Cyrtodactylus zhaoermii, Shi, Lei & Zhao, Hui, 2010

Shi, Lei & Zhao, Hui, 2010, A new species of Cyrtodactylus (Reptilia: Squamata: Geckkonidae) from Xizang Autonomous Region, China, Zootaxa 2336, pp. 51-60 : 52-56

Cyrtodactylus zhaoermii sp. nov.

Figures 1–3 .

Holotype. CIB 97979, adult male, collected 2 September 2008 at 12:35 h, from China: Nyemo County, Xizang Autonomous Region, (29°21΄N, 90º10΄E) at 3696 m. Collected by Shi Lei.

Paratopotypes. CIB 97980, adult female, CIB 97978, sub-adult male, all other data are the same as for the holotype.

Etymology. The specific epithet is a patronyn honoring Zhao Er-Mi (born 1930) of the Chengdu Institute of Biology, Chinese Academy of Science, Chengdu, China, who was one of the first Chinese Herpetologist to go to Xizang Autonomous Region for field collection and described numerous reptiles, including a gecko from Mêdog County. Zhao has made substantial contributions to the herpetology of China and has been a strong influence on professional career of the first author. The name is masculine and is formed in the genitive case.

Diagnosis. Cyrtodactylus zhaoermii is distinguished from all other Cyrtodactylus species by the following characters: dorsal surface of the body with fine granules intermixed with larger sub-conical tubercles arranged into 20 more or less regular rows; proximal subdigital lamellae transversely expanded; 19–20 subdigital lamellae under toe IV; 30–32 mid-body ventral scales; most scales in femoral region small, granular, series of 12–14 enlarged femoral scales lacking pores on either side; a series of precloacal pores (4) present in male; tail with distinct segments, large, posteriorly directed tubercles in whorls, numbering nine to ten per caudal annulus, three on each side and three to four on the dorsal, situated at the posterior edge of each annulus; subcaudals not transversely expanded.

Description (based on holotype, CIB97979). Adult male SVL 59.75 mm. Head moderately long (HL/ SVL 0.32), somewhat broad (HW/HL 0.76), not depressed (HH/HL 0.55), distinct from neck; prefrontal region concave, canthus rostralis rounded and granular; rostrum short (RostL/HL 0.38) and narrow in dorsal profile. Eye is large (OrbD/HL 0.25); pupil vertical with crenulated margin. Ear opening is small (EarL/HL 0.1); eye-to-ear distance greater than diameter of eye. Rostral scale rectangular, width twice height, partially divided dorsally, bordered posteriorly by large left and right supranasals and two small internasals; external nares bordered anteriorly by rostral, dorsally by large supernasal, posteriorly by two small postnasals, and ventrally by the first supralabial. Supralabials square, 9/9 extending to center of eye, first supralabial is larger than remainder. Infralabials 7/8 extending to posterior of orbit; first six scales of series are largest. Scales of rostrum, lores, top of head, and occiput are small and granular; scales of occiput and top of head with infrequent, large tubercles. Mental triangular, bordered laterally by infralabials and posteriorly by left and right square postmentals; postmentals contact ( Fig. 3 A). One slightly enlarged and elongate row of sublabials extending posteriorly to the third infralabial; gular scales small and granular, grading posteriorly into slightly larger, flatter, imbricate pectoral and ventral scales.

Dorsal scales small and granular interspersed with moderate sized, triangular, semi-regularly arranged keeled tubercles; tubercles extending from occiput to anterior portion of tail; tubercles on occiput irregularly spaced, those on nape and anterior of body largest; approximately twenty longitudinal rows of tubercles; 30 flat, imbricate ventral scales between ventrolateral body folds, ventral scales larger than dorsals; 4 precloacal pores. There are two enlarged cloacal spurs on either side of tail base ( Fig. 2 ).

Forelimbs slender, short (ForeL/ SVL 0.13); granular scales of forearm slightly larger than those of body; tubercles present; scales on palmar surface slightly elevated; digits well developed, inflected at basal interphalangeal joints; subdigital lamellae transversely expanded proximal to joint inflections, digits narrow distal to joints; claws well developed, sheathed by dorsal and ventral scales; relative lengths of fingers: IV>III>II>V>I.

Hind limbs more robust than forelimbs (CrusL/SVL 0.18), covered dorsally with flat, granular scales interspersed with larger, raised tubercles; ventral scales of femora oval and larger than dorsals; ventral tibial scales granular, imbricate; eleven enlarged scales in pore-bearing femoral series, lacking pits; scales on plantar surface oval, imbricate, elevated; toes well developed, inflected at basal interphalangeal joints; subdigital lamellae transversely expanded proximal to inflected joints, digits narrow distal to joints; ten expanded subdigital lamellae, 9 unexpanded subdigital lamellae on right toe IV; claws well developed, sheathed by dorsal and ventral scales. Relative lengths of toes: IV>V>III>II>I ( Fig. 3 B). Tail regenerated, 8.27 mm in width at base; scales of tail dorsum granular; tubercles oriented with recurved points facing posteriorly, numbering nine to ten per caudal annulus, three on each side and three to four on the dorsum, situated at the posterior edge of each annulus ( Fig. 3 C).

Coloration. The main background is light brown. The head has a marbled pattern, which is formed by dark spots and vermiculate lines. There are fragments of a neck band, characteristic of the species from the genus Cyrtodactylus , visible on the neck. Back with irregular series of more or less transversely arranged darker bands between the shoulder and the lumbar area. These bands may be broken in the middle and may intersect with each other, yielding a more or less reticular pattern. The tail and limbs have similar patterns. The lower surface is white.

Variation. The paratopotypes closely resemble the holotype. All specimens except CIB97978 are adults. There is sexual dimorphism in precloacal pore structure. Male posses large, pore-bearing scales ( Fig. 3 ); female posses differentiated scales in the pore-bearing series but lack pores. The numbers of differentiated scales in the pore-bearing series do not differ between the sexes. Coloration is similar among all specimens. Meristic variation in the type series is presented in Table 1 .

Natural History. Nyemo County is located in the middle south of the Tibet Autonomous Region and north of the middle reaches of Yarlung Tsangpo River. The average altitude of the county is above 4000 metres. It is completely dry snow desert, with sparse vegetation of herbs, shrubs and grasses. The area is highly arid with a sub-tropical continental highlands cold climate. Vegetation generally confined to human occupation sites, seeps, streams, and forested valleys. The intervening barren landscape is characterized by stark and steep mountainsides, rock and boulder fields, and large areas of clay, caliche, and sand. We collected C. zhaoermii from rocky habitat. This gecko prefers desert areas with sparse vegetation, apparently avoiding the immediate neighborhood of human settlements.

Distribution. This species is only known to occur at the type locality of Nyemo County, Xizang Autonomous Region, China ( Fig. 4 ). It is possible that this species occurs outside of this area, most likely along the Yarlung Tsangpo River. This species is likely an endemic to Tibet.

Comparison to Tibet, Nepal, India and Pakistan high altitude species. Presence of large caudal tubercles and distinct tail segments and male with precloacal pores distinguishes it from Altigekko ( stoliczkai subgroup. Khan. 2001 = Cyrtopodion , sensu, Anderson, 1999): A. baturensis (Khan & Baig) , A. stoliczkai (Steindachner) , A. boehmei (= Alsophylax boehmei Szczerbak ), A. yarkandensis (Anderson) , A. brachykolon ( Krysko et al., 2007) ; absence of a single row of transversally enlarged subcaudals distinguishes it from all Indian-Pakistan Cyrtopodion species (sensu, Khan. 2003) C. agamuroides (Nikolsky) , C. caspius (Eichwald) , C. fedtschenkoi (Strauch) , C. kachhense (Stoliczka) , C. kohsulaimanai (Khan) , C. montiumsalsorum (Annandale) , C. potoharensis (Khan) , C. scabrum (Heyden) , C. turcmenicus (Szczerbak) , C. watsoni (Murray) ; presence of limb tubercles and tail segmentation distinct distinguishes it from Siwaligekko ( tibetanus subgroup, Khan, 2001 = Cyrtodactylus , sensu, Kluge, 2001): S. battalensis (Khan) , S. dattanensis (Khan) , S. fasciolatus (Blyth) , S. himalayanus (Annandale) , S. lawderanus (Stoliczka) , S. markuscombaii , S. martinstollii , S. mintoni (Golubev & Szczerbak) , S. nepalensis , S. tibetanus ; limbs and digits short, subcaudals in several rows distinguishes it from Indogekko (Sand-stone geckos: Khan, 2001 = Cyrtopodion , sensu, Anderson, 1999): I. fortmunroi (Khan) , I. indusoani (Khan) , I. rohtasfortai (Khan & Tasnim) , I. rhodocaudus (Baig) , I. longipes (Lantz) ; absence of femoral pores and (or) presence of a series enlarged femoral scales distinguishes it from C. gubernatoris (Annandale) , C. pulchellus (Gray) , and C. fasciolatus ; presence of precloacal pores distinguishes it from C. medogensis .

We have not seen the original description of C. mamahirm Duda and Sahi 1978 described from N. W. India (Jammu) but according to the article ( Sahi & Duda, 1985) where this species listed as Cyrtodactylus sp., it has no more than 28 scales across the belly.

characters CIB97978 CIB97979* CIB97980

Figures

FIGURE 1. Photo of holotype, Cyrtodactylus zhaoermii, showing color and pattern.

FIGURE 2. Pre-cloacal region of the holotype showing the 4 precloacal pores and series slightly enlarged femoral scales lacking pores.

FIGURE 3. Illustration of holotype features. (A) Ventral view of head showing contact of postmentals. (B) Palmar surface of right pes showing differential size between proximal and distal subdigital lamellae. (C) Tail base showing distinct segments and large, backwardly directed tubercles in whorls.

FIGURE 4. Map of middle and lower reaches of Yarlung Tsangpo River in Xizang Autonomous Region showing the type locality of Cyrtopodactylus zhaoermii and collection localities of other three Cyrtopodactylus species recorded in Xizang Autonomous Region.