Trimeresurus gunaleni, Vogel & David & Abstract.-Variation, 2014

Vogel, Gernot, David, Patrick & Abstract. - Variation, Irvan Sidik, 2014, On Trimeresurus sumatranus (Raffles, 1822), with the designation of a neotype and the description of a new species of pitviper from Sumatra (Squamata: Viperidae: Crotalinae), Amphibian & Reptile Conservation 8 (2), pp. 1-29 : 21-25

Trimeresurus gunaleni spec. nov. Fig. 3–7 , 13

urn:lsid:zoobank.org:act:548DBAC7-D5CC-4D49-9D4F-2A372F0F4520

Trimeresurus sumatranus (nec Coluber sumatranus Raffles, 1822 ): Sanders et al. (2002: 107, part.; 2004: 722, part.).

Holotype

MZB.Ophi.5452, adult female, from Mt. Sibayak , ca. 1,500–2,200 m a.s.l., west of Brastagi (Berastagi), Karo Regency (Kabupaten Karo), Sumatera Utara Province, Sumatra, Indonesia. Collected by the team of Danny Gunalen , Hidekazu Miyake, Cho Sangyeon, and Moon Suk Cha.

Paratypes (six specimens)

NHMW 28159:1 (male), ZMB 29642 (male), NHMW 23909:4, NHMW 28159:2 (females), “Padang, Sumatra;” NHMB 2599 (male), “Solok, Sumatra;” SMF 52844 (female), “Padang Mountains, Sumatra, 1,700 m,” all from Sumatera Barat Province, Sumatra.

Non-type material (two live male specimens)

Mt. Singkut, 1,600 m a.s.l., Karo Regency, Sumatra Utara Province, Sumatra.

Diagnosis

A large species of pitviper of the genus Trimeresurus , characterized by the combination of (1) body elongate, head long and massive in adults; (2) an overall green coloration with interstitial skin forming irregular, hollow, black dorsal crossbands, with a thin, pale ventrolateral line; (3) 21 DSR at midbody; (4) first supralabial totally separated from nasal scale; (5) large internasals, most usually separated by one scale, only exceptionally in contact; (6) three supralabials, third, fourth, fifth SL in contact with subocular; (7) supraoculars large but elongate, separated by 5–7 cephalic scales; (8) tail long, with a ratio TaL/TL between 0.201 and 0.210 in males and 0.144 and 0.180 in females; (9) 162–179 VEN; (10) 58– 72 SC (males: 71–72; females: 58–66); (11) eye yellowish-green in life and preservative; (12) cephalic scales strongly and broadly edged with black but not forming streaks; (13) no black postocular streak; (14) venter greenish-yellow or pale green, uniform, with posterior margin of ventrals paler green; and (15) tail greyish-red, rusty brown or reddish-brown, mottled with green crossbars anteriorly.

Main characters separating T. gunaleni spec. nov. from other taxa of the complex of T. sumatranus are summarized in Table 2. Trimeresurus gunaleni spec. nov. mainly differs from T. sumatranus by (1) a lower number of ventrals in males (162–179, x = 168.4 vs. 178–185, x = 181.5; U = 33.5, P <0.005) and females (164–171, x = 169.5 vs.175–191, x = 183.3); (2) a higher value of the ratio TaL/TL in males (0.201 –0.210, x = 0.206 vs. 0.150 – 0.168, x = 0.161); (3) the color of the tail with hues of red throughout mottled with green crossbars anteriorly vs. green as the body on its anterior half, becoming more or less abruptly red (see above description) posteriorly, strongly reticulate with black; (4) the color of the eyes: green or yellowish-green in T. gunaleni spec. nov. vs. dark brown, dark grey, or bronze in T. sumatranus ; (5) the color of the ventral scales, which are green with a paler posterior margin in T. gunaleni spec. nov. vs. pale green with a dark grey or black posterior margin in T. sumatranus .

Trimeresurus gunaleni spec. nov. differs from T. malcolmi by (1) the number of dorsal scales around midbody (21 vs. 19); (2) a higher value of TaL/TL in males (0.201 –0.210, x = 0.206 vs. 0.160 –0.179, x = 0.162, s = 0.009); (3) the presence of a white lateral stripe in T. gunaleni spec. nov., missing in T. malcolmi ; (4) the color of the tail: greyish-red, rusty brown or reddish-brown, mottled with green crossbars anteriorly in T. gunaleni vs. greenish-orange, salmon or pinkish-red, strongly reticulated with black in T. malcolmi ; below, the tail is yellowish green anteriorly, turning to brown posteriorly in T. gunaleni spec. nov. vs. green or greenish-yellow on its anterior half, with subcaudal scales broadly edged with black producing a conspicuous reticulation; (5) the color of the eyes: yellowish-green in T. gunaleni spec. nov. vs. dark grey in T. malcolmi .

Trimeresurus gunaleni spec. nov. differs from T. hageni by (1) a lower number of ventrals in males (162–179, x = 168.4 against 177–189, x = 181.8; U = 139.5, P <0.001) and females (164–171, x = 169.5 vs.176–196, x = 186.7); (2) by the internasals being separate (in eight out of nine specimens) against being most usually in contact in T. hageni (in 66 out of 73 specimens; U = 545.5, P <0.001); (3) by the number of supralabials, usually being nine (in 14 out of 18 cases, only exceptionally 8 or 10, x = 9.11) in T. gunaleni spec. nov. vs. usually 10 or 11 (in 123 of 148 occurrences, exceptionally 9, 12, or 13, x = 10.54; U = 637.0, P <0.001) in T. hageni ; (4) by the total number of supralabials (on both sides) touching the subocular, six (in one case in seven, x = 6.1) vs. usually being 2–4 (in 56 out of 74 cases, exceptionally 0, 1, 5, 6, x = 2.9; U = 632.0, P <0.001) in T. hageni ; (5) by the number of infralabials, usually 11 (in 11 out of 16 occurrences, only exceptionally 10 or 12, x = 10.93) vs. usually 12–14 (in 120 of 148 cases, exceptionally 11, 15, or 16, x = 13.08; U = 710.0, P <0.001) in T. hageni ; (6) the lack of a pale temporal streak in T. gunaleni spec. nov., usually present in T. hageni , especially in males (in 27 of 29 males of T. hageni ); and (7) the missing of dorsolat- eral white dots in T. gunaleni spec. nov., are usually present in T. hageni especially in males (in 27 of 29 males of T. hageni ).

Etymology

The specific nomen is dedicated to Mr. Danny Gunalen, who was the first to find the species alive and who great- ly supported the work resulting in the description of this new species. Suggested common names: English: Gunalen’s Pitviper. Bahasa Indonesia: Ular Hijau Gunung. Karo: Nipe Ratah. Padang (Minang): Ular Ijo Babiso. French: Trimérésure de Gunalen. German: Gunalen’s Grubenotter.

Description of the holotype ( Fig. 3 , 5–7 , 13 ) Body elongate, compressed; head elongate, distinctly triangular, wide at its base, clearly distinct from the neck, flattened anteriorly, thick posteriorly, 1.6 times as long as wide; snout long, round when seen from above, strongly obliquely truncated when seen from the side, with a moderate canthus rostralis, totaling 32.0 % of head length, and 2.7 times as long as diameter of eye; a large oval nostril piercing in the middle of nasal scale; nostril-loreal pit distance about 0.5 times the distance between the nostril and the eye; eye average, totaling 0.65 times the distance between the lower margin of eye and upper lip border; tail rather long, tapering, and prehensile.

SVL 995 mm, TaL 195 mm, TL 1,170 mm; largest head width 35.0 mm; ratio TaL / TL 0.167.

Body scalation

DSR: 21–21–13 scales, rhomboid, distinctly keeled with the exception of scales of first DSR which are smooth; 171 VEN (+ two preventrals); 60 SC, all paired; anal entire.

Head scalation

Rostral barely visible from above, triangular, much broader than high; nasals pentagonal, partly divided by a shallow furrow; on each side, one large, subtriangular internasal, the rounded apex pointing outwards; internasals separated by one small scale; 2/2 canthal scales bordering the canthus rostralis, not larger than the large adjacent snout scales on each side, one elongate loreal scale between nasal and the upper preocular; 2/2 preoculars above the loreal pit, the upper one visible from above, both scales elongated and in contact with loreal; lower preocular forming the lower margin of loreal pit; 1/1 thin, elongated, crescent-like subocular; 2/2 small postoculars, followed by 2/3 small scales between postoculars and first temporals; 1/1 large, subtriangular, elongate supraocular on each side, 1.8 times as long as wide, 1.1 times as wide as internasal, not indented by adjacent cephalic scales; three much enlarged scales on upper snout surface on a line between the scale separating the internasals and a line connecting the anterior margins of eyes, smooth and juxtaposed; seven cephalic scales on a line between supraoculars, smaller than upper snout scales, smooth, flat, and juxtaposed; occipital scales not larger than cephalic scales, smooth; temporal scales smooth, large, subequal, arranged in two rows anteriorly, three rows posteriorly; 9/9 supralabials, third–fifth SL in contact with subocular; first SL entirely separated from nasal; second SL tall, entirely bordering the anterior margin of the loreal pit, in contact with nasal; third SL longest and highest, 1.4/1.5 times longer than high; fourth SL tall and relatively narrow, 1.1/1.2 times higher than long, as high as third SL; fifth SL relatively narrow; 12/12 IL; scales of the first pair longitudinally in contact; first three pairs of infralabials in contact with anterior chin shields; six rows of smooth gular scales; throat shields irregularly arranged.

Coloration and pattern

The body is uniformly deep green (bright emerald green in life), with some scales narrowly edged with black, more strongly on the fore part of the body; a faint, diffuse pattern of black, hollow crossbars resulting from irregular areas of interstitial skin around dorsal scales, more conspicuously visible on the fore part of the body, producing about 25 crossbars, three or four DSR long and separated by one or two scales around which the skin is grey, reaching downwards the first or second DSR; from about midbody, the black skin is progressively restricted to the eighth or ninth DSR, producing irregular dorsal bars, disappearing entirely before the vent; a narrow ventrolateral stripe, pale blue in life, white in preservative, extends from the neck to the vent on the upper edge of scales of the first DSR, and lower edge of scales of the second DSR; posterior edge of scales of the first DSR also pale blue. The tail is greyish-red throughout, with scales narrowly edged with pale grey and with five pale green incomplete rings anteriorly.

The head is deep green above (bright emerald green in life) and on the temporal region, with scales of the snout, preoculars, supraoculars, cephalic, occipital, and lower temporal scales narrowly edged with black and surround- ed with black interstitial skin, producing a conspicuous pattern of a “mixed” black background with bright green spots; no cephalic or occipital streaks; supraoculars narrowly edged with black; top of rostral black; anterior supralabials greenish-yellow, distinctly paler than upper head surface, others supralabials bright yellow in life; first–third SL narrowly edged with black posteriorly; no postocular streak; upper temporals green as the upper head surface. Chin and throat pale bluish-grey (cream in preservative); mental and first three infralabials greenish-yellow; other infralabials more or less marbled with greenish-yellow; posterior gular scales dotted with green.

The venter is uniformly yellowish-green, with the posterior edge of each ventral pale bluish-grey, distinctly paler than the background color of the venter. The tail is greenish-yellow on the first two subcaudals then greyish-red throughout as the upper surface of tail, with scales narrowly edged with pale grey.

Description of the paratypes

A summary of morphological and meristic data of the paratypes is given in Table 3. None of the paratype significantly differs from the description given for the holotype.

Description and variation

The maximal confirmed total length known is 1,170 mm (SVL 995 mm, TaL 195 mm; holotype). The second largest female has a length of 1,154 mm (SVL 972 mm, TaL 182 mm; NHMW 28159:2, from Padang). The largest known male is 927 mm long (SVL 732 mm, TaL 195 mm; NHMW 28159:1, from Padang). In our sample of nine specimens, there is a noteworthy difference of size between males and females (see below, sexual dimorphism).

The body is robust but elongate in both males and in females. In adults, the snout is 28.0–32.8 % as long as head or 2.3–2.8 times as long as diameter of eye. Eye average, amounting for 0.7–0.9 times the distance eye– lower edge of the lip in both sexes. Ratio TaL/TL: 0.144 – 0.210, with a sexual dimorphism (see below).

Hemipenis

Unknown.

Body scalation

DSR: 21–22 one head length posterior to the head, 21 at midbody, 13–15 scales one head length before vent, distinctly keeled, smooth on first DSR; VEN: 162–179 (plus preventrals), without sexual dimorphism; SC: 58–72, all paired, with a sexual dimorphism (see below); anal entire.

In our sample of nine specimens, only one specimen has 22 DSR on the neck, all others have 21 rows. Furthermore, all males have 13 rows before the vent but two females have 15 rows .

Head scalation

As described for the holotype, with the following variation for major characters: internasals separated by one small scale in 8/ 9 specimens, in contact only in specimen ZMB 29642; only two canthal scales on each side in all specimens, not larger than adjacent snout scales or slightly smaller, bordering the canthus rostralis between the internasal and corresponding supraocular; two small postoculars, in contact with first temporals or followed by 2–3 small scales between postoculars and first temporals; one large, elongate, subtriangular supraocular on each side, 1.6–2.1 times as long as wide, 1.0–1.3 times as wide as internasal, not indented by adjacent cephalic scales; 3–4 enlarged scales on upper snout surface on a line between the scale separating the internasals and a line connecting the anterior margins of eyes, smooth, and juxtaposed; 5–7 cephalic scales (5: 1/ 9 specimens; 6: 5/9; 7: 3/9) on a line between supraoculars, smaller than upper snout scales, smooth, flat, and juxtaposed; occipital scales not enlarged and smooth; temporal scales smooth, large, subequal, in two or three rows; 8–10 supralabials (8: 2/18 occurrences; 9: 12/18; 10: 4/18); third, fourth, fifth SL in contact with subocular in all specimens; first SL always separated from nasal; second SL tall, entirely bordering the anterior margin of the loreal pit, always in contact with nasal; third SL longest and highest, 1.2–1.5 times as long as high; fourth SL higher than long; fifth SL tall and narrow; 10–12 IL (10 or 11 in most specimens); scales of the first pair longitudinally in contact; first three see Table 1. pairs of infralabials in contact with anterior chin shields; 5–8 rows of smooth gular scales; throat shields irregularly arranged.

Coloration and pattern

The body is bluish-green or deep green (bright green or emerald green in life) with most of the dorsal scales narrowly edged with black, usually more strongly on the anterior part of the body; a faint, diffuse pattern of dark, hollow crossbars created by irregular areas of black interstitial skin surrounding three or four rows of dorsal scales, most conspicuous and extensive on the fore part of the body, separated by one or two scales around which the skin is grey; these dark crossbands reach downwards the first or second DSR on the anterior part of the body, progressively restricted to the upper DSR posteriorly, producing irregular dorsal bars and disappearing entirely before the vent; a narrow ventrolateral, stripe, white, cream, or pale yellow in preservative (cream or pale blue in life), extends from the neck to the vent on the upper half of scales of the first DSR and sometimes on low- er edge of scales of the second DSR; posterior edge of scales of the first DSR also white or cream (cream or pale blue in life). The tail is greyish-red or rusty-red throughout, with scales narrowly edged with cream to pale grey, and mottled with incomplete cream, pale grey or pale greenish-grey rings (pale greyish-green in life), present on the anterior half of the tail or throughout.

The head is deep green above and on the temporal region; scales of the snout, preoculars, supraoculars, cephalic, occipital and lower temporal scales narrowly edged with black and entirely surrounded with interstitial black skin, producing a conspicuous pattern made of a black background “mixed” with bright green spots; no cephalic, occipital, or postocular streaks; supraoculars narrowly edged with black; top of rostral usually black; anterior supralabials green or yellowish-green, distinctly paler than upper head surface, others supralabials yellow, greenish-yellow or green; first–third SL usually narrowly edged with black on their posterior edge; upper temporals green as the upper head surface. Chin and throat cream (pale bluish-grey in life); mental and first three infralabials greenish-yellow or pale yellowish-green; other infralabials more or less marbled with greenish-yellow; posterior gular scales sometimes dotted with greyish-green or green spots.

The venter is uniformly bluish-green or yellowish-green in preservative (yellow, greenish-yellow, or green in life), with the posterior edge of each ventral pale bluish-grey or greyish-green, distinctly paler than the background color of the venter. The tail is greenish-yellow or green anteriorly on a distance varying from the first subcaudals to the middle of the tail then greyish-red or rusty-red throughout as the upper surface of tail, with scales narrowly edged with pale grey and with cream, pale grey or pale greenish-grey blotches (pale greyish-green in life) corresponding to the rings of the upper surface.

Sexual dimorphism

Males and females differ in the relative length of the tail, in total length, and in the number of subcaudals: (1) Strong difference in the ratio TaL/TL:

males: 0.201 –0.210 (x =0.206); females: 0.144 –0.180 (x =0.162).

(2) Total length:

Largest male: 927 mm vs. largest female 1,170 mm.

(3) Differences in the number of subcaudals:

71–72 (x =71.5) in two males vs. 58–66 (x =60.5) in four females.

There is no difference in the numbers of ventral scales or in other scalation characters, nor in pattern or in eye color.

Distribution

Indonesia near open water, the biotopes are dense humid montane forests.

Based on regurgitated prey items and direct observations in the wild, the diet includes rodents, amphibians, and lizards ( Gonocephalus lacunosus Manthey and Denzer, 1991 ; E. Manik, pers. comm.). In captivity, T. gunaleni spec. nov. feeds on mice, birds, and lizards (D. Gunalen, pers. comm). Reproductive habits are still unknown.

Figures

Fig. 3A. MZB.Ophi.5452 live holotype of Trimeresurus gunaleni spec. nov. from Mt. Sibayak, ca. 1,800 m a.s.l., west of Brastagi, Sumatera Utara Province, Sumatra, adult female. Photo: G. Vogel.

Fig. 4A. Live male of Trimeresurus gunaleni spec. nov. from Mt. Singkut, 1,600 m a.s.l., Sumatra Utara Province, Sumatra. Photo: G. Vogel.

Fig. 5. Comparative dorsal view of the head of Trimeresurus gunaleni spec. nov. (left) and T. sumatranus (right). Left from above: Male, female (holotype), male, all from Sumatra Utara Province, Sumatra alive, right adult female alive from Bengkulu Province, Sumatra, adult male alive from Bengkulu Province, Sumatra, preserved female from Borneo. Photos: N. Maury.

Fig. 6. Comparative lateral view of the head of Trimeresurus gunaleni spec. nov. (left) and T. sumatranus (right). Left from above: Male, female (holotype), male, all from Sumatra Utara Province, Sumatra alive, right adult female alive from Bengkulu Province, Sumatra, adult male alive from Bengkulu Province, Sumatra, preserved female from Borneo. Photos: N. Maury.

Fig. 7. Comparative ventral view of the head of Trimeresurus gunaleni spec. nov. (left) and T. sumatranus (right). Left from above: Male, female (holotype), male, all from Sumatra Utara Province, Sumatra alive, right adult female alive from Bengkulu Province, Sumatra, adult male alive from Bengkulu Province, Sumatra, preserved female from Borneo. Photos: N. Maury.

Fig. 13. MZB.Ophi.5452 holotype of Trimeresurus gunaleni spec. nov., adult female. Photo: N. Maury.