Oligodon saintgironsi, David, Patrick, Vogel, Gernot & Pauwels, Olivier S. G., 2008

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 : 21-27

publication ID	https://doi.org/ 10.5281/zenodo.274609
DOI	https://doi.org/10.5281/zenodo.5620107
persistent identifier	https://treatment.plazi.org/id/863DBA62-FFF8-FFFA-FF5E-F3ED8295EFE0
treatment provided by	Plazi
scientific name	Oligodon saintgironsi
status	sp. nov.

Treatment

Oligodon saintgironsi spec. nov.

( Figs. 1–10 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 )

Holotype. MNHN 1974.1264 (adult male), from “Arboretum de Trang Bôm”, now Arboretum of Bien Hoa, Dong Nai Province, southern Vietnam. Deposited by Sergeant Poilane, no date but probably collected around 1930–40.

Paratypes. MNHN 1877.0050 (formerly MNHN 5236) (adult male), “ Cambodge ”, Cambodia. Deposited by Mr. Harmand; MNHN 1974.1272 (adult female), “Institut de Recherches agronomiques, Saïgon”, now in Ho Chi Minh City. Deposited by Sergeant Poilane, no date.

Diagnosis. A species of the genus Oligodon cyclurus- group, characterized by (1) very long, deeply forked hemipenes, reaching to at least 28th SC, thin, smooth and not spinose throughout; (2) a long and thick tail in males with a ratio Tal/TL> 0.19; (3) 19–17(18)–15 dorsal scale rows; (4) reductions between 19 and 17 rows occurring between VEN 62 and 84 (x = 77.3); (5) 10–12 maxillary teeth, the last three strongly enlarged; (6) anal plate single; (7) full complement of head scales, including a presubocular in all specimens; (8) 8 supralabials; (9) 2 anterior temporals; and (10) blotched dorsal pattern, with large blotches.

Oligodon saintgironsi spec. nov. can be diagnosed by the combination of 19 dorsal scale rows on the anterior half to third of the body, 17–18 dorsal scale rows at midbody, a long and strong tail in both sexes, very long, deeply forked hemipenes, and a blotched dorsal pattern. It differs from all other species of the Oligodon cyclurus -group by the combination of (1) the length of hemipenes, (2) the relative length of the tail, and (3) in having only 17 or 18 scale rows at midbody vs. 19, 21, and 23 rows in all others. Oligodon saintgironsi spec. nov. differs from O. chinensis which has also 17 MSR by (1) much longer hemipenes (28–29 SC vs. 12–13 SC in O. chinensis ), and the dorsal scale row formula, 19–17(18)– 15 in O. saintgironsi vs. 17–17– 15 in O. chinensis . Additional comparisons with other species of the Oligodon cyclurus -group and of the genus Oligodon appear below in the Discussion.

The specimens do not seem to have been mentioned previously under any name in the literature, although specimens of Oligodon cyclurus with “rarely 17 rows” cited in Campden-Main (1970b: 40) may refer to O. saintgironsi spec. nov. Wagner (1975) had not examined these specimens.

Etymology. This species is named in honour of Dr. Hubert Saint Girons (1926–2000), noted French histologist and herpetologist, formerly in the Centre National de la Recherche Scientifique, in the Paris University and in the Muséum National d’Histoire Naturelle. This name is a genitive based on the author’s last name. Although a specialist of European vipers, H. Saint Girons conducted research in Cambodia (a. o., Saint Girons, 1972) and was the first recent author to recognize the validity of Oligodon ocellatus (Morice, 1875) for Indochinese populations with 19 dorsal scale rows, and the synonymy of O. analepticos with this taxon.

Description of the holotype ( Figs. 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 ). Body robust but elongate; head ovoid, short, thick, barely distinct from the poorly defined neck; snout elongate, long (28.9 % of HL, or 1.8 times as long as diameter of eye); pupil round; tail long, robust, tapering.

Dentition: 12 (9+3) maxillary teeth, the last three being strongly enlarged and blade-shaped. SVL: 435 mm; TaL: 103 mm; TL: 538 mm; HL: 18.90 mm; ratio TaL/TL: 0.191.

Body scalation: DSR: 19–17–15; scales small and all smooth. VEN: 170 (plus 2 preventrals), angulated; SC: 59, all paired; anal plate entire. Scale row reductions as follows:

4+5 ↔ 4 (62) 4+5 ↔ 4 (125)

19 —————— 17 —————— 15

4+5 ↔ 4 (66) 4+5 ↔ 4 (127)

Head scalation: Rostral thick, curved onto upper snout surface, well visible from above, separating internasals by about one half of their length; nasals divided, “butterfly-shaped”, about 1.8 times as long as high, vertically divided, with the posterior part smaller; nostril large, oval, piercing top of middle of nasal; internasals subrectangular, in broad contact, shorter than prefrontals; prefrontals subrectangular, distinctly wider than long; suture between prefrontals 1.7 times longer than the suture between the internasals; 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, subrectangular loreal scales, in contact with nasal; 8/8 supralabials, 1st SL small, 2nd and 3rd in contact with loreal, 4th and 5th entering orbit, 6th and 7th largest; 1/1 preoculars, tall and narrow; 1/1 small presuboculars; 2/2 postoculars; 2 + (1+1)/1 / 2 + (1+1)/1 temporals, anterior ones elongated; 9 / 9 infralabials, first pair in contact, IL 1–4 in contact with anterior chin shields, 2nd small, 5th IL largest.

Coloration and pattern in alcohol: The upper surface is brownish-ochre, darker on the upper part of the back than on the lower, greyish-tan sides, with scales densely dotted with minute dark brown dots; many scales of the sides more or less strongly edged with very dark brown; a pale yellowish-tan vertebral stripe, as wide as the vertebral scale row, extends from the occipital marking up to the tip of the tail; 13 butterfly-shaped vertebral blotches straddling and interrupting the vertebral stripe, maroon and narrowly edged with blackishbrown, about 1–2 scales long on the vertebral line, 2–3 scales long at their longest part on each side, and a total of 7 dorsal scales wide, thus reaching the 5th dorsal scale row on each side at midbody; 3 irregular, oblique faint bands made up 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 under the tip of each dorsal blotch on the 4th DSR. The dorsal surface of the tail is as the upper body surface, with the vertebral stripe and 4 butterfly-shaped dorsal blotches, but without distinct faint bands although many scales are very narrowly edged with black.

The head is dark greyish-brown, slightly darker than body, with numerous minute scattered dark dots; side of the snout lighter; SL 1–3 pale greyish-yellow on lower half, strongly powdered with dark brown on upper part; a conspicuous darker maroon transverse marking on the 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 irregular, oblique and diffuse dark brown streak from posterior temporals to corner of the mouth; a large, conspicuous arrow-shaped cephalic marking, dark maroon, narrowly edged with blackish-brown, apex pointing forward and reaching the middle of the frontal, backwards obliquely across the neck, nearly reaching each tip of the 7th VEN; infralabials, chin and throat uniformly pale yellowish-cream.

Venter pale yellowish-cream, most ventrals with a small brown blotch near both tips, small, dot-shaped or even often absent in the anterior half of body, then progressively larger, subrectangular and more conspicuous in posterior half; tail uniformly yellowish-cream below.

Variation ( Figs. 8–10 View FIGURE 8 View FIGURE 9 View FIGURE 10 ). Major characters of the three available specimens are summarized in Table 1 View TABLE 1 . All other main morphological characters of the paratypes agree with those described for the holotype and are not repeated here. In contrast to the holotype, they have only 10 maxillary teeth (7 + 3 enlarged). Maximal TL: 676 mm (MNHN 1974.1272, female); snout 1.7–1.8 times as long as diameter of eye; frontal 1.2–1.3 times as long as wide. MNHN 1877.0050 has 18 dorsal scale rows at midbody, the first scale row reduction occurring at exactly VEN/2. Full complement of head scales with, in all specimens: 8/8 SL, 1/1 presubocular and 2/2 anterior temporals, followed by 2 or 3 posterior temporals, and 9/9 IL.

The colour and pattern of the paratypes are similar to that of the holotype, but the vertebral stripe is very faint in MNHN 1974.1272, which also has a darker background colour, more reddish-ochre than yellowishochre. The blotches below the lower tips of dorsal blotches are quite variable, reduced to an irregular faint zigzag in MNHN 1877.0050 or producing extensive extensions below the main blotch in MNHN 1974.1272. This latter specimen also has a venter with one row of large, subrectangular blotches on tips of ventrals, making the venter nearly dark posteriorly.

Hemipenes (based on MNHN 1974.1264 and MNHN 1877.0050). —In situ ( Figs. 7 View FIGURE 7 , 10 View FIGURE 10 ), each organ is very long and thin, reaching SC 27 or 28 and bifurcating opposite SC 5. Entirely smooth with large calyces throughout, smaller on the third proximal part, larger and scalloped on the distal part. The sulcus is not prominent but is visible up to the tip of each branch of the organ.

Distribution ( Fig. 11 View FIGURE 11 ). Vietnam. Currently known only from the south of the country: Dong Nai Province: Bien Hoa. District of Ho Chi Minh City. Ho Chi Minh City. Cambodia. No precise locality. Oligodon saintgironsi spec. nov. occurs in sympatry with O. ocellatus . Both species are quite similar in pattern. Because the latter species has been considered valid only quite recently ( Saint Girons, 1972), we provide a summary of its taxonomy and variation.

Number	Sex	Dorsal colour	Dorsal and tail patterns	Ventral pat- tern	SVL (mm)	TaL (mm)	Ratio TaL/TL	VEN	SC	1st red.	DSR
MNHN 1974.1264	ɗ	Ochre-tan	13 + 4 blotches	Uniform	435	103	0.191	170	59	62	19–17–15
MNHN 1877.0050	ɗ	Ochre	10 + 2 blotches	Small spots	425	108	0.203	166	55	83	19–18–15
MNHN 1974.1272	Ψ	Ochre brown	12 + 3 blotches	Uniform	567	109	0.161	184	53	84	19–17–15