Calamaria andersoni Yang & Zheng, 2018

Calamaria andersoni Yang & Zheng, 2018 View in CoL

Materials

Type status: Other material. Occurrence: catalogNumber: ANU ZR 25022 ; individualCount: 1; sex: male; lifeStage: adult; occurrenceID: E82D8737-6380-5668-BC4A-0939E497D4F9; Taxon: taxonID: urn:lsid:biosci.ohio-state.edu:osuc_names:275502; scientificNameID: Calamaria andersoni; scientificName: Calamaria andersoni; class: Reptilia; order: Squamata; family: Calamariidae; genus: Calamaria; specificEpithet: andersoni; scientificNameAuthorship: Yang & Zheng, 2018; Location: country: China; countryCode: CN; stateProvince: Yunnan; locality: Mangshi City, Dehong Dai and Jingpo Autonomous Prefecture ; verbatimElevation: 1315 m; verbatimLatitude: 24.520531°N; verbatimLongitude: 98.589152°E; verbatimCoordinateSystem: WGS 84; Event: eventDate: 5 / 3 / 2025; eventRemarks: collected by J. D. Deng; Record Level: language: en; collectionCode: Reptilia; basisOfRecord: PreservedSpecimen GoogleMaps

Type status: Other material. Occurrence: catalogNumber: HS R 21036 ; individualCount: 1; sex: female; lifeStage: adult; occurrenceID: C3122350-A780-5D0A-A867-21B1B0CFB089; Taxon: taxonID: urn:lsid:biosci.ohio-state.edu:osuc_names:275502; scientificNameID: Calamaria andersoni; scientificName: Calamaria andersoni; class: Reptilia; order: Squamata; family: Calamariidae; genus: Calamaria; specificEpithet: andersoni; scientificNameAuthorship: Yang & Zheng, 2018; Location: country: China; countryCode: CN; stateProvince: Yunnan; locality: Lianghe County, Mangdong Town, Dehong Dai and Jingpo Autonomous Prefecture ; verbatimElevation: 1185 m; verbatimLatitude: 24.674581°N; verbatimLongitude: 98.221510°E; verbatimCoordinateSystem: WGS 84; Event: eventDate: 6 / 15 / 2021; eventRemarks: collected by J. D. Deng; Record Level: language: en; collectionCode: Reptilia; basisOfRecord: PreservedSpecimen GoogleMaps

Type status: Other material. Occurrence: catalogNumber: ANU ZR 24017 ; individualCount: 1; sex: male; lifeStage: adult; occurrenceID: AF0FF5F1-E3D6-5819-9139-1B313EE7FD69; Taxon: taxonID: urn:lsid:biosci.ohio-state.edu:osuc_names:275502; scientificNameID: Calamaria andersoni; scientificName: Calamaria andersoni; class: Reptilia; order: Squamata; family: Calamariidae; genus: Calamaria; specificEpithet: andersoni; scientificNameAuthorship: Yang & Zheng, 2018; Location: country: China; countryCode: CN; stateProvince: Yunnan; locality: Lianghe County, Mangdong Town, Dehong Dai and Jingpo Autonomous Prefecture ; verbatimElevation: 1185 m; verbatimLatitude: 24.674581°N; verbatimLongitude: 98.221510°E; verbatimCoordinateSystem: WGS 84; Event: eventDate: 7 / 8 / 2024; eventRemarks: collected by J. D. Deng; Record Level: language: en; collectionCode: Reptilia; basisOfRecord: PreservedSpecimen GoogleMaps

Type status: Other material. Occurrence: catalogNumber: QHU R 2025016 ; individualCount: 1; sex: male; lifeStage: adult; occurrenceID: 4971066E-766B-546C-81B9-ED2A161A67BD; Taxon: taxonID: urn:lsid:biosci.ohio-state.edu:osuc_names:275502; scientificNameID: Calamaria andersoni; scientificName: Calamaria andersoni; class: Reptilia; order: Squamata; family: Calamariidae; genus: Calamaria; specificEpithet: andersoni; scientificNameAuthorship: Yang & Zheng, 2018; Location: country: China; countryCode: CN; stateProvince: Yunnan; locality: Lianghe County, Mangdong Town, Dehong Dai and Jingpo Autonomous Prefecture ; verbatimElevation: 1185 m; verbatimLatitude: 24.674581°N; verbatimLongitude: 98.221510°E; verbatimCoordinateSystem: WGS 84; Event: eventDate: 5 / 5 / 2025; eventRemarks: collected by J. D. Deng; Record Level: language: en; collectionCode: Reptilia; basisOfRecord: PreservedSpecimen GoogleMaps

Type status: Other material. Occurrence: catalogNumber: QHU R 2025017 ; individualCount: 1; sex: male; lifeStage: adult; occurrenceID: 253E96DA-1AC2-5A2E-914F-D2CCFB7A5814; Taxon: scientificNameID: Calamaria andersoni; scientificName: Calamaria andersoni; class: Reptilia; order: Squamata; family: Calamariidae; genus: Calamaria; specificEpithet: andersoni; scientificNameAuthorship: Yang & Zheng, 2018; Location: country: China; countryCode: CN; stateProvince: Yunnan; locality: Lianghe County, Mangdong Town, Dehong Dai and Jingpo Autonomous Prefecture ; verbatimElevation: 1185 m; verbatimLatitude: 24.674581°N; verbatimLongitude: 98.221510°E; verbatimCoordinateSystem: WGS 84; Event: eventDate: 5 / 5 / 2025; eventRemarks: collected by J. D. Deng; Record Level: language: en; collectionCode: Reptilia; basisOfRecord: PreservedSpecimen GoogleMaps

Type status: Other material. Occurrence: catalogNumber: QHU R 2025018 ; individualCount: 1; sex: male; lifeStage: adult; occurrenceID: 8E047098-C3BE-5A2B-8F70-C58A4F2436B6; Taxon: scientificNameID: Calamaria andersoni; scientificName: Calamaria andersoni; class: Reptilia; order: Squamata; family: Calamariidae; genus: Calamaria; specificEpithet: andersoni; scientificNameAuthorship: Yang & Zheng, 2018; Location: country: China; countryCode: CN; stateProvince: Yunnan; locality: Lianghe County, Mangdong Town, Dehong Dai and Jingpo Autonomous Prefecture ; verbatimElevation: 1185 m; verbatimLatitude: 24.674581°N; verbatimLongitude: 98.221510°E; verbatimCoordinateSystem: WGS 84; Event: eventDate: 5 / 5 / 2025; eventRemarks: collected by J. D. Deng; Record Level: language: en; collectionCode: Reptilia; basisOfRecord: PreservedSpecimen GoogleMaps

Description of the female specimen ( HS R 21036 )

Measurements and scalation (Fig. 2 View Figure 2 ). Specimen HS R 21036 is in excellent condition. Body slender and cylindrical (SVL 294 mm, TL 312 mm). Tail short, not as thick as body (TaL 18 mm, TaL / TL 5.8 %); tail uniformly cylindrical in the anterior part, tail slowly tapering anteriorly, then abruptly tapering at tip; head small, elliptical in dorsal view (HL 7.8 mm, HW 4.2 mm, HH 3.5 mm); eye small and round (ED 0.9 mm), larger than eye-mouth distance (Eye-MouthD 0.9 mm), ED / HL 11.5 %.

Rostral wider than high, portion visible from above almost equal to the length of the prefrontal suture; prefrontal slightly shorter than frontal, not entering orbit, in contact with 1 st and 2 nd supralabial; frontal hexagonal, longer than wide, about 3.0 times the maximum width of the supraocular; paraparietal surrounded by six scales; preocular 1 / 1, higher than wide, slightly higher than postocular, not as high as eye diameter; postocular 1 / 1, higher than wide; nasals small, barely surrounding nostrils, surrounded by the 1 st supralabial, rostral, and prefrontal; supralabials 4 / 4, 2 nd and 3 rd entering orbit, 4 th largest, relative supralabial width 4> 2> 1> 3; mental triangular, not in contact with the anterior chin shields; infralabials 5 / 5, first three pairs touching anterior chin shields, first pair meeting in midline, 4 th largest; anterior chin shields longer than wide, pentagonal, meeting in midline; posterior chin shields shorter than the anterior ones, touching at their foremost ends and separated posteriorly by first gular scales.

Dorsal scales in 13 rows throughout the body, reducing to six rows above the fifth subcaudal and to four rows above the second to last subcaudals. Dorsal scales homogeneous in size, entirely smooth; vertebral row not enlarged. Ventrals 186. Anal plate undivided. Subcaudals 14, paired and smooth; terminal scale single and rigid.

Dentition. Maxillary teeth enlarged, uniformly arranged, nine on each side (9 / 9).

Colouration in preservative (Fig. 2 View Figure 2 ). Dorsal surface of the head, body, and tail light to dark brown, with a slightly faded pattern compared to the colouration in life. Lateral stripes are obscure or absent. The dorsal head scales are uniformly brown, with faint lighter mottling along the edges of the supralabials. The eye appears cloudy white due to fixation. The ventral surface is pale cream to yellowish white, with irregular brown to dark brown mottling along the outer margins of the ventral scales, especially pronounced on the anterior half of the body. The posterior venter and subcaudals are more uniformly cream-coloured with sparse dark markings. The chin and throat are pale, with scattered brown speckling on the infralabials and gular region. The tail tip is slightly darker dorsally and lighter ventrally, and has the same color as the adjacent trunk areas.

Description of additional specimens

Morphology. Body slender and cylindrical [the longest known specimen is 312 mm long ( HS R 21036 ); the longest known male is 295 mm long (SVL 269 mm, TaL 26 mm; ANU ZR 24017 ); tail uniformly cylindrical in the anterior part, tail slowly tapering anteriorly, then abruptly tapering at tip (TaL / TL 8.8–9.2 % in males (n = 6) and 5.8 % in females (n = 1 )).

Body scalation. Dorsal scales in 13 rows throughout the body, reducing to 6 rows above the 4 th – 9 th subcaudals and to 4 rows above the second and 5 th to last subcaudals. Dorsal scales homogeneous in size, entirely smooth; vertebral row not enlarged. Ventrals 164–172 in males (n = 6), 186 in the female (n = 1). Anal plate undivided. Subcaudals 20–23 in males (n = 6), 14 in the female (n = 1), paired and smooth; terminal scale single and rigid.

Head scalation. Rostral wider than high; portion visible from above almost equal to the length of the prefrontal suture; prefrontal slightly shorter than frontal, not entering orbit, in contact with 1 st and 2 nd supralabial; frontal hexagonal, longer than wide; paraparietal surrounded by six scales; preocular 1 / 1, higher than wide, slightly higher than postocular, not as high as eye diameter; postocular 1 / 1, higher than wide; nasals small, barely surrounding nostrils, surrounded by 1 st supralabial, rostral and prefrontal; supralabials 4 / 4, 2 nd and 3 rd entering orbit, 4 th largest, relative supralabial width 4> 2> 1> 3; mental triangular, not in contact with the anterior chin shields; infralabials 5 / 5, first three pairs touching anterior chin shields, first pair meeting in midline, 4 th largest; anterior chin shields longer than wide, pentagonal, meeting in midline; posterior chin shields shorter than the anterior ones, touching anteriorly and separated posteriorly by first gular scales.

Dentition. Maxillary teeth enlarged, uniformly arranged, nine on each side (9 / 9).

Hemipenis (based on fully everted organ of adult male specimen QHU 2025018 ; Fig. 3 View Figure 3 G-I). The hemipenis is bilobed, relatively short and thick, with two hemispherical lobes approximately equal in size. Lobes moderately expanded and rounded distally. The organ is deeply bifurcated, with the bifurcation starting at approximately the level of the 4 th subcaudal scale and extending terminally to the tip of each lobe. The entire organ extends posteriorly to the level of the 7 th subcaudal scale. Sulcus spermaticus is single, centrally positioned, bifurcating shortly before the base of the lobes, and terminating apically on each lobe. The truncus (stem) is cylindrical, unornamented, and smooth, lacking spines, folds, or calyces. The surface of both lobes and the proximal part of the truncus is smooth throughout, without papillate or spinulate structures. In preservative, the organ is uniformly pinkish to pale reddish, with the lobes slightly more pigmented than the basal stem.

Colouration in life (Fig. 4 View Figure 4 A-F). Dorsal surface of head, body, and tail uniformly dark brown to blackish, with subtle iridescence visible under direct light. A series of indistinct narrow dark stripes is present on the lateral sides of the body, often only faintly visible. Dorsal scales lack any conspicuous markings or collars. Supralabials and lower jaw are dark brown, with diffuse yellow to orange suffusion on the infralabials and throat region. Ventral surface bright orange to orange-yellow, bordered laterally by a narrow line of dark pigmentation at the outermost edges of the ventral scales. No light-coloured rings or collar markings are present on the nape or tail. The colouration of the tail tip is similar with that of the dorsum or slightly paler ventrally.

Variation. Species variation is discussed based on the holotype ( SYS r 001699 ; described in Yang and Zheng 2018) and six additional specimens reported in this study (see Table 2, Figs 2 View Figure 2 , 3 View Figure 3 A-F, the overview measurements are listed in Suppl. material 1 Table S 4).

Revised diagnosis.

C a lam ar ia and erso ni can be distinguished from its congeners by the following combination of characters: (1) nine enlarged maxillary teeth; (2) body wider than high; prefrontal shorter than frontal, contacting the first two supralabials; (3) mental not in contact with the anterior chin shields; (4) single preocular and postocular; (5) four supralabials, with the 2 nd and 3 rd contacting the eye; (6) five infralabials; five scales surrounding the paraparietal; (7) ventrals 164–172 in males, 186 in the female; subcaudals 20–23 in males, 14 in the female, paired; tail relatively short (8.8–9.2 % of total length in males, 5.8 % in the female), tapering gradually anteriorly and abruptly at the tip; (8) dorsal surface of the head, body, and tail uniformly dark brown to blackish; (9) no light-coloured rings or blotches on the neck or tail; (10) ventral surface bright orange to orange-yellow, bordered laterally by a narrow line of dark pigmentation along the outermost edges of the ventral scales.

Natural history, distribution, and conservation status.

Calamaria andersoni is currently known only from tropical evergreen forests in Dehong Dai and Jingpo Autonomous Prefecture, Yunnan Province, China, specifically from Tongbiguan (Yingjiang County), Mangshi City, and Mangdong Town (Lianghe County), at elevations around 1,520 m a. s. l. The species has been observed at night in moist, mossy microhabitats within mature forest environments. This region harbours high herpetofaunal diversity, and C. andersoni occurs sympatrically with several other snake species, including Trimeresurus popeiorum Smith, Ovophis jenkinsi Qiu, Wang, Xia, Jiang, Zeng, Wang, Li & Shi, Lycodon fasciatus (Anderson), and Oligodon cf. albocinctus (Cantor) (personal observations during field survey in May, 2025). As the type locality lies near the international border, it is plausible that the species also occurs in adjacent mountainous regions of northern Myanmar ( Kachin State) (Fig. 1). Given the limited available information on its ecology, population size, and potential threats, we recommend that Calamaria andersoni be classified as Least Concern (LC) under the IUCN Red List Categories and Criteria ( IUCN 2024 ).