Hemiphyllodactylus linnwayensis, 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 : 906-911

Hemiphyllodactylus linnwayensis sp. nov.

Linn-Way dwarf gecko

( Figure 12 )

Holotype

Adult female ( LSUHC 12987) collected on 14 October 2016 at 1800 hours by L. Lee Grismer, Evan S. H. Quah, Perry L. Wood, Jr., Matthew L. Murdoch, Thaw Zin, Myint Kyaw Thura, Htet Kyaw, and Marta S. Grismer from Linn-Way Village, 64.7 km north of Kalaw, Taunggyi District, Shan State, Myanmar (21°13.356N, 96°32.780E; 1306 m).

Paratype

Adult female ( LSUHC 12969) collected on 13 October 2016 by Myint Kyaw Thura from the same locality as the holotype.

Diagnosis

Hemiphyllodactylus linnwayensis sp. nov. can be separated from all other species of Hemiphyllodactylus by possessing the unique combination of having a maximum SVL of 41.5 mm; 4–6 chin scales; enlarged postmentals; five circumnasal scales; two scales between supranasals (=postrostrals); nine or 10 supralabials; eight infralabials; 13 or 14 longitudinally arranged dorsal scales at midbody contained within one eye diameter and eight ventral scales; varied digital formulae ( Table 3); three or four subdigital lamellae on the first finger; four or five subdigital lamellae on the first toe; no plate-like subcaudal scales; adult females not yellow; dark postorbital stripe not extending onto trunk; pairs of light-coloured paravertebral spots on trunk; dorsal body pattern not unicolour; postsacral marking not bearing lightcoloured anteriorly projecting arms; and caecum and gonads unpigmented. These characters are scored across all species of Hemiphyllodactylus from clades 3 and 4 ( Table 3).

Description of holotype

Adult female; head triangular in dorsal profile, depressed, distinct from neck; lores and interorbital regions flat; rostrum moderate in length (NarEye/HeadL 0.31); 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, bordered posteriorly by supranasals; two internasals (=postnasal); 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; 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, similar in size throughout; mental triangular, bordered laterally by first infralabials and posteriorly by two large postmentals; each postmental bordered laterally by a single large, sublabial; four 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 0.49), 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, eight scales contained within one eye diameter; precloacal scales slightly larger than abdominal scales; pore-bearing precloacal scales continuous with pore-bearing femoral scales, pores small, poorly developed; 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 4-4-4-4 ( R,L); four transversely expanded lamellae on digit I; claws on digits II– V well developed, partially 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 4-5-4-4 ( R,L); five transversely expanded lamellae on digit I; claws on digits II– V well developed, partially 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 than dorsals, flat, imbricate; ventrolateral caudal scales forming a weak fringe; and tail oval in cross-section. Morphometric data are presented in Table 9.

Coloration before preservation ( Figure 12 )

Ground colour of top of head and vertebral and paravertebral region of trunk grey; side of head, flanks, limbs, and tail light-grey to beige; thin, dark, preorbital stripe; thicker, dark postorbital stripe extending to shoulder region; thin, dark stripe on each side of nape; area between nape and postorbital stripes light-coloured; trunk overlain with small, square to rectangularly shaped, dark, paravertebral markings highlighted posteriorly by small, diffuse, light-coloured blotches; dark, square, postsacral, marking lacking well-defined, light-coloured, anteriorly projecting arms; nine dark, irregularly shaped, caudal markings forming a weak banding pattern; ventral region of head, body, and limbs generally lighter medially and darker laterally due to increased stippling; and midventral, subcaudal region dull-orange, lateral regions dark.

Variation ( Figure 12 )

The colour pattern of the paratype closely matches that of the holotype. The overall ground colour is generally lighter and the dark, paravertebral markings on the dorsum are more paired than broken. The intensity of coloration and contrast in the pattern changes with mood and activity. Differences in scales counts are presented in Table 9.

Distribution

Hemiphyllodactylus linnwayensis sp. nov. is known only from the type locality of Linn- Way Village, Taunggyi District, Shan State, Myanmar ( Figure 1 ).

Natural history

Linn-Way village is a small, spread-out, somewhat isolated village on the western fringes of the Shan Plateau surrounded by secondary, upland forest ( Figure 13 ). Four Hemiphyllodactylus linnwayensis sp. nov. were seen in this region but only two were collected. The paratype ( LSUHC 12969) was found beneath a small log on the grounds of a monastery at 0100 hours and the holotype ( LSUHC 12987) was collected from an interior wall of a small house in the village at 2200 hours while we were being served dinner. Another specimen was observed on the same wall the following night but escaped collection. Another specimen that we presume was the same species was observed on a small wooden structure in the middle of a fallow field 3.4 km south of Linn-Way Village outside Yae Whin Cave that also escaped collection. No specimens were seen on karst microhabitats in the region that we extensively explored.

Etymology

This specific epithet ‘ linnwayensis ’ refers to the type locality of Linn-Way Village.

Comparisons

The molecular analyses indicate that Hemiphyllodactylus linnwayensis sp. nov. is embedded within clade 4 of the typus group and is the sister lineage to the sister species H. tonywhitteni sp. nov. and H. montawaensis sp. nov. Hemiphyllodactylus linnwayensis sp. nov. can be separated from all species of clades 3 and 4 except H. montawaensis sp. nov. by having fewer chin scales (4–6 as opposed to 5–12, collectively). It differs further from H. jinpingensis , H. chiangmaiensis , H. changningensis , and H. longlingensis in lacking as opposed to having dark, dorsolateral stripes on the trunk and dark, dorsal, transverse blotches. It differs from H. tonywhitteni sp. nov. in lacking well-defined, light-coloured, anteriorly projecting arms of the postsacral marking. It differs from H. montawaensis sp. nov. in that adult females are grey as opposed to yellow and having pairs of light-coloured, paravertebral spots on the trunk. See comparison section for H. tonywhitteni sp. nov. for a discussion of the PCA and DAPC results.

Remarks

The molecular phylogeny of Grismer et al. (2013) identified a specimen from Pyin Oo Lwin, Mandalay Region in the western Shan Hills as an undescribed new species they referred to as Hemiphyllodactylus sp. nov. 8. The molecular phylogeny herein ( Figure 2 ) recovers this specimen as the sister lineage to H. linnwayensis sp. nov. from Linn-Way Village in Shan State, 90 km to the south. The uncorrected pair-wise sequence divergence (p-distance) between these two species is 4.6%, less than the 5% Grismer et al. (2013) used to flag potential unconfirmed candidate species they were unable to examine. In sharp contrast, we note that the p-distance between the sister species H. montawaensis sp. nov. and H. tonywhitteni sp. nov. is 6.4% and they are separated by only 25 km ( Figures 1 and 14 ). Additionally, we propose that latter are karst-adapted species that cannot range continuously throughout forested habitats whereas H. linnwayensis sp. nov. is a forest-adapted species and may even be in a human commensal relationship, given that they can be found on man-made structures and within homes. The collection data of the Pyin Oo Lwin specimen are similar to H. linnwayensis sp. nov. in that it was found in a secondary growth forest in a botanical garden on a wooden viewing platform (2017 email from GR Zug to LLG). Based on the above, we hypothesize the potential for gene exchange between these two populations is likely, and thus conservatively consider Hemiphyllodactylus sp. nov. 8. as H. cf. linnwayensis sp. nov. until specimens become available for examination.

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 2. A Bayesian inference topology illustrating the phylogenetic relationships of the 28 species of Hemiphyllodactylus. Black circles are nodes supported by BPP and ML values of 0.95 and 95 or greater, respectively. Grey circles are nodes supported only by ML values 95 or greater.

Figure 12. (a) Adult female holotype (LSUHC 12987) of Hemiphyllodactylus linnwayensis sp. nov. from the type locality of Linn-Way Village, 64.7 km north of Kalaw, Taunggyi District, Shan State, Myanmar. (b) Adult female paratype (LSUHC 12869) from the type locality.

Figure 13. Forested village habitat of Hemiphyllodactylus linnwayensis sp. nov.

Figure 14. Bar graph comparing the relationship of distance (km) of separation and uncorrected pairwise sequence divergence (p-distance) within and between the pairs of sister lineages Hemiphyllodactylus tonywhitteni–H. montawaensis and H. linnwayensis–H. cf. linnwayensis.