Oligodon taeniatus ( Günther, 1861 )

David, P., Vogel, G. & van Rooijen, J., 2008, A revision of the Oligodon taeniatus (Günther, 1861) group (Squamata: Colubridae), with the description of three new species from the Indochinese Region, Zootaxa 1965, pp. 1-49 : 8-18

Oligodon taeniatus ( Günther, 1861)

( Figs. 4–9)

Simotes taeniatus Günther, 1861: 189 . – Type locality. not given in the original description but “ Cambodia ” according to the BMNH Catalogue. – Holotype. BMNH 1946.1 .3.27 (male). Collected by Henri Mouhot.

Simotes quadrilineatus Jan & Sordelli, 1865 : Pl. IV: Fig. 3. – Type locality, by virtue of neotype designation. Bangkok, Thailand. – Neotype, by present designation: MNHN 1991.1819 (adult female), from “ Bangkok ”, Thailand. Collected by Firmin Bocourt. The holotype was the specimen depicted on Jan & Sordelli’s plate, from “ Bangkok ”, according to page 8 of the Index of the volume; specimen now lost (see below). – Synonymized with Simotes taeniatus Günther, 1861 by Boulenger (1914: 70).

Material (108 specimens). – THAILAND. Ayuthaya Province . BMNH 1910.6 .3.20 (male), “Ayuthia”, now Ayuthaya. Bangkok Province and region. BMNH 1914.5 .11.6, BMNH 1969.1825 – 1826 (3 males) , BMNH 97.10 .8.26, BMNH 1956.1 .13.3, BMNH 1969.1777 , BMNH 1969.1820 – 1821 , BMNH

1969.1823–1824 (7 females), Bangkok; MNHN 0598 (1), MNHN 630 (2 males), MNHN 0598 (2) (female), MNHN 1991.1819 (female, neotype of Simotes quadrilineatus ), “ Bang-kok ( Siam )”, now Bangkok. Chachoengsao Province. MNHN 1885.0400 (female), “Petriou”, now Chachoengsao. Chonburi Province. BMNH 97.10 .8.32 (juvenile), “Bourtong, Siam”, now Bo Thong . Nakhon Ratchasima Province. BMNH 1969.1819 (unsexed), “Ban Taang, Korat”, an unidentified locality . Prachinburi Province. MNHN 1885.0380 (female), MNHN 1885.0381 (male), “Entre Kabin et Pékim”, now between Kabinburi and Prachinburi. Prachinburi or Sa Kaew Province. MNHN 1885.0365 (female), “Entre Vatana et Kabin”, now between Watthana Nakhon, Province of Sa Kaew and Kabinburi, Province of Prachinburi. Ubon Ratchathani Province. BMNH 1969.1814 (female), “Nong Wah, Ubon”, now Nong Wa, near Ubon Ratchathani. No precise locality. BMNH 65.4 .28.6, BMNH 78.2 .14.12, BMNH 1969.1815 – 1816 , BMNH 1987.1767 (5 males), BMNH 1987.1768 (female) “ Siam ”. – THAILAND OR CAMBODIA. MNHN 1885.0355 – 0356 (2 females), “ Entre Batambang et Vatana ( Siam )”, now between Battambang, Province of Battambang, Cambodia and Watthana Nakhon, Province of Sa Kaew, Thailand. – CAMBODIA . Koh Song Province. MNHN 1970.0425 , MNHN 1970.0428 (2 males), MNHN 1970.0426 – 0427 (2 females) , Kirirom. Kompong Chhnang Province. MNHN 1970.0430 , MNHN 1970.0432 – 0434 (3 females), MNHN 1970.0431 , MNHN 1970.0435 (2 males) , Trapeang Chan. Phnom Penh Province. BMNH 1920.1.20.4075A–C (3 males), “Pneum-Penh”, now Phnom Penh . Siem Reap Province. MNHN 1970.0429 (female), Angkor. No locality. BMNH RR1946.1.3.24 (ex 61.4.12.40) (female), BMNH RR1946.1.3.27 (male; holotype), “ Cambodia ”. – LAOS . Champasak Province. MNHN 2005.0239 (juvenile, probably female), Paksé. – VIETNAM . An Giang Province. BMNH 1920.1 .20.2867 (male), Long Xuyen . Bac Kan Province. IEBR A.0755 ( Field Number LM 24) , Lung Minh, Ba Be (female). District of Ho Chi Minh. BMNH 1920.1.20.4077A, BMNH 1920.1.20.4077C–D, BMNH 1969.1818 (4 males), BMNH 1920.1.20.4077B, BMNH 1920.1.20.4077E–G (4 females), “ Saigon ”; CAS 16705 (male), “ Saigon ”; MNHN 1180 (female), MNHN 1999.8164 (female; ex MNHN 1180 ), “ Saïgon, Cochinchine ( Indochine )”, now Ho Chi Minh City; MNHN 1974.1265 , MNHN 1974.1270 (2 males), MNHN 1974.1268 , MNHN 1974.1271 (2 females), “ Région de Saïgon, Vietnam Sud ”, now region of Ho Chi Minh City; MNHN 1975.0126 (male), “ Saïgon, Bun-Buik”, in the vicinity of Ho Chi Minh. Minh Hai Province. MNHN 1885.0321 , MNHN 1885.0323 – 0326 (5 males), “ Ba-Chieu, Cochinchine ”, now Bac Lieu. Tay Ninh Province. ITBCZ 127 (male), Lo Go National Park, Xa Mat ; MHL 42002098–1 , MHL 42002098–2 , MHL 42002098–5 , MHL 42002098–6 (4 males), MHL 42002098–3 , MHL 42002098–4 (2 females), MHL 42002104 (sex unknown), “ Tay Ninh, Cochinchine” . Tiên Giang Province. MHL 42000378–1 , MHL 42000378–2 (2 males), MHL 42000378–3 , MHL 42000378–4 (2 females) “Mi-Tho, Basse Cochinchine”, now My Tho . Vinh Long Province. MHL 42000303–1 , MHL 42000303–2 , MHL 42000303–4 (3 males), MHL 42000303–3 , “Tra-On”, now Tra On. No precise locality. North Vietnam. MHL 42006375 (male), “Tonkin”. Southern Vietnam. MHL 42002111–1 , MHL 42002111–5 , MHL 42002155 , MHL 42006414–1 , MHL 42006414–2 (5 females), MHL 42002111–2 , MHL 42002111–3 , MHL 42002111–4 , MHL 42002178 , MHL 42002229 (5 males), “Cochinchine”; MNHN 1864.0313 , MNHN 1999.8165 (2 males), MNHN 1999.8166 (female), MNHN 1865.0024 , MNHN 1884.0406 (2 males), MNHN 1908.0054 (female), MNHN 1999.8161 , MNHN 1999.8163 (2 females; both ex MNHN 1908.0054 ), MNHN 1999.8162 (male; ex MNHN 1908.0054 ), “Cochinchine”. – NO LOCALITY. MNHN 1910.0018 , MNHN 1912.0422 (2 females), “Indochine” .

Taxonomic comments. – Boulenger (1894: 228) erroneously mentioned five specimens as types of Simotes taeniatus . Two are indeed referable to Oligodon taeniatus . The three other specimens from the same locality deposited by H. Mouhot are referable to Oligodon mouhoti (see below). The presence of specimens with 19 and 17 dorsal scale rows in the same collection misled Günther (1864). Thus, the collections of the BMNH include two specimens collected by Henri Mouhot in Cambodia, BMNH 1946.1.3.24 (previously 61.4.12.40) and BMNH 1946.1.3.27 (original number unknown). However, it is obvious that Günther (1861) established the description on the basis of a single specimen. Although the values of ventrals and subcaudals cited by Günther do not agree well with either of these two specimens, they are quite close to those of BMNH 1946.1.3.27. As H. Mouhot deposited only five specimens ( Boulenger, 1894: 228; C. J. McCarthy, pers. comm, October 2007), of which only two are referable to Oligodon taeniatus , we consider the specimen BMNH 1946.1.3.27 to be the holotype. This specimen has 158 ventrals and 42 subcaudals instead of 155 and 44 as cited by Günther.

The confusion between Oligodon taeniatus , O. quadrilineatus and, to a lesser extent, O. mouhoti , was discussed in the Introduction. The combination Oligodon quadrilineatus was used as recently as by Chan-ard et al. (1999) and Nabhitabhata et al. (2004). Examination of Jan & Sordelli’s (1865) plate makes it clear that the sole specimen that they depicted, and thus the holotype of Simotes quadrilineatus , had 19 scale rows and no spots on the tail. Four specimens, all collected by Bocourt during his travel to Siam ( Bocourt, 1866) were considered syntypes of Simotes quadrilineatus in the catalogues of the MNHN, all under the single number MNHN 630. Subsequently, three of them were renumbered as MNHN 1991.1817 to 1819. Two of them, MNHN 1991.1817–1818 are typical Oligodon mouhoti , and cannot qualify as the holotype of Simotes quadrilineatus . MNHN 630 and 1991.1819 are indeed typical Oligodon taeniatus , but, thanks to the precision of Jan & Sordelli’s drawing, especially of the ventral pattern where blotches are clearly visible, it appears that none of them is the specimen depicted on Plate 7 of Jan & Sordelli (1865). Furthermore, the characters noted in the description provided by Jan in Bocourt (1866) confirms that neither can be considered the holotype of Simotes quadrilineatus . We could not trace this specimen, which is neither in Paris or in the Museo Civico di Storia Naturale in Milan, of which Jan was then the head. According to Dr Stefano Cali (pers. comm., September 2007), the whole of Jan’s collection was destroyed in 1943, when the museum was set on fire. No type specimen described by Jan is still extant. So, we consider the holotype to be lost. We describe here a neotype for Simotes quadrilineatus , from the series collected by Bocourt:

Neotype of Simotes quadrilineatus ( Figs. 8–9): MNHN 1991.1819 (adult female), from “ Bangkok ”, Thailand. Collected by Firmin Bocourt.

Morphology. Body elongated but robust; head barely distinct from neck; snout projecting over the lower jaw, long, rounded, amounting to 30.0 % of HL or 1.7 times as long as diameter of eye; pupil black and round; tail thick at its base and tapering.

SVL 259 mm, TaL 39 mm; HL 11.2 mm; ratio Tal/TL 0.131.

Dentition. 14 (11 + 3 enlarged) maxillary teeth.

Body scalation. DSR: 19–19–15 rows, scales all smooth, small and ovoid. VEN: 161 (+ 1 preventral); SC 34, paired; Anal entire.

Head scalation. As described for the species with: rostral distinctly curved onto the upper snout surface, well visible from above, separating internasals by half of their length; nasals subrectangular, vertically divided; prefrontals subrectangular, distinctly wider than long; frontal hexagonal, ogive-like, 1.3 times as long as wide; a large supraocular on each side, distinctly longer than wide, as wide as prefrontals; two large, subtriangular parietals, much longer than the frontal, in broad contact; 1/1 small subrectangular loreal scale, about 1.5 times as long as high, in contact with the nasal; 8/8 SL, 1 st SL small, 2 nd and 3 rd in contact with loreal, 4 th and 5 th entering orbit, 6 th and 7 th largest; 1/1 high preocular; no presubocular on either sides; 2/2 postoculars; temporals 1+2/1+2; 9/9 infralabials, first pair in contact, IL 1–4 in contact with anterior chin shields.

Colouration. The upper body surface is greyish-brown, with scales narrowly edged with dark brown; a narrow greyish-yellow vertebral stripe extends from the nuchal marking up to the base of the tail, edged on each of its sides with a wider brown paravertebral stripe, intersected with small, irregular dark brown subrectangular blotches every 4 scales; an irregular, dark brown lateral stripe on each side on DSR 3–4, extends from the neck to the vent. Dorsally, the tail is as the upper body surface, with a greyish-yellow vertebral stripe wider than on the body and strongly edged with a blackish-brown stripe on each side; a dark brown lateral stripe on each side on the edges of subcaudals.

The head is greyish-brown, darker than body; supralabials lighter, strongly variegated with brown; five main markings present: a transversal dark brown marking on the snout, in front of eyes, extending downwards and backwards across the eye down to SL 5–6; a short, narrow, ogive shaped, longitudinal streak on the frontal; on each side, an oblique dark brown bar extends along frontal, anterior part of parietals and posterior temporals, the neck side behind the corner of the mouth, then, downwards, vanishes well before reaching the ventrals; a conspicuous, arrow or heart-shaped, dark brown nuchal blotch, with two branches pointing backwards; infralabials, chin and throat uniformly creamish-yellow.

The venter is creamish-yellow with two (rarely one) irregular blackish-brown subrectangular blotches near tips of the ventrals; some ventrals without blotches. Tail below with few subrectangular blotches in its anterior half, uniform towards its tip.

Diagnosis. – A species of the genus Oligodon characterized by: (1) a large size for the O. taeniatus -group, up to about 450 mm in total length; (2) deeply forked hemipenes, not spinose but fitted with two large papillae; (3) 19 dorsal scale rows at midbody, 15 before vent; (4) 14–17 maxillary teeth, the last two strongly enlarged; (5) head scalation complete, rarely including a presubocular; (6) 8 supralabials; (7) anal plate single; (8) the presence of two dark longitudinal paravertebral stripes edging a pale (yellow in life) vertebral stripe, and two narrower dorsolateral stripes; (9) five main, well defined blotches on upper head surface: one anterior transverse marking across the snout; one longitudinal blotch on the frontal; two temporal oblique bars, directed posteriorly downwards; and one large, arrow-shaped nuchal blotch; and (10) bases of the oblique central streaks often (about 50 % of the examined specimens) reach the ventral scales at least on one side.

Oligodon taeniatus differs from all other species of the taeniatus -group by the combination of (1) 19 scale rows at midbody and (2) a pattern made of one vertebral stripe edged with two paravertebral stripes, plus one dorsolateral stripe on each side. This pattern is constant in all examined specimens.

Description and variation (based on Campden-Main [1969] and 105 examined specimens). – Morphology. Body rather elongated but not especially thin; head ovoid, short, thick, barely distinct from the poorly defined neck; snout projecting over lower jaw, long, amounting to 26.4–30.3 % (x = 28.6 %, s = 1.3) of HL, or 1.7–2.0 (x = 1.8, s = 0.1) times as long as diameter of eye; eye rather small, with a round pupil; tail rather thick but tapering. Maximal total length 447 mm (SVL 367 mm, TaL 80 mm) for a male (BMNH 1920.1.20.4075A). The largest examined female is 424 mm long (SVL 367 mm, TaL 57 mm; IEBR A.0755 (Field Number LM 24)). In our sample (105 specimens), there is no noticeable difference in maximal sizes of males and females. Ratio TaL/TL: 0.165 –0.204, with a strong sexual dimorphism (see below).

Dentition. 14–17 maxillary teeth (x = 15.5, s = 0.8), the last two being strongly enlarged and blade-like.

Body scalation. DSR: 19–19–15, without exception; scales small, ovoid, all smooth.

VEN: 146–165 (plus 1–2 preventrals), slightly angulate; SC: 31–48, all paired (with a strong sexual dimorphism); anal plate entire.

Head scalation. Rostral thick, curved onto the upper snout surface, well visible from above, separating internasals up to one half of their length; nasals subrectangular, about 1.6–2.0 times as long as high, slightly “butterfly-shaped”, vertically divided, with the posterior part distinctly smaller than anterior one; nostril crescentic, piercing middle of nasal just forward of the division; internasals subrectangular, in broad contact, much shorter than prefrontals; prefrontals subrectangular, distinctly wider than long; frontal hexagonal, ogivelike pointing caudally, 1.25–1.45 times as long as wide (x = 1.35, s = 0.06); an undivided supraocular on each side, distinctly longer than wide, about as wide as prefrontals; behind, two very large, subtriangular parietals, much longer than the frontal, in broad contact; 1/1 small, elongate subrectangular loreal scale, about 1.3–1.8 times as long as high, in broad contact with the nasal; loreal absent in only 1 out of 105 specimens; 8/8 supralabials (7 on one side in only 1/210 occurrences), 1 st SL small, 2 nd and 3 rd in contact with loreal in all specimens, 4 th and 5 th entering orbit (in 208/210 occurrences), 5 th only in only 1/210 occurrences, 6 th and 7 th largest; 1/1 preocular, high and narrow, in all examined specimens; a small presubocular present (in 94/210 occurrences; 44.8%) or absent (116/210; 55.2%); in only 9 specimens out of 105 the presubocular is present on one side only; 2/2 small postoculars in all examined specimens; 1/1 elongated anterior temporal in all specimens, 2/2 or rarely 1/(1+1) posterior temporals; 9/9 infralabials (exceptionally 10/ 10 in 2/ 105 specimens), first pair in contact, IL 1–4 (exceptionally 1–5 in 5/ 105 specimens) in contact with anterior chin shields, 5 th IL the largest.

Colour and pattern in alcohol and in life. The upper surface is brownish-grey or sea grey or greyish-tan (same in life, with brighter colours), with dorsal scales finely edged with dark brown posteriorly; from the nape mark up to about the level of the vent, a conspicuous but narrow, pale, cream or greyish-yellow vertebral stripe (lemon yellow or yellowish-brown in life), edged on each side with a much wider dark greyish-brown or tan blackish-brown paravertebral stripe (brown edged with yellow in life), intersected with small black or dark brown subrectangular blotches every 4 or 5 scales (interstitial skin yellow in life); another lateral dark brown stripe on each side, narrower than paravertebral stripes, extends on DSR 3–4 from the neck to the vent; these dorsolateral stripes are more or less regular or broken into spots but are present in all specimens. The tail resembles the upper body surface but the vertebral stripe widens and is only edged on each side with a dark brown stripe which does not reach the tip of the tail; a dark brown lateral stripe on each side at the limit with subcaudals; there are never large dark blotches on upper surface of the tail.

The head is brownish-grey or mid grey or greyish-brown, darker than body; supralabials paler (cream in life), more or less variegated with dark brown; a total of five main markings above, as follows: a transverse dark brown marking on the snout, just in front of eyes, extends downwards obliquely backwards across the eye down to SL 5–6; a short, narrow, water drop or arrow shaped, longitudinal streak on the frontal; on each side, a large, oblique dark brown or blackish-brown bar, not in contact with the opposite other one on the top of the head, extends on frontal, anterior part of parietals, posterior temporals, side of the neck behind the corner of the mouth, then, downwards, reaches (in 55/ 105 specimens; 52.4%) or not (in 50/105; 47.6%) the corresponding ventral (in contrast to Campen-Main’s [1969] statement); lastly, a large conspicuous, arrow or heart-shaped, dark brown nuchal blotch, pointing forward, with two short horizontal branches pointing backwards in between which starts the vertebral stripe. Infralabials, chin and throat uniformly creamish-yellow (ivory), or sometimes infralabials with a few dark brown spots.

The venter is creamish-yellow or light grey (pink or bright coral red in life, cream on ventral tips), with, on most ventral scales, an irregular black subrectangular blotch near one or both tips; lower tail surface as venter, with subrectangular blotches in the anterior half of the tail, uniform posteriorly (white in life). Juvenile specimens are coloured and patterned like adults, with a brighter and better defined pattern. The vertebral stripe is bright yellow.

Hemipenis (in situ). – According to Smith (1943) and our material, the hemipenis is long, forked opposite the 5 th or 6 th SC and reaches SC 14–16. On approximately its proximal third, up to the point of bifurcation, it is covered with calyces and a few folds; the distal parts are smooth, covered with flounces and entirely devoid of spines. However, at the most distal part of each fork originates a very large smooth papilla, included in a membranous sheath; each papilla, of equal length, is free and its anterior end, when adpressed, reaches forward to the proximal part of the hemipenis, well beyond the point of bifurcation anteriorly. From the proximal part, the sulcus spermaticus extends backwards on each papilla up to the end of this organ.

Sexual dimorphism. – Clearly visible in the two following characters: (1) difference in the ratio TaL/TL: males: 0.165 –0.204 (x = 0.184, s = 0.009), females: 0.128 –0.151 (x = 0.139, s = 0.006); and (2) Difference in the number of subcaudals: males: 38–48 (x = 42.7, s = 2.0); females: 31–39 (x = 34.7, s = 1.8).

Distribution. – This species is known from: Thailand. Centre, east and southeast of the country: provinces or region of Ayuthaya (Ayuthaya), Bangkok, Chaiyaphum (Phu Khieo), Chachoengsao (Chachoengsao), Chonburi (Bo Thong), Nakhon Ratchasima (Khorat), Nonthaburi (no locality), Prachinburi (between Kabinburi and Prachinburi), Sa Kaew (near Watthana Nakhon), Saraburi (no locality), Si Sa Ket (Bung Bun), and Ubon Ratchathani (Nong Wa, near Ubon Ratchathani) ( Taylor, 1965 [as O. quadrilineatus ]; Nabhitabhata et al., 2004 [as O. quadrilineatus ]; examined material). – Cambodia. In the South and Centre of the country: provinces of Koh Song (Kirirom), Kompong Chhnang (Trapeang Chan), Phnom Penh, and Siem Reap (Angkor) ( Saint Girons, 1972; examined material); probably throughout the country but precise locality lacking. – Laos. Definitely know only from the south of the country: Champasak Province (Paksé). – Vietnam. Known from throughout the country (see below): provinces or regions of An Giang (Long Xuyen), Bac Kan (Ba Be), Bà Ria-Vung Tàu (Côn Dao), Cao Bàng (Nguyên Bình), District of Hô Chí Minh (Ho Chi Minh City), Dông Nai (Dinh Quan), Hai Duong (Chí Linh), Khánh Hoa (Nha Trang), Lam Dong (Da Lat), Minh Hai (Bac Lieu), Nghê An (Vinh), Ninh Bình (Cúc Phuong), Sóc Trang (Soc Trang), Tây Ninh (Tây Ninh, Xa Mat), Tiên Giang (My Tho), Vinh Long (Tra On), and Vinh Phúc (Tam Dao) (Campden- Main, 1970; Nguyên et al., 2005; examined specimens). This distribution calls for several comments, arranged by countries:

Myanmar. Several specimens of “ Oligodon quadrilineatus ” were recorded by Zug et al. (1998: 113, 117) from Chatthin Wildlife Sanctuary, Sagaing Division, in the centre west of that country. Such a record far west from the known range of O. taeniatus was surprising. O.S.G. Pauwels kindly examined one of these specimens (USNM 520624, from Burma: Sagaing; Kanbalur Township; Chatthin, ca. 2 km WNW of Chatthin Wildlife Sanctuary, San Myaung Camp, 360 ft, 23°34'46''N, 095°44'26''E; the other one, USNM 520625, could not be traced; collection numbers appearing in Zug et al. [1998] were erroneous). Its main characters are: Sex unknown; round pupil; SVL 116 mm; TaL 16 mm; 17-17-15 DSR, smooth, without apical pit; VEN: 159 (no preventrals), slightly angulated; SC: 35; anal divided; SL 8/8, 4+5 entering orbit; 1/1 PreOc, 2/2 PostOc; 1+2 / 1+2 Tem; 9 / 9 IL, 1–5 in contact with anterior chin shields. Body light brown, with indistinct black fasciatures; 3 light stripes (1 vertebral and 2 paravertebral stripes) running from the head to the vent; the vertebral stripe runs on the tail; 6 symmetrical blotches under the head; 2 nuchal collars on sides of the neck; venter pale ivory with dark quadrangular blotches, more numerous on its posterior part; only six blotches beneath the anterior part of the tail.

By all evidence this specimen is referable to Oligodon theobaldi (Günther, 1868) , a striped species (see Boulenger, 1894: Pl. 3) that differs from O. taeniatus by a divided anal scale, 17 MSR, a higher number of ventrals, and a dorsal pattern made of three light stripes. Thus we exclude Oligodon taeniatus from the fauna of Myanmar.

Thailand. Specimens cited by Nabhitabhata et al. (2004) from Pattani and Songkhla, in southern Peninsular Thailand, were initially referred by Taylor (1965) to O. taeniatus sensu Smith (1943) , namely now Oligodon mouhoti (see below). Furthermore, some specimens cited from Nakhon Ratchasima might be referable to Oligodon pseudotaeniatus spec. nov. (see below). Oligodon taeniatus is still unknown from the northern part of Peninsular Thailand.

Laos. We have seen other specimens previously identified as Oligodon taeniatus . They in fact belong either to O. mouhoti or O. deuvei spec. nov. ( Teynié & David, 2007).

Vietnam. We have examined only two specimens from North Vietnam, MHL 42006375 (“ Tonkin ”) and IEBR A.0755 (Field Number LM 24) (Lung Minh, Ba Be, Bac Kan Province). Both are typical specimens of Oligodon taeniatus . We hence assume that all records cited by Nguyên et al. (2005) are based on correctly identified specimens, in spite of the wide gap between populations of northern and southern Vietnam.

China. Yang et al. (1980) mentioned “ Oligodon taeniatus ” from the Chinese province of Yunnan. On this basis, this species was also included by Zhao (2006) in the snake fauna of China. However, this latter author followed Smith (1943) and cited values of 17 and 15 dorsal scale rows. We cannot identify this specimen, which may be referable to Oligodon deuvei .

Biology. – Although this species is widespread, little is known of its biology. This small species is terrestrial and rather secretive. According to Manthey & Grossmann (1997), it remains hidden during the day under stones, pieces of wood and fallen leaves and becomes active at dusk. It feeds on frogs, lizards and their eggs. When aroused, this species raises and curls its tail, showing the red colour of its ventral side (see Manthey & Grossmann, 1997: 372). Oligodon taeniatus is oviparous but very little is known about its reproduction.

Discussion. – Oligodon taeniatus is a well defined species with a constant number of 19 dorsal scale rows. However, we examined four specimens from central eastern Thailand that show several characters of O. taeniatus , especially the dentition and the general pattern, but with only 17 scale rows at midbody as well as other differences. The number of dorsal rows excludes the validity of the specific nomen quadrilineatus for these specimens. They are also different from all other taxa with 17 MSR. As these specimens are clearly identifiable, we refer them to a new species described as: