Amphiesma leucomystax David, Bain, Truong, Orlov, Vogel, Thanh & Ziegler, 2007, spec. nov.
Creators: name: David, Patrick
name: Bain, Raoul H.
name: Truong, Nguyen Quang
name: Orlov, Nikolai L.
name: Vogel, Gernot
name: Thanh, Vu Ngoc
name: Ziegler, Thomas
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Colubridae
Amphiesma
Amphiesma leucomystax

description: Amphiesma leucomystax spec. nov.
(Figs. 1–11)
Holotype. – ZFMK 71702, an adult female, from the southeastern border of the Ky Anh - Ke Go lowland forest protected area, surroundings 18°00’ N- 106°06’E, Cam Xuyen District, Ha Tinh Province, Vietnam, 125 m asl. Coll. by Thomas Ziegler, 12 July1997.
Paratypes (22 specimens). – VIETNAM. Nghe An Province. ZISP 23665 (female), Khe Kam River, Bu Cam (summit of mountain), 19°37’99”N – 105°14’93”E, Chau Nga Village, Ban Man Town, Quy Chau District, 1000 m. Coll. by Nikolai L. Orlov, Sergei A. Ryabov and Ho Thu Cuc, 29 March 2003.—Ha Tinh Province. ZFMK 71703 (female), lowland forest bordering Lake Ke-Go, surroundings 17°59’N – 106°03’E, Cam Xuyen District, 170 m asl. Coll. by Thomas Ziegler, 26 September 1998. - ZFMK 71704 (female), southeastern border of Ky Anh - Ke Go Tropical forest protected area, Cam Xuyen District, 270 m asl. Coll. by Thomas Ziegler, 29 August 1997. - ZISP 23664 (female), Rao An river, 18°20’62” N- 105°14’24”E, Son Kim Village, Huong Son District, 300 m. Coll by Nikolai L. Orlov, 24 April 2000.—Quang Binh Province. MNHN 2006.0447 (female), karst forest of Phong Nha - Ke Bang National Park, Bo Trach and Minh Hoa Districts. Coll. by Thomas Ziegler & A. Heidrich, 20 June 2006. - VNUH 16.6.’05-1 (female), karst forest of Phong Nha - Ke Bang National Park, Bo Trach and Minh Hoa Districts. Coll. by Thomas Ziegler & Vu Ngoc Thanh, 16 June 2005. - ZFMK 80660 (female), karst forest of Phong Nha - Ke Bang National Park, Bo Trach and Minh Hoa Districts. Coll. by Thomas Ziegler, 2 September 2003. - ZISP 23666 (female), Phong Nha-Ke Bang National Park, 350 m, Bo Trach and Minh Hoa Districts. Coll. by Nikolai L. Orlov, Sergei A. Ryabov and Ho Thu Cuc, 10 July 2003.—Quang Tri Province. ZISP 23669, ZISP 23671, ZISP 23674–23675 (males), ZISP 23668, ZISP 23670, ZISP 23672-23673 (females), Ban Cup, 16°55’N – 106°35’E, Huong Lap Village, Huong Hoa District, 350– 480 m. Coll. by Nikolai L. Orlov, Nguyen Quang Truong and Ho Thu Cuc, 20 April–13 May 2005.—Thua Thien Hue Province. AMNH 154175 (female), from Khe Huong, a tributary to Khe Dau (Dau River), 16°18'24"N – 107°32'38"E, Binh Thanh Commune, Huong Thuy District, 109 m asl. Coll. by Nguyen Quang Truong, Raoul H. Bain, C. K. Dang, and T. D. Nguyen, 8 September 2005. - IEBR 2314 (female), from A Bong Stream, Huong Nguyen Commune, near 16°14' 26"N – 107°27'11"E, A Luoi District, ca. 152 m. Coll. by Raoul H. Bain, Nguyen Quang Truong and V. M. Tran, 19 August 2005. - ZISP 23667 (male), Bach Ma Bang National Park, 500 m, Phu Loc District. Coll. by Nikolai L. Orlov and Ho Thu Cuc, 15 October 2003.—Gia Lai Province. FMNH 252118-252119 (females), from An Khe District (= Ke Bang). Coll. by Ilya S. Darevsky and Nikolai L Orlov, 25 March 1995 and 11 April 1995 respectively. - ZISP 23663 (male), Buon Luoi village, 14°20’N –108°36E’, Kannack Town, Ang Khe District, 750 m. Coll. by Nikolai L. Orlov, 4 April 1995.
Additional material (2 specimens).— VIETNAM. PNKB RH06213 (adult male), Phong Nha - Ke Bang National Park, Bo Trach and Minh Hoa Districts, Quang Binh Province, Vietnam. Coll. by Ralf Hendrix and Dang Ngoc Kien, 26 August 2006.— THAILAND. PSUaa 0 0 54 (male), from “ Thailand ”. This specimen was previously deposited in the former Thai National Collection, in which many specimens were only labeled as “ Thailand ”. However, the origin of this specimen remains questionable.
Etymology.—The specific nomen derives from the Greek adjective ευκO, leucos, meaning white, and the Greek noun μύσταξ, mystax, meaning either a moustache or an upper lip, a reference to the broad white stripe extending on the upper lips of this species.
We suggest the following common names: White-lipped Keelback (English), Amphiesme à lêvres blanches (French), Weißlippen-Gebirgswassernatter (German) and Ran sai mep trang (Vietnamese).
Diagnosis.—A species of the genus Amphiesma, characterized by a combination of the following characters: (1) a broad, continuous, white stripe extending under the eye from the tip of the snout across the upper half of supralabials and the nape to produce a V-like chevron; (2) vertically elongated or divided dorsolateral spots, salmon or rusty red (cream in preservative) on a dark grey background; (3) tips of ventrals black, with additional faint and ill defined dark blotches on inner side; (4) 19-19-17 DSR, distinctly keeled on rows 3–10 or 4–10, smooth on rows 1–2 or 1–3; scales of 1st DSR enlarged; (5) 154–166 ventral plates; (6) internasals narrowed anteriorly; (7) 1 anterior temporal, 1 preocular and usually 3 postoculars; (8) a moderately sized eye (see below).
Description of the holotype (Figs. 1–7).—Body moderately stout; head average (4.8% of SVL), distinct from the neck, flat anterior to eye; snout long, 28.5% of HL, 2.2 times as long as horizontal diameter of the eye, blunt from above, subrectangular in profile; nostril lateral, crescentic, piercing in middle of divided nasal in its lower half; eye moderately sized, diameter 1.3 times greater than distance between its inferior margin and edge of upper lip; pupil round; tail cylindrical and tapering.
Size. - SVL: 406 mm; TaL: 189 mm; TL: 595 mm; HL: 19.4 mm; ratio TaL/TL: 0.318.
Dentition. - Maxillary teeth: 26 gradually enlarged + 2 distinctly enlarged teeth posteriorly, without diastema.
Body scalation. - DSR: 19-19-17. Scales not notched at their posterior extremities.
Dorsal scale row reduction:
Scales of rows 3–10 distinctly keeled with narrow, sharp keel, more keeled on posterior half of body; scales of rows 1–2 smooth.
158 VEN (+ 2 preventrals); 100 SC, all paired. Anal divided.
Length of tail with 6 scale rows, in number of subcaudals spanned (see Malnate & Underwood, 1988): 32; length of tail with 4 scale rows: 33. Ratio Length 4 rows / Length 6 rows: 1.03.
Head scalation. - Rostral hexagonal, wider than high; nasals subrectangular, longer than high, divided below the nostril, with crescentic, laterally opening nostril in its middle; internasals distinctly subtriangular and narrow anteriorly, 1.4 times as long as wide and about 0.5 times as wide anteriorly than posteriorly; prefrontals subrectangular, broader than long, reaching loreal; frontal hexagonal, small, 1.55 times as long as wide, with apex directed posteriorly, 2.3 times longer than suture between prefrontals; parietals long and wide, in contact for a length 1.0 times as great as the frontal length; loreal 1/1, small, rectangular, elongate horizontally, 0.7 time as high as long, in broad contact with nasal; preoculars 1/1; postoculars 3/3, much larger than the two lower ones; supralabials 10/10, SL 1–2 at left, 1–3 at right in contact with nasal, 3–4 at left, 2–4 at right in contact with loreal, 5–7 entering orbit on both sides, 8th and 9th largest; temporals: 1+1 on both sides; infralabials 10/10, first pair in contact behind the mental, four anteriors in contact with anterior chin shields; posterior chin shields shorter than anterior ones, followed by one pair of gulars.
Coloration in alcohol.—Body dark ashy brownish-grey, darker above than on sides, resulting from dense, intricate speckling of dark grey minute dots on paler greyish-brown background; many scales edged with black, giving variegations or a loose network on upper surface of body and sides; sides with irregular faint black blotches, alternate in two rows, giving an indistinct quincuncially arranged pattern; dorsolateral stripe from side of neck to the vent, faint beige, more visible in the posterior half of the body, marked with a series of spots on DSR 6–7, conspicuous, light brown or beige, transversally elongated or divided into two parts, better defined anteriorly than posteriorly, about 70 in total, some edged with dark brown; tail as body, dorsolateral series of horizontally elongated beige spots, progressively vanishing on the tip of the tail.
Head and parietal region dark brown, with irregular paler vermiculations and some scattered beige dots; a short cream sagittal line just behind parietal suture; rostral cream, dotted with minute grey spots; broad, continuous, pure white stripe extends from tip of snout, across supralabials to the corner of the mouth, curving dorsally on neck to vertebral scale, nearly connecting to stripe of other side, producing a very conspicuous Vlike chevron on nape; this stripe is continuous on whole of the upper half of SL 1 to 6, largely dotted with minute brown or grey spots and with an irregular lower edge in the region of SL 1–4, expands on the lowest parts of loreal and preocular, then directly borders the orbit; on SL 7–10, the stripe extends on a width equal to nearly one half of the scale, expands on lower part of the lower preocular at level of SL 7, leaving only a narrow upper margin of brown on SL 8, found on upper parts of SL 9 and in center of SL 10, becomes progressively more narrow as it curves dorsally.
Venter cream, with tip of each ventral greyish-brown and another small, faint greyish-brown blotch on the inner side; infralabials heavily spotted with greyish-brown near edge of the lip.
Coloration in life. - Rather similar to that in alcohol, with the exception of dorsolateral spots, which are rusty red, and the apex of the chevron on the neck, which is bright yellow (see Figs. 6–7).
Description of paratypes (Figs. 8–9). – A summary of morphological and meristic data of the 22 paratypes is given in Table 1. Other important characters that vary with the holotype are discussed below in the description of the species (see “Variation”).
Variation.—The largest total length known is 772 mm for a male (SVL 527 mm, TaL 245 mm; ZISP 23671). The largest known female is 517 mm long (SVL 517 mm, TaL 228 mm; ZFMK 80660). The shortest specimen in our sample is only 238 mm long (SVL 163 mm, TaL 75 mm; ZISP 23667).
Dentition (Fig. 10): 28–30 maxillary teeth in a continuous series, gradually enlarged, posterior two slightly more enlarged.
Body relatively slim in males, more stout in females; head elongated, distinct from the neck, accounting (in adults above SVL 300 mm) for 4.0–5.2 % of SVL (x = 5.0 %); snout long, in adults 23.9–34.4 % (x = 29.7 %) of HL in both sexes, or 1.9–2.2 (x = 2.0) times as long as diameter of eye, without sexual size dimorphism; eye 1.4–1.6 (x = 1.5) times the distance eye–lip in both sexes. Tail tapering progressively. Ratio TaL/TL: 0.279–0.327, weakly sexually dimorphic (see below).
DSR: 19–19–17, more or less strongly keeled on rows 3–10 in both sexes, always smooth on 1st and 2nd DSR.
The reduction (DSR 4+5 → 4) appears at VEN 92–99 (x = 94.7, s = 2.1) at left, at VEN 96–102 (x = 99.2, s = 2.3) at right.
VEN: 154–166 (plus 1–2 preventrals); SC: 94–109, all paired; anal shield divided. In females, length (in number of subcaudals spanned) of 6 caudal scale rows (see Malnate & Underwood, 1988): 34–44; length of 4 caudal scale rows: 27–36. Ratio length 4 caudal rows / length 6 caudal rows: 0.75– 1.03 (x = 0.82; s = 0.11).
The head scalation is as described for the holotype and paratypes, with the following variation: internasals 1.2–1.4 times as long as wide, 0.45–0.55 times as wide anteriorly than posteriorly; prefrontals subrectangular, broader than long; frontal hexagonal, 1.4–1.6 times as long as wide, with apex directed posteriorly, 1.1–1.2 times longer than the prefrontals; parietals in contact for a length 1.1–1.2 times as great as the frontal length; 1 subrectangular loreal, 0.65–0.75 times as high as long, in broad contact with the nasal; 1/1 preoculars; usually 3 postoculars (2 in 1 / 50 occurrences), the upper much larger than the two lowers; 9 (47 / 50 occurrences) or 10 (3 / 50 occurrences) supralabials, SL 1–2 (rarely 1––3) in contact with the nasal, SL 2–3 (9 / 46 occurrences), 2–4 (7 / 46) or 3–4 (5 / 20) in contact with loreal, SL 4–5–6 (33 / 48 occurrences), 4–5 (1 / 48), 5–6– 7 (3 / 48) or 5–6 (1 / 48) entering orbit; SL 6–7 or 6–7–8 largest; 1+1 temporals in all specimens; 10 infralabials in all specimens, first pair in contact behind the mental, the four first are in contact with the anterior chin shields; posterior chin shields shorter than anterior shields.
Coloration in alcohol largely as described for holotype; body usually more grey (as dark ashy grey) than brown, darker above than on sides; variegations or a loose network on upper surface of body and sides more or less visible; dorsolateral stripe usually faint or absent, more visible in posterior half of body, always marked with a series of 70–75 light brown or beige (in alcohol; orange or rusty red in life) spots on DSR 6–7, transversally elongated or divided into two parts, better defined anteriorly than posteriorly. The tail is patterned as the body, with dorsolateral series of horizontally elongated beige spots.
Head dorsal surface and parietal region dark brown as in holotype, with irregular paler vermiculations and scattered beige dots; sagittal line behind parietals more or less visible; a broad, continuous, white stripe from snout tip to corner of the mouth, continuing to neck, present and conspicuous in all specimens; on nape, V-like chevron is present in all animals; stripe extends on whole of upper half of SL 1 to 6, bordering orbit and reaching lower part of lower preocular; in specimens with 9 SL, white stripe broadly crosses upper part of SL 7, leaving only a narrow upper margin of brown on this latter scale, then center of SL 8 and 9; on these latter scales, stripe occupies at least half of the scale.
Venter cream or pale yellow; tip of each ventral greyish-brown; a medial small, more or less faint greyishbrown blotch, never well defined (as in Amphiesma boulengeri, for example). Infralabials heavily spotted with greyish-brown near the edge of the lip.
In life, coloration and pattern are very similar to conditions in preservative; most notable differences are color of dorsolateral spots (salmon or rusty red in life), and posterior extremity of lateral streak of head (becoming yellow on the nape; see Figs. 6-9); dorsolateral spots are each connected by a narrow, weak reddish-brown band; upper dorsal surface dark grey, dark to bluish-grey or dark brownish-grey, with dark spots and irregular bars; dorsolateral spots extend to tail; upper head surface rather dark, reddish-brown in its middle with few small light spots; a weak light longitudinal line extends medially on hind part of head; in all specimens, lateral head streak white or cream and stretches from snout tip along the upper supralabials to neck, where both stripes nearly meet each other in a V-like chevron; tongue light behind, then darker, tips - including bifurcation point - light again; venter cream, pale yellowish-grey or very light grey, with a more or less conspicuous dark spot on tips of ventrals.
Sexual dimorphism.—It is best defined in the numbers of ventrals of subcaudals:
(1) Differences in the number of ventrals:
159–166 (x = 161.9, s = 2.9) in males vs. 154–159 (x = 156.9, s = 1.9) in females.
(2) Differences in the number of subcaudals:
101–109 (x = 104.6, s = 3.6) in males vs. 95–103 (x = 97.9.9, s = 2.8) in females.
There is no clear difference in the ratio TaL/TL (males: 0.309–0.332 [x = 0.319, s = 0.010]; females: 0.279–0.0326 [x = 0.309, s = 0.012].
Hemipenes (Fig. 11).—From specimen PNKB RH06213 (both hemipenes are only partly everted, with only the base visible while the lobular region is still inverted): hemipenes short, massive. The everted part is uniformly covered with small to medium sized spines; a pair of larger spines visible close to the sulcus on the proximal half of the hemipenial body.
Distribution (Fig. 12).— Vietnam. Amphiesma leucomystax spec. nov. is currently known from several localities in the provinces (from North to South) of Nghe An (Quy Chau District), Ha Tinh (Cam Xuyen and Huong Son Districts), Quang Binh (Bo Trach and Minh Hoa Districts), Quang Tri (A Luoi, Phu Loc and Huong Hoa Districts), Thua Thien-Hue (Huong Thuy and A Luoi Districts), Quang Nam (Ba Na National Park, Hoa Vang District), Kon Tum (Ngoc Linh Mt., on the border between Quang Nam and Kon Tum Provinces), and Gia Lai (An Khe District).— Thailand (?). The Thai specimen has no exact locality, based on a single specimen (see above) of unconfirmed origin.
Based on the Vietnamese distribution, this species may be expected in eastern Laos, especially in the western slopes of the Annamite Range.
Biology.— This species inhabits lowland and montane monsoon evergreen tropical forests of the Annamite Range (or Truong Son) and Tay-Nguyen Plateau (Central Vietnam) between about 100 and 1300 m, although most specimens were obtained above 350 asl. Specimens for which data are available were collected in primary or disturbed forests; one was obtained in the clearing of a disturbed lowland forest.
FIGURE 12. Distribution of Amphiesma leucomystax spec. nov.
Most specimens were associated with forest streams on slopes of the hills or mountains, but specimens AMNH 154175 and IEBR 2314 were collected in lowlands. Most snakes were collected at night, either during the rainy or the dry season. All of them were in or next to water, either coiled on leaves or stones, or, for specimens ZFMK 71703-704, perched on branches above the stream. Specimen ZFMK 71703 was coiled and digesting at 2.5 meters above the ground. To the best our knowledge, this is the first record of arboreality in the genus Amphiesma.
Specimen ZFMK 71703 had in its stomach a large female of Leptobrachium chapaense (Field number TZ '98/121, see Ziegler 2002: 45) swallowed hindlegs first, with partly digested hindlegs.
Specimen ZFMK 71704 contained 4 large eggs, up to 25 x 7 mm. Other gravid females (ZISP 23670, 23671-23672) were collected in April-May. They contained 3, 5 and 7 eggs respectively in the lower part of oviducts. Juvenile specimens were found on 15th October (SVL 163 mm) and 20th April (SVL 205 mm).
description: Published as part of David, Patrick, Bain, Raoul H., Truong, Nguyen Quang, Orlov, Nikolai L., Vogel, Gernot, Thanh, Vu Ngoc & Ziegler, Thomas, 2007, A new species of the natricine snake genus Amphiesma from the Indochinese Region (Squamata: Colubridae: Natricinae), pp. 41-60 in Zootaxa 1462 on pages 43-54, DOI: 10.5281/zenodo.176453