Cyrtodactylus sadansinensis, Grismer & Wood & Jr. & Thura & Zin & Quah & Murdoch & Grismer & Lin & Kyaw & Lwin, 2018

CYRTODACTYLUS SADANSINENSIS View in CoL SP. NOV.

SADAN SIN CAVE BENT-TOED GECKO

( FIG. 19; TABLE 12)

Holotype: Adult male LSUHC 12857 View Materials collected on 6 October 2016 at 1600 h by Evan S. H. Quah, Perry L. Wood, Jr., Matthew L. Murdoch, Thaw Zin, Myint Kyaw Thura, Htet Kyaw and L. Lee Grismer from Sadan Sin Cave 10.5 km north-west of Mawlamyine, Mawlamyine District, Mon State, Myanmar (N16°31.729, E97°43.056; 26 m in elevation). GoogleMaps

Paratypes: Adult females BYU 52220 View Materials , 12858–59 View Materials and juvenile male LSUHC 12856 View Materials bear the same collection data as the holotype GoogleMaps .

of characters: 8–11 supralabial scales; seven or eight infralabial scales; dorsal body tubercles low, weekly keeled, not extending beyond base of tail; 25–31 paravertebral tubercles; 9–14 longitudinal rows of body tubercles; 31–41 ventral scales; 20–24 subdigital lamellae on the fourth toe; 14–34 enlarged femoral scales; femoral scales usually equal in size; 8–21 femoral pores in males; 9–15 enlarged precloacal scales; 5–14 precloacal pores in males; two or three post-precloacal scale rows; medial subcaudal scales three times wider than long, extending onto lateral subcaudal region; top of head bearing dark, mottled pattern with no yellow reticulum; no anterior, azygous notch in nuchal loop; dark band on nape; 4–6 regularly shaped body bands with lightened centres, not edged with light tubercles; anterodorsal margins of thighs and brachia pigmented; ventrolateral fold not whitish; 6–11 light caudal bands Diagnosis: Cyrtodactylus sadansinensis sp. nov. differs from all congeners by having the unique combination of 8–10 supralabials; seven or eight infralabials; 25–28 paravertebral tubercles; 9–11 longitudinal rows of body tubercles; 31–34 ventral scales; relatively long digits with eight or nine expanded subdigital lamellae on the fourth toe proximal to the digital inflection, 14–16 unmodified distal subdigital lamellae, 22–24 total subdigital lamellae; low and rounded, weakly keeled, dorsal, body tubercles not extending onto tail; enlarged femoral and precloacal scales not continuous; 19–23 enlarged femoral scales; 20 or 21 femoral pores in males; 12–15 enlarged precloacal scales; 12–14 precloacal pores in males; three rows of enlarged post-precloacal scales; subcaudal scales three times as wide as long, extending onto sides of tail; top of head bearing a dark mottled pattern, no yellow reticulum; nuchal loop not divided medially, lacking an azygous notch, and usually having a sinuous posterior border; five dark, regularly shaped, dorsal bands never wider than interspaces, bearing lightened centres, not edged with white tubercles; first dorsal band lacking azygous notch; dark markings in dorsal interspaces; ventrolateral fold not whitish; anterodorsal margin of thighs and brachia pigmented; 9–11 light caudal bands bearing dark markings, not encircling tail; 8–10 dark caudal bands never wider than light caudal bands; and regenerated tails immaculate, uniform brown.

Description of holotype: Adult male SVL 69.6 mm; head moderate in length (HL/SVL 0.30), wide (HW/ HL 0.66), flat (HD/HL 0.37), distinct from neck,

Abbreviations are listed in the Material and Methods. R, right; L, left; /, data unobtainable or not applicable; r, regenerated.

triangular in dorsal profile; lores inflated, prefrontal region weakly concave, canthus rostralis flattened; snout elongate (ES/HL 0.42), rounded in dorsal profile, flat in lateral profile; eye large (ED/HL 0.25); ear opening elliptical, vertically oriented, moderate in size (EL/HL 0.10); eye to ear distance greater than diameter of eye; rostral rectangular, partially divided dorsally by an inverted Y-shaped furrow, bordered posteriorly by large left and right supranasals and one small azygous internasal, laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by large supranasal, posteriorly by two postnasals, ventrally by first supralabial; 9(R,L) square supralabials extending to below midpoint of eye; 7(R,L) infralabials tapering posteriorly to below orbit; 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 slightly enlarged 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 45% of their length posterior to mental; one row of slightly enlarged chinshields bordering all infralabials; gular and throat scales small, flat, grading posteriorly into larger, subimbricate pectoral and ventral scales.

Body relatively short (AG/SVL 0.44) with well-defined ventrolateral folds; dorsal scales small, raised, interspersed with small, low, subconical, semi-regularly arranged, weakly keeled tubercles; tubercles extend from occiput onto base of tail but no farther; tubercles on occiput and nape very small, those on posterior portion of body larger and keeled; approximately ten longitudinal rows of body tubercles; 28 paravertebral tubercles; 33 flat, subimbricate, ventral scales larger than dorsal scales; enlarged femoral and precloacal scales discontinuous; 21 enlarged femoral scales; 21 femoral pores; 15 large precloacal scales; 14 precloacal pores; three rows of large, post-precloacal scales; and no deep, precloacal groove or depression.

Forelimbs moderate in stature, relatively short (FL/SVL 0.17); flat scales of forearm larger than those on body, not interspersed with tubercles; palmar scales flat; digits well-developed, relatively long, inflected at basal, interphalangeal joints; digits much more narrow distal to inflections; claws well-developed, sheathed by a dorsal and ventral scale at base; hindlimbs more robust than forelimbs, moderate in length (TBL/SVL 0.19), covered dorsally by granular scales and anteriorly by flat, slightly larger scales, and generally atuberculate; ventral scales of thigh flat, imbricate, larger than dorsal scales, one row of 11(R)10(L) enlarged femoral scales on distal one-half not in contact with enlarged precloacal scales; 11(R)10(L) femoral pores; subtibial scales flat, imbricate; small postfemoral scales form an abrupt union with larger, flat ventral scales of posteroventral margin of thigh; plantar scales low, flat; digits relatively long, well-developed, inflected at basal, interphalangeal joints; 8(R,L) transversely expanded subdigital lamellae on fourth toe proximal to joint inflection, 14(R,L) unmodified subdigital lamellae distal to inflection; 22 total subdigital lamellae; claws well-developed, base of claw sheathed by a dorsal and ventral scale.

Proximal two-thirds of tail original, moderate in proportions, 87.0 mm in length, 7.9 mm in width at base, tapering to a point; dorsal scales of base of tail granular rapidly becoming flatter and larger posteriorly; median row of wide, transversely expanded subcaudal scales three times as wide as long extending onto lateral surface of tail; two enlarged postcloacal tubercles at base of tail on hemipenal swelling; and postcloacal scales flat.

Coloration in life ( Fig.19): Dorsal ground colour of head body, limbs and tail tan to faintly magenta; top of head and rostrum covered with faint, irregular mottlings, no yellow reticulum; superciliary scales yellowish; nuchal band faint, unnotched anteromedially and bearing a sinuous posterior margin; cruciform pattern on nape; five regularly shaped body bands with lightened centres, not wider than interspaces, and one sacral band; limbs irregularly banded; dorsal interspaces bearing dark markings; proximal, dorsal portion of thighs lacking pigment; brachia and ventrolateral folds dark; dark caudal bands bearing lightened centres; light caudal bands bear dark markings, do not encircle tail; ventral surfaces of head body and limbs beige with stippled lateral edges; and subcaudal region brown.

Variation ( Fig. S4): The paratypes differ most notably from the holotype in having bolder, better-defined, dorsal markings. BYU 52220 View Materials is generally darker overall and the juvenile LSUHC 12856 View Materials ( SVL = 48.7 mm) generally lacks dark pigment in the dorsal body interspaces. Meristic and mensural differences are presented in Table 12 .

Distribution: Cyrtodactylus sadansinensis sp. nov. is known only from Sadan Sin Cave 10.5 km north-west of Mawlamyine, Mawlamyine District, Mon State, Myanmar ( Fig. 20).

Etymology: The specific epithet, sadansinensis , is a noun in apposition in reference to the type locality of Sadan Sin Cave.

Natural history: Sadan Sin Cave is situated on the eastern side of a small, isolated karst hill approximately 520 m wide, 1650 m long and 74 m high that is surrounded by paddy fields. The opening of the cave is approximately 60 m above the base of the hill. The interior of the cave

Abbreviations are listed in Material and Methods. R, right; L, left; /, data unobtainable or not applicable.

is extensive, very dark and airy with several alcoves, cracks and passageways, providing adequate retreat for geckos. The more open interior is crowded by fluted stalactites and stalagmites that are bathed in a thin sheet of running water ( Fig. 21). During both day and night, C. sadansinensis sp. nov. was found on these cave structures. Amazingly, three of the five specimens collected were found in the flutes of stalagmites of the cave wall with water flowing over their bodies. To our knowledge, this has never been reported for geckos and is an indication that not only do these caves generate and harbour endemic species they also select for novel life styles. The forest habitat outside the cave is highly disturbed and the vegetation had been cleared, leaving the face vulnerable to direct sunlight during the day ( Fig. 21). As such, only one specimen was seen at night on the outside of the cave. Gekko gecko was observed on the outside of the cave as well.

Comparisons: Cyrtodactylus sadansinensis sp. nov. is part of the sadansinensis group that includes C. sadansinensis and the sister species C. pharbaungensis sp. nov. and C. sanpelensis sp. nov. ( Fig. 9). The PCA and DAPC analyses indicate that the species of this group are completely separate in morphospace ( Fig. 12) where the first two principal components account for 59% of the total variation and load most heavily for longitudinal rows of tubercles, enlarged precloacal scales, and number of unmodified and total number of fourth toe subdigital lamellae ( Table S2). These species are even further separated in the DAPC analysis where only the first four components are retained ( Fig. S5). Additionally, all three species have statistically significant different mean values for their number of paravertebral tubercles, longitudinal rows of dorsal body tubercles, enlarged femoral scales, enlarged precloacal scales, unmodified subdigital lamellae on the fourth toe, post-precloacal scales rows and precloacal pores, and not lacking pigment in the anterodorsal margins of the thighs and brachia ( Table 5). It differs further from C. pharbaungensis by not having continuous, enlarged femoral and precolacal scales ( Table 8). Varying combinations of other differences between C. pharbaungensis sp. nov. and C. sanpelensis sp. nov. as well as the other newly described species in the Indo-Chinese clade are presented in Table 8. Genetic distances among the species of this group range from 8.7 to 13.1% ( Table 10).