Amphiesma kerinciense, David & Das, 2003

David, Patrick & Das, Indraneil, 2003, A New Species Of The Snake Genus Amphiesma (Serpentes: Colubridae: Natricinae) From Western Sumatra, Indonesia, Raffles Bulletin of Zoology 51 (2), pp. 413-419 : 414-416

Amphiesma kerinciense new species

( Figs. 1-4 )

Material examined. – Holotype – adult female ( ZRC 2.3521 ), Sungai Jalnei Dalam , at base of Gunung Tugu (or Tujuh) [= Mt. Tugu or Tujuh] (01 42’59.0"S- 101 21’43.1"E), Gunung Kerinci [= Mt. Kerinci], Sumatera Barat Province, Sumatra Island, Indonesia, coll. Darren Yeo & Heok Hui Tan, 12 Jun.1996.

Diagnosis. – A species of the genus Amphiesma , characterized by: (1) a stout body; (2) a moderately large eye (see below); (3) 19 scale rows at midbody, strongly keeled on upper rows, many of which are distinctly notched posteriorly; scales of first dorsal row enlarged, feebly keeled; (4) a single preocular; (5) a broad, dark vertebral band, with irregularly placed dark scales producing faint and irregular, discontinuous crossbars; (6) a faint pale ochre brown dorsolateral stripe bordering the vertebral band on each side, widening to produce three or four irregular blotches on the neck; (7) two distinct postocular streaks (see the description below) and (8) ventral scales purple greyish-brown at their outer border, with a row of well defined dark brown blotches at 3/4 of their width.

This species differs from all other members of the genus by the combination of these characters. Especially diagnostic are the combination of the dorsal colour and pattern, the single preocular and the notching of the dorsal scales. These and other characters are detailed below in the discussion.

Description of the holotype. Habitus. – Body stout; head rather short (4.8% of SVL), barely distinct from the neck, depressed in front of the eye; snout long, accounting for 26.0% of HL, or 1.6 times as long as horizontal diameter of the eye, blunt when viewed from above, rectangular when viewed from the side; nostril lateral; eye moderate, diameter 2.0 times greater than the distance between its inferior margin and edge of upper lip; pupil rounded; tail cylindrical and tapering.

Size. – SVL: 358mm; TaL: 158mm; TL: 516mm; HL: 17.2mm; ratio TaL/TL:0.308.

Dentitional morphology.– Maxillary teeth: 18/19 + 2/2 distinctly enlarged teeth, without diastema.

Body scalation. – 140 VEN (+ 2 preventrals); 89 SC, all paired. Anal divided.

DSR: 19-19-17, distinctly keeled with a narrow, sharp keel, and notched at their posterior extremities, feebly keeled or nearly smooth on the first scale row; scales more keeled and notched in the posterior half of the body.

Head scalation.– Rostral trapezoidal, wider than high; nasals rectangular, distinctly longer than high, divided into two parts on their lower half, with a rounded, lateral nostril in its middle; internasals subtriangular, 1.2 times as long as wide and about 0.45 times wider anteriorly than posteriorly; prefrontals subrectangular, wider than long, reaching the loreal; frontal hexagonal, rather small, 1.4 times as long as wide, with apex directed posteriorly, 2.5 times longer than the suture between the prefrontals; parietals long and wide, in contact for a length 1.1 times as great as the frontal length; 1/1 small, rectangular loreal, elongate horizontally, contacting the nasal; 1/1 PrO; 3/3 PoO, the upper one much larger than the two lower ones; 1/1 undivided narrow SpO; 9/9 SL, 1st and 2nd SL in contact with the nasal, 2nd, 3th and 4th in contact with the loreal, 4th, 5th and 6th entering orbit, 7th and 8th the largest ones; temporals: at left and right: 1 ATe + 1 large upper and 1 smaller lower PTe; 11/11 IL, first pair in contact behind the mental, the four first ones are in contact with the anterior chin shields; posterior chin shields shorter than anterior ones, followed by one pair of gulars.

Coloration in alcohol. – Flanks, up to 4th row, dark reddish grey-brown, due to an intricate speckling of dark reddish-brown pigments on a pale greyish-ochre background, with lower rows 1-2 rather purple greyish-brown, slightly iridescent, with ventroposterior extremities of scales of the 1st row dark brown; widely scattered small blackish-brown spots on 2nd, 3rd and 4th rows; these dark brown spots produce faint and irregular, discontinuous crossbars, more visible on the posterior part of the body. A broad blackish-brown vertebral band on 5th-9th rows and the vertebral row, with indistinct irregular black crossbars. A dorsolateral stripe extending from the neck to the tail on top of 5th row and the whole of 6th row, well defined and greyish-pink on the neck and foremost part of the body (up to VEN 6), becoming discontinuous and broken into 4 or 5 irregular and diffuse blotches more or less connected, then changing into a diffuse, ill defined pale ochre-brown stripe.

The tail is blackish-brown above, greyish-ochre on the upper part of the side in the extension of the dorsolateral band of the body, with a blackish-brown band on its lower side and extremities of subcaudals, divided into two equal parts by a narrow greyish-purple line in the extension of the colour present on rows 1 and 2 of the body.

Head dorsal surface dark reddish grey-brown with ochre vermiculations, turning into blackish-brown on its posterior part; a fine speckling with purple greyish-brown on temporals; two small faint yellowish-white spots on the parietals and a very faint whitish-brown sagittal line just behind the parietals.

Anterior supralabials ochre brown, with brown speckling and edged with dark brown on their posterior part. Posterior supralabials light ivory cream; posterior part of 6th SL blackish-brown; 7th SL with a curved dark brown marking in the posterior part of its centre and with its posterior upper corner dark brown; 8th SL divided into a lower anterior part ivory cream and an upper posterior part dark reddish grey-brown, these two parts being separated by an oblique blackish-brown streak connecting the upper tip of the 7th SL to the lip edge at the junction of 8th and 9th SL; 9th SL dark reddish grey-brown, with its lower part blackish-brown and its upper part ochre brown, narrowly bordered with blackish-brown above. An ill defined and narrow postocular streak, pale ochre brown narrowly edged below with blackish-brown, extending from the upper preocular to 9th SL through the anterior temporal and the upper tip of 8th SL. Behind the 9th SL, the postocular streak, which is irregular, is bent upwards and is more or less distinctly connected with the thin greyish-pink dorsolateral stripe of the neck.

Venter uniformly ivory cream, with about 1/4th of the outer part of each scale purple greyish-brown as dorsal rows 1-2, becoming blackish-brown on the scale outer tip; a subrectangular, irregular blackish-brown spot between the purple greyish-brown and ivory parts; these spots become progressively larger backwards and are connected to the purple greyish-brown colour of the flank from about the 20th VEN onwards; before this point, the blackish-brown ventral spots are separated from the purple greyish-brown colour of the lower flank by a narrow ivory cream line, producing a thin and conspicuous but discontinuous series of dark brown See “Materials and methods” for the explanation of abbreviations.

spots at the bottom of the flanks; the ivory line is progressively replaced by the purple greyish-brown hue.

Ventral part of tail as the venter, bordered on each side by a blackish-brown stripe described above, with a middle line made of irregular and faint dark brown speckling. Throat, chin and ventral part of the neck ivory cream, uniform in their middle, with some dark brown speckling on the outer parts of the throat and lower side of the neck; posterior margins of infralabials dark brown.

The coloration in life has not been recorded. The colour of the belly suggests, by analogy with other species of the genus such as Amphiesma optatum after some time in preservative, a pink or red coloration in life (see David et al., 1998).

Etymology. – The specific epithet derives, in modern Latin, from the name of the type locality, Gunung Kerinci, the highest peak in Sumatra (3805m asl). The grammar of the gender of Amphiesma being neuter ( Toriba, 1994; David et al., 1999), the specific epithet is treated in concordance to the sex of the generic name. We suggest the following western common names: Mt. Kerinci Keelback (English), Amphiesma du Mont Kerinci (French), Mt. Kerinci Gebirgswassernatter (German).

Distribution and biology.- Amphiesma kerinciense is currently known only from its type locality. It might be expected from other forested parts of Banjaran Barisan. The holotype was caught from a shallow (less than 30 cm deep) hill stream (elevation unfortunately not recorded), fast flowing in parts through an open, grassy area. The clear water flowed over a substratum of stone and gravel. The snake was collected while it was feeding on tadpoles, possibly of the genus Huia , which it later regurgitated.

Figures

Fig. 1. Amphiesma kerinciense. Holotype (ZRC2.3521). Lateral view of the head (left side).

Fig. 2. Amphiesma kerinciense. Holotype (ZRC2.3521). Dorsal view of the head.