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| Rhabdophis chiwen Chen, Ding, Chen et Piao in Piao, Chen, Wu, ... et Ding, 2020 Chiwen Keelback | “螭吻颈槽蛇” || Photos: Shengchao Shi. |
Abstract
The genus Rhabdophis is a group of widely distributed snakes with more than 20 species. Recent field surveys uncovered a species in southwestern China, which has long been considered as R. pentasupralabialis. Combined molecular and morphological analyses revealed it as a new species Rhabdophis chiwen sp. nov. Based on 12 specimens, this new species is distinguished by the following characters: 1) dorsal body saddlebrown, dorsal scales typically with black margins forming spots and stripes, the margin of the outer row forming two faint dorsolateral black cross-bars alongside body; 2) ventral scales 151–159, the outer margin of ventral scales and several lateral rows of dorsal scales forming ventrolateral longitudinal brownish-red coloration, with faint black spots in the middle of ventral scales; 3) a black oblique stripe present below eyes, often with a black spot between the 2nd and 3rd supralabial and a black stripe on the 5th supralabial; 4) eyes dark khaki, pupils black; 5) infralabials usually 7, the first four in contact with anterior chin-shields; 6) temporal scales 1+1; 7) dorsal scales in 15 rows, feebly keeled except the outer 1–2 rows; 8) anal scale divided; subcaudals 45–59; 9) preocular 1 and postoculars 3 (occasionally 2); 10) body medium-sized (snout-vent length: adult males 404–431 mm, adult females 409–476 mm); 11) tail moderate (tail length/ total length in adult males 0.205–0.238, in adult females 0.172–0.193). With the discovery of this new species, the total number of species in genus Rhabdophis is 28 with 12th species known to occur in China.
Key words: Rhabdophis chiwen sp.nov.; morphology; Natricinae; phylogenetics; taxonomy
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| Figure 2: Dorsal (A) and ventral (B) view of the holotype of Rhabdophis chiwen sp. nov. (CIB116092). Photo by Shengchao Shi. |
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| Figure 3: The holotype of Rhabdophis chiwen sp. nov. (CIB116092) in life. A-E: Different views of head. C and E: showing the same 5 supralabials as R. pentasupralabialis. D: ventral view of head, displaying the representative 7 infralabials. F: Lateral view of trunk, demonstrating several smooth outer rows. Photo by Shengchao Shi. |
Rhabdophis chiwen sp. nov. Chen, Ding, Chen and Piao
Rhabdophis nuchalis pentasupralabialis: Jiang and Zhao, 1983 pp.
59–62;
Rhabdophis pentasupralabialis: Zhao, 1998, pp. 271–274; Zhao, 2006,
pp.268–269; Takeuchi et al., 2018, Figure 2 and 3, p. 10226 (part).
Diagnosis: 1) nuchal groove present, with enlarged and paired
scales on each side; 2) Dorsal body saddlebrown, DSR in 15
rows throughout, feebly keeled, the outer 1–2 rows smooth; 3)
dorsal scales typically with black margins forming some spots
and stripes, the margin of the outer row forming two faint
dorsolateral black cross-bars alongside body; 4) a black oblique
stripe below the eye, often with a black spot between the 2nd
and 3rd SL and a black stripe (or separated as black spots) on the
5th SL and the 1st TEM; 5) Eyes dark khaki, pupils black; 6) SL
5, the 3rd and 4th touching the eye: 7) usually 7 ILs (occasionally
6 or 8), the first four contact with anterior chin-shields; 8) 1 LR,
and TEM 1+1; 9) VEN 151-159, the outer margin of ventral scales
and several lateral rows of dorsal scales forming ventrolateral
longitudinal brownish-red coloration, with faint black spots in the middle of each ventral scale and between scales which line a
black stripe; 10) anal divided; SC 45–59; 11) PRO 1 (rarely 2) and
PTO usually 3 (occasionally 2); 12) medium-sized body (SVL of
adult males: 404–431 mm and adult females: 409–476 mm); 13)
tail moderate and longer in males than in females (adult males:
104-131 mm, adult females: 91–107 mm).
Etymology. The species name of the new species “chiwen” is in
reference to the ninth son of Loong in ancient Chinese myth
who likes eating fire, and indicates the firefly-eating habit
of this new species (Yoshida et al., 2020). Its common name is
suggested as “Chiwen Keelback” in English and “ 螭吻颈槽蛇 ”
in Chinese.
Yige Piao, Zening Chen, Yanqing Wu, ShengChao Shi, Hirohiko Takeuchi, Teppei Jono, Masaya Fukuda, Akira Mori, Yezhong Tang, Qin Chen and Li Ding. 2020. A New Species of the Genus Rhabdophis Fitzinger, 1843 (Squamata Colubridae) in Southwestern Sichuan, China. Asian Herpetological Research. 11(2); 95-107. DOI: 10.16373/j.cnki.ahr.190068
Yoshida et al., 2020. Dramatic dietary shift maintains sequestered toxins in chemically defended snakes. Proc Nat Acad Sci. 117(11): 5964–5969.
Researchgate.net/publication/339474943_Dramatic_dietary_shift_maintains_sequestered_toxins_in_chemically_defended_snakes
Researchgate.net/publication/339474943_Dramatic_dietary_shift_maintains_sequestered_toxins_in_chemically_defended_snakes
