemiphyllodactylus by possessing the unique combination of having a maximum SVL of 36.9 mm; 12 chin scales; enlarged postmentals; five circumnasal scales; five intersupranasals (=postrostrals); nine supralabials; 10 infralabials; 16 longitudinally arranged dorsal scales at midbody contained within one eye diameter and seven ventral scales; varied digital formulae on hands and feet; four subdigital lamellae on the first finger and toe; no pore-bearing, femoroprecloacal scales; no plate-like subcaudal scales; adult females not yellow; a dark postorbital stripe extending to at least base of neck; dorsolateral light-colored spots on trunk; no dark dorsolateral or ventrolateral stripe on trunk; dark paravertebral markings on trunk; light-colored postsacral marking bearing anteriorly projecting arms; and caecum and gonads unpigmented. These characters are scored across all Burmese species in Tables 3 and 6 and from all other species of Hemiphyllodactylus from southern China and western Thailand (clades 3 and 4 in Grismer et al. (2017: Table 3)).

Description of holotype. Adult female SVL 36.9 mm; head triangular in dorsal profile, depressed, distinct from neck; lores flat; rostrum moderate in length (SN/SVL 0.09); prefrontal region 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 large supranasals; five equally sized intersupranasals (=postnasals); external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by two postnasals, ventrally by first supralabial (=circumnasals); 9, 10 (R, L) rectangular supralabials tapering to below posterior margin of eye; 10, 10 (R, L) rectangular infralabials tapering to below posterior margin of eye; scales of rostrum, lores, top of head, and occiput small, raised, those of rostrum largest; dorsal superciliaries flat, mostly square, subimbricate, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by two differently sized, square-shaped postmentals; each postmental in contact with first infralabial and bordered laterally by a smaller sublabial; 12 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.

Body somewhat elongate (AG/SVL 0.51), dorsoventrally compressed; ventrolateral folds absent; dorsal scales small, granular, 16 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 larger than abdominal scales; no pore-bearing femoroprecloacal scales; single enlarged tubercle on lateral margin of tail base; forelimbs short, robust in stature, covered with flat, subimbricate scales dorsally and ventrally; palmar scales slightly raised, 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; distal lamellar formula of digits II–V 4-4-4-4 (R, L); four 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 slightly raised, juxtaposed scales dorsally and by larger, flat subimbricate scales anteriorly and ventrally; plantar scales slightly raised, 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; distal lamellar formula of digits II–V 4-5-5-4 (R, L); four 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; tail original, complete; caudal scales occurring in whorls; dorsal caudal scales larger than dorsal body scales, flat, subcycloid, subimbricate; ventrolateral caudals slightly enlarged, weakly flared anteriorly giving a fringe-like appearance; subcaudals flat, slightly larger than dorsal caudals, not plate-like. Morphometric data are presented in Table 9.

Coloration in life ( Fig . 7). All Hemiphyllodactylus are capable of considerable change in the intensity and boldness of their coloration and pattern. The description below is of that when the holotype was photographed the morning after capture, approximately 12 hours after the time of collection when in its light-phase. Ground color of top of head, body, and limbs, light-brown and densely mottled with darker markings; top of head overlain with dark, semi-reticulate pattern; broad, dark, diffuse pre- and postorbital stripe extends from the external nares, through the eye to forelimb insertion; pairs of diffuse, dark, paravertebral markings counter-shaded posteriorly with diffuse white markings extend from nape to base of tail transforming into a distinct black, post-sacral marking; lightcolored counter shaded areas appear as dorsolateral spots along the trunk; faint yellow post-sacral marking bears light-colored anteriorly projecting arms (most obvious on left side); dorsum and flanks heavily mottled with faint, dark, diffuse speckling; limbs bearing irregularly shaped diffuse dark markings and bands; gular region generally immaculate, except for darker lateral areas, scales faintly stippled, and pigmentation density increases posteriorly with abdomen being generally gray; ground color of dorsal caudal region dull-yellow, bearing three faint diffuse bands anteriorly that do not encircle the tail and irregular dark mottling posteriorly; median subcaudal region heavily stippled.

Distribution. Hemiphyllodactylus zwegabinenis sp. nov. is known only from the type locality of Zwegabin Mountain, Kayin State ( Fig. 1 ).

Natural History. The holotype was collected on a metal building in stunted, wind-blown, primary forest at the crest of Zwegabin Mountain ( Fig. 8 ).

the south lineage. Bold values are intraspecific values.

Etymology. The specific epithet is a toponym referring to the type locality of Zwegabin Mountain. Comparisons. The molecular analyses indicate that Hemiphyllodactylus zwegabinensis sp. nov. is a genetically distinct member of the south lineage and is the sister species to a clade composed of the sister species H. kyaiktiyoensis sp. nov., and H. pinlaungensis sp. nov. ( Fig. 1 ) from which it bears an uncorrected pairwise sequence divergence of 13.7% and 14.1%, respectively ( Table 10). Hemiphyllodactylus zwegabinensis sp. nov. differs from H. pinlaungensis sp. nov. and H. kyaiktiyoensis sp. nov. by having significantly different centroid position based on the factor loadings of the PC1–3 (p = 0.002 and 0.022, respectively). Hemiphyllodactylus zwegabinensis sp. nov. differs from H. kyaiktiyoensis sp. nov. by having 12 as opposed to 8–10 chin scales (CS), 10 as opposed to eight or nine infralabials, seven as opposed to eight or nine ventral scales (VS) ( Fig. 3 , Table 6), and lacking as opposed to having a nearly dorsum-wide, brown vertebral stripe ( Fig. 7 ). Hemiphyllodactylus zwegabinensis sp. nov. differs from H. pinlaungensis sp. nov. by having significantly shorter adjusted SN (1.065 vs 1.363, p = 0.005; Fig. 3 , Table 6).

Figures

FIGURE 1. Maximum likelihood consensus tree of Hemiphyllodactylus clades with UFB and BI support value coding at the nodes. Topographical map showing the distribution of the species in the north and south lineages on the Shan Plateau and in the Salween Basin. Localities of H. ngwelwini sp. nov. from north to south are Pwe Hla Village, Thayeumin Cave, and Myintmahati Cave, Shan State.

FIGURE 3. Graphics of statistical analyses among species of the south lineage. A. Principal component analysis (PCA). B. Discriminant function of principal components (DAPC). C. Boxplots of characters bearing significantly different mean values. Species pairs bearing significantly different mean values between them are listed above each plot. Abbreviations are in the Materials and methods.

FIGURE 7. A. Adult female holotype of Hemiphyllodactylus zwegabinensis sp. nov. (LSUHC 14184) from Zwegabin Mountain, Kayin State, Myanmar. Color pattern variation in B. Adult female paratype (LSUHC 14033) H. kyaiktiyoensis sp. nov. from Kyaiktiyo Mountain, Mon State, Myanmar and C. Adult female paratype (LSUHC 14030) H. kyaiktiyoensis sp. nov. from Kyaiktiyo Mountain, Mon State, Myanmar. Photos by L. Lee Grismer.

FIGURE 8. Natural wind-blown upland karst habitat of Hemiphyllodactylus zwegabinensis sp. nov. from the peak of Zwegabin Mountain, Kayin State, Myanmar.