Opisthotropis tamdaoensis Ziegler, David & Vu 2008

Opisthotropis tamdaoensis Ziegler, David & Vu, 2008 Materials Type status: Other material. Occurrence: lifeStage: juvenile; occurrenceID: D9E2B425-59B2-5B33-89A7-44A75C710694; Taxon: scientificName: Opisthotropis tamdaoensis; class: Reptilia; order: Squamata; family: Natricidae; genus: Opisthotropis; specificEpithet: tamdaoensis; scientificNameAuthorship: Ziegler, David & Vu, 2008; Location: country: China; stateProvince: Yunnann; county: Hekou Yao Autonomous County; locality: Baisha River, Nanxi Town; verbatimElevation: 152 m; decimalLatitude: 22.688042; decimalLongitude: 103.960274; Event: eventDate: 11 April 2015; fieldNumber: CIB 103778 Type status: Other material. Occurrence: sex: female; lifeStage: adult; occurrenceID: F5AC49FC-216E-571D-9AC2-384C90F2F50D; Taxon: scientificName: Opisthotropis tamdaoensis; class: Reptilia; order: Squamata; family: Natricidae; genus: Opisthotropis; specificEpithet: tamdaoensis; scientificNameAuthorship: Ziegler, David & Vu, 2008; Location: country: China; stateProvince: Yunnan; county: Hekou Yao Autonomous County; locality: Baisha River, Nanxi Town; verbatimElevation: 152 m; decimalLatitude: 22.688042; decimalLongitude: 103.960274; Event: eventDate: 11 April, 2015; fieldNumber: CIB 103779 Etymology According to the original description, the specific name “ tamdaoensis ” refers to the type locality of this species, Tam Dao Mountain ridge (Vinh Phuc Province) in Vietnam (Ziegler et al. 2008). The English name was “ Tam Dao Mountain Stream Snake ”. As this species is now also reported from China, we suggest its Chinese name as “ 三岛后棱蛇 ” (Sān Dăo Hòu Léng Shé), derived from its scientific name. Description of the specimens from China (n = 2) The morphological measurements and scalation features are listed in Table 2. Body medium size, TL 558 mm (except the juvenile), cylindrical, slenderly built; head short and broad, HL / HW 1.18, dorsally depressed, indistinct from neck (except the juvenile); snout moderate; pupil round; tail relatively short, TaL / TL 0.161 –0.182, tapering posteriorly. Head scalation. Rostral arc, broad, approximately twice as long as high, visible from above. Internasal two, crescent-shaped, in contact with each other medially behind the rostral, not in contact with loreal, posteriorly in contact with prefrontal. Prefrontal one, in contact with internasal, nasal, loreal, pre-ocular, frontal and supraocular. Frontal one, sub-hexagonal, in contact with supra-ocular and parietals. Parietals large and in contact medially. Nasal directed dorsally, polygonal, not divided, in contact with rostral anteriorly, with the 1 st and 2 nd supralabials ventrally, with loreal and prefrontal posteriorly and with internasal dorsally. Nostril long, oval, piecing in middle of nasal, oblique, directed upwards. Loreal one, not entering the orbit, in contact with the 2 nd, 3 rd and 4 th supralabials. Pre-ocular one, height larger than width, in contact with the 5 th supralabial. Supra-ocular one, nearly twice as long as wide. Postoculars two, the upper one much larger than the lower one. A single anterior temporal (rarely two) and two posterior temporals. Supralabials nine (rarely eight) and the fourth and fifth supralabials entering the orbit. Infralabials nine (rarely ten), the first one in contact with each other behind the mental. Two pairs of chin shields, anterior chin shields larger than the posterior chin shields. Body scalation. Dorsal scale rows 17: 17: 17, dorsal scales of the anterior body smooth and of the posterior body keeled. Ventrals 160–165. Cloacal plate divided. Subcaudals 51–56, paired. Colouration in life. (Fig. 2) Eye brown, pupil black; scales on dorsal surface of head olive grey with scattered dark green patches; chin shields light yellow with brownish-black mottling at each margin; body olive-grey with black spots on each junction of the dorsal scales, black spots becoming larger on sides of body and connecting into a side line pattern and the dorsal scales below the lateral lines turning to light yellow; ventrals light yellow; tail olive-grey also with black spots on each junction of the dorsal scales, black spots becoming larger on sides of tail and connecting into a side line pattern and faded at the tail tip; subcaudals light yellow with discontinuous black scattered mottling. Colouration in preservation. (Figs 3, 4) Scales on dorsal surface of head brown with scattered dark patches; chin shields light creamy-yellow with brownish-black mottling at each margin; body olive-brown with black spots on each junction of the dorsal scales, black spots becoming larger on sides of body and connecting into a side line pattern and the dorsal scales below the lateral lines turning to light creamy-yellow; ventrals light creamy-yellow; tail olive-brown also with black spots on each junction of the dorsal scales, black spots becoming larger on sides of tail and connecting into a side line pattern and fading at the tail tip; subcaudals light creamy-yellow with discontinuous black scattered mottling. Extended diagnosis (1) Nasal not divided below nostril; (2) loreal usually 1, not in contact with internasals; (3) pre-oculars 1–2, postoculars 2 subocular, usually 1; (4) anterior temporals 1–2, posterior temporals 2–4; (5) supralabials usually 9, only the fifth or fifth to sixth supralabial (rarely none) in contact with the orbit; (6) infralabials usually 9–10; (7) first pair of chin shields longer than the second pair; (8) dorsal scales smooth anteriorly, keeled posteriorly, in (17–19) - 17-17 rows; (9) tails telatively short, TaL / TL 0.143 –0.161; (10) pre ventrals 0–4, ventrals 160–176, precloacal divided; 4856 divided subcaudals; (11) uniform olive-grey dorsum, with a dark longitudinal lateral stripe within the dark flank colouration, ventral side pale or light yellow, without sharp transition towards the dark dorsal colouration, subcaudal region may bear dark mottling. Distribution O. tamdaoensis is currently only known from two localities, where one is from its type localities, Silver Stream in Tam Dao, Vinh Phuc Province, northern Vietnam and the other one is from Baisha River, Nanxi Town, Hekou Yao Autonomous County, Honghe Hani and Yi Autonomous Prefecture, Yunnan Province, China. The Vietnamese specimens were found at elevations in between 750 to 1,500 m above sea level and the Chinese specimens were found at 152 m above sea level, thus the elevation range of O. tamdaoensis is from 152 m to 1,500 m a. s. l. (Ziegler et al. 2008, Ziegler et al. 2017). Natural history notes O. tamdaoensis inhabits in secondary monsoon tropical evergreen forest on granitic soil or karst landscapes. The Vietnamese specimens were found between 09: 00 to 12: 00 am and the Chinese specimens were found at night in April and October, respectively. The snakes were in the shallow water in stream sections with open forest and we also found Odorrana cf. graminea (Boulenger, 1899), Cyrtodactylus gulinqingensis Liu, Li, Hou, Orlov & Ananjeva, 2021 and Calotes emma Gray, 1845 as co-occurring with the Chinese records (Ziegler et al. 2017).