Oligodon condaoensis Nguyen, Nguyen, Le & Murphy, 2016, sp. nov.
Creators: name: Nguyen, Sang Ngoc
name: Nguyen, Vu Dang Hoang
name: Le, Son Hong
name: Murphy, Robert W.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Colubridae
Oligodon
Oligodon condaoensis

description: Oligodon condaoensis sp. nov.
(Figs. 2 & 3)
Holotype. ITBCZ 2595, adult male, collected from Hon Ba Island, Con Dao District, Ba Ria–Vung Tau Prov., Vietnam; coordinates 8°39’03”N, 106°33’29”E; elevation 15 m a.s.l. by Sang Ngoc Nguyen on 24 October 2015.
Paratypes. ITBCZ 2596, adult male; ITBCZ 2597–8, two adult females; collected around the site of the holotype on Hon Ba Island by Sang Ngoc Nguyen on 24 and 25 October 2015.
Diagnosis. Oligodon condaoensis sp. nov. is distinguished from all of its congeners by a combination of the following morphological characters: (1) medium size in adults (total length up to 552 mm); (2) dorsal scale rows 17–17–15; (3) deeply forked hemipenes without papillae and spines, extending to SC 13 or 14; (4) maxillary teeth 11–13, the posterior three being enlarged; (5) cloacal plate undivided; (6) head scalation complete; (7) nasal divided; (8) presubocular absent; (9) ventrals 168–176; (10) subcaudals 33–37; (11) overall dorsal coloration dark gray, faint body stripes present or absent; (12) venter cream to dark gray without rectangular blotches.
Description of holotype. Adult male; body robust, rather elongate; SVL 461 mm; tail quite short (TL/SVL = 0.15) and robust, 70 mm in length; head short (HL/SVL = 0.04), faintly distinct from neck; eye small (ED/HH = 0.35) with round pupil, eye diameter equal to distance between eye and nostril; snout obtuse; large oval nostril piercing the upper part of nasal.
Head scalation. Rostral high 3.37 mm, wide 3.57 mm, thick and curved on to upper snout surface, well visible from above, pointed posteriorly, touching internasals, nasals, and first supralabial on each side; supralabials 8/8, the 4th and 5th bordering eye, the 7th being largest; 1/1 loreal; presubocular absent; nasal divided vertically; 1/1 preocular; 2/2 postoculars; 1+2/1+2 temporals, anterior one elongated; prefrontal large, somewhat hexagonal, wider than long; frontal large and pentagonal, slightly longer than wide; parietals larger than frontals, bordered laterally by the first and the upper second temporals and posteriorly by four small scales; 8/8 infralabials, fist pair medially in contact with each other, first four InLs in contact with anterior chin shield, the 5th largest and touching posterior chin shield.
Body scalation. Dorsal scales smooth, in 17–17–15 rows; scale row reductions from 17 to 15 around the position corresponding to ventral 98th; vertebral scales similar to other dorsal scales in size and shape; ventrals 172; cloacal plate entire; subcaudals 37, all paired; terminal caudal scale forming a pointed cap.
Dentition. Maxillary teeth 13, curved posteriorly, the posterior three being enlarged (Fig. 2 C); palatine and pterygoid teeth 7 and 14, respectively, slightly curved posteriorly (Fig. 2 D).
Hemipenis. Hemipenis with two enlarged lobes, deeply forked at the level of 6th SC and tip of each organ reaching the SC 13th; proximal part with faint folds forming more or less hexagonal cells, these cells fainter at distal part (Fig. 2 E–G).
Coloration. In life, overall dorsal coloration dark gray, including dorsal, lateral scales, and lateral sides of ventral scales. No distinct stripes or blotches. Head more or less uniform dark gray. Infralabials, lower part of supralabials, and rostral whitish. Underside of head and anterior part of body white to cream. The ventral color of body changes backwardly from cream anteriorly to dark gray dots or blotches and then to dark gray posteriorly, not forming rectangular blotches. Two white stripes along ventral-lateral part of ventral scales. Ventral surface of tail white with some gray dots. Pupil round and black. In alcohol, the pattern paler, becoming gray. Pupil white.
Variation. Table 1 summarizes variation in size and scalation. Head scalation complete but presubocular absent in all specimens. In the three paratypes, brighter longitudinal stripes are faint in life and in alcohol. A narrow grayish vertebral stripe extends from neck to the vent level, the width of this stripe is narrower than the width of the vertebral scale but in the neck the stripe width expanding to about two dorsal scales; paravertebral stripes very faint; a faint but broad, grayish stripe extends up to the vent on dorsal scale rows 4–6. In general, the faint stripe pattern of the new species, if present, is as follows: lateral side of ventral scale and DS 1–3 dark gray or gray; DS 4–6 brighter; DS 7–8 dark gray or gray; and vertebral scale brighter (Fig. 3 C). Paratypes ITBCZ 2597–8 with a dark oblique streak below the eye, on SL 5–6; frontal and parietals with faint blotches. Ventral pattern of paratype ITBCZ 2596 cream to white with few gray dots; paratypes ITBCZ 2597–8 similar to that of the holotype. Hemipenis of the paratype ITBCZ 2596 similar to that of the holotype. The palatine and pterygoid teeth of the paratypes ITBCZ 2596–8 are 6+12, 7+13, and 7+12, respectively. The posterior three maxillary teeth of the paratypes are also enlarged.
Natural history. All specimens were collected in the daytime, between 9:00 am and 12:00 pm. The animals were found active on the ground of evergreen forest (Fig. 3 D) near by Hon Ba Forest Ranger Station. Two nights of searching in the area failed to find the snake. This infers that the new species is diurnal. Another species, O. fasciolatus, was recorded sympatrically with the new species.
Sexual dimorphism. The males are larger (SVL 461–481 mm vs. 395–401 mm) and darker than the females. The faint stripes on females are more visible than on the males. Tails in males are longer than in females (SC 37 vs. 33–34; TL/SVL 0.15 vs. 0.14).
Distribution. The new species is currently known only from Hon Ba Island, Con Dao District, Ba Ria–Vung Tau Prov., Vietnam.
Etymology. The specific epithet condaoensis is derived from Con Dao Islands, where the new species was discovered.
Comparisons. Oligodon condaoensis sp. nov. differs from all other congeners within the Oligodon taeniatus group, the O. cinereus group, the O. cyclurus group (David et al. 2008 a, b; Green et al. 2010; Neang et al. 2012), the O. dorsalis group (Smith 1943, Vassilieva 2015), and the O. torquatus group (Green et al. 2010, Smith 1943, Vassilieva 2015), and other species of the genus in Indochina by the combination of the following characters: body and head scalation, maxillary teeth, hemipenis, body size, and dorsal color pattern.
By having deeply forked hemipenis without obvious papillae, O. condaoensis sp. nov. differs from the O. taeniatus group (David et al. 2008b; Neang et al. 2012), including O. barroni (Smith), O. deuvei David, Vogel & Rooijen, O. moricei David, Vogel & Rooijen, O. mouhoti (Boulenger), O. pseudotaeniatus David, Vogel & Rooijen, and O. taeniatus (Günther), except for O. moricei in which males remain unknown (Table 2). The new species is also distinguishable from O. barroni by having a larger size (TL 552 mm vs. 401 mm), a higher number of ventrals (168–176 vs. 136–160), and different dorsal color pattern (gray or faint stripes vs. butterfly-like blotches on dorsum and tail); from O. deuvei by having a higher number of ventral scales (168–176 vs. 140–155), different body and head color pattern (uniform or faint vertebral stripe vs. broad and bright vertebral stripe, uniform or faint blotches vs. four or five major markings, respectively); from O. moricei by having a lower number of subcaudals (33–34 in females vs. 41), a lower number of infralabials (8 vs. 9), a higher number of maxillary teeth (13 in females vs. 12), and different dorsal color pattern (uniform or faint dorsal stripes vs. broad vertebral stripe, clear paravertebral and dorsolateral stripes); from O. mouhoti by having a bigger size (TL 552 mm vs. 339 mm), a higher number of ventrals (168–176 vs. 145–163), lower number of infralabials (8 vs. 9 or 10) and maxillary teeth (11–13 vs. 14–16), a shorter hemipenis (extending to SC 13–14 vs. 18–19), and the absence of blotches on tail and clear marks on head (vs. presence); from O. pseudotaeniatus by having a bigger size (TL 552 mm vs. 320 mm), a higher number of ventrals (168–176 vs. 137–156), fewer maxillary teeth (11–13 vs. 15), and the absence of presubocular (vs. presence); from O. taeniatus by having a bigger size (TL 552 mm vs. 447 mm), fewer dorsal scale rows at neck and midbody (17–17–15 vs. 19–19–15), more ventrals (168–176 vs. 142–165), fewer infralabials (8 vs. 9), and the absence or faintness of body stripes (vs. presence).
continued.
Oligodon condaoensis sp. nov. differs from members of the O. cinereus group (David et al. 2008a, 2012; Green et al. 2010; Neang et al. 2012; Vassilieva 2015), including O. albocinctus (Cantor), O. cinereus (Günther), O. inornatus (Boulenger), O. joynsoni (Smith), O. maculatus (Taylor), O. melanozonatus Wall, O. nagao David, Nguyen, Nguyen, Jiang, Chen, Teynie & Ziegler, O. splendidus (Günther), and O. woodmasoni (Sclater), by having a deeply forked hemipenis (vs. unforked) except for O. melanozonatus, in which the hemipenis is unknown. The new species also differs from O. albocinctus by dorsal scale rows (17–17–15 vs. 19–17[19]–15[17]), fewer ventrals and subcaudals (168–176 vs. 177–208, 33–37 vs. 40–69, respectively), more supralabials (8 vs. 7), a shorter hemipenis (extending to SC 13–14 vs. 24), dark uniform or faint body stripes (vs. cross-bars); from O. cinereus by having smaller size (TL 552 mm vs. 700 mm) and dorsal color pattern (dark uniform or stripes vs. cross-bars [based on O. cinereus from Con Dao Islands, as also mentioned by Smith 1943: 216–217 as form IV and Campden- Main 1970]); from O. inornatus by dorsal scale rows (17–17–15 vs. 15–15–15); from O. joynsoni by having fewer ventrals and subcaudals (168–176 vs. 186–197, 33–37 vs. 43–50, respectively) and dorsal color pattern (dark uniform or faint stripes vs. blotches and reticulated cross-bars); from O. maculatus by having more ventrals (168–176 vs. 156–164) and different dorsal color pattern (dark uniform or strips vs. dark blotches); from O. melanozonatus by having loreals (vs. absence), an entire cloacal plate (vs. divided), fewer subcaudals (33–37 vs. 42–45), higher numbers of supralabials, infralabials, and maxillary teeth (8, 8, and 11–13 vs. 6, 6, and 8, respectively); from O. nagao by having a smaller size (TL 552 mm vs. 786 mm), fewer ventrals (168–176 vs. 184–193), more maxillary teeth (11–13 vs. 9–10), and dorsal color pattern (dark uniform or stripes vs. blotches); from O. splendidus by having fewer scale rows at midbody (17 vs. 21), different supralabials entering the eye (SL 4–5 vs. 2–3), more infralabials (8 vs. 5), and shorter hemipenis (SC 13–14 vs. 19); from O. woodmasoni by having fewer ventrals (168–176 vs. 180–190) and more supralabials (8 vs. 6).
By having deeply forked hemipenis without spines, O. condaoensis sp. nov. is similar to members of the O. cyclurus group (David et al. 2008a, Green et al. 2010, Neang et al. 2012, Smith 1943, Vassilieva 2015), which includes O. cattienensis Vassilieva, Geissler, Galoyan, Poyarkov, Van Devender & Böhme, O. chinensis (Günther), O. cyclurus (Cantor), O. fasciolatus (Günther), O. formosanus (Günther). O. juglandifer (Wall), O. kampucheaensis Neang, Grismer & Dattry, O. kheriensis Acharji & Ray, O. macrurus (Angel), O. ocellatus (Morice), and O. saintgironsi David, Vogel & Pauwels. However, the new species can be distinguished from the following species by having 17 dorsal scale rows at midbody: O. cyclurus (19), O. fasciolatus (21), O. formosanus (19), O. juglandifer (19), O. kampucheaensis (15), O. khariensis (19), and O. ocellatus (19). It also differs from O. cyclurus by having smaller size (TL 552 mm vs. 710 mm), fewer dorsal scale rows on its neck (17 vs. 19), more maxillary teeth (11–13 vs. 9–10), arrangement of temporals (1+2 vs. 2+2), and dorsal color pattern (dark uniform or stripes vs. reticulate or narrow blotches); from O. fasciolatus by having smaller size (552 mm vs. 807 mm); fewer dorsal scale rows on the neck (17 vs. 21 or 23) and before the vent (15 vs. 17), more maxillary teeth (11–13 vs. 8–10), arrangement of temporals (1+2 vs. 2+2), and dorsal color pattern (dark uniform or stripes vs. reticulate or large blotches); from O. formosanus by having a smaller size (552 mm vs. 942 mm), fewer dorsal scale rows on the neck (17 vs. 19), fewer subcaudals (33–37 vs. 43–55) and infralabials (8 vs. 9), dorsal color pattern (dark uniform or stripes vs. reticulate) and hemipenis shape (no papillae vs. short papillae); from O. juglandifer by having fewer dorsal scale rows on the neck (17 vs. 19), fewer subcaudals (33–37 vs. 53–68), more supralabials (8 vs. 7), and dorsal color pattern (dark uniform or stripes vs. dark dots and cross-bars); from O. kampucheaensis by having more dorsal scale rows on the neck (17 vs. 15), fewer subcaudals (33–37 vs. 39), and dorsal color pattern (dark uniform or stripes vs. cross-bars); from O. khariensis by having fewer dorsal scale rows on the neck (17 vs. 19), fewer ventrals (168–176 vs. 196), and more maxillary teeth (11–13 vs. 8); and from O. ocellatus by having smaller size (552 mm vs. 852 mm), fewer dorsal scale rows on the neck (17 vs. 19), fewer infralabials (8 vs. 9 or 10), arrangement of temporals (1+2 vs. 2+2), and dorsal color pattern (dark uniform or stripes vs. reticulate or large blotches). Oligodon condaoensis sp. nov. differs from O. cattienensis by having more maxillary teeth (11–13 vs. 8–10), nasal (divided vs. entire), and dorsal color pattern (dark uniform or faint stripes vs. large blotches); from O. chinensis by having a smaller size (552 mm vs. 729 mm), more maxillary teeth (11–13 vs. 9–10), fewer subcaudals (33–37 vs. 47–64), and dorsal color pattern (dark uniform or faint stripes vs. black cross-bars); from O. macrurus by having more ventrals (168–176 vs. 143–152), fewer subcaudals (33–37 vs. 76–83), and much shorter hemipenis (SC 13–14 vs. 29); and from O. saintgoronsi by having a smaller size (552 mm vs. 676 mm), fewer dorsal scale rows on the neck (17 vs. 19), fewer subcaudals (33–37 vs. 53–59), much shorter hemipenis (SC 13–14 vs. 27–28), and dorsal color pattern (dark uniform or faint stripes vs. reticulate or large blotches). Table 3 compares the new species and other members of the O. cyclurus group.
For members of the O. dorsalis group (Smith 1943, Vassilieva 2015), which includes O. catenatus (Blyth), O. dorsalis (Gray & Hardwicke), O. eberhardti Pellegrin, O. erythrogaster Boulenger, O. hamptoni Boulenger, O. lacroixi Angel & Bourret, and O. macdougalli Wall, O condaoensis sp. nov. differs from O. catenatus, O. dorsalis, O. eberhardti, O. erythrogaster, and O. hamptoni, by having deeply a forked hemipenis (vs. unforked or slightly forked) and an entire cloacal plate (vs. divided). It also differs from O. catenatus by having more dorsal scale rows at midbody (17 vs. 13), more maxillary teeth (11–13 vs. 7), and fewer ventrals (168–176 vs. 186–208); from O. dorsalis by having more dorsal scale rows at midbody (17 vs. 15) and more maxillary teeth (11–13 vs. 6–7); from O. eberhardti by having more dorsal scale rows (17–17–15 vs. 13–13–13), more supralabials (8 vs. 6), and fewer ventrals (168–176 vs. 189–190); from O. erythrogaster by having more maxillary teeth (11–13 vs. 7–8) and fewer subcaudals (33–37 vs. 42–59); and from O. hamptoni by having more scale rows at midbody (17 vs. 15), and more maxillary teeth (11–13 vs. 7) and more subralabials (8 vs. 5). The new species differs from O. lacroixi by having an entire cloacal plate (vs. divided), more scale rows at midbody (17 vs. 15), more supralabials (8 vs. 5), the presence of two internasals (vs. absent) and loreals (vs. absent); and from O. macdougalli by having an entire cloacal plate (vs. divided), the presence of loreals (vs. absent), more dorsal scale rows at midbody (17 vs. 13), fewer ventrals (168–176 vs. 200), and more supralabials (8 vs. 7).
Oligodon condaoensis sp. nov. differs from members of the O. torquatus group (Green et al. 2010, Smith 1943, Vassilieva 2015), which includes O. cruentatus (Günther), O. planiceps (Boulenger), O. theobaldi (Günther), and O. torquatus (Boulenger), by having a deeply forked hemipenis (vs. unforked) without papillae (vs. presence) and an entire cloacal plate (vs. divided). It also differs from O. cruentatus by lacking spines on hemipenis (vs. presence) and having fewer maxillary teeth (11–13 vs. 14–16); from O. planiceps by lacking spines on hemipenis (vs. presence), more dorsal scale rows at midbody (17 vs. 13), more ventrals (168–176 vs. 132–145), more subcaudals (33–37 vs. 22–27), and more supralabials (8 vs. 4 or 5); from O. theobaldi by lacking spines on hemipenis (vs. presence) and having fewer maxillary teeth (11–13 vs. 15–16); and from O. torquatus by having more dorsal scale rows at midbody (17 vs. 15) and more ventrals (168–176 vs. 144–159), and fewer maxillary teeth (11–13 vs. 15–16).
Oligodon condaoensis sp. nov. differs from other congeners in Indochina (Vietnam, Laos, Cambodia, Thailand, Myanmar, Malaysian Peninsular, and southern China [Yunnan]) as follows: from O. annamensis Leviton by having more dorsal scale rows (17–17–15 vs. 13–13–13), more supralabials (8 vs. 6), more infralabials (8 vs. 6), and more maxillary teeth (11–13 vs. 8), and by dorsal color pattern (dark uniform or faint stripes vs. cross-bars); from O. arenarius Vassilieva by having deeply forked hemipenis (vs. unforked), a larger size (552 mm vs. 389 mm), more maxillary teeth (11–13 vs. 6–8), and more ventrals (168–176 vs. 131–144); from O. booliati Leong & Grismer by having more supralabials (8 vs. 6 or 7), more ventrals (168–176 vs. 143–153), fewer subcaudals (33–37 vs. 54–60), and different dorsal color pattern (dark uniform or faint stripes vs. cross-bars); from O. jintakunei Pauwels, Wallach, David & Chanhome by having more dorsal scale rows at midbody (17 vs. 15), fewer ventrals (168–176 vs. 189), entire cloacal plate (vs. divided), and dorsal pattern (dark uniform or faint stripes vs. cross-bars) (see from Vassilieva 2015); from O. octolineatus (Schneider) by having a smaller size (552 mm vs. 780 mm), more supralabials (8 vs. 6), the 4th and 5th supralabials entering the eye (vs. SL 3rd and 4th), fewer subcaudals (33–37 vs. 43–61), and different dorsal color pattern (dark uniform or faint stripes vs. clear and broad stripes); from O. purpurascens (Schlegel) by lacking of presubocular (vs. 1–2 presuboculars), having fewer dorsal scale rows at midbody (17 vs. 19 or 21) and fewer subcaudals (33–37 vs. 40–60), fewer temporals (1+2 vs. 2+3 or 2+2), a smaller size (TL 552 mm vs. 790 mm), and different dorsal color pattern (dark uniform or faint stripes vs. crossbars); and from O. vertebralis Günther by having more supralabials (8 vs. 7) and the SL 4th and 5th entering the eye (vs. SL 3rd and 4th), more dorsal scale rows at midbody (17 vs. 15), and an entire cloacal plate (vs. divided).
description: Published as part of Nguyen, Sang Ngoc, Nguyen, Vu Dang Hoang, Le, Son Hong & Murphy, Robert W., 2016, A new species of kukri snake (Squamata: Colubridae: Oligodon Fitzinger, 1826) from Con Dao Islands, southern Vietnam, pp. 261-273 in Zootaxa 4139 (2) on pages 263-270, DOI: 10.11646/zootaxa.4139.2.9, http://zenodo.org/record/256798