Hemiphyllodactylus montawaensis, Grismer & Wood Jr & Kyaw Thura & Zin & Quah & Murdoch & Grismer & Li & Kyaw & Lwin, 2017

Grismer, L. Lee, Wood Jr, Perry L., Kyaw Thura, Myint, Zin, Thaw, Quah, Evan S. H., Murdoch, Matthew L., Grismer, Marta S., Li, Aung, Kyaw, Htet & Lwin, Ngwe, 2017, Phylogenetic taxonomy of Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) with descriptions of three new species from Myanmar, Journal of Natural History 52 (13 - 16), pp. 881-915 : 899-906

Hemiphyllodactylus montawaensis sp. nov.

Montawa dwarf gecko

( Figures 9 and 10 )

Holotype

Adult male ( LSUHC 13010) collected on 17 October 2016 at 1600 hours by Evan S. H. Quah, Perry L. Wood, Jr., Matthew L. Murdoch, Thaw Zin, Myint Kyaw Thura, Htet Kyaw,

Marta S. Grismer, and L. Lee Grismer from Montawa , Cave 3.7 km south-west of Taunggyi, Taunggyi District, Shan State, Myanmar (20°47.521N, 97°01.222E; 1171 m) .

Paratypes

Adult male ( LSUHC 13011 ) and adult females ( LSUHC 13012–13 ) bear the same data as the holotype .

Diagnosis

Hemiphyllodactylus montawaensis sp. nov. can be separated from all other species of Hemiphyllodactylus by possessing the unique combination of having a maximum SVL of 40.1 mm; 4–7 chin scales; enlarged postmentals; 4–6 circumnasal scales; 1–4 scales between supranasals (=postrostrals); 8–10 supralabials; eight or nine infralabials; 13 or 14 longitudinally arranged dorsal scales at mid-body contained within one eye diameter and seven or eight ventral scales; varied digital formulae ( Table 3); three or four subdigital lamellae on the first finger and toes; 19–21 pore-bearing femoroprecloacal scales; no plate-like subcaudal scales; dark, postorbital stripe not extending onto trunk; no pairs of paravertebral light spots on trunk; dorsal body pattern not unicolour; postsacral marking generally not bearing lightcoloured, anteriorly projecting arms; and caecum and gonads unpigmented. These characters are scored across all species of Hemiphyllodactylus from clades 4 and 5 ( 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 0.32); prefrontal region flat to weakly concave; canthus rostralis smoothly rounded, barely discernible; snout moderate, rounded in dorsal profile; eye large; ear opening round, small; eye to ear distance greater than diameter of eye; rostral wider than high, partially divided dorsally, bordered posteriorly by small supranasals; one internasal (=postnasal); external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by four postnasals, ventrally by first supralabial (=circumnasals); 8 (R,L) rectangular supralabials tapering to below posterior margin of orbit; 8 (R,L) subrectangular 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 large, sublabial; seven chin scales; gular scales small, subimbricate, grading posteriorly into slightly larger, subimbricate, throat and pectoral scales which grade into slightly larger, subimbricate ventrals.

Body somewhat elongate (Trunk/SVL 0.51), dorsoventrally compressed; ventrolateral folds absent; dorsal scales small, granular, 13 dorsal scales at midbody contained within one eye diameter; ventral scales, flat, subimbricate much larger than dorsal scales, seven scales contained within one eye diameter; precloacal scales slightly larger than abdominal scales; pore-bearing precloacal scales continuous with pore-bearing femoral scales, totalling 21; forelimbs short, robust in stature, covered with flat, subimbricate scales dorsally and ventrally; palmar scales flat, subimbricate; all digits except digit I welldeveloped; digit I vestigial, clawless, larger on right than on left; distal, subdigital lamellae of digits II–V undivided, angular and U-shaped; lamellae proximal to these transversely expanded; lamellar formula of digits II–V 3-4-4-3 (R,L); four transversely expanded lamellae on digit I; claws on digits II–V well developed, sheathed; 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 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 3-4-4-4 (R,L); three transversely expanded lamellae on digit I; claws on digits II–V well developed, sheathed; distal portions of digits strongly curved, terminal joint free, arising from central portion of lamellar pad; dorsal caudal scales small, square, subimbricate; tail original, subcaudals larger, flat, imbricate; ventrolateral caudal scales forming a weak fringe; and tail oval in cross-section. Morphometric data are presented in Table 8.

Coloration before preservation ( Figure 9 )

Top of head, body, limbs, and tail grey overlain with a darker, broken reticulate pattern transforming to poorly defined bands on the posterior one-half of the tail and smaller irregularly shaped markings on the lower flanks; spotting or striping on trunk absent; distinctive, dark, preorbital stripe; dark, postorbital stripe irregular, bifurcated, and broken on the right side; limbs bearing irregularly shaped, dark markings; ventral surfaces light-coloured with minute dark spots in each scale; spotting more dense beneath hind limbs and tail.

Variation ( Figures 9 and 10 )

The colour patterns of the paratypes generally match that of the holotype. Light dorsal spotting is more prevalent in LSUHC 13011 and 13013 and the light-coloured postsacral mark is more vivid in the latter . The adult female LSUHC 13012 has a yellow ground colour and an orangish subcaudal region . The intensity of coloration and contrast in colour pattern changes with mood and activity. Differences in scales counts are presented in Table 8.

Distribution

Hemiphyllodactylus montawaensis sp. nov. is known only from the type locality of Montawa Cave , Taunggyi District, Shan State, Myanmar ( Figure 1 ) .

Natural history

Montawa Cave is situated at 1171 m in elevation along a steep, fast-flowing stream and lies approximately two-thirds the way up a precipitous 130 km north to south tending karstic ridge edging the eastern margin of a flat basin containing Inle and Nam Belu Lakes. The cave is associated with a small monastery and the mouth is approximately 30 m above the monastery level. Steep, vertical karst walls frame the mouth of the cave and extend into the forest in both directions ( Figure 11 ). The limestone at this locality was not as weathered and porous as that of the Phapant Cave region but was more sedimentary in composition. We believe H. montawaensis sp. nov. is a karst-adapted species. All lizards were found at night between 1900 and 2300 hours 1–3 m above the ground on the flat, unerroded limestone faces outside the cave in open areas generally devoid of vegetation. No Hemiphyllodactylus were seen on the surrounding man-made structures of the monastery, within the cave, or on vegetation. Adult female LSUHC 13012 contained two eggs.

Etymology

This specific epithet ‘ montawaensis ’ refers to the type locality of Montawa cave.

Comparisons

The molecular analyses indicate that Hemiphyllodactylus montawaensis sp. nov. is embedded within clade 4 of the typus group and is the sister species of H. tonywhitteni sp. nov. Hemiphyllodactylus montawaensis sp. nov. can be distinguished from all other species in clade 3 by having 4–7 as opposed to 7–12 chin scales, collectively; it differs further from all species of these two clades by having a dark, reticulate, dorsal pattern. It differs further from H. tonywhitteni sp. nov. in having relatively narrower head (0.16–0.17 versus 0.17–0.19) throughout its growth trajectory ( Figure 8 ) and a statistically signifi- cantly narrower head (p <0.024, n = 6) as an adult. Uncorrected pair-wise sequence divergence between H. montawaensis sp. nov. and all other species of clades 3 and 4 ranges from 6.4–19.3% ( Table 7). See comparison section for H. tonywhitteni sp. nov. for a discussion of the PCA and DAPC results and for comparisons to H. tonywhitteni sp. nov.

Figures

Figure 1. Distribution of Hemiphyllodactylus montawaensis sp. nov., H. tonywhitteni sp. nov., H. linnwayensis sp. nov., and H. cf. linnwayensis in the Shan Hills of eastern Myanmar.

Figure 8. Comparative growth trajectories of head width between Hemiphyllodactylus montawaensis sp. nov., H. tonywhitteni sp. nov. and H. linnwayensis sp. nov. Shaded areas represent the 95% confidence intervals.

Figure 9. (a) Adult female paratype (LSUHC 13012) of Hemiphyllodactylus montawaensis sp. nov. from the type locality of Montawa Cave 3.7 km south-west of Taunggyi, Taunggyi District, Shan State, Myanmar. (b) Adult male holotype (LSUHC 13010) from the type locality.

Figure 10. Type series of Hemiphyllodactylus montawaensis sp. nov. from the type locality of Montawa Cave 3.7 km south-west of Taunggyi, Taunggyi District, Shan State, Myanmar.

Figure 11. Forested karstic ridge of the type locality of Hemiphyllodactylus montawaensis sp. nov.