Cyrtodactylus naungkayaingensis, Grismer & Wood & Thura & Quah & Murdoch & Grismer & Herr & Lin & Kyaw, 2018

Grismer, L. Lee, Wood, Perry L., Thura, Myint Kyaw, Quah, Evan S. H., Murdoch, Matthew L., Grismer, Marta S., Herr, Mark W., Lin, Aung & Kyaw, Htet, 2018, Three more new species of Cyrtodactylus (Squamata: Gekkonidae) from the Salween Basin of eastern Myanmar underscore the urgent need for the conservation of karst habitats, Journal of Natural History 52 (19 - 20), pp. 1243-1294 : 1282-1286

Cyrtodactylus naungkayaingensis sp. nov.

Naung Ka Yaing Hill bent-toed gecko ( Figures 13 and 14 )

Holotype

Adult male LSUHC 13209 collected on 8 May 2017 at 2000 hrs by Myint Kyaw Thura, Mark W. Herr, L. Lee Grismer, Perry L. Wood, Jr., Matthew L. Murdoch, Evan S.H. Quah, and Htet Kyaw from Naung Ka Yaing Hill, 17 km north-east of Hpa-an, Hpa-an District , Kayin State, Myanmar (17.01558°N, 97.70641°E; 14 m in elevation).

Paratypes

Adult male LSUHC 13208 and juvenile LSUHC 13207 bear the same collecting data as the holotype .

Diagnosis

Cyrtodactylus naungkayaingensis sp. nov. differs from all congeners by having the unique combination of maximum SVL 66.9 mm; eight or nine supralabials; seven infralabials; 34 or 35 paravertebral tubercles; 16–18 longitudinal rows of body tubercles; 27 longitudinal rows of ventral scales; relatively long digits with seven expanded subdigital lamellae proximal to the digital inflexion on the fourth toe, 11 or 12 unmodified distal subdigital lamellae, 18–19 total subdigital lamellae; raised, moderately keeled, dorsal body tubercles in adults; tubercles extending beyond base of tail; enlarged femoral and precloacal scales continuous; enlarged proximal femoral scales less than one-half the size of enlarged distal femoral scales; 30–35 enlarged femoral scales; 11 femoral pores in males; three or four precloacal pores in males; pore-bearing femoral and precloacal scales discontinuous; 8–12 enlarged precloacal scales; three rows of enlarged postprecloacal scales; medial subcaudal scales 3 times as wide as long, extending onto lateral surface of tail; top of head mottled in adults, no yellow reticulum; nuchal loop not divided medially, no pronounced anterior azygous notch, posterior border jagged; four jagged, dark, dorsal bands with lightened centres bearing paravertebral elements, narrower than interspaces, not edged with white tubercles; nape band variably present; dark markings in dorsal interspaces; ventrolateral folds not whitish; anterodorsal margins of thighs and brachia not pigmented; 11 light-coloured caudal bands bearing dark markings, not encircling tail; 10 dark caudal bands wider than light caudal bands; and mature regenerated tail not spotted. These characters are scored against all other species in the sinyineensis group in Table 4 and all other species of the Indochinese clade in Grismer et al. (2017a, table 8).

Description of holotype

Adult male SVL 66.9 mm; head moderate in length (HL/SVL 0.29), wide (HW/HL 0.66), flat (HD/HL 0.38), distinct from neck, triangular in dorsal profile; lores inflated, prefrontal region concave, canthus rostralis rounded; snout elongate (ES/HL 0.43), rounded in dorsal profile, not flat in lateral profile; eye large (ED/HL 0.27); ear opening round, moderate in size (EL/HL 0.13); eye-to-ear distance greater than diameter of eye; rostral rectangular, depressed dorsomedially, bearing a short dorsal cleft, bordered posteriorly by left and right supranasals and one small azygous internasal, laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by two postnasals, ventrally by first supralabial; 8 (R, L) square supralabials extending to below midpoint of eye; 7 (R, L) infralabials tapering posteriorly to below midpoint of eye; scales of rostrum and lores slightly raised, larger than granular scales on top of head and occiput; scales on top of head and occiput intermixed with small tubercles; dorsal superciliaries not elongate or keeled; mental triangular, bordered laterally by first infralabials and posteriorly by large left and right trapezoidal postmentals contacting medially for 65% of their length posterior to mental; one row of slightly enlarged chinshields bordering all infralabials, first chinshield largest; and gular and throat scales small, flat, grading posteriorly into larger, subimbricate pectoral and ventral scales.

Body relatively short (AG/SVL 0.42) with well-defined ventrolateral folds; dorsal scales small, raised and interspersed with large, subconical, semi-regularly arranged, strongly keeled tubercles; tubercles extend from top of head to beyond base of tail; tubercles on nape smaller than those on posterior portion of body, less sharply keeled; approximately 18 longitudinal rows of body tubercles; 34 paravertebral tubercles; 27 flat, subimbricate, ventral scales larger than dorsal scales; 12 enlarged precloacal scales; three precloacal pores; three rows of large post-precloacal scales; and no deep, precloacal groove or depression.

Fore limbs moderate in stature, relatively short (FL/SVL 0.17); raised scales of forearm larger than those on body, interspersed with tubercles; palmar scales flat; digits well developed, relatively long, inflected at basal, interphalangeal joints; digits much more narrow distal to inflexions; widened proximal subdigital lamellae do not extend onto palm; claws well developed, sheathed by a dorsal and a ventral scale at base; hind limbs more robust than fore limbs, moderate in length (TBL/SVL 0.20), covered dorsally by granular scales intermixed with large tubercles and bearing flat, slightly larger scales anteriorly; ventral scales of thigh flat, imbricate, larger than dorsals, one row of 18 R, 17 L enlarged femoral scales in contact with enlarged precloacal scales; enlarged femoral scales generally equal in size; 5R,6L porebearing femoral scales not in contact with pore-bearing precloacal scales; subtibial scales flat, imbricate; small postfemoral scales form abrupt union with larger, flat ventral scales of posteroventral margin of thigh; plantar scales slightly raised; digits relatively long, well developed, inflected at basal, interphalangeal joints; 7 (R, L) transversely expanded subdigital lamellae on fourth toe proximal to joint inflexion, 11 (R, L) unmodified subdigital lamellae distal to inflexion, 18 total subdigital lamellae; claws well developed, base of claw sheathed by a dorsal and a ventral scale.

Tail moderate in proportions, original, 101.0 mm in length, 7.3 mm in width at base, tapering to a point; dorsal scales of tail flat; median subcaudal scales 3 times as wide as long, extending onto lateral surface of tail; 3 (R, L) enlarged postcloacal tubercles at base of tail on hemipenal swellings; and postcloacal scales flat.

Colouration in life ( Figure 13 )

Dorsal ground colour of head, body, and limbs tan; top of head and rostrum bearing diffuse, dark-brown blotches, no yellow reticulum; superciliary scales dull-yellow; darkbrown, irregularly shaped nuchal band un-notched anteromedially and bearing a jagged posterior margin with two large, posterior projections; short band on nape; four jagged body bands bearing lightened centres, not wider than interspaces, bearing paravertebral elements and not edged with white tubercles; interspaces bearing dark vertebral and lateral spots; one sacral band, nearly bifurcated medially; limbs faintly mottled, anterodorsal margins unpigmented, thighs bearing yellowish tubercles; ventrolateral body fold not whitish; ventral surfaces head, body and limbs dull-white, pigmented peripherally; tail bearing 11 light caudal bands with dark markings; 10 dark caudal bands wider than light caudal bands; subcaudal region darkly mottled.

Variation ( Figures 13 and 14 )

The paratypes generally resemble the holotype in aspects of colouration and pattern. The body bands on adult male LSUHC 13208 are not as bold as the holotype and the interspace mottling is less evident . The posterior one-half of the tail of LSUHC 13208 is regenerated and dark with light mottling . The interspace areas of the dorsal pattern of the juvenile LSUHC 13207 are more clear and much less mottled . LSUHC 13207 has a broken tail with only slight regeneration . Additional variation in meristic and mensural characters is presented in Table 9.

Distribution

Cyrtodactylus naungkayaingensis sp. nov. is known only from Naung Ka Yaing Hill, 17 km north-east of Hpa-an, Hpa-an District, Mon State, Myanmar ( Figure 6 ).

Etymology

The specific epithet, naungkayaingensis , is a noun in apposition in reference to the type locality of Naung Ka Yaing Hill.

Natural history

Naung Ka Yaing Hill reaches approximately 125 m in elevation and is approximately 370 m in diameter. It is one of two small isolated karst towers near the village of Naung Ka Yaing. The other karst tower, approximately 400 m to the south-east, was not surveyed but we expect Cyrtodactylus naungkayaingensis sp. nov. occurs there as well ( Figure 15 ). The base of the karst tower is densely vegetated and difficult to access. We did find one stretch of approximately 60 m that was suitable habitat that we could survey. Between 2000 and 2100 hrs we saw a total of eight specimens and were able to catch three. The lizards were very wary, and seen on the ground, vegetation, and the base of the karst wall and surrounding boulders. None were seen over 0.5 m high on the karst. One specimen was seen running across the ground before it took refuge beneath a limestone rock, and another was seen running across the ground to a tree where it climbed as high as 2 m before it escaped. This appears to be a scansorial forest species that moves about on the ground and is opportunistically occupying the limestone forest habitat because the surrounding forest has been cleared for agricultural endeavours ( Figure 15 ). This population may be seriously threatened in that there are small ongoing quarrying operations on both karst towers. One operation was only a few hundred metres away from where the specimens were collected.

Comparisons

The PCA analysis indicates that Cyrtodactylus naungkayaingensis sp. nov. is completely separate in morphospace from C. bayinnyinensis sp. nov., C. chaunghanakwaensis sp. nov. and C. dammathetensis . Although it overlaps C. sinyineensis and C. welpyanensis along PC1 and PC2, it is completely separated from them in the DAPC and along PC3 which loads most heavily for fourth toe lamellae and accounts for 11% of the total variation ( Figure 3 ; Table 6). Differences between C. naungkayaingensis sp. nov. and C. bayinnyiensis sp. nov. and C. chaunghanakwaensis sp. nov. are presented above in the comparison sections for those species. Cyrtodactylus naungkayaingensis sp. nov. differs from all other species in the sinyineensis group by having dorsal bands that are narrower rather than wider than the interspaces. It differs further from C. aequalis , C. sinyineenensis and C. welpyanensis in that the median subcaudal scales extend onto the lateral surface of the tail as opposed to being confined to the subcaudal region. It differs from C. sinyineenensis and C. welpyanensis in that the dorsal bands have, as opposed to lack, paravertebral elements. It differs from C. aequalis and C. sinyineensis by having a much smaller maximum SVL (66.9 mm vs 87.0– 91.6 mm, collectively). Additional nonmeristic differences between varying combinations of species in the sinyineenis group are illustrated in Table 4. The phylogenetic analyses recover Cyrtodactylus naungkayaingenis sp. nov. as the sister species of the C. aequalis-C. bayinnyiensis sp. nov. lineage ( Figure 6 ). It differs from C. aequalis by having significantly (p <0.05) different mean values of dorsal body bands, enlarged femoral scales, and ventral scales, and from C. bayinnyiensis sp. by having significantly different mean values of dorsal body bands, enlarged femoral scales, post-precloacal scales, paravertebral tubercles, total fourth toe lamellae, expanded fourth toe lamellae, and precloacal pores ( Tables 4 and 7). Table 7 lists additional characters whose mean values differ significantly from those of other species of the sinyineensis group.

Figures

Figure 3. Plots of the principal component (PC) analysis ordinations along PC1 and PC2, and PC2 and PC3; and the discriminant analysis of principal components (DAPC) showing the morphospatial relationships of the species of the sinyineensis group.

Figure 6. Distribution of the Burmese species of Cyrtodactylus from the Salween Basin and the phylogenetic relationships of the species of the sinyineensis group. Black circles denote nodes with Bayesian posterior probability (BI) support>0.95 and Maximum Likelihood bootstrap support>95. Grey circles denotes the node with only BI support>0.95.

Figure 13. (a) Adult male holotype of Cyrtodactylus naungkayaingensis sp. nov. (LSUHC 13209) from Naung Ka Yaing Hill, 17 km north-east of Hpa-an, Hpa-an District, Kayin State, Myanmar. (b) Juvenile paratype of C. naungkayaingensis sp. nov. (LSUHC 13207) from the type locality.

Figure 14. Type series of Cyrtodactylus naungkayaingensis sp. nov. from Naung Ka Yaing Hill, 17 km north-east of Hpa-an, Hpa-an District, Kayin State, Myanmar.

Figure 15. (a) Microhabitat structure of the karst wall of the type locality of Naung Ka Yaing Hill, 17 km north-east of Hpa-an, Hpa-an District, Kayin State, Myanmar. (b) Microhabitat structure of karst wall and the associated vegetation at the type locality. (c) Satellite view of the type locality and a nearby karst tower to the east. The white circle on Naung Ka Yaing Hill denotes the collecting site adjacent to a quarrying operation on the right. Another quarrying operation is visible on the adjacent karst tower to the east.