Wednesday, May 20, 2020

[Herpetology • 2020] Cnemaspis lineatubercularis • Integrative Taxonomy of the Rock-dwelling Gecko Cnemaspis siamensis complex (Squamata, Gekkonidae) reveals A New Species from Nakhon Si Thammarat Province, southern Thailand


Cnemaspis lineatubercularis
Ampai, Wood, Stuart & Aowphol, 2020

Lan Saka Rock Gecko | จิ้งจกนิ้วยาวลานสกา || DOI: 10.3897/zookeys.932.50602

Abstract
The rock-dwelling gecko genus Cnemaspis is one of the most species-diverse genera of gekkonid in Thailand. Earlier studies relied on morphological data to identify species, but cryptic morphology often obscured species diversity in Cnemaspis. In this study, an integrative taxonomic approach based on morphological characters and sequences of the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene were used to clarify current taxonomy of the Cnemaspis siamensis complex and delimit a new species from Lan Saka District, Nakhon Si Thammarat Province, southern Thailand. Cnemaspis lineatubercularis sp. nov. is distinguished from other congeneric species by the combination of morphological characters: (1) maximum snout-vent length (SVL) of 40.6 mm (mean 38.8 ± SD 1.4, N = 12) in adult males and maximum SVL of 41.8 mm (mean 39.5 ± SD 1.9, N = 7) in adult females; (2) 8–9 supralabial and infralabial scales; (3) gular, pectoral, abdominal, and subcaudal scales keeled; (4) rostral, interorbitals, supercilium, palmar scales, and ventral scales of brachia smooth; (5) 5–6 small, subconical spine-like tubercles present on flanks; (6) 19–21 paravertebral tubercles linearly arranged; (7) 27–29 subdigital lamellae under the fourth toe; (8) 4–7 pore-bearing precloacal scales, pores rounded arranged in chevron shape and separated only in males; (9) one postcloacal tubercles each side in males; (10) ventrolateral caudal tubercles present anteriorly; (11) caudal tubercles restricted to a single paravertebral row on each side; (12) single median row of subcaudal scales keeled and lacking enlarged median row; and (13) gular region, abdomen, limbs and subcaudal region yellowish only in males. Genetically, the uncorrected pairwise divergences between the new species and their congeners in the C. siamensis group were between 15.53–28.09%. The new species is currently known only from granitic rocky streams at Wang Mai Pak Waterfall in the Nakhon Si Thammarat mountain range. Its discovery suggests that additional unrecognized species of Cnemaspis may still occur in unexplored areas of southern Thailand.

Keywords: Cnemaspis, morphology, phylogeny, species diversity, taxonomy, Thailand



Figure 3. Male holotype (ZMKU R 00828) of Cnemaspis lineatubercularis sp. nov. from Wang Mai Pak Waterfall, Lan Saka District, Nakhon Si Thammarat Province, Thailand.

Figure 4. Male holotype (ZMKU R 00828) of Cnemaspis lineatubercularis sp. nov. from Wang Mai Pak Waterfall, Lan Saka District, Nakhon Si Thammarat Province, Thailand, in life
A dorsal view B ventral view C lateral view of the head D dorsal view of trunk E precloacal region showing distribution of pore-bearing scales (red arrows) F dorsal view of tail G ventral view of tail.
Scale bar: 10 mm (in dorsal and ventral views).

Cnemaspis lineatubercularis sp. nov.
Lan Saka Rock Gecko
จิ้งจกนิ้วยาวลานสกา - Jing Jok Niew Yaow Lan Saka

Diagnosis: Cnemaspis lineatubercularis sp. nov. can be distinguished from all other Cnemaspis by having the following combination of characters: (1) maximum SVL of 40.6 mm (mean 38.8 ± SD 1.4, N = 12) in adult males and maximum SVL of 41.8 mm (mean 39.5 ± SD 1.9, N = 7) in adult females; (2) 8–9 supralabial and infralabial scales; (3) gular, pectoral, abdominal, and subcaudal scales keeled; (4) rostral, interorbitals, supercilium, palmar scales, and ventral scales of brachia smooth; (5) 5–6 small, subconical spine-like tubercles present on flanks (6) 19–21 paravertebral tubercles linearly arranged; (7) 27–29 subdigital lamellae under the 4th toe; (8) 4–7 pore-bearing precloacal scales, pores rounded, arranged in chevron shape and separated in males; (9) one postcloacal tubercle each side in males; (10) ventrolateral caudal tubercles anteriorly present; (11) caudal tubercles restricted to a single paravertebral row on each side; (12) single median row of subcaudal scales keeled and lacking enlarged median row; and (13) gular region, abdomen, limbs and subcaudal region yellowish only in males. These differences are summarized among geographically close congeners in the siamensis group (Table 5).

Figure 6. Coloration of Cnemaspis lineatubercularis sp. nov. in dorsal (above) and ventral (below) views of A male paratype ZMKU R 00830 and B female paratype ZMKU R 00835. Note yellowish ventral coloration that is present in males but absent in females.





       

Figure 2. A The single best maximum likelihood tree of the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene and flanking tRNAs from geckos of the genera Cnemaspis, Cyrtodactylus and Hemidactylus, shown in full view
B map illustrating the localities of Cnemaspis siamensis group samples used in this study and
C close-up view of the C. siamensis group. Support values at nodes are bootstrap values from a Maximum Likelihood analysis of the same dataset followed by posterior probabilities of the Bayesian Inference analysis.

Figure 9. Habitats of Cnemaspis lineatubercularis sp. nov. A Wang Mai Pak Waterfall at type locality B microhabitat of holotype in granitic rocky stream (white arrow) C microhabitat of paratypes in granitic rocky outcrops (white arrows) at Wang Mai Pak Waterfall, Lan Saka District, Nakhon Si Thammarat Province, Thailand.





Distribution and natural history: 
Cnemaspis lineatubercularis sp. nov. is known only from Wang Mai Pak Waterfall (96 m a.s.l.), Kam Lon Subdistrict, Lan Saka District, Nakhon Si Thammarat Province, southern Thailand (Fig. 9). The type locality is surrounded by lowland evergreen forest along a river basin in the southern part of the Nakhon Si Thammarat mountain range. Specimens were found only along granitic rocky streams of Wang Mai Pak Waterfall. The rocky boulder microhabitats of this species are dry with cool surface temperatures (24.8–26.7 °C, 73.2–86.1% relative humidity). When disturbed, some individuals retreated deeper into rock crevices, cracks, more shaded areas or beneath rock boulders.

Seven specimens (ZMKU R 00822–00825, ZMKU R 00827, THNHM 28696–28697) were collected during the day (1650–1847 h) and 12 specimens (ZMKU R 00821, ZMKU 00826, ZMKU R 00828–00832, THNHM 28694–28695 and ZMKU R 00833–00835) were collected at night (1913–1951 h).

The male holotype was found during the night (1943 h) perched head down on a vertical surface in a crevice of a granitic rock boulder near a stream. A female paratype (ZMKU R 00832) was found with the male holotype, separated by only a distance of approximately 10 cm.

Paratypes that were found during the day were in shaded areas, crevices of boulders, rock walls and on boulder outcrops near streams. Paratypes found at night were in shaded surfaces of the boulders, within deep crevices, or perched on vegetation near a rocky stream. Three gravid females (ZMKU R 00832–00834) contained one or two eggs during January 2019. Some juveniles (SVL < 30 mm; not collected) were found in rock cracks and perched on a rock near a stream on 25 January 2019.

Cnemaspis lineatubercularis sp. nov. appears to be a diurnal species in that observed specimens during daytime were active and fast-moving when disturbed, but those at night were inactive, slow-moving or asleep on dry granitic rocks and vegetations. At night, Cyrtodactylus lekaguli and Gehyra mutilata were found in syntopy with the new species on a rock wall and vegetation near a stream. 

Etymology: The specific epithet lineatubercularis is taken from linea (Lat. for line) and tubercularis (Lat. for having tubercles), in reference to the new species having paravertebral tubercles linearly arranged.

      


Natee Ampai, Perry L. Wood Jr, Bryan L. Stuart and Anchalee Aowphol. 2020. Integrative Taxonomy of the Rock-dwelling Gecko Cnemaspis siamensis complex (Squamata, Gekkonidae) reveals A New Species from Nakhon Si Thammarat Province, southern Thailand.  ZooKeys. 932: 129-159. DOI: 10.3897/zookeys.932.50602