Cryptelytrops macrops (Kramer, 1977)

Malhotra, Anita, Thorpe, Roger S. & Stuart, Bryan L., 2011, Two new species of pitviper of the genus Cryptelytrops Cope 1860 (Squamata: Viperidae: Crotalinae) from Southeast Asia, Zootaxa 2757 (1), pp. 1-23 : 15-20

Cryptelytrops macrops sensu stricto ( Kramer 1977)

(Big-eyed Green Pitviper)

Fig. 7 , 8 ; Tables 1 –4

Trimeresurus macrops Kramer 1977 : Kramer (1977): 757 (part); Regenass and Kramer (1981):184 (part); Viravan et al. (1992):102; Gumprecht (1998): 25 (part); Orlov et al. (2002a): 193 (part); Orlov et al. (2002b): 353 (part); Gumprecht et al. (2004): 230 (part), Teynié et al. (2004): 47.

Material examined. MHNG 1400.85, holotype, adult male, Bangkok, Thailand ; MHNG 1400.73, 1400.78, 1400.79, 1400.87, 1400.96 –100, paratypes, Bangkok, Thailand ; FMNH 258954–58, Dong Hua Sao National Biodiversity Conservation Area, Bolaven Plateau , Champasak Province, Laos ; FMNH 255249, 255251–52, 255256– 57, Dong Khanthung National Biodiversity Conservation Area , Champasak Province, Laos ; FMNH 255253–55, Phou Khao Khouay National Biodiversity Conservation Area , Bolikhamxai Province, Laos ; FMNH 255248, Hin Nam No National Biodiversity Conservation Area , Khammouan Province, Laos ; FMNH 262715–16, Virachey National Park , Siem Pang District, Stung Treng Province, Cambodia ; NMW 23899:4, NMW 23899:10, NMW 23899:13, Dong Rek Mountains , Thailand ; NMW 23897:1, NMW 23897:3, NMW 23897:4, NMW 23897:7, NMW 23897:13, NMW 23897:15, NMW 23897:17, Don Pia Fei Mountains , Thailand . The senior author also examined a number of live Thai specimens under anaesthesia; these included a juvenile male found behind the headquarters of Jae Sorn National Park , Lampang province, on 24 th July 1996, two specimens from the vicinity of Sakaerat Experimental Station , Nakhon Ratchasima Province in June 1999, and five specimens obtained from dealers through the Queen Savoabha Memorial Institute (QSMI), Bangkok from Nonthaburi and Ang Thong Provinces, as well as the outskirts of the city itself, in 1998. Although morphological data from these specimens have been used in all analyses, under the conditions of permission, these specimens could not be taken as vouchers and were returned unharmed to the site of capture, or retained by the QSMI for further study.

Revised diagnosis. Cryptelytrops macrops s.s. is distinguished from all other Asian pitviper species which also have the typical "green pitviper" colouration (uniform green dorsal colour and a lateral stripe present on the first few dorsal scale rows in one or both sexes), except other species of Cryptelytrops , by the presence of a fused first supralabial and nasal scale. It can be distinguished from C. albolabris , C. insularis and C. septentrionalis primarily by the relatively larger size of the eye (most obvious in adults), the relatively wider supraoculars, and the shape of the head, which is more elongate – oval in C. albolabris , C. insularis and C. septentrionalis , but widens quite abruptly behind the eyes in C. cardamomensis sp. nov., C. macrops s.s. and C. rubeus sp. nov. to give a characteristically triangular shaped head. Cryptelytrops macrops s.s. can be distinguished from both C. cardamomensis sp. nov. and C. rubeus sp. nov using the characters detailed above (further details are also given in Tables 2 and 3 ).

Redescription of holotype. We supplement Kramer’s (1977) original description (Appendix 2) of the holotype, as follows. Body cylindrical, head triangular in dorsal aspect and very distinct from neck. Canthus rostralis distinct. Head scales small (no large dorsal shields), smooth except for weak tubercular keeling in temporal region and region between suprabials and temporal region and strong keeling on rear of head. Body scales also strongly keeled dorsally. 168 ventral scales, 68 pairs of subcaudals, 21 dorsal scales at mid – body. Rostral scale somewhat triangular, upper edge more than half the width of lower edge (ratio between the lengths of the upper to lower edge 0.58). Pupil vertically elliptical. Loreal pit present. Nostril completely enclosed in nasal scale. Nasal scale partially fused with first supralabial, partial suture present behind the nostril, but not to anterior on one side, on both sides of the nostril on the other. Ten supralabials, 13 sublabials, two postocular scales. Shield bordering anterior edge of pit fused with second supralabial, in contact with nasal scale. Subocular scale touches third supralabial, but separated by one scale from fourth and fifth supralabials. At least 7 scales between supraoculars, 13 scales between their posterior edges. Snout – vent length 50.6 cm; tail length 13.3 cm. Head length measured from tip of snout to posterior edge of lower jawbone 23.2 mm; head width measured between rear outer edges of supraoculars 11.55 mm, at widest point of head 16.9 mm. Supraocular scale (on right) 5.05 mm long, 2.3 mm wide. Distance from eye to nostril 4.95 mm, eye to pit 1.1 mm, posterior edge of pit to anterior edge of nostril 5.0 mm. Eye diameter 4.15 mm. Scale reduction formula:

Colour of holotype in preservative. Dorsal surface of head and body brownish grey; sublabials, last three supralabials, and lateral edges of ventral scales steely blue. Apart from mental, sublabials and a few scale rows below sublabials posterior to eighth sublabial, scales on the underside of the head creamy white. Central part and rear edge of ventral scales same creamy white colour. Postocular stripe and lateral stripe not apparent.

Colour in life. This description is based on colour plates on p. 230 – 235 (with the exception of those listed above) of Gumprecht et al. (2004) of specimens from Lampang, Nakhon Ratchasima (Plate 3), and the vicinity of Bangkok, Thailand, as well as macro photographs of the dorsal, lateral, and ventral aspects of the head and body of specimens from Nakhon Ratchasima, Lampang, Nonthaburi and Ang Thong provinces of Thailand by AM. Ground colour varable, bluish green, grass green or yellow – green, ventral surface slightly paler, often with bluer hue than dorsal surface especially on anterior of body and excepting lateral edges of ventral scales. Prominent lateral white stripe in males (sometimes encroaching onto second dorsal scale row), usually extending onto head as postocular stripe passing below the eye and fading out on lower preocular, below pit. In some specimens, lateral stripe pale blue rather than white. Scales below postocular stripe lighter in colour than rest of head. Females lack obvious postocular stripe, but may have indistinct pale or blue streak. Usually little distinction between colour of supralabials and upper surface of head. Females occasionally have lateral stripes, although covering less than one – third of first scale row at mid – body and not extending onto second scale row. Tail dull brick red, dorsally extending as far as vent, with clear margin on lateral side of tail. Eye golden yellow to light orange in both sexes. Males may have small whitish flecks mid – dorsally, more prominent in juveniles, sometimes retained in adults. Interstitial skin blue – grey, with black banding. Sublabial scales often suffused with pale blue; rest of the scales on the underside of the head (genials, chin shields, and scales between these and sublabials) are white. Scattered blue pigment on some dorsal scales on head may be present, but not as well developed as in other two species.

Variation. There is geographic variation between different populations of C. macrops s.s., summarised in Table 4. Within each population, sexual dimorphism is not pronounced, and is most obvious in the prominence of postocular and lateral stripes in males compared to females, and the relatively shorter tails and more massive girth of females. Females also reach an overall larger size (maximum recorded 62.9 cm SVL compared to 56.4 cm for males).

Distribution. Kramer (1977) reported the species from Thailand (Bangkok) and Vietnam, and it was presumed to occur in the intervening area. However, it is apparent that the species has a wider distribution ( Fig. 1 ). Viravan et al. (1992) reported it from western, northern and northeastern Thailand, and although the present study has not been able to confirm its presence in western Thailand (unfortunately, the majority of specimens resulting from Viravan et al.’s study, now deposited in the Natural History Museum, London, have since lost their labels carrying the locality information), it is very likely to be present there. One adult female at the QSMI was said to have been obtained from southern Thailand via a dealer based in Thung Song. Mitochondrial DNA analysis showed that it was highly similar to C. macrops s.s. from the Bangkok region (Genbank accession numbers AF517184 , AF517219 , AF517163 , and AF517176 ). Nevertheless, the occurrence of this species in southern Thailand must remain speculative at present until it can be confirmed by the collection of additional specimens in the field. Orlov et al. (2002a) also illustrate a specimen (Fig. 20: Pg 191) of C. macrops said to be from southern Thailand. However, this specimen seems to be a misidentified male C. albolabris . The species is also present in southern ( Teynié et al. 2004) and central Laos (see also “Material examined”, this paper).

Ecology. Cryptelytrops macrops s.s. occupies hilly areas up to c. 600 m. It has mainly been found in dry evergreen and mixed deciduous forest mixed with bamboo forest, but also in dry dipterocarp/grassland vegetation. Most specimens were found within a couple of metres of the ground, but occasionally up to 4 m high. Specimens were frequently found in the vicinity of water. Food items found in the digestive tracts of specimens examined included mammals (NMW 23899:4 from the Dong Rek mountains and AFS96.5 from Lampang Province, Thailand), frogs (FMNH 255252 and 255254 from Champasak and Bolikhamxai Provinces, Laos respectively; FMNH 262715 and 262716 from Stung Treng Province, Cambodia) and reptiles (FMNH 255253 from Bolikhamxai Province, Laos).

Figures

FIGURE 1. Map of Southeast Asia, showing the distribution of the two new species and Cryptelytrops macrops s.s. Symbols indicate sampling localities used in the genetic analysis to define species. Grey circles: C. macrops s.s; open diamonds: C. cardamomensis sp. nov.; black triangles: C. rubeus sp. nov. The empty circle and triangle denotes localities of specimens that have either been referred to the corresponding species on the basis of photographs, or for which the locality is uncertain and requires confirmation.

FIGURE 7. Line drawings of the head scalation of the holotype of Cryptelytrops macrops s. s. (MHNG 1400.85). Labelling as in Fig. 3 (a: 4.15mm, b: 2.30mm, c: 3.00mm, d: 23.2mm).

FIGURE 8. Cryptelytrops macrops sensu stricto. A. Juvenile male from Jae Sorn National Park, Lampang Prov., Thailand (photo: A Malhotra); B. Adult male from Sakaerat Experimental Station, Nakhon Ratchasima Prov., Thailand (photo: A Malhotra); C. Adult female from the vicinity of Bangkok, Thailand (photo: A Gumprecht); D. Adult male (left) and female (right) from north of Khao Yai National park, Nakhon Ratchasima Prov., Thailand (photos: A Gumprecht); E. Juvenile male from Nakhon Ratchasima Prov., Thailand (photo: A Gumprecht). F. Cryptelytrops albolabris from southern Thailand, for comparison. Note the more elongated head, relatively smaller eye, yellower eye and lack of any blue pigmentation (photo: A. Malhotra).