Cnemaspis thayawthadangyi, Lee & Miller & Zug & Mulcahy, 2019

Lee, Justin L., Miller, Aryeh H., Zug, George R. & Mulcahy, Daniel G., 2019, The discovery of Rock Geckos Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) in the Tanintharyi Region, Myanmar with the description of two new species, Zootaxa 4661 (1), pp. 40-64 : 40-64

Cnemaspis thayawthadangyi sp. nov.

Thayawthadangyi Islands Rock Gecko

Figs. 6–7 .

urn:lsid:zoobank.org:act:8283FBDF-76A1-4F10-90CD-C26333EE2CAC

Holotype. USNM 595053 (GenBank accession no. MN 104951 ), adult male collected by Daniel G. Mulcahy and Grant Connette on 12 May 2017, 2100–2230 h, from Za Let Aw ( Escape Bay ), southeast side of Linn Lune Kyun , Thayawthadangyi Kyun Group, Myeik Archipelago, Tanintharyi Region, Myanmar (12.30849°N, 98.0043°E; 80 m elevation).

Paratype. USNM 595052 (GenBank accession no. MN 104950 ) , adult male, same collection data as the holotype .

Diagnosis. Cnemaspis thayawthadangyi sp. nov. is a small diminutive member of the C. kandiana species group and can be distinguished from all other members of the group by a combination of the following morphological characters: 1) a maximum SVL of 29.9 mm; 2) each postmental bordered posteriorly by four scales; 3) four spine-like ventrolateral tubercles on flank; 4) gular scales keeled; 5) pectoral scales and abdominal scales keeled; 6) ventral scales keeled; 7) three precloacal pores; 8) four femoral pores on each leg; 9) subcaudal scales smooth, scales on median row enlarged and smooth; 10) coloration of the gular region silver with dark-gray irregularly shaped streaks; 11) 6–7 supralabials; 12) 6–7 infralabials; 13) 16–18 subdigital lamellae on the 4 th toe; 14) 18–20 ventral scales at midbody.

Description of the holotype. Adult male ( USNM 595053) in good condition with some skin missing from the dorsal surface at midbody. Left lateral incision for gonadal examination, testes pigmented marbled black. Summary of measurements: SVL 29.5 mm, TailL 38.7 mm, TailW 3.1 mm, BrachiumL 3.8 mm, ForearmL 4.5 mm, AxillaGroinL 12.6 mm, ThighL 5.7 mm, CrusL 6.0 mm, HeadL 9.0 mm, HeadW 4.9 mm, HeadD 3.1 mm, EyeD 1.6 mm, EyeEar 2.3 mm, SnEye 3.8 mm, NarEye 3.1, InterorbD 2.7 mm, EarL 0.5 mm, InternarD 1.1 mm, HeadL/SVL 30.5%, HeadW/SVL 16.6%, HeadD/HeadL 34.4%, SnEye/HeadL 42.2%, EyeD/HeadL 17.8%.

Head triangular, moderately oblong dorsally, slightly flattened, distinct from neck; snout moderately sized, flat in lateral view; rostral scale concave and partially divided by median groove dorsally, posteroventrally in contact with first supralabial; rostral contacted posteriorly by two supranasals, no medial internasal; nostrils round, dorsally oriented; scales along snout and occipital region granular, distinctly elevated, scales on snout larger than scales on occipital region; occipital scales small, granular and elevated; tubercles absent on snout but present on occipital region; seven supralabials; from eye approximately five or six scales blocking contact with supralabials; mental scale subtriangular, wider than long, in contact along its posterolateral edge with two large postmental scales and one smaller medial postmental scale blocking enlarged scales from contact; lateral postmental scales bordered pos- teriorly by four smooth scales; gular scales keeled; seven infralabials, both supra and infralabials decrease in size posteriorly.

Body slender and elongate; ventrolateral furrow separating dorsal scales from ventral scales; dorsal tubercles slightly enlarged, mostly keeled, separated from one other by 2–6 scales; 15 paravertebral tubercles form a straight line; four ventrolateral spine-like tubercles; dorsal scales smooth, raised, granulate, smaller than ventral scales; pectoral scales keeled; ventral scales at midbody and abdominal region keeled; ventrolateral scales smooth, round, slightly elevated; 18 ventral scales at midbody; two precloacal pores, arranged in a small medial patch; four femoral pores on each side, in small singular row, separated from precloacal pores. Scales on underside of brachium smooth, weakly keeled under thigh; hindlimb digits slender, elongate, lacking webbing, bearing distinct recurved claws; 16 subdigital lamellae on 4 th toe; relative length of fingers and toes 4 = 3> 5> 2> 1; no significantly enlarged submetatarsal scale on toes.

Tail base swollen, complete two postcloacal openings, one on each side, presumably openings of hemipenial sheaths; longitudinal furrows present dorsally and ventrally; tail with two ventrolateral whorls of lateral tubercle rows each bordered by four to six scales; dorsal caudals keeled; dorsal scales on tail pointed; subcaudals smoth, medial scales enlarged, around 1.5–2.0x as large as surrounding scale rows.

Coloration in preservative. After formalin fixation and two years in ethanol the dorsum is gray-brown; a series of faint trapezoidal-shaped silver-gray blotches starting at nape and terminating posterior to hind limbs on anterior portion of the tail; midbody with scattered gray and white mottling concentrated on tubercles; area around eyelids blue; scattered broken dark-brown bands on limbs and toes. Top of head gray-brown, labial scales mainly graybrown, edged with silver; dark-brown postorbital stripe starting at neck, continuing through eye and ending at nostril. Venter cream; median of pectoral and midbody region immaculate bordered laterally by gray-brown mottling; limbs and abdominal regions bear scattered gray-brown mottling and dark colored scale edges; subdigital lamellae gray-brown; gular region silver with scattered irregular-shaped dark-gray streaks. Coloration in life not recorded.

Description of the paratype. The male paratype has a broken tail, but in all other aspects of morphology, agrees with the holotype. A summary of differences is shown in Table 2 .

Comparisons. We compare the species Cnemaspis thayawthadangyi sp. nov. to all other members of the Cnemaspis kandiana group from Southern Thailand, Sumatra and islands off its west coast and the Bay of Bengal. Further comparisons can be found in Table 3. C . thayawthadangyi sp. nov. is distinguished from C. phuketensis by having an enlarged medial subcaudal row (versus subcaudals equal in size), precloacal and femoral pores in males (versus both absent), smooth gular scales (versus keeled) and by four scales bounding each postmental scale (versus three). For distinctions between C. tanintharyi sp. nov. and C. thayawthadangyi sp. nov., see the comparisons section in the species account for C. tanintharyi sp. nov. From the Cnemaspis found in the Bay of Bengal, C. thayawthadangyi sp. nov. is distinguished from C. andersonii by having four bounded scales bordering the postmental (versus three scales), ventral scales throughout belly keeled (versus all ventral scales smooth), the presence of enlarged medial subcaudal row (versus subcaudals equal sized) and a blotched color pattern (versus immaculate coloration) as well as C. wicksi by three precloacal pores (versus 4–5), 16–18 subdigital lamellae on 4th toe (versus 14), keeled abdominal scales (versus smooth), ventral scales on thigh weakly keeled (versus smooth), and a blotched color pattern (versus immaculate coloration).

The presence of keeled ventral scales on the thigh distinguishes C. thayawthadangyi sp. nov. from all members of the C. kandiana species group found in Sumatra and islands off its west coast ( C. aceh , C. andalas , C. phuketensis , C. minang , and C. tapanuli ) except for C. dezwaani , C. jacobsoni , C. modiglianii , C. pagai and C. whittenorum . Cnemaspis thayawthadangyi sp. nov. is distinguished from C. dezwaani by having three precloacal pores (versus 8–12) and the absence of a pale vertebral stripe (versus present), from C. jacobsoni by having femoral and precloacal pores (versus absent), 16–18 subdigital lamellae on 4 th toe (versus 14), from C. modiglianii by having 18–20 ventral scales at midbody (versus 24–26); only four precloacal pores (versus 2–4), only four scales surrounding each postmental (versus 3–5) and by a gular coloration consisting of thick dark irregular stripes (versus unpatterned gular coloration), from C. pagai by having 16–18 subdigital lamellae on 4 th toe (versus 20), three precloacal pores (versus two), four femoral pores (versus three) and four scales bordering each postmental (versus three), from C. whittenorum by having three precloacal pores (versus four), four femoral pores (versus six), 6–7 supralabials (versus 5–6), and the absence of a pale vertebral stripe (versus present).

Etymology. The specific epithet “ thayawthadangyi ” is a reference to the type locality of this species—the Thayawthadangyi Kyun ( Island) group in the Myeik Archipelago. We recommend the common name “Thayawtha- dangyi Islands Rock Gecko” for this species, a reference to the island group in which it was first found.

Distribution & natural nistory. Cnemaspis thayawthadangyi sp. nov. is currently known from a single locality on Linn Lune Kyun, Thayawthadangyi Island Group, Myeik Archipelago, Tanintharyi Region, Myanmar, near the top of a waterfall in Za Let Aw (Escape Bay) on the southeast side of the island. The two specimens were collected on large tree trunks at night close to a stream. This species is probably more widely distributed than currently documented and likely inhabits similar microhabitats on this and other islands in the group.

Figures

FIGURE 6. Cnemaspis thayawthadangyi sp. nov. Holotype. USNM 595053. Dorsal (A) and Ventral (B) views of the after preservation. Scale Bar = 10 mm. Photographs by Esther M. Langan.

FIGURE 7. Cnemaspis thayawthadawgyi sp. nov. Holotype. USNM 595053. Ventral view of cloacal, femoral and caudal region (A), underside of forefoot (B), underside of hindfoot (C), ventral (D) dorsal (E) and lateral (F) views of the head. Scale bars = 1 mm. Photographs by Esther M. Langan.