Dendrelaphis cf. cyanochloris (Wall, 1921)

Nguyen, Tan Van, Brakels, Peter, Maury, Nathanael, Sudavanh, Somchit, Pawangkhanant, Parinya, Idiiatullina, Sabira, Lorphengsy, Sengvilay, Inkhavilay, Khamla, Suwannapoom, Chatmongkon & Poyarkov, Nikolay A., 2020, New herpetofaunal observations from Laos based on photo records, Amphibian & Reptile Conservation (e 248) 14 (2), pp. 218-249 : 233

Dendrelaphis cf. cyanochloris (Wall, 1921)

Wall’s Bronzeback ( Fig. 7C–D )

One adult individual of D. cf. cyanochloris was observed by P. Brakels and N. Maury on 24 August 2019 in Xay District , Oudomxai Province (20°39.598’N, 102°04.241’E; elevation 800 m asl) .

Morphological characters of the individual from Oudomxai Province agreed well with the descriptions of Vogel and van Rooijen (2007) and Chan-ard et al. (2015). The photographed individual ( Fig. 7C–D ) generally agrees with the diagnosis of D. cyanochloris in the following characters: very elongate, slender body; tail long; head long, distinct from neck; eye rather large; pupil round; nasal divided; loreal present, not entering the orbit; 1 preocular; 2 postoculars; 2 anterior temporals; 2 posterior temporals; 9 supralabials, 1 st and 2 nd in contact with the nasal, 2 nd and 3 rd in contact with the loreal, 4 th –6 th entering orbit, 6 th and 7 th largest; dorsal scales smooth without apical pits; anterior vertebral scales slightly enlarged; ventrals 184; cloacal scale undivided; subcaudals 153; divided. Coloration of dorsum grayishbronze; reddish bronze on head and flanks, pale lateral stripe along flanks absent, skin between dorsal scales on flanks bluish-brown; supralabials, ventral surfaces of chin and anterior part of venter yellowish-green turning pale green posteriorly.

Ecological notes. The individual was found at ca. 2000 h while climbing a tree at a height of 3 m near a small forest stream with dense vegetation of shrubs and liana. The surrounding habitat was secondary mixed sub montane evergreen forest.

Distribution. In Laos, this species has been previously recorded from Phongsali, Xiangkhouang, Houaphan, and Champasak provinces (Teynié et al. 2014). This is the first record from Oudomxai Province. Elsewhere, this species has been reported from India, Bangladesh, Bhutan, Myanmar, Thailand, and Malaysia ( Jiang et al. 2020; Uetz et al. 2020).

Remarks. Dendrelaphis cyanochloris is morphologically similar to D. ngansonensis (Bourret) , but differs from it by more distinctly bluish-brown flanks with brighter bluish tint vs. bronze-brown flanks with generally more subdued bluish hue, pale green belly vs. cream belly, the first row of dorsals bronze-brown vs. cream, and a generally smaller number of dentary teeth of 20–23 vs. 24–27 (see Ziegler and Vogel 1999; Vogel and van Rooijen 2007; data above). Based on molecular and morphological data, Jiang et al. (2020) demonstrated that D. ngansonensis likely belongs to the D. cyanochloris complex; genetic differentiation between these two taxa was found to be minimal while the main morphological differences relate to coloration in life (see above). Thus, recognizing the problematic taxonomy of D. cyanochloris complex, we tentatively indicate this population as D. cf. cyanochloris , pending further research. Additional sampling and molecular analysis are required for clarification of the taxonomic status of these two species.

Figures

Fig. 7. (A) Boiga cyanea in Phiang District, Xaignabouli Province; (B) B. multomaculata in Nakay District, Khammouan Province; (C) lateral view and (D) ventral view of Dendrelaphis cf. cyanochloris in Xay District, Oudomxai Province; (E) Gonyosoma prasinum in Xay District, Oudomxai Province. Photos by P. Brakels.