Cryptelytrops cardamomensis, Malhotra & Thorpe & Stuart, 2011

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 : 3-9

Cryptelytrops cardamomensis sp. nov.

(Cardamom Mountains Green Pitviper)

Figs. 3 , 4 ; Tables 1 , 2 .

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

Cryptelytrops macrops ( Kramer 1977) : Stuart and Emmett (2006): 23; Grismer et al. (2007): 232; Grismer et al. (2008a): 24; Grismer et al. (2008b): 166.

Holotype. FMNH 259191, adult female, collected on a root of a strangler fig growing from a tree trunk 1 m above the ground in semi-evergreen forest on Phnom Chan Mountain , Cardamom Mountains, Sre Ambel District, Koh Kong Province, Cambodia (11.44 N, 103.79 E), 100 – 200 m elevation, on 25 August 2000 by BLS and S. Platt.

Paratype. FMNH 259192, an adult male, collected at 2000 hrs swimming mid–stream in the Prek Kroch River (tributary of the Prek Sre Ambel River) in melaleuca/mangrove coastal swamp forest, Sre Ambel District, Koh Kong Province, Cambodia (11.105 N, 103.659 E), <10 m elevation, on 27 August 2000 by BLS and S. Platt .

Referred material. FMNH 263387, female, collected on bamboo 0.5 m above the ground, 1 m from a small stream in hill evergreen forest, Central Cardamoms Protected Forest , Thmar Baing District , Koh Kong Province, Cambodia (11.67 E 103.71 N), 800 m elevation, on 1 March 2004 by D. Emmett. FMNH 267732, female, collected at 2000 hrs on a tree trunk 0.5 m above the ground, 10 m from a river, in seasonally flooded lowland evergreen forest, Central Cardamoms Protected Forest, Thmar Baing District, Koh Kong Province, Cambodia (11.63 N, 103.5 E), 180 m elevation, on 24 August 2004 by D. Emmett .

Additional material. Two live specimens, an adult male and female, collected at 2215 hrs in low vegetation by the fourth tier of Krathing Waterfall, Khao Kitchakut National Park, Chantaburi Province, Thailand (12.80 N 102.13 E), 75 m elevation, on 11 November 1998, by AM and RST. Data from these living specimens has been used in all analyses, but under the conditions of permission, these specimens could not be preserved as vouchers and were released at the site of capture .

Diagnosis. Cryptelytrops cardamomensis sp. nov. is distinguished from C. venustus , C. honsonensis and C. kanburiensis , by the absence of purple-red marking (banding on the body and blotches on the head). It is distinguished from all other Asian pitviper species which 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 (including C. albolabris , C. insularis and C. septentrionalis ), 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. The latter is more elongate – oval in C. albolabris , C. insularis and C. septentrionalis , but widens quite abruptly behind the eyes in C. cardamomensis , C. macrops s.s. and C. rubeus sp. nov. (described below) to give a characteristically triangular shaped head. Cryptelytrops cardamomensis can be distinguished from both C. macrops s.s. and C. rubeus using a combination of the following characters (for further details see Table 2 ). In males, C. cardamomensis tends to have more scales between the rear edges of the supraoculars (BTWSUPOC2), a relatively larger eye (DEYE), and a more prominent postocular white stripe (SCROC) than either C. macrops s.s, or C. rubeus . Furthermore, compared to C. macrops s.s, the scale reduction from 19 to 17 scale rows around the body (VS19TO17) tends to occur further away from the head, it tends to have fewer (larger) scales bordering the supralabial scales (BORSUPOC), and less keeled temporal scales (KTEMP). Compared to C. rubeus , the scale reduction from 19 to 17 scale rows around the body tends to involve higher (i.e., more dorsal) scale rows (DV19TO17); it tends to have more keeled body scales at mid-body (BSCK), and more scales between the last supralabial and the chin shields (VENTEDGE). In females, the lateral white stripe is much more prominent (STRIPE), always involving the first two dorsal scale rows. Furthermore, it tends to cover a larger proportion of the first scale row (SCR1) than in females of C. macrops s.s. A small scale is present between the nasal scale and the scale bordering the anterior edge of the pit (NASPIT), whereas this is infrequently present in C. macrops s.s. and never present in C. rubeus . Crytpelytrops cardamomensis tends to have more (smaller) scales bordering the supralabial scales (BORSUPOC) than C. rubeus , but fewer (larger) than in C. macrops s.s. The scale reduction from 19 to 17 scale rows around the body (DV19TO17) tends to involve lower scale rows in C. cardamomensis and the fusion between the first labial and nasal scale tends to be more complete (LABNAS) and involve partial sutures on both sides of the nostril (compare Figs. 3 , 5 and 7 ), than in either C. macrops s.s, or C. rubeus . Furthermore, compared to C. macrops s.s,, the scale reduction from 19 to 17 scale rows around the body (VS19TO17) tends to occur further away from the head, it tends to have more scales between the rear edges of the supraoculars (BTWSUPOC2), a higher number of sublabial scales (SUBLAB), and a relatively smaller eye (DEYE). Compared to C. rubeus , it has more keeled body scales at mid-body (BSCK), the scale reduction from 12 to 10 scale rows around the tail (SC12O10) also tends to occur further away from the vent, and there are a larger number of ventral scales in C. cardamomensis females than in C. rubeus females.

Description of holotype. Body cylindrical, head triangular in dorsal aspect and very distinct from neck. Canthus rostralis distinct. Head scales small (no large dorsal shields), smooth except in temporal region, region between the suprabials and temporal region, and on the rear of head, which show weak tubercular keeling. Dorsal body scales weakly keeled. 171 ventral scales, 63 pairs subcaudal scales, 21 dorsal scales at mid – body. Rostral scale roughly triangular, upper edge about half the width of lower edge. Pupil vertically elliptical. Loreal pit present. Nostril completely enclosed in nasal scale. Nasal scale partially fused with first supralabial, bearing a suture present behind the nostril, but not anterior to it. Ten and 11 supralabials on the right and left sides respectively, similarly 13/12 sublabials, three postocular scales. Shield bordering anterior edge of pit fused with second supralabial, but separated from nasal by one small scale on either side. Subocular scale touches third supralabial, but separated by one scale from fourth and fifth supralabials. At least 11 scales between supraoculars, with 14 scales between their posterior edges. Five teeth on palatine, 16 on pterygoid, and 16 on dentary. Snout – vent length 29.1 cm; tail length 5.6 cm. Head length measured from tip of snout to posterior edge of lower jawbone 18.75 mm; head width measured between rear outer edges of supraoculars 8.3 mm, and at widest point of head 12.9 mm. Supraocular scale (on right hand side) 3.9 mm long, 1.55 mm wide. Distance from eye to nostril 3.85 mm, eye to pit 0.9 mm, posterior edge of pit to anterior edge of nostril 3.6 mm. Eye diameter 3.3 mm. Scale reduction formula (derived as in Thorpe [1975]):

Colour of holotype in preservative. Dark brownish grey dorsally, the ventral surface somewhat paler than the dorsal surface towards anterior of body, but less distinct posteriorly. Pale lateral stripe well developed, covering approximately one – third of first dorsal scale row, increasing in width towards head. Upper and lower labials not distinct in colour from the rest of the head, but chin shields, scales between chin shields and sublabial scales are creamy white.

Colour in life ( Fig. 4 ). No notes or photographs were taken of the holotype in life. This description is based on photographs of the male and female specimens from Khao Kitchakut NP, Thailand as well as photographs on p. 230 Plate II and p. 232 Plate I (adult male from Khao Soi Dao wildlife sanctuary, Chantaburi Province), and p. 233 Plate II, and p. 235 Pl II (adult male and female respectively, from Koh Kong Province, Cambodia) of Gumprecht et al. (2004). Dorsal and ventral surface grass green, very similar in shade. Lateral white stripe more prominent in male, extending onto the second dorsal scale row (confined to the first in female). In female, obvious bright blue dot on the upper rear quadrant of first scale row; present in some males, but less obvious. In male only, lateral white stripe extends onto the head as postocular stripe. Upper lip slightly paler than rest of dorsal surface of head, more obvious in female. Sublabials, and to lesser extent supralabials, also suffused with pale blue, mostly confined to edges of scales. Same pale blue also covers most scales on ventral surface of head to first part of body, more saturated and extensive on underside of head than in C. macrops s.s. Occasional small patches of white and green pigment on scales of underside of head. Interstitial skin bright blue, black banding sometimes on anterior body, scales here have narrow edging of black pigment at base. Tail solid brick red, to vent on dorsal surface, approximately one-third (male) to half (female) distance to the vent on ventral surface. Eye golden yellow in both sexes.

Variation. Sexual dimorphism is not very obvious in coloration. Females never have postocular stripes, but they may be only indistinct white streaks in males. The lateral white stripe may be much more prominent in males. Females have relatively shorter tails and fewer subcaudals (58 – 63 in females, versus 69 in the single male in which this count could be made). Females also are likely to reach an overall larger size (maximum recorded 53.6 cm SVL versus 49.9 cm for males), but the sample is small. The number of ventral scales is similar in both sexes, varying between 169 and 173. Keeling of body scales at mid – body is usually strong. Temporal scales and scales in the region between the temporal scales and supralabials show weak tubercular keeling, and keeling is strong on the scales covering the rear of the head. The ratio between the lengths of the upper and lower edges of the rostral scale varies between 0.35 and 0.56. Supralabials vary between 10 and 11 and sublabials between 11 and 14. The suture between the nasal scale and first labial scale is always more extensive to the rear of the nostril, usually absent in front of the nostril, but there may be a slight kink in the anterior margin of the fused scale at the likely position. The minimum number of scales between supraoculars varies between 8 – 12 and there are 13 – 16 scales between the posterior edges of the supraoculars. The number of scales between the nasals and shield bordering the anterior of the pit varies between 0 – 2, and there are 0 – 1 scales separating the internasals. There are 0 – 1 scales between the third supralabial and the subocular, one scale between the fourth supralabial, and 1 – 2 scales between the fifth supralabial and the subocular scale. Hemipenes were examined in FMNH 259192, in which they were both partly everted, and do not differ notably from those of C. macrops s.s. Teeth were also counted in this specimen, and were identical to the holotype except for the number of pterygoid teeth, which numbered 14.

Distribution. Cryptelytrops cardamomensis is currently known from Koh Kong Province in southwestern Cambodia and Chantaburi Province in southeastern Thailand. ( Fig. 1 ). The species probably occurs in appropriate habitat throughout the Cardamom Mountains in southwestern Cambodia and adjacent southeastern Thailand, and offshore islands (e.g., Koh Chang).

Ecology. Cryptelytrops cardamomensis is currently known from low-lying coastal areas up to 800 m elevation in semi-evergreen, evergreen, and mangrove/melaleuca swamp forest. All specimens were found within a couple of metres above the ground, and most within 10 m of water. No food items were found in the digestive tracts of the types.

Etymology. The name refers to the mountain range wherein the type locality of this species occurs.

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 3. Line drawings of the head scalation of the holotype of Cryptelytrops cardamomensis sp. nov. (FMNH 259191) A. lateral, B. dorsal, C. ventral. Small letters identify the following measurements: a (eye width): 3.3mm, b (supraocular width): 1.55mm, c (bottom edge of rostral): 2.5mm, d: (head length): 18.75 mm.

FIGURE 4. Cryptelytrops cardamomensis sp.nov. A. Close-up of head and mid-body region of adult male (left) and female (right) from Khao Kitchakut National Park, Chantaburi Prov., Thailand (photos: A Malhotra). B. Adult male (left) and female (right) from Kâmpóng Saôm Bay, Koh Kong Prov., Cambodia (photos: A Gumprecht); C. and D. Adult specimens from Mount Da Lai in Cardamom Mountains, southwest Cambodia (photos: Jeremy Holden).

FIGURE 5. Line drawings of the head scalation of the holotype of Cryptelytrops rubeus sp. nov. (FMNH 262718). Labelling as in Fig. 3 (a: 4.00mm, b: 2.05mm, c: 3.45mm, d: 24.9mm).

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).