Sphenomorphus preylangensis, Grismer & Wood & Quah & Anuar & Poyarkov & Thy & Orlov & Thammachoti & Seiha, 2019

Grismer, L. Lee, Wood, Perry L., Quah, Evan S. H., Anuar, Shahrul, Poyarkov, Nikolay A., Thy, Neang, Orlov, Nikolai L., Thammachoti, Panupong & Seiha, Hun, 2019, Integrative taxonomy of the Asian skinks Sphenomorphus stellatus (Boulenger, 1900) and S. praesignis (Boulenger, 1900) with the resurrection of S. annamiticus (Boettger, 1901) and the description of a new species from Cambodia, Zootaxa 4683 (3), pp. 381-411 : 392-403

Sphenomorphus preylangensis sp. nov.

Suggested Common Name: Prey Lang Forest Skink

( Figs. 7–9 , 11 )

Holotype. Adult female CBC 02348 from Phnom Chi, Prey Lang Wildlife Sanctuary, Preah Vihear Province, Cambodia (11°34.187’ N 104°53.274’ E, at 320 m in elevation) was collected by Neang Thy & Hun Seiha on 23 June 2014.

Paratypes. CBC 02349 (female) and CBC 02403-06 (juveniles) bear the same collection data as the holotype .

Diagnosis. Sphenomorphus preylangensis sp. nov. can be separated from all other species of Sphenomorphus by having the unique combination of a maximum adult female SVL of 87.6 mm; head, body, and supracaudal scales smooth; frontal scale not divided; prefrontals not in contact; parietals in contact posterior to interparietal; parietals not divided; six scales bordering the parietals; four nuchals; four supraoculars; two loreals; anterior loreal not divided; loreals in contact with supralabials; no deep postnasal groove; eight or nine superciliaries; superciliary row not interrupted by fourth supraocular; lower eyelid scales large; seven or eight supralabials; seven infralabials; three pairs of chinshields; one primary temporal scale; two secondary temporals; upper secondary temporal large; no subtemporals; 24 midbody scale rows; 61–68 paravertebrals; paravertebrals slightly wider than other dorsals; 63–71 ventrals; two enlarged precloacals; 11–13 scales around tail at level of tenth subcaudal; anterior subcaudals divided; unpaired subcaudals enlarged; 17–19 subdigital lamellae beneath fourth toe; 11–14 subdigital lamellae beneath fourth finger; no wide, dark, vertebral or lateral stripes or blotches; dark blotches on top of head; no dark anterolateral spots on the flanks; dark transverse subcaudal bars on original tail; thin, dark, dorsal caudal bands; and labial margins edged with black. The nine diagnostic meristic and the six color pattern characters are scored across all clade members in Table 6 .

Description of holotype. Adult female, SVL 79.9 mm; TAL 53.3 mm, partially regenerated; head moderate, snout slightly pointed, rounded in dorsal and lateral profile, subtriangular, distinct from neck; head scales large, smooth; HL 16.5 mm, longer than wide, HW 10.5 mm; head somewhat depressed, HH 8.1 mm; rostral 2.5 mm wide, 0.9 mm long, in contact with first supralabials and nasals laterally, frontonasal dorsally; frontonasal wider than long, single, in contact with nasal and first loreal laterally, prefrontals and frontal posteriorly; prefrontals separated, contacting loreals and preoculars laterally and first superciliary posteriorly; frontal subtriangular, in lateral contact with first superciliary and first, second, and third supraoculars, and frontoparietals posteriorly; four supraoculars, first subtriangular, second subrectangular, third rectangular, fourth semicircular; frontoparietals divided medially, each in lateral contact with third and fourth supraoculars, and parietals and interparietal posteriorly; interparietal subtriangular, eyespot present; large parietals in contact posterior to interparietal, contacting upper secondary temporal laterally and nuchals posteriorly; six scales bordering posterolateral margins of parietals; four nuchals in contact with parietals; 7R/L supralabials, seventh largest, fifth below center of eye; nostril in lower part of nasals; nasals large, in contact with first and second supralabials ventrally, first loreal posteriorly; two undivided loreals similar in size contacting supralabials; second loreal larger than first, horizontally subrectangular, in contact with second and third supralabials ventrally, preoculars posteriorly, first superciliary and frontonasal dorsally; two preoculars, lower slightly larger; eight superciliaries, not interrupted by fourth supraocular; two presuboculars; lower eyelid bearing large scales; one postocular, in contact with first postsubocular anteriorly, primary temporal ventrally, post- supraocular dorsally, upper secondary temporal and parietal posteriorly; four postsuboculars, last three contacting seventh supralabial; one postsupraocular; one primary temporal, two secondary temporals, lower one overlapping the upper one; three tertiary temporals; one postsupralabial; seven infralabials, first smallest, first two contacting postmental; mental large, semicircular; postmental large, single; three pairs of large chinshields in broad contact with supralabials; second pair separated by a gular scale, third pair separated by three gulars; external ear opening large, vertically elongate, vertical diameter 2.3 mm, horizontal diameter 1.2 mm, lacking anterior lobules; tympanum deeply recessed.

Body scales smooth, cycloid, imbricate; dorsals larger than ventrals and flank scales; paravertebrals slightly larger than adjacent dorsals; 24 longitudinal scale rows around midbody; 65 paravertebral scale rows intermittently interrupted by smaller scales; 69 ventrals; two enlarged, medial, precloacals; subcaudals similar in size to dorsal caudals, larger than lateral caudals; limbs moderate in length, in contact when adpressed; palmar and plantar scales rounded; single row of supradigitals; 14(R,L) smooth, subdigital lamellae beneath fourth finger; 19 (L,R) smooth, subdigital lamellae beneath fourth toe.

Coloration in preservation ( Fig. 8 ). Dorsum, head, flanks, limbs and tail bronze overlain with small, transverse dark-brown markings countershaded posteriorly with light-brown markings giving the appearance of scattered, short light-colored bars; darker scale edges in paravertebrals most distinct anteriorly; upper flanks bear a darker bronze than the dorsum; irregularly shaped dark markings on head and neck. Scattered light-colored bars on flanks and tail; ventral flanks and surfaces of body dull-yellow; dark edges on caudal scales form faint crossbands encircling tail.

Variation ( Fig. 9 ). All paratypes closely resemble the holotype in coloration and pattern. Paratype CBC 02405 is lighter and less boldly marked overall. Only the holotype CBC 02348 has the paravertebral scale series intermittently interrupted by smaller scales. Caudal banding on juvenile paratypes (CBC02404-06) is more distinct and pronounced. Paratype CBC 02403 has a regenerated tail and the tails of CBC 02405–06 are broken one-half to twothirds of the way down, respectively. That of CBC 02349 is missing. There seems to be no appreciative ontogenetic change in color pattern although hatchlings have never been observed. Variation in meristics and mesurements is presented in Table 7 .

Distribution ( Fig. 1 ). Sphenomorphs preylangensis sp. nov. is known only from Phnom Chi in the Prey Lang Wildlife Sanctuary, Kampong Thom Province, Cambodia ( Fig. 1 , locality 21). Cox et al. (1998) state that S. stellatus occurs in northeastern Thailand although no voucher specimens exist. They did present a photograph of a Thai specimen (p. 117) taken by the late Jarujin Nabhitabhata but with no locality data. Chan-ard et al. (2015:127) state that S. stellatus occurs at “Phu Wiang, Khon Kean Province in northeastern Thailand ” ( Fig. 1 , locality 24) and at “Khao Sa Bab (=Khao Soi Da), Chantaburi Province, in southeastern Thailand ” ( Fig. 1 , locality 9). We suspect Phu Wiang is likely the northeastern locality to which Cox et al. (1998) and Chan-ard et al. (2015) are referring to being that Jarujin Nabhitabhata took the photograph and was an author on both books. Furthermore, skinks from Khao Sa Bab (=Khao Soi Da) are S. annamiticus . Chan-ard et al. (2015) also stated that S. stellatus is found in “dead bark of standing trees” which is from Taylor (1963:1009 “underneath dead bark on a standing tree”) referring to the Khao Soi Da specimen and “in leaf litter” (p. 234) which likely refers to the Phu Wiang specimen. The photograph in Cox et al. (1998) however, is not S. stellatus as the body stature is less robust and the color pattern is far too bold and its lack of black vertebral and lateral stripes also precludes it from being S. annamiticus . However, the specimen is indistinguishable in appearance from S. preylangensis sp. nov. (approximately 470 km to the southeast) and based on the above inferences, we suspect this is another population of S. preylangensis sp. nov. or more likely a new, closely related species. At this point we refer to this population as Sphenomorphus sp.

Etymology. The specific epithet preylangensis is a Latinized toponymic adjective named after the Prey Lang Wildlife Sanctuary.

Comparisons ( Fig. 6 ; Table 4 ). Sphenomorphs preylangensis sp. nov. can be distinguished from S. stellatus by having statistically fewer fourth toe (17–19 vs. 20–26) and fourth finger (11–14 vs. 14–18) subdigital lamellae and having large, dark blotches as opposed to small speckles on the top of the head as well as dark transverse dorsal and subcaudal bars/bands and black labial sutures as opposed to their absence. From S. annamiticus it is differentiated by having statistically more paravertebral (61–68 vs. 53–62) and ventral (63–71 vs. 55–65) scales, and lacking as opposed to having wide, dark vertebral and lateral blotches. Sphenomorphus preylangensis sp. nov. is distinguished from S. praesignis by having statistically more infralabial scales (seven vs. six or seven, modally six) and statistically fewer midbody scale rows (24 vs. 27–30); and by the absence of large, dark anterolateral spots.

Natural history. Sphenomorphs preylangensis sp. nov. inhabits semi-evergreen forests in the vicinity of 200 m elevation ( Fig. 10 ) where lizards are most often found on tree trunks during the day approximately 2 m above the ground where they commonly take refuge in tree cavities. Local people cut cavities into the trunks of the trees in order to harvest resin that accumulates within the cavities. Lizards utilize the cavities, often submerging themselves in the resin with no apparent harm ( Fig. 11 ). Lizards also seek shelter beneath loose bark on the trunk. CBC 02349, however, was found in a rock crevice. Others were seen foraging among rocks during the day.

Miscellaneous notes on Sphenomorphus annamiticus . Based on this study, it appears Sphenomorphus annamiticus has a disjunct circum-continental distribution along the southern and eastern hilly margins of the Indochinese Peninsula from at least Khao Soi Dao, Thailand through the Cardamom Mountains of southern Cambodia to the Bokor Plateau at the western margin of the Mekong Delta. Its distribution begins again in the lowland areas of Ma Da and Cat Tien, Dong Nai Province on the eastern margin of the Mekong Delta in Vietnam and continues northward to at least the type locality of Phuoc Son in Quang Nam Province ( Fig. 1 ). Despite this, our limited genetic data showed no evidence of geographically structured genetic variation nor were any such trends recovered with the morphological data ( Table 8 ; Fig. 3 ).

Little has been written concerning the natural history of Sphenomorphus annamiticus . CBC 02350 from Bokor National Park (no. 11 in Fig. 1 ) was found among rocks during the day at 126 m and Stuart and Emmet (2006) report finding FMNH 267739 (no. 10 in Fig. 1 ) in a pitfall trap at 200 m. LSUDPC 10975 from Khao Soi Dao Wildlife Sanctuary (no. 9 in Fig. 1 ) was photographed on the side of a tree at 350 m in elevation, and CUMZ 35440 was taken from the summit of Khao Soi Dao at approximately 1550 m in elevation beneath exfoliating bark on a standing tree ( Taylor 1963). Vietnamese populations range from 80–2018 m in elevation. Darevsky & Ngyeun (1983) report finding a specimen on the ground along the side of a road at the edge of primary forest. Vassilieva et al. (2016), who first reported this species from lowland semideciduous forests in southern Vietnam, noted that S. annamiticus is a very secretive, mainly terrestrial species, but sometimes was observed climbing on tree trunks. They reported their diet to include beetles and ants ( Vassilieva et al. 2016).

Miscellaneous notes on Sphenomorphus stellatus . Sphenomorphus stellatus is endemic to Peninsular Malaysia although it very likely ranges farther north up the Thai-Malay Peninsula to at least the Isthmus of Kra. Sphenomorphus stellatus is rarely seen, and in fact there are only five specimens known in collections ( Table 9 ) and only one other vouchered sighting from Fraser’s Hill (LSUDPC 10976; no. 3 Fig. 12 ). Prior to this study, Grismer (2011) reported S. stellatus from Bukit Larut, Perak (the type locality), Fraser’s Hill, Pahang, Ulu Muda, Kedah below 596 m in elevation ( Norsham et al. 2005), and the Bukit Lagong Forest Reserve, Selangor at 300 m in elevation ( Lim 1967). We now consider the latter two localities to be erroneous because no voucher specimens were collected for these reports and this species is not known to occur below 1100 m. We report two new localities here from Pahang accompanied by vouchered specimens: Cameron Highlands at 1500 m (MCZ 39283) and Genting Highlands at 1800 m (CM 65530) ( Fig. 1 ).

Grismer (2011) reports seeing individuals moving along the ground at the edge of a house at Bukit Larut and others (Nick Baker and Rupert Gassby-Lewis pers. comm.) have found specimens beneath pieces of wood and within leaf litter at Fraser’s Hill. We have seen specimens 3–5 meters up on the sides of trees at the type locality basking in sunlight ( Fig. 12B ) and often in pairs. These observations indicate that this species is terrestrial as well as tree trunk-dweller.

Figures

FIGURE 1. Known distribution and localities for Sphenomorphus annamiticus, S. praesignis, S. preylangensis sp. nov., and S. stellatus. Stars represent type localities. Peninsular Malaysia: 1 = Bukit Larut, Perak; 2 = Cameron Highlands, Pahang; 3 = Fraser’s Hill, Pahang; 4 = Genting Highlands, Pahang; 5 = Gunung Tahan, Pahang; 6 = Gunung Lawit, Terengganu; 7 = Gunung Tebu, Terengganu. Thailand: 8 = Khao Wang Hip, Nakon Si Thammarat Province; 9 = Khao Soi Dao Wildlife Sanctuary, Chantaburi Province; 24 = Phu Wiang, Khon Kean Province. Cambodia: 10 = Chum Noab, Koh Kong Province; 11 = Bokor National Park, Kampot Province; 21 = Phnom Chi, Prey Lang Wildlife Sanctuary, Kampong Thom Province. Vietnam: 12 = Ma Da, Dong Nai Province; 13 = Cat Tien, Dong Nai Province; 14 = Dalat, Annam, Lam Dong Province; 15 = Thac Nham, Kon Tum Province; 16 = Buon Luoi Village, Gia Lai Province; 17 = Tram Lap Village, Gia Lai Province; 18–20 = Mang Canh Village and vicinity, Kon Tum Province; 22 = Phuc-Son, Annam (now Phuoc Son District, Quang Nam Province); 23 = K Bang, Gia Lai Province; and 24 = Phu Wiang, Khon Kean Province from Cox et al. (1998).

FIGURE 3. Maximum likelihood consensus tree. Black circles represent nodes supported by BI and UFB support values of 1.00 and 100, respectively. Numbers in parentheses correspond to the localities in Figure 1.

FIGURE 6. Boxplots of characters bearing significantly different mean values between the species pairs listed above each plot as determined by Tukey HSD tests. Boxes represent the 50% quartiles, the horizontal black bars the medians, and the blue circles the means. Abbreviations are in the Materials and Methods.

FIGURE 7. A. Sphenomorphus stellatus (LSUHC 13483) from the Bukit Larut, Perak, Peninsular Malaysia. Photograph by L. L. Grismer. B. Sphenomorphus annamiticus (ZISP 30194) from Mang Canh Village, Kon Tum Province, Vietnam. Photograph by Nikolai Orlov. C. Sphenomorphus preylangensis sp. nov. (CBC 02404) from Phnom Chi, Prey Lang Wildlife Sanctuary, Cambodia. Photograph by Neang Thy. D. Sphenomorphus praesignis (LSUDPC 9558) from Fraser’s Hill, Pahang, Peninsular Malaysia. Photograph by L. L. Grismer.

FIGURE 8. Dorsal, lateral, and ventral view of the holotype of Sphenomorphus preylangensis sp. nov. (CBC 02348) from Phnom Chi, Prey Lang Wildlife Sanctuary, Cambodia. Photographs by Neang Thy.

FIGURE 9. Type series of Sphenomorphus preylangensis sp. nov. from Phnom Chi, Prey Lang Wildlife Sanctuary, Cambodia. Photograph by Neang Thy.

FIGURE 10. Semi-evergreen forest habitat of the type locality of Sphenomorphus preylangensis sp. nov. (CBC 2348) from Phnom Chi, Prey Lang Wildlife Sanctuary, Cambodia. Photograph by Neang Thy.

FIGURE 11. Human-made resin collecting depression cut into the side of tree (C) forming the microhabitat of a Sphenomorphus preylangensis sp. nov. (A and B; CBC 2403) from Phnom Chi, Prey Lang Wildlife Sanctuary, Cambodia. B. The skink is actually submerged in the resin. Photographs by Neang Thy.

FIGURE 12. Sphenomorphus stellatus from Peninsular Malaysia. A. LSUDPC 10976 subadult from Fraser’s Hill, Pahang. Photograph by Kurt Orion. B. In situ photograph of LSUDPC 9721 from Bukit Larut, Perak. Photograph by L. L. Grismer.