Zootaxa, A new species of insular pitviper of the genus Cryptelytrops ...

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Zootaxa 1715: 57–68 (2008) 

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Copyright © 2008 · Magnolia Press 

ISSN 1175-5326 (print edition) 

ZOOTAXA 

ISSN 1175-5334 (online edition) 

A new species of insular pitviper of the genus Cryptelytrops 

(Squamata: Viperidae) from southern Vietnam 

L. LEE GRISMER 1 , NGO VAN TRI 2 & JESSE L. GRISMER 3 

1 

Department of Biology, La Sierra University, Riverside California 92515-8247 USA. E-mail: lgrismer@lasierra.edu 

2 

Department of Environmental Management and Technology, Institute of Tropical Biology, 85 Tran Quoc Toan Street, District 3, Ho 

Chi Minh City, Vietnam. E-mail: trigeckonid@hotmail.com 

3 

Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, Pennsylvania 19085 USA. 

E-mail: jesse.grismer@villanova.edu 

Abstract 

We describe a new species of pitviper Cryptelytrops honsonensis sp. nov. from Hon Son Island in Rach Gia Bay, Kien 

Giang Province of southern Vietnam based on it having unique aspects of scalation, body proportions, and color pattern. 

It is similar to C. venustus in morphology and color pattern and the putative close relationship between these species 

would corroborate a biogeographical link across southern Indochina seen in a number of other taxa. The presence of this 

newly discovered insular endemic in Rach Gia Bay and other insular endemics of Rach Gia Bay addressed herein, underscores 

the understudied nature of these islands and the need for their continued conservation. 

Key words: Cryptelytrops honsonensis, C. venustus, Hon Son, Rach Gia Bay, Vietnam, Indochina 

Introduction 

Pitvipers of the genus Trimeresurus sensu lato are generally nocturnal, terrestrial or arboreal species that 

inhabit a wide variety of environments ranging from meadows to plantations, open bushy areas and, secondary 

lowland forests to primary cloud forests (Malkmus et al. 2002; Vogel 2006). It is the largest group of 

Asian pitvipers and its 45 or so species collectively range from northern India in the west, eastward through 

the majority of East Asia to Taiwan and the Ryukyu Archipelago, Japan; and southward through the Philippines, 

Thailand, West Malaysia, Borneo, and the other major islands of the Sunda Shelf (Sumatra, Java, 

Sulawesi and some smaller islands extending east to Pulau Kisar; Gumprecht et al. 2004; Malkmus et al. 

2002; Manthey & Grossmann 1997; Vogel 2006). 

In a combined molecular and morphological phylogeny, Malhotra & Thorpe (2004a) found the monophyletic 

Trimeresurus sensu lato to contain five major clades which they assigned to eight genera. One of these 

genera, Cryptelytrops, contains at least 12 species that collectively range from northern India, Bangladesh and 

the Andaman and Nicobar islands, across Indochina through southern China, Myanmar, Thailand, Cambodia, 

Laos, and Vietnam. From here the group extends southward through the Malay Peninsula to Sumatra and eastward 

across Wallace’s Line through many of the Lesser Sunda islands to as far Pulau Kisar (Gumprecht et al. 

2004). Orlov et al. (2003) reported Trimeresurus cf. kanburiensis from central Vietnam. Their recognition of 

this species as T. kanburiensis would place it in the genus Cryptelytrops (sensu Malhotra & Thorpe 2004a). 

Later, Orlov et al. (2004) described this population as the new species, T. truongsonensis, concluding that it 

could not be aligned with any of the genera constructed by Malhotra & Thorpe (2004a). In contradiction to 

this conclusion, however they noted character state similarities, including the derived condition of the Type 1 

Accepted by D. Gower: 11 Jan. 2008; published: 29 Feb. 2008 57

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spinose hemipenis (Malhotra & Thorpe 2004a) that, in our opinion places this species within Viridovipera. 

This working hypothesis will be tested by additional molecular studies currently in progress. 

An interesting biogeographical aspect of Cryptelytrops is that six, perhaps seven, of its 12 species (60%) 

can be considered insular endemics. Cryptelytrops andersoni (Theobold, 1968) is restricted to the Andaman 

Islands, India; C. cantori (Blyth, 1846) is known only from islands in the central portion of the Nicobar Archipelago, 

India; C. fasciatus (Boulenger, 1896) is endemic to the small island of Tanahjampea, Indonesia; C. 

insularis (Kramer, 1977) is known from at least 18 Indonesian islands extending from eastern Java to Kisar; 

and C. labialis (Fitzinger, 1867) is restricted to a few southern islands in the Nicobar Archipelago, India. 

Arguably, C. kanburiensis (Smith, 1943) from western Thailand and C. venustus (Vogel, 1991) from southern 

Thailand and Langkawi Island in northern West Malaysia Grismer, 2008 (Grismer et al. 2006a) could be considered 

habitat-island endemics in that they have small distributions which are restricted to rocky, mesic highlands. 

We report here on yet another insular pitviper population from Hon Son, a small island in Rach Gia Bay in 

the Kien Giang Province of southern Vietnam (Fig. 1). In both females and the single male collected, the first 

supralabial is fused to the anterior portion of the nasal scale and the male has thin, elongate, deeply forked 

hemipenes with small, soft, basal spines, characteristics that place these pitvipers in the genus Cryptelytrops 

(sensu Malhotra & Thorpe 2004a). Although the sample size is small, all three specimens share a unique combination 

of morphological and color pattern characteristics not found in any other species of Cryptelytrops and 

are thus described here as a new species. 

Materials and methods 

Field work was conducted from 20–29 March 2006 and 1–5 August 2006 by NVT and from 29–31 July 2007 

by all authors. Specimens were collected and photographed, and liver tissue was taken from each specimen 

prior to preservation and stored in 100% ethanol. UNS 0354–55 were preserved and stored in 70% ethanol 

and UNS 053 was fixed in 10% formalin and transferred to 70% ethanol. All material was collected by NVT. 

Measurements and scale counts obtained from preserved specimens of Cryptelytrops on hand (Appendix) 

follow Grismer et al. (2006b) and Vogel et al. (2004) with some modification. Measurement of body thickness 

(Ti) and observations of retracted hemipenes follows Inger & Marx (1965), a method used by David et al. 

(2004) for C. venustus and C. kanburiensis. All measurements except SVL, Tal, and TL [see below] were 

taken with dial calipers to the nearest 0.1 mm. The former were taken with a ruler to the nearest 1 mm. Measurements 

included: Snout-vent length (SVL); tail length (Tal); total length (TL); head width (HW), measured 

from the widest part of the head posterior to eye; head length (HL), measured from the posterior margin of the 

mandible to the tip of the rostrum; distance between facial pits (DBP), taken with the caliper tips inserted into 

the pits; distance between nostrils (DBN), taken with the caliper tips inserted into the nostrils; distance from 

the anterior edge of the eye to the posterior edge of the pit cavity (DETP); distance from anterior margin of 

eye to the posterior margin of the nostril (DETN); distance from the anterior edge of the eye to the tip of the 

rostral scale (DETR); horizontal eye diameter (HED); vertical eye diameter (VED); distance from the lower 

margin of the eye to the bottom edge of the third supralabial (DEL); width of the internasal scale (WInN); 

length of the internasal scale (LInN); length of the supraocular scale (LSupOc); width of the supraocular scale 

(WSupOc); length of the third supralabial (L3SL); height of the third the supralabial (H3SL); and length of 

the fourth supralabial (L4SL). All measurements were taken on the right and left side of the head but no asymmetry 

was found. Several of these measurements were expressed as morphometric ratios (Table 1). 

58 · Zootaxa 1715 © 2008 Magnolia Press 

GRISMER ET AL.

TABLE 1. Mensural and meristic characters of the type series of Cryptelytrops honsonensis. See Materials and Methods 

for abbreviations. 

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UNS 0353 UNS 0354 UNS 0355 

female male female 

Holotype Paratype Paratype 

Approximate number of bold body bands 92 80 89 

Body thickness (Ti) 0.02 0.04 0.04 

SUPRALABIALS 10 11 10 

INFRALABIALS 12 12 12 

HeSc 33 30 34 

Can 2 2 2 

Cep 11 9 11 

C3SL 1 0 1 

C4SL 2 1 1 

C45SL 2 2 2 

NInN 1 1 0 

CSupOc 11 10 10 

NMSR 21 21 21 

NASR 25 23 23 

NPSR 15 15 15 

VENTRALS 186 186 183 

SUBCAUDALS 58 74 54 

Tal 91 120 81 

SVL 557 523 545 

TL 648 643 626 

HW 19.4 15.6 18.1 

HL 25.7 21.4 25.5 

HED 3.9 3.6 3.8 

VED 3.7 3.2 3.4 

DETN 5.8 4.7 5.6 

DETR 7.3 6.8 7.5 

DEL 3.8 3.3 4 

DETP 1 0.9 1.2 

DBP 6.6 6.3 6.7 

DBN 4.3 4 4.4 

WInN 2.2 2 2.3 

L-InN 1.2 1.2 1.2 

LSupOc 4.5 4.4 4.4 

WSupOc 1.8 1.9 1.8 

L3SL 2.7 2.7 2.7 

H3SL 3.2 2.4 2.9 

L4SL 2.7 2.2 2.7 

Tal/SVL 0.16 0.23 0.15 

W-InN/L-InN 1.83 1.74 1.92 

NEW VIETNAMESE PITVIPER 

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WInN/WSupOc 1.21 1.14 1.33 

VED/DEL 0.97 0.97 0.85 

LSupOc/WSupOc 2.51 2.34 2.52 

HW/HL 0.75 0.73 0.71 

DBP/HL 0.26 0.29 0.26 

DBN/HL 0.17 0.19 0.17 

DETP/DETN 0.17 0.19 0.21 

DETP/HW 0.05 0.06 0.07 

DETR/HW 0.38 0.44 0.41 

DEPT/HL 0.04 0.04 0.05 

DETR/HL 0.28 0.32 0.29 

FIGURE 1. Distribution of Crytelytrops honsonensis in Rach Gia Bay, Kien Hai District, Kien Giang Province, Vietnam. 

Scale counts recorded were supralabials; infralabials; ventrals; subcaudals; number of dorsal scale rows at 

midbody (NMSR); number of dorsal scale rows one head length behind the head (NASR); number of dorsal 

scale rows one head length anterior to the vent (NPSR); number of scales between the internasals (NInN); 

number of scales bordering the supraocular (CSupOc); number of canthal scales between the nasal scale and 

the eye (Can); number of head scales across the top of the head in a transverse line between the midsection of 

the supraoculars (Cep); number of head scales on a longitudinal line from the rostral scale to the limit of the 

neck (HeSC); number of scales between the third supralabial and subocular (C3SL); number of scales 

between the fourth supralabial and subocular (C4SL); and number of scales between the fourth and fifth 

supralabial and the subocular (C45SL). All counts were taken on the both sides of the head and averaged. 


GRISMER ET AL.

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Color pattern characters recorded include: presence or absence of dark body bands; number of dark body 

bands; presence or absence of a ventrolateral stripe; tail coloration; and color of iris in life. 

Specimens examined are listed in the Appendix. Specimen and photographic repository acronyms are: 

LSUHC (La Sierra University Herpetological Collection, Riverside, California, USA); LSUDPC (La Sierra 

University Digital Photo Collection), and UNS (University of Natural Sciences, Ho Chi Minh City, Vietnam). 

Additional data were obtained from David & Vogel (1997), David et al. (2003, 2004), De Rooij (1917), Gumprecht 

et al. (2004), Kramer (1977), Malhotra & Thorpe (2004b), Manthey & Grossmann (1997), Renagass & 

Kramer (1981), and Smith (1943). 

Systematics 

Cryptelytrops honsonensis sp. nov. 

Fig. 2, Tables 1, 2 

Holotype. UNS 0353, adult female (Fig. 2) from Hon Son island in the Kien Hai District of the Kien Giang 

Province, Vietnam. It was collected at 09° 47’ 95.2” N, 104° 37’ 85.6” E at 100 m a.s.l. by Ngo Van Tri on 29 

July 2007. 

Paratypes.UNS 0354 (adult male) and UNS 0355 (adult female) collected at the same locality as the 

holotype by Ngo Van Tri on 24 March 2006 and 4 August 2006, respectively. 

Diagnosis. Cryptelytrops honsonensis differs from all other species of Cryptelytrops by the combination 

of having dark body bands; lacking a ventrolateral stripe and a red or reddish-brown tail; having a dull-yellow 

to brown ground color as opposed to being green; females having a maximum SVL of 557 mm and a SVL of 

523 mm in the single male; females having a TaL/SVL ratio of 0.15–0.16 and a ratio of 0.23 in the single 

male; 21 dorsal scale rows at midbody; 183–186 ventral scales in females and 186 in the male; 54–58 subcaudal 

scales in females and 74 in the male; 10 or 11 supralabials and 12 infralabials; 9–12 scales across the top 

of the head; smooth occipital and temporal scales; internasals in contact; and the third and fourth supralabials 

not contacting the subocular scale. Table 2 summarizes the states of these characters across all 13 species of 

Cryptelytrops. 

Description of holotype. Adult female; body long and thin (Ti = 0.02); head triangular, stout and pointed; 

distance between nostrils 4.3 mm, DBN/HL 0.17; distance between pits 6.6 mm, DBP/HL 0.26; head length 

25.7 mm; head width 19.4 mm; HW/HL 0.75; head 13.4 mm wider than neck; SVL 557 mm; Tal 91 mm; Tal/ 

SVL 0.16; dorsal scale rows 25-21-15; one tripartate preventral scale; 186 ventral scales; 58 paired subcaudal 

scales; lower five rows of dorsal body scales smooth, medial rows weakly keeled; all dorsal caudal scales 

smooth; anal plate undivided. 

Rostral narrow and rounded, base flared, followed posteriorly by a small, circular, azygous scale; azygous 

scale bordered laterally by an internasal, followed posteriorly by small, round, subimbricate, smooth 

head scales; internasals rectangular, twice as wide as deep, bordered anteriorly and anteroventrally by nasal, 

bordered posterolaterally by a small, round scale; two large, moderately sharp, triangularly shaped canthals 

between nasal scale and anterior border of eye; posterior canthal in contact with anteroventral margin of 

supraocular; supraocular 2.51 times longer than wide (LSupOc/WSupOc 2.51), surrounded by 11 (L) 8 (R) 

head scales, medial margins of supraoculars smooth; 11 head scales in a line between midsection of supraoculars; 

33 head scales across the top of the head along a line from rostral scale to limit of neck; naris visible in 

lateral view; rostral bordered laterally by nasal; nasal bordered ventrally by first supralabial and fused to it 

anteriorly; supralabials 10 (L and R); infralabials 12 (L and R); nasal bordered posteriorly by small, vestigial 

loreal on right (absent on left); second supralabial crescent shaped, twice as high as wide; upper margin of 

lower preocular and lower margin of upper preocular converge posteriorly to form the upper, lower, and 

pointed posterior borders of the triangularly shaped facial pit opening; upper and lower preocular bordered 



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posteriorly by eye; 11 (R) 10 (L) scales surround eye including preoculars and subocular; eye bordered ventrally 

by long, crescent shaped subocular and followed posteriorly by five small, round postoculars; mental 

triangular, equally high as wide, followed posterolaterally by first infralabials which contact on midline; first 

infralabials followed posteriorly by two large chinshields meeting on midline, followed in turn by four smaller 

(one-half the size) chinshields on right and five on left, all contacting along midline; no enlarged sublabial 

scales. 

Color in life (Fig. 2). The head is brown, heavily suffused with irregularly shaped, darker markings. The 

iris is orange centrally and brown peripherally. There is no ventrolateral striping. The lores are slightly lighter 

than the head and postorbital stripes are absent. The ground color of the body is straw-yellow with approximately 

92 zig-zagged, irregular, dark-brown, body bands. Reddish-brown markings occur ventrolaterally 

which show varying degrees of dark stippling. Caudal banding is very irregular and the ground color of the 

tail has a slightly orange-colored hue. The venter is dull-white anteriorly becoming progressively darker posteriorly 

reaching a dark-gray with dense stippling beneath the tail. The lateral gular region is heavily stippled 

in black and the mid-gular region is much lighter. Nearly every ventral scale is marked with a large, black, diffuse, 

squarish, lateral blotch and all ventrals are irregularly stippled in black. 

Paratypes. Variation in meristic and mensural characters are presented in Table 1. The adult male (UNS 

0354) differs from the holotype in having a beige ground color with approximately 80 irregularly shaped, 

light-brown bands (Fig. 2). The head is paler in color and stippling is restricted to the occiptal and temporal 

regions. The anterior two-thirds of the venter are dull-white and nearly immaculate. The posterior one-third, 

including the tail, is grayish with dark stippling. The retracted hemipenes are very long, bifurcated, and thin. 

The left hemipenis was dissected out and cut longitudinally. The bifurcation (fork) occurs at the level of the 

fourth subcaudal scale and the hemipenes extend to the level of approximately the 24 th caudal scale, although 

it is difficult to determine from the right hemipenis in situ. At the base of each lobe immediately following the 

bifurcation are a series of enlarged soft spines but otherwise the hemipenes appear naked. 

The female paratype (UNS 0355) approximates the holotype in all aspects of coloration except that the 

venter is much darker and the dorsum has approximately 89 body bands. Thus, dorsal coloration is likely to be 

sexually dimorphic. 

There is no indication of sexual dimorphism in the number of ventral scales (183–186 for females, n = 2; 

186 for the male). The relative length of the tail may be sexually dimorphic (TaL/TL for the male 0.23 vs. 

0.15–0.15 for females and 74 subcaudals for the male vs. 54–58 for the females). Additionally, the number of 

dorsal body bands may be sexually dimorphic with the male having approximately 80 and the females approximately 

89–92. Larger samples will be required to gain further insights into possible dimorphisms. 

Distribution and Natural History. Currently, Cryptelytrops honsonensis is known only from the small 

island of Hon Son, Kien Hai District, Kien Giang Province in Rach Gia Bay, 61.2 km southeast of the Rach 

Gia city of Rach Gia Province, Vietnam (Fig. 1) and is considered potentially endemic. Hon Son is a very 

small island (ca. 22 km 2 ) that reaches 405 m a.s.l. The island is composed of large granitic boulders that 

extend from the shoreline to its peaks and there is little to no primary vegetation remaining. Walking trails 

across the island have been cut through the highly degraded secondary vegetation that is heavily infused with 

large tracts of bamboo. The walking trails cross over large expanses of boulder outcrops that form cavities that 

may extend as much as 20 m below the surface of the ground. Cryptelytrops honsonensis is found among 

these outcrops along these trails. 

The holotype (UNS 0353) was collected in the afternoon at 1600 hrs following a rain shower. It was moving 

over small branches of bamboo that were lying across a small pile of rocks. UNS 0354 was collected in the 

early evening at 1940 hrs following an afternoon rain shower and was found coiled on the top of a large rock. 

UNS 0355 was also collected during the early evening at 1930 hrs among a thicket of bamboo growing out of 

a large rock outcrop. 


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FIGURE 2. Type specimens of Cryptelytrops honsonensis from Hon Son, Kien Hai District, Kien Giang Biosphere 

Reserve, Kien Giang Province, Vietnam. Upper: holotype UNS 0353, female SVL 557 mm. Lower: paratype UNS 0354, 

male SVL 523 mm. 

Amphibians and reptiles found in association with Cryptelytrops honsonensis and confirmed from Hon 

Son for the first time are Bufo melanostictus (LSUDPC 2977), Polypedates cf. leucomystax (LSUDPC 2893), 

Draco sumatranus (LSUDPC 3082), Calotes versicolor (LSUDPC 3036), Cyrtodactylus sp. 1 (LSUDPC 

3051; Ngo & Grismer, in prep.), Cyrtodactylus sp. 2 (LSUDPC 2978–80, 3166–70, 3172–76; Grismer & Ngo, 



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in prep.), Gekko gecko (LSUDCP 3068), Hemidactylus frenatus (LSUDPC 3179), and Hemidactylus platyurus 

(LSUDPC 3089). 

Etymology. The specific epithet honsonensis is in reference to the type locality, Hon Son Island. 

Comparisons with other species. Cryptelytrops honsonensis is readily distinguished from C. albolabris, 

C. erythrurus, C. insularis, C. macrops, and C. septentrionalis in being drably colored with shades of brown 

and dull-yellow. Additionally, it has dark body bands as opposed to being unicolor green or bright yellow and 

TABLE 2. Selected diagnostic characteristics of the species of the pitviper genus Cryptelytroprs. See materials and 

methods for literature citations. / = character unknown. Data sources: 1 = David and Vogel (1997), 2 = David et al. 

(2003), 3 = David et al. (2004), 4 = De Rooij (1917), 5 = Gumprecht et al. (2004), 6 = Kramer (1977), 7 = Malhotra & 

Thorpe (2004b), 8 = Manthey & Grossmann (1997), 9 = Renagass & Kramer (1981), 10 = Smith (1943) and 11 = specimens 

listed in Appendix. 

Bold body bands present (1) or 

absent (0) 

Ventrolateral stripe present (1) or 

absent (0) 

albolabris andersoni cantori erythrurus fasciatus insularis kanburiensis 

0 1 1 0 1 0 1 

0,1 1 0,1 1 0 0 1 

Tail reddish (1) or not (0) 1 0 0 1 0 1 0 

Color drab brownish (1) or green 0 1 1 0 1 0 1 

Max SVL (mm) - females 680 1100 1150 1045 780 524 582 

Max SVL (mm) - males 580 / 690 575 375 432 415 

TaL/TL - females 0.16 0.15 0.12 0.16 0.20–0.21 0.35 0.13–0.14 

TaL/TL - males 0.21 / 0.20 0.21 0.18–0.21 0.28 0.18 

Midbody dorsal scale rows 19,21 23,25 27,29,31 23,25 21 21 19 

Ventral scales - females 149–173 171–185 172–182 151–180 159–163 156–167 170–178 

Ventral scales - males 150–169 171–183 171–177 153–174 158–162 156–164 172–177 

Subcaudals - females 44–73 50–62 56–74 49–61 61–65 54–59 41–52 

Subcaudals - males 56–78 66–78 67–76 62–79 63–65 70–75 59–61 

Supralabials 7–13 10–12 11–13 9–13 9–11 7–12 10–11 

Infralabials 6–16 12–14 12–14 12–14 10–11 11–14 11–13 

Min. no. scales between midsection 8–12 9–12 13–16 11–14 6–10 9–12 7–9 

of supraoculars 

Occipitals and temporals strongly 0 0 0 1 0 0 1 

keeled (1) or smooth to weakly 

keeled (0) 

Internasals separate (1) or in contact 

0,1 1 1 0,1 1 0 1 

(0) 

4th supralabial in contact with subocular 

0,1 0 0 0 0 0 0 

(1) or not (0) 

3rd supralabial in contact with subocular 

1 0,1 0 0,1 0 1 0,1 

(1) or not (0) 

Sample size 187 23 Not 13 6 65 3 

given 

Data source 1,9, 

10,11 

6,10 5,10 1,9, 10 2,4 6,9 8 

to be continued. 


GRISMER ET AL.

TABLE 2. (continued.) 

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Bold body bands present (1) or 

absent (0) 

Ventrolateral stripe present (1) or 

absent (0) 

labialis macrops purpureomaculatus septentrionalis venustus honsonensis 

1 0 1 0 1 1 

0,1 1 0 1 1 0 

Tail reddish (1) or not (0) 0 1 0,1 1 1 0 

Color drab brownish (1) or 1 0 0,1 0 0 1 

green 

Max SVL (mm) - females 372 / 900 / 486 557 

Max SVL (mm) - males 340 629 665 483 434 523 

TaL/TL - females 0.18 / 0.16 / 0.14–0.15 0.15–0.16 

TaL/TL - males 0.24 0.21 0.19 0.23 0.16–0.21 0.23 

Midbody dorsal scale rows 21,23 21 19,21,23,25,27,29 21 19,21 21 

Ventral scales - females 154–174 159–175 168–183 160–181 166–183 183–186 

Ventral scales - males 158–170 159–175 160–179 162–172 166–183 186 

Subcaudals - females 46–57 49–63 56–63 55–71 48–66 54–58 

Subcaudals - males 60–65 62–74 74–76 68–83 60–72 74 

Supralabials 9–12 9–12 11–13 10–14 9–11 10–11 

Infralabials 10–11 10–13 11–14 11–15 9–13 12 

Min. no. scales between midsection 

8–11 8–11 12–15 10–13 6–10 9–11 

of supraoculars 

Occipitals and temporals strongly 0 0 1 0 0,1 0 

keeled (1) or smooth to weakly 

keeled (0) 

Internasals separate (1) or in contact 

0,1 0,1 1 0,1 0,1 0 

(0) 

4th supralabial in contact with subocular 

0 0,1 0 0 0,1 0 

(1) or not (0) 

3rd supralabial in contact with 0 1 0 1 0,1 0 

subocular (1) or not (0) 

Sample size 11 90 22 70 33 3 

Data source 1,10 6,9 9,10,11 6,9 3,7,11 This report 

lacks a red tail. Cryptelytrops honsonensis has a known maximum female SVL length of 557 mm and a maximum 

male SVL of 523 mm, whereas C. andersoni females reach 1100 mm SVL (data unavailable for males), 

lacks a ventrolateral stripe which is present in C. andersoni, has 21 vs. 23 or 25 dorsal scale rows at midbody 

as in C. andersoni, has more ventral scales than C. andersoni in both males and females (Table 2), the internasals 

are in contact as opposed to being separate as in C. andersoni; C. cantori females reach 1150 mm SVL 

and males reach 690 mm SVL; female C. fasciatus reach 780 mm SVL; and female C. purpureomaculatus 

reach 900 mm SVL and males reach 665 mm SVL. Cryptelytrops honsonensis is further separated from C. 

purpureomaculatus by males having a longer tail (Tal/TL 0.23 vs. 0.19) and more ventral scales (186 vs. 160– 

176), having smooth as opposed to keeled temporal and occipital scales, and the internasals being in contact 

as opposed to being separate. Female and male C. honsonensis are much larger than male and female C. labialis 

(SVL 557 mm vs. 372 mm for females and 523 mm vs. 340 mm SVL for males) and male C. honsonensis 

are larger than male C. fasciatus (SVL 523 mm vs. 406 mm). 



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Table 2 shows that Cryptelytrops honsonensis differs from all other species of the genus in combinations 

of scale counts and morphometric characteristics. These data indicate that C. honsonensis is most similar to C. 

kanburiensis and C. venustus but differs from both of these species in lacking a ventrolateral stripe. It is further 

differentiated from C. kanburiensis in that the males are larger (SVL 523 mm vs. 415 mm); the females 

have a thinner body (Ti 0.02–0.04 vs. 0.10–0.11); having 21 as opposed to 19 dorsal scale rows at midbody; 

having a higher number of ventral scales (183–186 vs. 170–178, this character is not sexually dimorphic in C. 

kanburiensis or C. venustus [Malhotra & Thorpe 2004b]); having more subcaudal scales (54–88 in females vs. 

41–52 and 74 in the single male vs. 59–64); having smooth as opposed to strongly keeled occipital and temporal 

scales; the internasals being in contact as opposed to being separated; having a wider internasal scale (W- 

InN/L-InN 1.7–1.9 vs. 1.4–1.6); having a wider supraocular scale (W-InN/WSupOc 1.1–1.3 vs. 0.77–0.95); 

and having a longer supraocular scale (L-SupOc/W-SupOc 2.3–2.5 vs. 1.7–2.2). Of all the species of Cryptelytrops, 

C. honsonensis is most similar to C. venustus (Table 2) but differs from it further in being brownish as 

opposed to greenish; being larger in size (557 mm maximum SVL for females vs. 486 maximum SVL and 523 

mm SVL for the single male vs. 434 mm SVL); and possibly by males having a relatively longer tail (TaL/ 

SVL 0.23 vs. 0.16–0.21 and 74 vs. 63–72 subcaudals). 

Discussion 

Until a phylogenetic analysis of Cryptelytrops including C. honsonensis is undertaken, the relationships of 

this species to others in the genus will remain somewhat uncertain. Nonetheless, legitimate hypotheses can be 

proposed which will remain open to future testing. Based on color pattern and morphological data (Table 2), 

C. honsonensis appears more similar to C. venustus than to any other species, although this could be the result 

of plesiomorphy or convergence due to a similar life history. Like C. venustus which prefers rocky habitats 

and is often found on and within rock piles (Bulian 2001; Malhotra & Thorpe 2004b), all specimens of C. 

honsonensis were found within or coiled upon granitic rocks. Furthermore, their dark, mottled color pattern 

suffused with dark ventrolateral stippling renders them cryptic in this microhabitat. Bulian (2001) goes on to 

state that C. venustus is usually diurnal and particularly active after rain. UNS 0353 was also found during the 

day and it and UNS 0354 were both collected following rain showers. If C. honsonensis and C. venustus are 

sister taxa, this would be in accord with similar biogeographic patterns seen in other Indochinese and Indo- 

Malayan groups (Pauwels et al. 2003; Teynié et al. 2004), many of whose ranges thus far show a large hiatus 

across southern Cambodia (Grismer & Ngo, 2007; Grismer et al. 2007, 2008). 

The presence of endemic species on the islands in Rach Gia Bay (three on Hon Son alone) is just now 

beginning to be realized. Grismer & Ngo (2007) described Cnemaspis caudanivea from Hon Tre and have discovered 

several new species of reptiles on the surrounding islands that are in the process of being described. 

This underscores the understudied nature of these islands and serves to flag them as areas in desperate need of 

conservation. 

Comment on the commercialization of pitvipers. Southeast Asian pitvipers are high-value items in the 

commercial pet trade world-wide and Cryptelytrops venustus, a species very similar to the new species 

described here, is common in private collections (Malhotra & Thorpe 2004b). Collecting, selling, and exporting 

reptiles from islands in Rach Gia Bay is illegal, being that these islands are protected as part of the Kien 

Giang Biosphere Reserve of southern Vietnam. Nonetheless, it is highly likely that this new species description 

will serve to amplify such illegal activities in the way that species descriptions of other Asian species 

have done in the past (Stuart et al. 2006). This time, however, certain factions of the scientific community, 

will remain vigilant and take note of the first environmental criminals to place C. honsonensis on their price 

lists under the transparent façade that illegally trafficking and selling this species to private breeders and hobbyists 

is somehow an insurance against potential extinction as opposed to a potential cause of extinction. 


GRISMER ET AL.

Acknowledgements 

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Ngo Van Tri wishes to thank Dr. Hoang Nghia Son, Director of the Institute of Tropical Biology for permission 

to work on Hon Son. LLG wishes to thank the College of Arts and Sciences of La Sierra University for 

partial support of this research. We all thank P. David and A. Malhotra for assistance with access to literature 

and P. David, K. Sanders, G. Vogel, and N. Vidal for their constructive criticisms of the manuscript. 

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Appendix 

Specimens examined in this study. No type material was examined. 

Cryptelytrops albolabris (N =6) 

CAMBODIA: Kampong Speu Province, Phnom Aural LSUHC 7468, 7485; Pursat Province, base of Phnom Samkos 

LSUHC 7873, 7937. 

CHINA: Hainan Island, 10 km SW of Yinggen on route 3, LSUHC 4143; 9.4 km SW of Mao Yang, LSUHC 4189. 

Cryptelytrops honsonensis (N = 3) 

VIETNAM: Kien Hai District, Kien Giang Province, Son Island, UNS 0353–55. 

Cryptelytrops purpureomaculatus (N=1) 

WEST MALAYSIA: Selangor, Kuala Selangor, LSUHC 6640. 

Cryptelytrops cf. venustus (N=1) 

WEST MALAYSIA: Kedah, Pulau Langkawi, road to Gunung Raya, LSUHC 6793. 


GRISMER ET AL.

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