Oligodon bivirgatus QIAN, QI, SHI, LU, JENKINS, MO & LI, 2021
Can you confirm these amateur observations of Oligodon bivirgatus?
|Higher Taxa||Colubridae, Colubrinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: Double Striped Kukri Snake|
Chinese: 双线小头蛇 (Shuāng Xiàn Xiǎo Tóu Shé)
|Synonym||Oligodon bivirgatus QIAN, QI, SHI, LU, JENKINS, MO & LI 2021|
Type locality: China, Hainan, Shangxi Nature Reserve (18.834167° N, 110.130833° E), 319 m elevation
|Types||Holotype: SYNU 1907027|
Paratypes: SYNU 1808001
|Diagnosis||Diagnosis: Oligodon bivirgatus sp. nov. can be distinguished from its congeners known to occur in southern China and mainland Southeast Asia by having the following combination of characters: (1) eight maxillary teeth; (2) nasal divided; (3) absence of a loreal; (4) single preocular and two postoculars; (5) seven supralabials, third and fourth touching the orbit, sixth excluded from the lip; (6) seven infralabials, anterior four contacting chin shields; (7) internasals separate from prefrontals; (8) single anterior and two posterior temporals; (9) anal plate divided; (10) 15/15/15 dorsal scale rows; (11) dorsum reddish-brown in life, with two distinct narrow dark stripes, two dorsolateral lines are faintly visible; and (12) ventral surface reddish in life, edge cream with irregular dark blotches. (Qian et al. 2021).|
Comparisons: Oligodon bivirgatus sp. nov. share similar scale patterns with O. ornatus, but differs from the latter by having different dorsal coloration (longitudinal stripes vs. crossbars in O. ornatus), and ventral coloration (wide red band vs. narrow red line in O. ornatus). The dorsal coloration of O. bivirgatus is also similar with O. pseudotaeniatus, but this new species can be distinguished from the latter by having 15/15/15 dorsal scale rows (vs. 17/17/15 in O. pseudotaeniatus), a divided anal plate (vs. entire in O. pseudotaeniatus), absence of a loreal (vs. present in O. pseudotaeniatus), a larger count of 173–176 ventrals (vs. 137–156 in O. pseudotaeniatus), and smaller count of 8 maxillary teeth (vs. 15 in O. pseudotaeniatus).
By having 15/15/15 dorsal scale rows, Oligodon bivirgatus sp. nov. can be distinguished from its congeners occurring in mainland Southeast Asia having different numbers of MSR: O. albocinctus (19), O. annamensis (13), O. barroni (17), O. catenatus (13), O. cattienensis (17), O. chinensis (17), O. cinereus (17), O. condaoensis (17), O. cruentatus (17), O. culaochamensis (17 or 19), O. deuvei (17), O. eberhardti (13), O. fasciolatus (21 or 23), O. formosanus (19 or 17), O. joynsoni (17), O. lipipengi (19), O. macrurus (17), O. mcdougalli (13), O. melanozonatus (17), O. moricei (17), O. mouhoti (17), O. nagao (17 or 15), O. ocellatus (19), O. pallidocinctus (17), O. planiceps (13), O. saintgironsi (17 or 18), and O. taeniatus (19).
By having a divided nasal, Oligodon bivirgatus sp. nov. can be distinguished from its congeners occurring in mainland Southeast Asia having an entire nasal scale: O. catenatus, O. cattienensis, O. eberhardti, O. erythrorhachis, O. hamptoni, O. lacroixi, O. lungshenensis, O. melanozonatus, O. planiceps, and O. torquatus.
By having a divided anal plate, Oligodon bivirgatus sp. nov. can be distinguished from its congeners occurring in mainland Southeast Asia having an entire anal plate: O. albocinctus, O. annamensis, O. barroni, O. cattienensis, O. chinensis, O. cinereus, O. condaoensis, O. culaochamensis, O. deuvei, O. fasciolatus, O. formosanus, O. inornatus, O. joynsoni, O. kampucheaensis, O. lipipengi, O. macrurus, O. moricei, O. mouhoti, O. nagao, O. ocellatus, and O. pallidocinctus.
By the absence of a loreal, Oligodon bivirgatus sp. nov. can be distinguished from its congeners occurring in mainland Southeast Asia having one loreal or two: O. albocinctus, O. barroni, O. cattienensis, O. chinensis, O. cinereus, O. condaoensis, O. cruentatus, O. culaochamensis, O. deuvei, O. dorsalis, O. eberhardti, O. fasciolatus, O. formosanus, O. inornatus, O. jintakunei, O. joynsoni, O. kampucheaensis, O. lipipengi, O. melaneus, O. moricei, O. mouhoti, O. nagao, O. ocellatus, O. pallidocinctus, O. planiceps, O. saintgironsi, and O. torquatus.
By having eight maxillary teeth, Oligodon bivirgatus sp. nov. can be distinguished from its congeners occurred in mainland Southeast Asia having a larger or smaller number of maxillary teeth: O. albocinctus (10–12), O. barroni (10–13), O. chinensis (9–10), O. cinereus (10–12), O. condaoensis (11–13), O. cruentatus (14–16), O. culaochamensis (9–10), O. deuvei (12–15), O. fasciolatus (9–10), O. formosanus (10–11), O. inornatus (10–11), O. joynsoni (11–12), O. kampucheaensis (11), O. lipipengi (11), O. macrurus (13), O. melaneus (7), O. moricei (12), O. mouhoti (14–16), O. nagao (9–10), O. ocellatus (10), O. pallidocinctus (10–12), O. planiceps (10), O. pseudotaeniatus (15), O. rostralis (6), O. saintgironsi (10–12), O. taeniatus (14–17), and O. torquatus (15–16).
By having a dorsal coloration of longitudinal stripes, Oligodon bivirgatus sp. nov. differs from its congeners occurred in mainland Southeast Asia having a dorsal coloration of crossbars or blotches: O. albocinctus, O. annamensis, O. barroni, O. cattienensis, O. chinensis, O. culaochamensis, O. erythrorhachis, O. fasciolatus, O. formosanus, O. jintakunei, O. joynsoni, O. kampucheaensis, O. lipipengi, O. melanozonatus, O. nagao, O. ocellatus, O. pallidocinctus, O. rostralis, and O. saintgironsi. (Qian et al. 2021).
Color in life: Holotype: Dorsal surface of head reddish-brown as dorsum, but paler on snout and rostral. Three pointing forward chevrons on head and neck. Chevrons maroon, somewhat paler maroon in the mesial, edged by darker pigmentation. The first chevron with its apex at the level of the posterior edge of the rostral, covering part of internasals, prefrontals, supraoculars and frontal, and descending through the eye to cover 3rd–5th SL. The apex of the second chevron starts at the middle of head and covers the posterior part of frontal, extending to neck on both sides of the head, through parietals, upper anterior temporals, two posterior temporals, and descending behind the head, covering part of 7th SL and 7th IL. The third chevron, with its anterior tip on the suture of parietals is connected to the second chevron in the middle, forming an arrow, this arrow gradually widens and extends from parietals to the nape. The two edges of this arrow extend to dorsal as two narrow dark stripes, ending at the tip of tail. At the beginning of dorsal stripes, there are small blotches at the lateral of neck, about 3 rows scale rows behind head. The dorsal stripes are about 1/3 scale wide, covering 6th and 10th scale rows; another two dashed lines are faintly visible on the flanks. Ventral surface of head cream with black spots on the anterior portion of 1st, 3rd–6th SL, anterior chin-shields, other small spots at the midline of the gular scales. Belly is coral-red with its edge cream and black blotches irregularly distributed on each side. The blotches are small on the body, at intervals of one or two ventral scales, sometimes continuous, 95 on left and 100 on right. Ventral surface of the tail shows the same pattern as the belly. On the tail, the blotches become denser and no more intervals at the end 10 pairs of subcaudals, 27 on left and 25 on right. Iris bicolored, upper part light yellow, lower part brown, matching the dorsal pattern; pupil round, black with golden edge. (Qian et al. 2021).
Paratype: The tip of the second chevron on head is in the middle of frontal and in contact with first chevron, a gap is formed in back of the middle, but no contact and divided posterior portion in holotype; The third chevron commences at the posterior end of parietals with a blunt tip. The condition of the third chevron in the holotype differs in that it commences at the middle of the parietals and forms a sharp angle. (Qian et al. 2021).
|Etymology||The specific name comes from Latin words "bi-" (double) and "virgatus" (striped), refers to this species has a dorsal color pattern made of two distinct dorsal stripes.|