Ptyas korros

Colubridae, subfamily Colubrinae

200 cm

Throughout Taiwan, up to 1000 m altitude. Less common in the North. Rare.

India (Assam, Arunachal Pradesh), Bangladesh, Indonesia (Sumatra, Borneo, Java, Bali), Laos, Thailand, Vietnam, West Malaysia, Singapore Island, Myanmar, Cambodia, South China (Zhejiang, Jiangxi, Fujian, Guangdong, Guangxi, Hainan, Hunan, Yunnan, Guizhou, Anhui), Taiwan.

Large snake; total length up to 200 cm. There are 11-17 rows of scales, which are smooth or feebly keeled posteriorly. Head is narrow, oval to slightly triangular; body is slender and tail is long. Eye is large; iris is dirty yellow to brown, heavily dappled or mottled with coarse black pigment and pupil is round, jet black, surrounded by narrow ring of dirty yellow. There are 2-4 loreals and a moderate rounded ridge from upper eye to nostril at each side. Tongue is large, with a dark gray to blue-black stem. Upper head is uniform dark olive brown and the sides are lighter in color; the labials are not black-edged. Upper body and tail are uniform dark olive to gray brown, with dark-edged scales mainly posteriorly resembling a net pattern. There are about 9 indistinct or grey longitudinal stripes along body. Juveniles have transverse rows of white spots across body anteriorly. Ventral head is creamy white to yellow. Ventral body is variable, usually yellow in neck region and anterior fifth to quarter of body, gradually merging with lighter yellow or dirty white posteriorly. Anal scale is divided and subcaudals are paired.

It can be identified by its relatively large eyes, the olive-colored tail with dark-edged scales, and the faint pale brown banding which occurs on the thickest part of the body (though this feature does not occur in mature adults). (Source)

The Chinese name 細紋南蛇 (xi4wen2nan2she2) literally means "fine-striped (細紋) Ptyas mucosus (南蛇, aka Dhaman Ratsnake)"; as this species resembles P. mucosa, but has a slender body and thinner, almost faint stripes.