Oligodon ocellatus (Morice, 1875)

David, Patrick, Vogel, Gernot & Pauwels, Olivier S. G., 2008, A new species of the genus Oligodon Fitzinger, 1826 (Squamata: Colubridae) from southern Vietnam and Cambodia, Zootaxa 1939, pp. 19-37 : 27-33

publication ID	https://doi.org/ 10.5281/zenodo.274609
DOI	https://doi.org/10.5281/zenodo.5620109
persistent identifier	https://treatment.plazi.org/id/863DBA62-FFF2-FFFC-FF5E-F4CE83FFEF4B
treatment provided by	Plazi
scientific name	Oligodon ocellatus (Morice, 1875)
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( Figs. 12–16 View FIGURE 12 View FIGURE 13 View FIGURE 14 View FIGURE 15 View FIGURE 16 )

Simotes brevicauda Steindachner, 1867: 61 View in CoL . Type locality. “ Cochinchina ”. Holotype. NMW 16530 (female). Collected by M. Verreaux, 1865. Status. Name preoccupied in the genus Oligodon by Oligodon brevicauda Günther, 1862 (a valid taxon from India).

Simotes ocellatus Morice, 1875a: 61 View in CoL [ Morice, 1875b: 57]. Type locality. “Tay-ninh, Cochinchine Française ”, now Tay Ninh, Tay Ninh Province, southern Vietnam, 11°18'N 106°06'E. Syntypes. MHL 42000347 (formerly MHL 1571; male), MHL 42000354 (1) (formerly MHL 1569a; male), MHL 42000354 (2) (formerly MHL 1569b; female), MHL 42000359 (formerly MHL 1572; female).

Oligodon analepticos Campden-Main, 1970a: 763 . Replacement name for Simotes brevicauda Steindachner, 1867 . Synonymized with Oligodon ocellatus (Morice, 1875) by Saint Girons (1972: 63).

Taxonomic comments. Morice (1875a: 61; 1875b: 57) described this species in naming it as follows: “ Simotes ocellé, Simotes ocellatus ou plutôt binotatus ” (Ocellated Simotes , Simotes ocellatus or rather binotatus ). This dual name has never been discussed in the literature because the description of Simotes ocellatus remained overlooked until Saint Girons (1972), who did not mention this problem but implicitly selected Simotes ocellatus . Anyway, Simotes binotatus Morice, 1875 is a junior primary homonym of Simotes binotatus Duméril, Bibron & Duméril, 1854 , a subjective junior synonym of Xenodon venustus Jerdon, 1853 , now Oligodon venustus , a valid species of southwestern India.

We have examined the holotype of Simotes brevicauda Steindachner, 1867 (nec Oligodon brevicauda Günther, 1862 ), NMW 16530 ( Figs. 12–14 View FIGURE 12 View FIGURE 13 View FIGURE 14 ) and refer it without ambiguity to Oligodon ocellatus . As a consequence, Oligodon analepticos Campden-Main, 1970 , a replacement name for Simotes brevicauda Steindachner, 1867 , is also considered by us to be a synonym of O. ocellatus (Morice, 1875) . This species has 19 dorsal scale rows at midbody in all known specimens. It was not recognized as a valid taxon, distinct from Oligodon cyclurus , until Campden-Main (1970a). This confusion explains the numerous mentions of Oligodon cyclurus or Oligodon purpurascens (Schlegel, 1837) from Indochina (for example in Bourret, 1936 and Deuve, 1970), both species having 19 dorsal scale rows at midbody. Oligodon cyclurus , as now defined, does not occur east of a line extending from southern Yunnan to Western Thailand, whereas Oligodon purpurascens is unknown north of southern Thailand. A chresonymy is beyond the scope of the present paper but O. cyclurus was mentioned from Vietnam as recently as in Nguyên et al. (2005).

Diagnosis. A species of the genus Oligodon cyclurus- group, characterized by (1) long and deeply forked hemipenes, reaching 15th–17th SC, thin, smooth and not spinose throughout; (2) 19–19–15 (rarely 13) dorsal scale rows; (3) reductions between 19 and 17 rows occurring between VEN 79–107 (mean 90.3); (4) a very short tail, TaL/TL 0.097–0.141; (5) 9–11 maxillary teeth, the last two or three strongly enlarged; (6) anal plate single; (6) head scalation complete, including a presubocular; (7) 8 (rarely 7) supralabials; (9) 2 anterior temporals; and (10) a typically blotched dorsal pattern, with large blotches in most specimens, or sometimes merely a reticulated pattern with very faint blotches.

Variation (based on Wagner [1975] and 24 examined specimens). – Body robust but elongate; head short, thick, barely distinct from the poorly defined neck; snout elongate (24.5–31.5 % of HL, or 1.85–2.0 times as long as diameter of eye); pupil round; tail robust, tapering. Dentition. 9–11 maxillary teeth, the last 2 or 3 strongly enlarged and blade-shaped. Maximal TL 852 mm (SVL 757 mm; TaL 95 mm; MHL 42006419) for a male. The longest known female is 618 mm (SVL 550 mm, TaL 68 mm long; MNHN 1939.0002). Ratio TaL/ TL: 0.097–0.141, with a weak sexual dimorphism (see below).

Body scalation: DSR: 19–19–15(13); scales small, all smooth, ovoid.

Scale row reductions: first reduction (19?17) at VEN 79–107; second reduction (17?15) at VEN 97–115. According to Wagner (1975), a third reduction (15?13), not encountered by us, may occur between VEN 140– 150. VEN: 157–180 (plus 2 preventrals), angulated; SC: 26–44, all paired; anal plate entire. Note: Wagner (1975) mentioned a maximum of 180 ventrals, a value much higher than our counts for 24 specimens; however Stuart et al. (2006) recorded a female from Cambodia with 173 VEN.

Head scalation: Rostral thick, curved onto upper snout surface, well visible from above, separating internasals by about half of their length; nasals subrectangular, about 1.8 times as long as high, vertically divided, with the posterior part distinctly smaller; nostril crescentic, piercing middle of nasal; internasals subrectangular, in broad contact, shorter than prefrontals; prefrontals subrectangular, distinctly wider than long; frontal hexagonal, 1.2 times as long as wide; 1/1 supraoculars, distinctly longer than wide, about as wide as prefrontals; two large, subtriangular parietals, much longer than frontal, in broad contact; 1/1 small, elongate loreal scales, in contact with nasal; 8 (rarely 7 or 9) supralabials, 1st SL small, 2nd and 3rd in contact with loreal, usually 4th and 5th entering orbit, 6th and 7th largest; 1/1 preoculars, tall and narrow; 1/1 small presuboculars; 2/2 postoculars; 2+2 / 2+2 temporals, anterior ones elongated; 8 or 9 infralabials, first pair in contact, IL 1–4 in contact with anterior chin shields, 5th largest.

Coloration and pattern in alcohol. The upper surface is yellow ochre, beige brown, brownish-ochre or dark yellowish brown, with many scales distinctly edged with very dark brown-grey producing usually strong, irregular, dark bands; this pattern is met in 14 of our 26 specimens; in three of them, the dark bands are so strong that they could be considered to be narrow blotches; in the 12 other specimens, the dorsal pattern comprises 11–14 rhomboid vertebral blotches, sometimes constricted in their middle, yellowish-brown, greyishbrown, 3 scales long at their longest part on the vertebral row, and a total of 7 dorsal scale wide; in this second pattern, 3 strong, irregular, oblique bands formed by wider and stronger dark anterior edge of scales between each vertebral blotch, forming a zigzag on the side; on each side, a small, irregular dark brown blotch dark brown below the tip of each dorsal blotch on the 4th and 5th DSR, more or less distinct and large, connected or not to the dorsal blotch. The dorsal surface of the tail is as the upper body surface, with the vertebral stripe and 2–3 dorsal blotches, with or without distinct fasciatures although many scales are very narrowly edged with black.

The head is dark ochre-brown or dark greyish-brown, darker than body, with numerous minute scattered dark dots; side of snout paler; supralabials pale greyish-yellow on lower half, strongly powdered with dark brown on upper part; a more or less distinct, large darker maroon transverse marking on snout, in front of eyes, not reaching internasals, extending downwards and backwards across the eye then downwards, to produce a short, dark, conspicuous oblique streak on SL 5 (top) and SL 6; SL 7–8 pale yellow on lower half, dotted with brown on upper part; an oblique and diffuse dark brown streak from posterior temporals to corner of mouth; a large, conspicuous arrow-shaped cephalic marking, dark maroon, narrowly edged with blackishbrown, the apex pointing forward and reaching the middle of the frontal, backwards oblique across the neck, nearly reaching each tip of the 6th or 7th VEN; infralabials, chin and throat uniformly cream, yellowish-tan or pale yellowish-brown. The venter is pale yellowish-cream or pale yellowish-ochre, usually entirely uniform. Tail uniformly yellowish-cream below.

Hemipenes. In situ, each organ is long and thin, reaching SC 15–17 and bifurcating opposite SC 4 or 5, entirely smooth, proximal third covered with oblique flounces, distal part covered with small calyces, scalloped proximally, smooth distally; sulcus spermaticus reaching the tip of each branch.

Sexual dimorphism. It is weakly present in (1) the ratio TaL/TL (based on our material): males: 0.111– 0.141 (x = 0.124, s = 0.012); females: 0.094–0.122 (x = 0.111, s = 0.008); (2) the number of subcaudals (based on Wagner [1975] and our material): males: 32–44 (x = 35.9, s = 3.6); females: 26–33 (x = 30.2, s = 2.1).

Distribution ( Fig. 11 View FIGURE 11 ). Vietnam. South ( Nguyên et al., 2005; examined specimens): Quang Nam-Danang Province: Chu Lai, Nui Quieu, Phùc Son. Binh Dinh Province: Bông Son (or Hoai Nhon). Lam Dong Province: Bao Loc; Fyan (or Ngoc Son). Phu Yen Province: Tuy Hoa. Dac Lac Province: M’Drak District. Dong Nai Province: near Phuong Lam. Tay Ninh Province: Tay Ninh. Cambodia. Koh Song Province: Kirirom ( Saint Girons, 1972). Ratanakiri Province: Taveng ( Stuart et al., 2006). Laos. Champasak Province: Xépian National Biodiversity Conservation Area ( Teynié et al., 2004).