sawtooth-necked bronzeback

Dendrelaphis nigroserratus is relatively large species among the bronzeback snakes. The holotype (QSMI 1282) is a juvenile female collected by Sjon Hauser in 2011 from Umphang District in Tak Province. It is 42.8 cm long, and its tail is 13.5 cm long, which is 31.5% of the total body length. Its eyes are conspicuous measuring 0.4 cm in diameter. The largest specimen is a dead female found on the road in Umphang District, and measures 1.63 m long. On average it is much longer than the closely related species such as Dendrelaphis cyanochloris and Dendrelaphis striatus. The general body colour is olive-brown. The head and back are greenish bronze, and the belly is yellowish or greyish green. It can be distinguished from other species from its thick black stripe behind the eye. The broad black streak is relatively broad on the head and runs from behind the eyes, continues as a broad bar on the neck where it breaks up incompletely. This splitting gives rise to a saw-toothed pattern, the reason for its common name as well as its specific epithet, nigroserratus (a Latin niger for "black", and serrare meaning "to saw"). Slightly posterior to this point, it splits completely into broad oblique bars that gradually disappear. This colour pattern in not seen in another species. It is a carnivore and is known to feed on frogs.

Other than Mergui region in Myanmar, Dendrelaphis nigroserratus is found in isolated areas around the Thailand-Myanmar border, such as Phetchaburi, Kanchanaburi and Tak provinces. It is most abundant in southern Tak Province, where a number of road kills occur every year. They are found in the hill evergreen forests at elevations of over 800 metres, near streams and in bamboo thickets.