Achalinus formosanus formosanus

黃頷蛇科，Xenoderminae 亞種
Colubridae, subfamily Xenoderminae

90 cm

台灣全島海拔 1000 - 2000 m 可見。

台灣特有亞種。

Small snake; total length up to 90 cm. Whole body is iridescent under light. There are 23-29 (mostly 27 at mid-body) rows of scales, which are keeled throughout body (and tail). The scales of an outermost row in upper face of postcloacal region are not much enlarged when compared with adjacent scales. Head is small, oval and not distinct from neck; body is slender; tail is moderately short. Eye is small, bead-like; iris is black, indistinct since it blends with dark head and pupil is round, black, and blends with rest of eye. Tongue has reddish stem and diffuse gray fork tips whose base is dark brown. The frontal is slightly broader than long; the parietal is nearly twice as long as broad and contacted posterolaterally by an enlarged paraparietal scale. Upper head, body and tail is uniform olive (dark-edged in anterior part of scale), grayish tan, or black. There is a dark longitudinal line on mid-dorsal row of scales on body and tail. Ventral surface is olive-yellow (dark-edged in anterior part of scale) or dark gray; the color is slightly darker on tail than on body. Whole body is usually black in the young. Anal scale is entire, and subcaudals are not divided.

標蛇為夜行性陸棲蛇類，喜歡居住在潮濕的環境，像是山林底層、亂石縫與落葉堆中。以蚯蚓與蛞蝓為主食，也有可能會捕食青蛙。攻擊性弱，甚少有相關的襲擊紀錄。

台灣標蛇、台灣脊蛇。