Pseudoxenodon macrops (Blyth, 1854)

Ziegler, Thomas, Hendrix, Ralf, Thanh, Vu Ngoc, Vogt, Martina, Forster, Bernhard & Kien, Dang Ngoc, 2007, The diversity of a snake community in a karst forest ecosystem in the central Truong Son, Vietnam, with an identification key, Zootaxa 1493, pp. 1-40 : 15

Pseudoxenodon macrops (Blyth, 1854) : Big-eyed mountain keelback / Ran ho xien mat

At 4 November 2006, during the rainy season, we photographed a snake crawling at daytime on the forest ground at an altitude of about 385 m above sea level. Although this medium-sized snake could not be collected, its large eyes with round pupils in combination with a cylindrical body, a black chevron on the neck (with its apex pointed toward the head), the white supralabials with narrow black edges, a brownish body with light spots along the vertebral ridge (anteriorly greater in length than width, becoming greater in width than length posteriorly) as well as black spots on the sides, and a white anterior portion of the ventral surface with black markets that decrease in size (see Figure 16 ) allowed a determination as Pseudoxenodon macrops ( Cox 1991, Manthey & Grossmann 1997, Chan-ard et al. 1999, Cox et al. 1998). In addition, an adult specimen from Nui Chua in Ba Na (Da Nang Province), that is preserved in the Zoological Museum of the Vietnam National University, Hanoi, showed the same pattern and coloration. Furthermore, we were able to identify the following scalation features from our photographs of the specimen from Phong Nha - Ke Bang: eight supralabials (4–5 in contact with eye); one preocular; three postoculars; dorsal scale rows keeled (as given as characteristic in Manthey & Grossmann 1997). We also were able to observe the flattening of the snake's reared head and neck to mimic a cobra, which is a typical behaviour known from this species. P. macrops is known in Vietnam from Lao Cai, Lang Son and Vinh Phuc Provinces in the north, from Da Nang Province in the centre and from Lam Dong Province in the south ( Nguyen et al. 2005). Orlov et al. (2000) report on this species to live in northern Vietnam (Tam Dao) in high mountain areas in 900 to 1500 m altitude. In general, the species is known to occur along forest streams at altitudes between 150 and 2,000 m ( Cox et al. 1998). Our observation represents the first record for the Quang Binh Province and for Phong Nha - Ke Bang National Park in particular.

Figures

FIGURE 16. Big-eyed mountain keelback (Pseudoxenodon macrops) in its habitat in Phong Nha - Ke Bang. Photo: Bernhard Forster