Research Article |
Corresponding author: Jing-Song Shi ( shijingsong@ivpp.ac.cn ) Corresponding author: Ying-Yong Wang ( wangyy@mail.sysu.edu.cn ) Academic editor: Robert Jadin
© 2021 Shuo Qi, Jing-Song Shi, Yan-Bo Ma, Yi-Fei Gao, Shu-Hai Bu, L. Lee Grismer, Pi-Peng Li, Ying-Yong Wang.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Qi S, Shi J-S, Ma Y-B, Gao Y-F, Bu S-H, Grismer LL, Li P-P, Wang Y-Y (2021) A sheep in wolf's clothing: Elaphe xiphodonta sp. nov. (Squamata, Colubridae) and its possible mimicry to Protobothrops jerdonii. ZooKeys 1048: 23-47. https://doi.org/10.3897/zookeys.1048.65650
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Based on combined morphological and osteological characters and molecular phylogenetics, we describe a new species of the genus Elaphe that was discovered from the south slope of the Qinling Mountains, Shaanxi, China, namely Elaphe xiphodonta sp. nov. It is distinguished from the other congeners by a combination of the following characters: dorsal scales in 21-21-17 rows, the medial 11 rows keeled; 202–204 ventral scales, 67–68 subcaudals; two preoculars (including one subpreocular); two postoculars; two anterior temporals, three posterior temporals; reduced numbers of maxillary teeth (9+2) and dentary teeth (12); sharp cutting edges on the posterior or posterolateral surface of the rear maxillary teeth and dentary teeth; dorsal head yellow, three distinct markings on the head and neck; a distinct black labial spot present in supralabials; dorsum yellow, 46–49 complete (or incomplete) large black-edged reddish brown blotches on the body and 12–19 on the tail, two rows of smaller blotches on each ventrolateral side; ventral scales yellow with mottled irregular black blotches, a few irregular small red spots dispersed on the middle of the ventral. Based on molecular phylogenetic analyses, the new species forms the sister taxon to E. zoigeensis. The discovery of this new species increases the number of the recognized species in the genus Elaphe to 17.
Colubrid, morphology, osteology, Qinling Mountains, taxonomy
The colubrid genus Elaphe sensu lato Fitzinger (in Wagler), 1833, once contained approximately forty species ranging throughout temperate, subtropical, and tropical zones in both the eastern and western hemispheres (
The main part of Qinling Mountains, lies on the south of Shaanxi Province, having an average elevation of approximately 2000 m and have long been regarded as the geographical, biological and climatological boundary between North (Palaearctic Realm; warm temperate monsoon climate) and South China (Oriental Realm; subtropical monsoon climate,
During our recent herpetological surveys in the south slope of the Qinling Mountains, Shaanxi, China, two colubrid specimens were collected, which look quite different to any of the known species but similar to Protobothrops jerdonii (Figs
Morphological examinations were performed on two specimens collected from Chengguan Town, Ningshaan County, Shaanxi Province, China (Fig.
Comparison between Elaphe xiphodonta sp. nov. and sympatric Protobothrops jerdonii in different age stages A adult Elaphe xiphodonta sp. nov. (SYS r002534, holotype) B adult Protobothrops jerdonii C juvenile E. xiphodonta sp. nov. (IVPP OV 2721, paratype), road-killed specimen D juvenile P. jerdonii specimen in preservative. The black arrow points to the labial spot. Photos A, B, D by Shuo Qi, photo C by Liang Sun.
Morphological descriptions follow
Scalation features and their abbreviations are as follows: DSR dorsal scale rows, counted at one head length behind head, at midbody, and at one head length before vent; SPL supralabials; IFL infralabials; CS chin shields; PrO preoculars; PtO postoculars; LoR loreal; aTMP anterior temporals; pTMP posterior temporals; PrV preventral scales; V ventral scales; PrC precloacal plate; SC and subcaudals. Gender was determined by dissection or by the presence/absence of everted hemipenes. The numbers of maxillary teeth (MT) were counted based on the three-dimensional reconstructed model.
Other morphological characters (e.g., coloration, scalation, and size) for Elaphe taxonomy were obtained from
The following abbreviations for museum collections are used throughout the paper:
BFU Beijing Forest University;
BM British Museum;
CAS Chinese Academic of Sciences;
IVPP Institute of Vertebrate Paleontology and Paleoanthropology;
SYS Sun Yat-sen University.
The X-ray scanning was carried out with Nano-computerized tomography. Specimens were scanned using a GE v|tome|x m dual tube 300/180kV system in the Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences. The specimen was scanned with an energy beam of 80 kV and a flux of 80*μA using a 360° rotation and then reconstructed into the 4096*4096 matrix of 1536 slices. The final CT reconstructed skull images were exported with a minimum resolution of 6.099 μm. The skull images were exported from the virtual 3D model which was reconstruct by Volume Graphics Studio 3.0.
The dataset of the 3D model included in this study is available online in the repository (ADMorph,
For the molecular analyses, two tissue samples of the new species were included, which were taken prior to fixation, preserved in 99% alcohol, and stored at -40 °C.
Genomic DNA was extracted from muscle or liver tissue samples, using a DNA extraction kit from Tiangen Bio-tech (Beijing) Co., Ltd. Partial segments of the mitochondrial genes, 16S ribosomal RNA gene (16S), cytochrome C oxidase 1 gene (CO1) and Cytochrome b gene (cytb) were amplified. Nested PCR experiments were performed as described in
Gene | Primer name | Assay | Sequence |
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16S | 12S-16S_Phe_F1 | 1st PCR | AAGCDYDGCRCTGAAAATGC |
12S-16S_ND1_R1 | AANGCNACNGCDATNAR | ||
S12S902L2 | 2nd PCR | YACACACCGCCCGTCA | |
S16S2984H2 | GACCTGGATTDCTCCGGTCTGAACTC | ||
COI | COI_Asn_F1 | 1st PCR | GDTTRGRYKDYTARYTGTTAAYTA |
COI_Asp_R1 | GTDATTYRRYYDYGACA | ||
COI_25_F2 | 2nd PCR | TCRACHAAYCAYAAAGAYATYGG | |
COI_706_R2 | TADACTTCWGGRTGDCCRAARAATCA | ||
cytb | Scytb15025F | 1st PCR | TGGTGGAAYTTYGGNWSNATGYT |
Scytb15726R | TANGCRAANARRAARTACCAYTC | ||
Scytb15082F | 2nd PCR | TTYTTYYTRGCNRTHCAYTAYAC | |
Scytb15692R | GCYTTDVWRAARTTKTCNGGRTC |
Fifty-nine sequences from 16 known Elaphe species plus six outgroup sequences from Euprepiophis mandarinus (Cantor, 1842) used to root the tree, were obtained from GenBank, and composed the dataset (Table
Localities, specimen vouchers and GenBank accession numbers of the specimens included in this study.
No. | Species name | Locality | Specimen voucher | Genbank accession number | References | ||
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16S rRNA | CO1 | Cytb | |||||
1 | Elaphe xiphodonta sp. nov. | Ningshaan, Shaanxi, China | SYS r002534 | MZ242100 | MZ19164 | MZ19166 | This study |
2 | Ningshaan, Shaanxi, China | IVPP OV 2721 | MZ242101 | MZ19165 | MZ19167 | This study | |
3 | Elaphe anomala | Huangshan, Anhui, China | HS11075 | MK193929 | MK064632 | MK201281 |
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4 | Elaphe bimaculata | Huangshan, Anhui, China | HS15168 | MK193931 | MK064634 | MK201283 |
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5 | Elaphe cantoris | Pailong, Tibet, China | JK201705 | MK194263 | MK064913 | MK201564 |
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6 | Elaphe carinata | Guangze, Fujian, China | HS13055 | MK193932 | MK064635 | MK201284 |
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7 | Longyou, Zhejiang, China | HS13062 | MK193934 | MK064637 | MK201286 |
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8 | Elaphe climacophora | Abashiri, Hokkaido, Japan | KUZ R64481 | N/A | LC328423 | LC327534 |
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9 | Deshikutsu, Hokkaido, Japan | KUZ R68813 | N/A | LC328426 | LC327537 |
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10 | Elaphe davidi | Taishan Mt., Shandong, China | N/A | KM401547 | KM401547 | KM401547 | Xu et al. 2015 |
11 | Elaphe dione | Taibai, Shaanxi, China | HS11036 | MK193928 | MK064631 | MK201280 |
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12 | Elaphe hodgsonii | Jilong, Tibet, China | HS13004 | MK193983 | MK064680 | MK201335 |
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13 | Elaphe moellendorffi | Yunlin, Guangxi, China | S-113 | N/A | KF698944 | KF913314 | Cao et al. 2014 |
14 | Elaphe quadrivirgata | N/A | N/A | AB738958 | AB738958 | AB738958 | Direct Submission |
15 | Ashiu, Kyoto, Kansai, Japan | As1352 | N/A | N/A | HQ122007 | Kuriyama et al. 2010 | |
16 | Elaphe quatuorlineata | Crkvino, Northern Macedonia | 1509 | MK334307 | MK334307 | MK334307 |
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17 | Galatas, Argolida, Greece | ZMUP 60 | N/A | N/A | MH444348 |
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18 | Elaphe sauromates | Taganrogskyi Gulf, Russia | ZISP 26197 | N/A | MK640250 | N/A |
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19 | Solenoe Ozero, “Crimea” | 1179 | MK070315 | MK070315 | MK070315 |
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20 | Elaphe schrenckii | Changbai, Jilin, China | HS16031 | MK193935 | MK064638 | MK201287 |
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21 | Elaphe taeniura | Zhouzhi, Shaanxi, China | HS2010025 | MK193982 | MK064679 | MK201334 |
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22 | Heishiding, Guangdong, China | SYS r001057 | MK194113 | MK064790 | MK201445 |
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23 | Elaphe urartica | Kısıklı, Süphan Mts., Bitlis, Turkey | ZDEU 26/2012 | N/A | MK640299 | N/A |
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24 | Guzdak, Qobustan, Azerbaijan | IZANAS T17 | N/A | MK640269 | N/A |
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25 | Elaphe zoigeensis | Zoige, Sichuan, China | HS11251 | MK193927 | MK064630 | MK201279 |
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26 | Zoige, Sichuan, China | HS2010015 | MK193930 | MK064633 | MK201282 |
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27 | Euprepiophis mandarinus | HuangShan, Anhui, China | HS12062 | MK193939 | MK064643 | MK201291 |
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28 | HuangShan, Anhui, China | HS14017 | MK193940 | MK064644 | MK201292 |
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DNA nucleotide sequences were aligned in the ClustalW algorithm with default parameters (
Holotype. SYS r002534, adult female (Figs
Etymology. The specific epithet “xiphodonta” of the new species comes from the Ancient Greek “ξίφοσ (ksίfos, refer to ‘knife’ or ‘blade’)” and “δοντι (dónti, refer to ‘tooth’)”, meaning “blade-shaped teeth”, indicating that the new species has unique blade-shaped MT and DT (Figs
Palatomaxillary apparatus and mandibles of Elaphe xiphodonta sp. nov. (IVPP OV 2721, paratype). Implemented by Peng-Fei Yin, Ye-Mao Hou and Jing-Song Shi A ventral (A1) and dorsal (A2) view of left palatomaxillary apparatus B posterolateral view of left maxilla (B1) and right dentary (B2), with cutting edges (ce) and caudolateral ridges indicated C labial (C1, right), ventrolateral (C2, left), ventral (C3, right, mirrored) and dorsal (C4, left) view of maxilla D Labial (D1) and lingual (D2) view of right dentary E labial (E1), lingual (E2), ventral (E3) and dorsal (E4) view of right mandible. Abbreviations: an. angular, at. atlas, ax. axis, bo. basioccipital, bs. basisphenoid, bt. blade teeth (“xiphodont”), ce. Posterior cutting edge of the blade teeth, chp. choanal process of palatine, clr. caudolateral ridge of the teeth, cp. compound bone, d. dentary, dpd. dorsal process of dentary, ecp. ectopterygoid, epm. ectopterygoid process of maxilla, etp. empty tooth position, exo. exoccipital, f. frontal, f5b. foramen for maxillary branch of trigeminal, f5c. foramen for mandibular branch of trigeminal, lf. lacrimal foramen, lfe. lateral furcula of ectopterygoid, m. maxilla, na. nasal, mfe. mesial furcula of ectopterygoid, mp. maxillary process of palatine, nf, nutrient foramen, p. parietal, pcr. prearticular crest of compound bone, pfr. prefrontal, pmx. premaxilla, po. postorbital, pp. palatine process of maxilla, pro. prootic, psp. parasphenoid rostrum, pt. pterygoid, pVf. posterior Vidian foramen, rpt. replacement teeth, sac. surangular crest of compound bone, smx, septomaxilla, so. supraoccipital, sp. splenial, st. supratemporal, v. vomer, vpd. ventral process of dentary, fs. fracture surface.
Elaphe xiphodonta sp. nov. can be differentiated from its congeners by the combination of the following morphological characters: (1) medium body size , SVL 785 mm in single adult female; (2) dorsal scales in 21-21-17 rows, the medial 11 rows keeled; (3) supralabials seven or eight, third/fourth (right) or fourth/fifth (left) in contact with eye, infralabials 9 or 10; (4) ventral scales 202–204; (5) subcaudals 67–68; (6) loreal single, not in contact with eye, not in contact with internasals; (7) two preoculars (including one subpreocular), two postoculars; (8) two anterior temporals, three posterior temporals; (9) precloacal plate divided; (10) reduced teeth number in maxilla and dentary bones (MT 9+2, DT 12; (11) sharp edges on the posterior or posterolateral surface of the rear MT and DT; (12) top of head yellow, three distinct markings on head and neck; (13) a distinct black labial spot present on supralabials; (14) ground color of dorsum yellow, 46–49 entire (or incomplete) reddish brown blotches with black edges on body and 12–19 similarly colored spots on tail; (15) ventral surface of body yellow with mottled irregular black blotches, a few irregular small red spots dispersed on middle of ventral scales.
Adult female (Figs
Uncorrected P-distance of CO1 gene among 17 Elaphe species used in this study.
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Elaphe xiphodonta sp. nov. | 0.0 | ||||||||||||||||
2 | E. anomala | 12.2 | / | |||||||||||||||
3 | E. bimaculata | 16.4 | 12.9 | / | ||||||||||||||
4 | E. cantoris | 14.2 | 17.9 | 18.4 | / | |||||||||||||
5 | E. carinata | 13.9 | 11.3 | 13.4 | 17.9 | 0.3 | ||||||||||||
6 | E. climacophora | 15.7 | 16.0 | 15.7 | 19.1 | 14.4 | 0.0 | |||||||||||
7 | E. davidi | 14.4 | 12.2 | 11.5 | 19.5 | 13.5 | 13.5 | / | ||||||||||
8 | E. dione | 15.3 | 16.0 | 10.9 | 18.2 | 14.3 | 13.9 | 14.2 | / | |||||||||
9 | E. hodgsonii | 13.8 | 17.1 | 16.7 | 13.7 | 16.2 | 17.3 | 14.8 | 16.4 | / | ||||||||
10 | E. moellendorffi | 14.6 | 16.4 | 17.1 | 13.7 | 16.6 | 16.1 | 17.4 | 16.8 | 12.2 | / | |||||||
11 | E. quadrivirgata | 10.7 | 8.7 | 12.5 | 17.9 | 8.5 | 14.9 | 11.4 | 12.6 | 13.4 | 16.6 | / | ||||||
12 | E. quatuorlineata | 17.1 | 14.1 | 12.5 | 18.4 | 13.8 | 17.9 | 12.5 | 13.6 | 16.1 | 15.8 | 12.5 | / | |||||
13 | E. sauromates | 15.5 | 13.9 | 14.1 | 19.1 | 15.5 | 14.7 | 14.5 | 13.4 | 17.3 | 16.6 | 15.6 | 8.5 | 0.3 | ||||
14 | E. schrenckii | 12.2 | 0.0 | 12.9 | 17.9 | 11.3 | 16.0 | 12.2 | 16.0 | 17.1 | 16.4 | 8.7 | 14.1 | 13.9 | / | |||
15 | E. taeniura | 15.2 | 16.3 | 16.7 | 16.0 | 16.0 | 15.5 | 15.6 | 15.3 | 13.2 | 16.2 | 13.8 | 14.7 | 16.1 | 16.3 | 6.8 | ||
16 | E. urartica | 14.1 | 14.0 | 13.9 | 16.8 | 12.7 | 13.7 | 13.3 | 11.8 | 15.2 | 15.6 | 12.5 | 9.4 | 8.9 | 14.0 | 16.5 | 0.0 | |
17 | E. zoigeensis | 8.4 | 13.3 | 14.9 | 16.9 | 15.0 | 16.4 | 13.3 | 15.5 | 13.5 | 14.6 | 12.3 | 16.0 | 14.2 | 13.3 | 16.3 | 14.0 | 0.0 |
Uncorrected P-distance of cytb gene among 16 Elaphe species used in this study.
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Elaphe xiphodonta sp. nov. | 0.0 | |||||||||||||||
2 | E. anomala | 17.1 | / | ||||||||||||||
3 | E. bimaculata | 13.7 | 17.0 | / | |||||||||||||
4 | E. cantoris | 17.2 | 16.6 | 18.2 | / | ||||||||||||
5 | E. carinata | 18.7 | 14.1 | 14.6 | 19.1 | 0.0 | |||||||||||
6 | E. climacophora | 17.9 | 11.0 | 16.2 | 19.4 | 12.9 | 0.4 | ||||||||||
7 | E. davidi | 18.8 | 15.2 | 12.1 | 17.2 | 14.8 | 15.9 | / | |||||||||
8 | E. dione | 19.6 | 19.0 | 15.0 | 15.2 | 18.6 | 17.6 | 16.1 | / | ||||||||
9 | E. hodgsonii | 16.7 | 15.5 | 17.1 | 14.5 | 17.7 | 15.0 | 14.1 | 19.6 | / | |||||||
10 | E. moellendorffi | 21.7 | 18.5 | 21.8 | 16.3 | 16.4 | 17.6 | 18.6 | 20.7 | 14.8 | / | ||||||
11 | E. quadrivirgata | 19.7 | 13.1 | 15.4 | 16.9 | 12.6 | 13.3 | 13.8 | 15.5 | 15.8 | 18.9 | 0.9 | |||||
12 | E. quatuorlineata | 16.7 | 13.0 | 16.5 | 14.5 | 13.7 | 11.0 | 13.7 | 15.5 | 17.4 | 17.1 | 11.7 | 0.0 | ||||
13 | E. sauromates | 20.0 | 15.3 | 18.6 | 14.3 | 16.0 | 15.5 | 15.4 | 20.8 | 17.2 | 17.5 | 15.6 | 6.8 | / | |||
14 | E. schrenckii | 17.7 | 0.4 | 17.6 | 17.2 | 14.7 | 11.6 | 15.2 | 18.3 | 16.1 | 19.1 | 12.5 | 13.5 | 15.9 | / | ||
15 | E. taeniura | 16.3 | 17.8 | 15.4 | 12.8 | 16.1 | 17.1 | 15.0 | 16.6 | 12.9 | 15.9 | 14.7 | 14.0 | 15.0 | 18.4 | 5.4 | |
16 | E. zoigeensis | 13.3 | 16.3 | 16.4 | 17.1 | 20.4 | 16.5 | 18.3 | 15.4 | 12.5 | 20.0 | 16.6 | 14.3 | 16.0 | 16.9 | 15.7 | 0.0 |
Dorsal surface of head yellow, three distinct markings on head and neck; the anterior transverse black stripe, somewhat reddish medially, extends from the posterior margin of rostral and through the each eye to last two supralabials and adjacent small scales; interorbital arcuate cross-band, covering anterior part of frontals, most part of prefrontals, top of supraoculars, bottom half of upper postoculars, intact bottom postoculars, bottom half of upper temporals, most of bottom of temporals, dorsal edge of sixth left supralabials (fifth on the right), dorsal half of seventh supralabials (sixth) and bottom half of posterior-most supralabials, not reaching internasals, connected to largest posterior marking from mediolateral part; largest marking is a distinct black “M”-shaped marking that is reddish medially, covering the posteromedial part of the frontals, posterior part of supraoculars, most of parietals, dorsal margin of upper temporals, posteriorly extended, forming two thick black-edged reddish brown stripes on nape. Lateral surface of head yellow, a few small black spots dispersed on supralabials (2, 4 and 5 on left and 2, 3 and 4 on right) and subpreocular, a distinct scutellate black labial spot on the junction of the 2, 3 and right subpreocular (absent on left). Ventral surface of head consistently light-yellow, a few small black spots dispersed on the mental, infralabials, and anterior chin shields. An irregular spot occurs on the posterior edge of the junction of two anterior chin shields. Mouth lining is pale-heather and tongue is black.
Ground color of dorsal surface yellow, 49 complete or incomplete, black-edged reddish brown blotches on body and 12 similarly colored spots on tail; dorsal blotches on body approximately three to five scales in length, and eight to eleven scales rows in width; each blotch is usually composed of reddish brown scale with dark-brown edges. Two rows of smaller, black-edged reddish brown blotches on both side of the larger mid-body blotches, alternating with the mid-body blotches, each blotch covers 2–4 dorsal scales and separated from ventral scales by two rows of the dorsolateral scales. Ground color of ventral surface is yellow, mottled with irregular black blotches, a few irregular small red spots scattered midventrally.
Measurements, body proportions and scale and pattern counts of the two specimens are listed in Table
Measurements and scale counts and body proportions of Elaphe xiphodonta sp. nov.
Voucher | SYS r002534 | IVPP OV 2721 |
---|---|---|
Sex | female | female |
SVL | 785.2 | 307.5 |
TaL | 182.3 | 62.5 |
TL | 967.5 | 370.1 |
TaL/TL | 0.19 | 0.17 |
HL | 26.5 | 17.64 |
HW | 18.1 | 11.14 |
HW/HL | 0.68 | 0.63 |
ED | 3.2 | 2.8 |
RW | 7.1 | 3.4 |
RH | 4.5 | 2.0 |
RW/RH | 1.58 | 1.70 |
RW/HW | 0.39 | 0.31 |
DSR | 21-21-17 | 21-21-17 |
SPL | 8/7 | 8/8 |
IFL | 10/9 | 11/11 |
CS | 4 (2 pairs) | 4 (2 pairs) |
V | 204 | 202 |
SC | 67 | 67/68 |
MT | 11 (9+2) | 11 (9+2) |
Dorsal blotches | 61 (49+12) | 65(46+19) |
The osteological description is based on a road-killed juvenile individual (Paratype, IVPP OV 2721, Figs
Snout (Fig.
Braincase (Fig.
(Fig.
The maxilla has 11 teeth on each side, with one or two rows of replacement teeth on the lingual side. In contrast to other species of Elaphe, the maxillary dentition of the new species is conspicuously differentiated. The anterior five MT have inconspicuous posterolateral ridges, while the posterior six teeth have a sharply edged ridge on their posterior margin (which could be also described as: the posterolateral ridge gradually moved posteriorly by the MT row, forming a sharp cutting edge on the posterior MT), forming blade-like teeth. The MT increase in size posteriorly, the posterior-most two being the largest, not separated from the anterior teeth by a diastema. The cutting edges of the posterior four MT slightly posteriorly convex, rendering them kukri shaped.
The palatine bears nine teeth, with one row of replacement teeth on the labial side. The choanal process of palatine (chp) forms a right triangular in dorsal view. The anterolateral margin of the maxillary process forms an approximate 30° angle with the medial line. The posterior margin of maxillary process is perpendicular to the medial line and collinear with the anterior margin of the choanal process. The pterygoid is slender and lanceolate in shape, 1.8 times the length of palatine, bearing 12 solid teeth (with one row of replacement teeth on the labial side). The ectopterygoid process and the medial transverse process of pterygoid are very small and difficult to see. The ectopterygoid is horizontally expanded, and outwardly curved in dorsal view. The labial furcula of ectopterygoid is oval, and distinct from the lingual process. The medial furcula (medial process) is elongate and spiculate, slightly curved ventrally.
(Figs
(IVPP OV 2721, paratype) Maxilla: 11/11 (9+2); pterygoid: 12/12; palatine: 9/9; dentary: 13/13. Dentitional comparisons within the genus Elaphe and some related colubrid groups are listed in Table
Dentition comparison of the Elaphe species and related colubrid species.
Taxon (n) | Maxillary | Blade teeth | Palatine | Pterygoid | Dentary | Reference |
---|---|---|---|---|---|---|
Elaphe | ||||||
E. xiphodonta sp. nov. (1) | 11/11 | Y | 9/9 | 12/12 | 13/13 | this study |
E. bimaculata (1) | 19/20 | N | 9/10 | 15/16 | 18/19 | this study |
E. carinata (5) | 17 | N | 9–11 | 13–16 | 19–21 | this study |
E. climacophora (2) | 17 | N | 11 | 17–20 | 23–25 |
|
E. dione (2) | 16–20 | N | 7–9 | 12–13 | 18–23 | this study |
E. davidi (3) | 16–17 | N | 9–12 | 12–16 | 16–19 |
|
E. moellendorffi (2) | 22–23 | N | 11 | 19–22 | 27–29 | this study |
E. schrenckii (2) | 16–17 | N | 10–11 | 12–13 | 19–21 | this study |
E. taeniura (3) | 17–23 | N | 10–11 | 16–19 | 19–23 | this study |
E. zoigeensis (2) | 14–17 | Y | 10–10 | 10–13 | 16–17 | this study |
Euprepiophis | ||||||
Eu. mandarinus (2) | 16–19 | Y | 10–11 | 19–24 | 19–22 | this study |
Eu. perlaceus (2) | 20–20 | Y | 12–12 | 18–21 | 21–22 | this study |
Coelognathus | ||||||
C. flavolineatus (1) | 23 | N | 11/13 | 25/26 | 27/28 | this study |
C. philippinus (1) | 25 | N | 12/13 | 26/27 | 29/28 | this study |
C. radiatus (5) | 20–23 | Y | 10–12 | 18–24 | 23–27 | this study |
Oligodon | ||||||
Ol. ornatus (1) | 8/8 | Y | 4/4 | 5/5 | 13/13 | this study |
Oocatochus | ||||||
Oo. rufodorsatus (2) | 18–19 | Y | 10–11 | 17–18 | 21–23 | this study |
Gonyosoma | ||||||
G. oxycephalum (1) | 23/23 | N | 10/10 | 14/13 | 26/26 | this study |
Ptyas | ||||||
P. carinata (2) | 24–25 | Y | 17–15 | 19–20 | 22 | this study |
P. dhumnades (1) | 26 | Y | 21/20 | 23 | 26 | this study |
Dasypeltis | ||||||
D. scabra (2) | 7–6 | N | 8–9 | 0 | 3–3 |
|
Thermophis | ||||||
T. zhaoermii (2) | 19–21 | Y | 12–16 | 18–23 | 21/24 | this study |
Detailed comparisons among Elaphe species are given in Table
Comparisons of general morphological characteristics with its congeners in China A Elaphe xiphodonta sp. nov. (SYS r002534, holotype), Ningshaan, Shaanxi, by Shuo Qi B E. anomala, Benxi, Liaoning, by Shuo Qi C E. bimaculata, Hong’an, Hubei, by Chong-Jian Zhou D E. cantoris, Bomê, Tibet, by Jing-Song Shi E E. carinata, Mentougou, Beijing, by Jing-Song Shi F E. davidi, Benxi, Liaoning, by Jing-Song Shi G E. dione, Yongdeng, Gansu, by Shuo Qi H E. hodgsonii, Gyirong, Tibet, by Shuo Qi I E. moellendorffi, Chongzuo, Guangxi, by Jia-Jun Zhou J E. schrenckii, Baishan, Jilin, by Shuo Qi K E. taeniura from Hangzhou, Zhejiang, by Wei-Liang Xie L E. zoigeensis, Jiuzhaigou, Sichuan, by Jin-Wang.
Elaphe xiphodonta sp. nov. is distinct from all of its congeners by having fewer MT, enlarged posterior MT, cutting edges on both MT and DT, and three rows of large, black-bordered reddish brown dorsal blotches.
Additionally, Elaphe xiphodonta sp. nov. can be distinguished from E. cantoris, E. climacophora (Boie, 1826), E. hodgsoni, E. moellendorffi, and E. taeniura by having fewer ventral scales (202–204 vs. 226–239 in E. cantoris, 222–236 in E. climacophora, 228–247 in E. hodgsoni, 270–278 in E. moellendorffi, and 223–261 in E. taeniura), fewer subcaudals (67–68 vs. 78–87 in E. cantoris, 97–116 in E. climacophora, 72–92 in E. hodgsoni, 92–102 in E. moellendorffi, and 73–121 in E. taeniura), smaller body size (SVL 785 mm in single adult female vs. maximum SVL 1158 mm in E. cantoris, > 2000 mm in E. climacophora, 1190 mm in E. hodgsoni, 1602 mm in E. moellendorffi, and > 2000 mm in E. taeniura), and vastly different color pattern (Table
Diagnostic characters separating all 17 species of the Elaphe, with distinguishing characters marked in bold. *: Counts of PrO contain subpreocular.
Species | maximum SVL (in mm) | DSR | SPL | IFL | PrO* | PtO | TMP | V | SC |
---|---|---|---|---|---|---|---|---|---|
Elaphe xiphodonta sp. nov. | 785 | 21-21-17 | 8 (7) | 9 (10) | 2 | 2 | 2+3 | 202–204 | 67–68 |
Elaphe anomala | 1925 | 23 (21–25)-23 (19–23)-19 (17–19) | 8 | 9–11 | 2 (1) | 2 (1) | 2 (3)+3 (2) | 203–225 | 45–77 |
Elaphe bimaculata | 760 | 23 (23–25)-23 (21–25)-19 (21) | 8 (7) | 9–12 | 2 (1) | 2 | 2+3 | 170–209 | 61–81 |
Elaphe cantoris | 1158 | 19 (20, 21)-19 (21–23)-17 | 8 | 9–10 | 2 | 2 | 2+3 (2) | 226–239 | 78–87 |
Elaphe carinata | > 2000 | 23 (21–25)-23 (21–25)-19 (17) | 8 (9) | 9–12 | 2 (1) | 2 | 2+3 | 186–227 | 69–102 |
Elaphe climacophora | > 1500 | NA-23 (25)-NA | 8 (9) | 11 | 2 | 2 | 2+3 (2) | 222–236 | 97–116 |
Elaphe davidi | 1227 | 25 (22–27)-23 (22–25)-19 (17–21) | 8 (7) | 11–13 | 2 (1, 3) | 2 (1–4) | 2 (1, 3)+4 (2–3) | 155–183 | 53–72 |
Elaphe dione | 893 | 25 (21–27)-25 (21–27)-19 (17–21) | 8 (9) | 9–11 | 2 (1) | 2 | 2+3 | 168–206 | 51–84 |
Elaphe hodgsoni | 1190 | 23 (21–25)- 23 (21–25)-17 | 8 (9) | 9–12 | 2 (1) | 2 | 2 (1, 3)+3 (2, 4) | 228–247 | 72–92 |
Elaphe moellendorffi | 1602 | 25 (23–27)-27 (5)-19 (21) | 9 (10) | 10–13 | 2 | 2 | 2 (3)+3 (4) | 270–278 | 92–102 |
Elaphe quadrivirgata | >1000 | NA-19-NA | 8 | 11 | 2 | 2 | 2 (1)+3 (2) | 195–215 | 70–96 |
Elaphe quatuorlineata | > 2000 | 25-25 (23–27)-19 | 8 (9) | 11 | 2 (3) | 2 (3) | 2 (3)+3 (4) | 187–234 | 56–90 |
Elaphe sauromates | 1250 | 25 (21–27)-25 (23, 24)-19 (18–21) | 8 (7–10) | 11 (9–12) | 2 (1, 3) | 2 (1) | 2(1, 3)+ 4 (2–5) | 199–222 | 61–79 |
Elaphe schrenckii | 1335 | 23 (21)-23 (21)-19 | 8 (7) | 8–11 | 2 (1) | 2 | 2+3 (2) | 208–224 | 57–75 |
Elaphe taeniura | > 2000 | 25 (23)-23 (21, 25)-19 (17) | 9 (6–10) | 9–13 | 2 (1) | 2 (3) | 2 (1, 3)+3 (2–5) | 223–261 | 73–121 |
Elaphe urartica | 970 | 25 (23, 24)- 25 (23, 24)-19 (18) | 8 (9) | 11 (10–13) | 2 (1, 3) | 2 (1, 3) | 2 (3)+ 4 (2, 3) | 154–211 | 60–74 |
Elaphe zoigeensis | 722 | 21-19(21)-17 | 7–8 | 9 | 3 | 2 | 2+3(2) | 202–212 | 68–79 |
Elaphe xiphodonta sp. nov. can be differentiated from E. quatuorlineata Lacepede, 1789, E. sauromates (Pallas, 1811) and E. urartica (Jablonski, Kukushkin, Avci, Bunyatova, Ilgaz, Tuniyev & Jandzik, 2019) by having fewer dorsal scale rows (21-21-17 vs. 25-25 (23–27)-19 in E. quatuorlineata, 25 (21–27)-25 (23, 24)-19 (18–21) in E. sauromates and 25 (23, 24)- 25 (23, 24)-19 (18) in E. urartica) and a vastly different color pattern. Beyond that, E. xiphodonta sp. nov. can be further differentiated from E. quatuorlineata and E. sauromates by its smaller body size (SVL 785 mm in single adult female vs. maximum SVL > 2000 mm in E. quatuorlineata and 1250 mm in E. sauromates).
Elaphe xiphodonta sp. nov. can be differentiated from Elaphe carinata, E. davidi and E. quadrivirgata (Boie, 1826) by its smaller body size (SVL 785 mm in single adult female vs. maximum SVL > 2000 mm in E. carinata, 1227 mm in E. davidi, and > 1000 mm in E. quadrivirgata), having fewer subcaudals (67–68 vs. 69–102 in E. carinata, 70–96 in E. quadrivirgata), and a vastly different color pattern.
Despite the morphological similarities to E. bimaculata, E. dione, and E. zoigeensis, Elaphe xiphodonta sp. nov. differs from them by having different dorsal scale row counts (21-21-17 vs. 23 (23–25)-23 (21–25)-19 (21) in E. bimaculata), fewer preoculars (2 vs. 3 in E. zoigeensis), fewer MT (11/11 vs. 19/20 in E. bimaculata, 16–20 in E. dione, and 14–17 in E. zoigeensis (Table
The ML and BI analyses produced identical topologies, which were integrated in Fig.
The phylogenetic analyses recovered a strongly supported monophyletic lineage containing all Elaphe (BS 100; BPP 1.00) which can be divided into three strongly supported clades (BS 95–97; BPP 1.00). Clade 1 includes all species previously in the genus “Orthriophis” with strong nodal support (BS 95; BPP 1.00). Notable intraspecific genetic differentiation within E. taeniura (mean p-distances 6.8% in CO1, 5.4% in cytb), pertains to different geographical clades.
The two samples from Chengguan Town, Shaanxi are clustered together with strong support (BS 100; BPP 1.00) with nearly no molecular divergence (mean p-distances 0% in CO1, 0% in cytb) between them. The clade of the above-mentioned specimens constitutes a sister clade with E. zoigeensis (Clade2, mean p-distances 8.4% in CO1, 13.3% in cytb).
Within Clade 3, the relationship between Elaphe anomala and E. schrenckii are worth noting. These two species form a strongly supported monophyletic group (BS 100; BPP 1.00) bearing low interspecific molecular divergence (mean p-distances 0.0% in CO1, 0.4% in cytb), suggesting they may be different color morphs of the same species, as mention before (
Based on their phylogenetic relationships, genetic differentiation, and morphological distinctiveness (see Taxonomic accounts below), we hypothesize that the population from Chengguan Town, Shaanxi represents a separately evolving lineage and should be described as a new species.
Elaphe xiphodonta sp. nov. is currently known only from the Chengguan Town, Ningshaan County, Shaanxi Province, China. The new species inhabits sunny or semi-sunny gravels and bushes on slopes of less than 20°, along Chang’an River with an average width of 3 m. Elevation of the habitat ranges from 1700 to 1900 m. The vegetation types are Abies fargesii forest with artificial Picea asperata, Salix fargesii, Rubus koereana, Betula albosinensis and Fargesia qinlingensis. The canopy density is 0.75 (
In feeding habits, the fecal samples from the holotype were checked and contained only feathers, indicating that this species is at least a bird-eater. The holotype was observed to prey on captive nesting quail and quail egg.
This study described a new Elaphe species which has a unique coloration and specialized teeth and had been overlooked for a long time during previous surveys. The new species was mistaken for P. jerdonii, which it mimics, at first glance during the field work. Nevertheless, the mimicry in E. xiphodonta is not unique within Elaphe. The coloration and head shape of E. davidi mimics that of the sympatric Gloydius spp. (
Elaphe dione was previously widely recorded from northern China (
Based on the dentition comparison in Table
We are grateful to Li Ding for sharing important specimens for osteological comparison, to Fan Yang, Shi-Chao He, Zi-Chuan Wei, Jun Yan, Liang Sun, Jun-Dong Deng, Zong-Chang Yang, Bo Tan, Zhao-Chi Zeng and Zhi-Tong Lyu for their help in the field and the preparation of the manuscript; to Jin-Wang, Jia-Jun Zhou, Wei-Liang Xie, Chong-Jian Zhou and Liang Sun for providing important photographs; to Ye-Mao Hou, Peng-Fei Yin and Hao Ding for their assistance with CT scanning and three-dimensional reconstruction; to Xue-Man Zheng for the help with illustrations, and to Sheng Zheng for providing priceless literature references. We thank Dr. Luis Ceríaco, Dr. Robert Jadin and an anonymous reviewer for their helpful comments and suggestions on the manuscript.
This study is supported by “the Second Tibetan Plateau Scientific Expedition and Research Program” (Grant No. 2019QZKK0705), “the Specimen Platform of Ministry of Science and Technology, China, teaching specimen’s sub-platform” (No. 2005DKA21403-JK) and “the National Park Project of Central Financial Subsidy” (No. ZX2020-09-43).
Details of the osteological specimens examined for dentition comparisons in this study.
Colubridae
Elaphe
E. xiphodonta sp. nov. IVPP OV 2721, 3D model of impregnated specimens, IVPP.
E. zoigeensis IVPP OV 2672, 3D model of impregnated specimens, IVPP.
E. carinata IVPP OV 2296, osteological specimens, IVPP.
E. climacophora SH 530, lateral and dorsal views of skull (
E. davidi BM 1916.1.15.17, lateral and dorsal views of skull, BM (
E. dione IVPP OV 2302, osteological specimen, IVPP.
E. moellendorffi IVPP OV 2686, osteological specimen, IVPP.
E. schrenckii IVPP OV 2295, osteological specimen, IVPP.
E. taeniura IVPP OV 2298, osteological specimen, IVPP.
Coelognathus
C. flavolineatus IVPP OV 2687, osteological specimen, IVPP.
C. radiatus IVPP OV 2411–2415, osteological specimens, IVPP.
Euprepiophis
Eu. mandarinus IVPP OV 2675, osteological specimen, IVPP.
Oligodon
Ol. ornatus SYS r001297, 3D model of Impregnated specimens, SYS.
Oocatochus
Oo. Rufodorsatus IVPP OV 2691, osteological specimen, IVPP.
Ptyas
P. dhumnades IVPP OV 2686, osteological specimen, IVPP.
Dipsadidae
Dasypeltis
D. scabra
Thermophis
T. zhaoermii BFU R_Th_001. 3D model of impregnated specimen, BFU.