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

Grismer, L. Lee, Wood, Perry L., Jr., Thura, Myint Kyaw, Zin, Thaw, Quah, Evan S. H., Murdoch, Matthew L., Grismer, Marta S., Lin, Aung, Kyaw, Htet & Lwin, Ngwe, 2018, Twelve new species of Cyrtodactylus Gray (Squamata: Gekkonidae) from isolated limestone habitats in east-central and southern Myanmar demonstrate high localized diversity and unprecedented microendemism, Zoological Journal of the Linnean Society 182, pp. 862-959 : 885-899

CYRTODACTYLUS LINNWAYENSIS SP. NOV.

LINN-WAY BENT-TOED GECKO

( FIG. 15; TABLE 9)

Holotype: Adult male LSUHC 12983 collected on 15 October 2016 at 1500 h by Evan S. H. Quah, L. Lee Grismer, Perry L. Wood, Jr., Myint Kyaw Thura, Thaw Zin, Matthew L. Murdoch and Htet Kyaw from the Yum Twing Gyi Cave , Linn-Way Village, 12.7 km north-east of Ywangan, Taunggyi District, Shan State, Myanmar (N21°12.964, E96°33.288; 1130 m in elevation).

Paratypes: Adult males LSUHC 12984 and BYU 52214 and adult female LUSHC 12986 bear the same collection data as the holotype. Adult male LSUHC 12980 , subadult male BYU 52213 and juvenile male LSUHC 12981 bear the same collection data as the holotype except they were collected from an adjacent cave ( Lay Htwat Cave ) 20 m away between 1800 and 2000 h. Adult male and female LSUHC 12971–72 , respectively, and juvenile males LSUHC 12970 and 19273 were collected on 14 October 2016 between 1500 and 2000 h by Myint Kyaw Thura, Evan S. H. Quah, L. Lee Grismer, Perry L. Wood, Jr., Thaw Zin, Matthew L. Murdoch, Marta S. Grismer and Htet Kyaw from the Yae Htwat Cave , Linn-Way Village , 13.3 km north-east of Ywangan, Taunggyi District, Shan State, Myanmar (N21°13.675, E96°33.403; 1132 m in elevation) and 1 km north of Yum Twing Gyi Cave .

Diagnosis: Cyrtodactylus linnwayensis sp. nov. differs from all congeners by having the unique combination of 7–9 supralabials; 6–8 infralabials; 25–33 paravertebral tubercles; 13–18 longitudinal rows of body tubercles; 34–42 ventral scales; relatively long digits with 8–10 expanded fourth toe subdigital lamellae proximal to the

SD, standard deviation; N, sample size.

*Significant statistical differences between means.

Abbreviations are listed in the Material and Methods. R, right; L, left; /, data unobtainable; r, regenerated; b, broken.

digital inflection, 12–14 unmodified distal subdigital lamellae and 21–23 total subdigital lamellae; low, weakly keeled, dorsal body tubercles; tubercles not extending beyond base of tail; enlarged femoral and precloacal scales not continuous; 24–32 enlarged femoral scales; enlarged femoral scales nearly equal in size; 10–22 femoral pores in males not continuous with pore-bearing precloacal scales; 9–12 enlarged, precloacal scales; 6–10 precloacal pores in males; four rows of enlarged post-precloacal scales; transverse subcaudal scales twice as wide as long midway down the tail and not extending onto the lateral margins of the tail; top of head bearing dark blotches and light-coloured, reticulum; nuchal loop rarely paired, bearing an anterior, azygous notch, and nearly always having a smooth posterior border; first body band bearing an anterior, azygous notch; no band on nape; three or four dark, variably shaped dorsal bands with no paravertebral elements, bands usually as wide or wider than interspaces bearing lightened centres, edged with light tubercles; dark markings in dorsal interspaces but no light-coloured tubercles; anterodorsal margins of thighs, brachia and ventrolateral fold pigmented; eight or nine light caudal bands bearing dark markings in adults and usually encircling tail; nine dark caudal bands wider than light caudal bands; and mature regenerated tail spotted.

Description of holotype: Adult male SVL 101.5 mm; head moderate in length (HL/SVL 0.28), wide (HW/ HL 0.72), flat (HD/HL 0.41), distinct from neck, triangular in dorsal profile; lores inflated, prefrontal region concave, canthus rostralis rounded; snout elongate (ES/HL 0.44), rounded in dorsal profile, broad in lateral profile; eye large (ED/HL 0.22); ear opening oval, small (EL/HL 0.10); eye to ear distance greater than diameter of eye; rostral rectangular, partially divided dorsally, bordered posteriorly by left and right supranasals contacting on midline, laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by two postnasals and ventrally by first supralabial; 7(R,L) rectangular supralabials extending to below midpoint of eye; 7(R,L) infralabials tapering posteriorly to below orbit; scales of rostrum and lores slightly raised, much larger than granular scales on top of head and occiput; scales on top of head and occiput intermixed with small tubercles; dorsal superciliaries weakly pointed and directed posteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by large left and right trapezoidal postmentals which contact medially for 70% of their length posterior to mental; two rows of variably enlarged chinshields border all infralabials; gular and throat scales granular, grading posteriorly into larger, subimbricate pectoral and ventral scales.

Body relatively short (AG/SVL 0.43) with well-defined ventrolateral folds; dorsal scales small, raised and interspersed with large, low, semi-regularly arranged, weakly keeled tubercles; tubercles extend from nape to base of tail but no farther; tubercles on nape smaller but sharper than those on posterior portion of body and less strongly keeled; 29 paravertebral tubercles; approximately 13 longitudinal rows of dorsal tubercles; 42 flat, subimbricate, ventral scales larger than dorsal scales; enlarged femoral and precloacal scales continuous; 28 enlarged, femoral scales; 21 femoral pores; 12 enlarged precloacal scales; ten precloacal pores; four rows of large, post-precloacal scales; and no deep precloacal groove or depression.

Forelimbs moderate in stature, relatively short (FL/SVL 0.16); slightly raised, juxtaposed scales of forearm larger than those on body, intermixed with tubercles; palmar scales flat; digits well-developed, relatively long, inflected at basal, interphalangeal joints; digits much more narrow distal to inflections; widened proximal subdigital lamellae do not extend onto palm; 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 small, raised, juxtaposed scales intermixed with large tubercles and bearing flat, slightly larger scales anteriorly; ventral femoral scales imbricate, larger than dorsals; one row of 14(R,L) enlarged femoral scales in contact with enlarged precloacal scales; enlarged femoral scales nearly equal in size; 11(R)10(L) femoral pores; small, postfemoral scales form an abrupt union with larger, flat ventral scales of posteroventral margin of thigh; subtibial scales flat, imbricate; plantar scales flat; digits relatively long, well-developed, inflected at basal, interphalangeal joints; 10(R,L) transversely expanded subdigital lamellae on fourth toe proximal to joint inflection that do not extend onto sole, 13(R,L) unmodified subdigital lamellae distal to inflection; and claws well-developed, base of claw sheathed by a dorsal and ventral scale.

Tail moderate in proportions, 97 mm in length, last 45 mm regenerated, 9.7 mm in width at base, tapering to a point; dorsal scales of tail flat; median row of transversely expanded subcaudal scales twice as wide as long, not extending onto lateral subcaudal region; two enlarged postcloacal tubercles at base of tail on left hemipenal swelling only; and postcloacal scales flat.

Coloration in life ( Fig. 15): Dorsal ground colour of head body, limbs and tail yellowish tan; top of head and rostrum bearing, diffuse, irregularly shaped, dark blotches outlined by a yellow reticulum; superciliary scales yellowish; dark nuchal loop outlined in yellow bearing an anterior, azygous notch and straight, posterior margin; three wide body bands wider than interspaces, bearing lightened centres, lacking paravertebral elements, edged with yellowish tubercles; first dorsal band bearing an anterior, azygous notch; no band on nape; one postsacral band; anterior interspaces yellowish, posterior interspaces brown, all bearing large, dark markings; limbs mottled with yellowish markings and diffuse dark spots; dark caudal bands bearing lightened centres, wider than light caudal bands; light caudal bands bearing dark markings, not encircling tail; regenerated portion of tail bearing dark and light spots; all ventral surfaces beige, generally unpigmented; and subcaudal region darker.

Variation ( Fig. S2): There is a subtle colour pattern polymorphism in the banding pattern in the type series. The paratypes LSUHC 12971 , 12980 and 12986 closely approximate the holotype in aspects of colour pattern by having three wide, light-brown, variably shaped, dorsal bands and mottled interspaces, whereas paratypes LSUHC 12972–73 , 12984 and BYU 52214 have four darker, more regularly shaped dorsal bands and immaculate interspaces. LSUHC 12970 and 12981 are juveniles with incomplete posterior bands. The azygous nuchal notch is so deep in LSUHC 12984 the nuchal loop is completely bifurcated. In the holotype LSUHC 12983 , the notch is closed anteriorly. LSUHC 12971 has a unicolour tan, newly regenerated tail, whereas the mature regenerated tails of LSUHC 12972 , 12980 and BYU 52214 have dark spots. The subcaudal scales of the regenerated scales in LSUHC 12970–72 , 12980 and BYU 52214 are transversely elongate and irregularly arranged. Meristic and mensural differences are presented in Table 9 .

Distribution: Cyrtodactylus linnwayensis sp. nov. is known only from Lay Htwat, Yae Htwat and Yum Twing Gyi caves near Linn-Way Village, 12.7–13.3 km north-east of Ywangan, Taunggyi District, Shan State, Myanmar ( Figs 2, 9).

Etymology: The specific epithet, linnwayensis , is a noun in apposition in reference to Linn-Way Village near the type locality.

Natural history: Lay Htwat, Yae Htwat and Yum Twing Gyi caves are situated along the same karst ridge that arcs around a low, flat depression that fills with water during the monsoon season. The northernmost cave, Yae Htwat, has a wide (~ 10 m), high (~ 40 m) opening formed by an underground river flowing out of the cave. The cave floor is approximately 10 m above the cave entrance and requires climbing to access it. Approximately 100 m back from the entrance, the cave opens up to 50–60 m in width. The centre of the cave has a small stream running though it and the cave floor is strewn with small, stream-worn stones. There are several cracks, holes and narrow side passages along the cave walls as well as several small to large stalactites and stalagmites and deep fissures (~ 15 m) bearing running water in the centre of the cave that provide the necessary microhabitat for geckos ( Fig. 16). Between 1300 and 1500 h, one specimen was found approximately 100 m in from the cave entrance running across the cave floor near the wall in near total darkness and another was found 2 m up on the cave wall only 20 m in from the cave entrance where light was still plentiful. After dark, between 1900 and 2100 h, two additional specimens were found on the sides of boulders along the karst ridge outside the cave entrance.

Lay Htwat and Yum Twing Gyi caves are approximately 1 km south of Yae Htwat Cave and the openings of the former are no more than 30 m apart. Lay Htwat Cave has a 2 m by 2 m opening and the interior of the cave is congested with numerous, narrow passages, cracks, holes, cave formations of all sizes and shapes, and a deep underground stream. At 1800 h we collected one C. linnwayensis sp. nov. 2 m up on the cave wall along a side passage just inside the entrance. Yum Twing Gyi Cave has an approximately 60 m wide and 15 m high opening. This cave too has water but is much more open and the centre of the cave has several boulder formations that looked as though they had fallen from the roof. Stalactites, stalagmites and side passages occur throughout the cave and specimens were collected and observed on all these structures. During the evening between 1900 and 2200 h, we collected and observed additional specimens on the sides of karst boulders along the hilly ridge outside the caves. One juvenile (LSUHC 12981) was found on the trunk of a tree growing across a karst boulder.

Comparisons: Cyrtodactylus linnwayensis sp. nov. is part of the linnwayensis group. Student’s t -tests indicate that C. linnwayensis sp. nov. and its sister species C. shwetaungorum are statistically different in their mean values of paravertebral tubercles and longitudinal rows of tubercles, generally indicating that C. shwetaungorum is more tuberculate than C. linnwayensis sp. nov. ( Table 8). It differs further from C. shwetaungorum sp. nov. by having four vs. three rows of enlarged post-precloacal scale rows, a much lighter ground colour, light caudal bands that do not encircle the tail and a mature regenerated tail that is spotted ( Table 8). The PCA analysis which loads most heavily for the total number of fourth toe lamellae and the number of post-precloacal scales—accounting for 54% of the total variation along the first two components ( Table S1)— shows they occupy non-overlapping regions in morphospace ( Fig. 12). The genetic distance between the species of this group is 10.2% ( Table 10) and morphological and colour pattern differences from other species in the Indo-Chinese clade are listed in Table 8.