Pseudoxenodon stejnegeri stejnegeri

黃頜蛇科，Natricinae 亞科；
Colubridae, subfamily Natricinae

90 cm

分布台灣全島1000-2500公尺之間。少見。

台灣特有亞種。

Small snake; total length up to 90 cm. There are 15-21 (17 at mid-body) rows of keeled scales; anteriorly dorso-lateral scales are oblique. Head is oval, triangular and distinct from neck; body is slightly stout; tail is long. Eye is medium to large size; iris is light flesh-colored with flecks of black, and darkened in lower two-thirds; pupil is round, black, surrounded by narrow ring of light flesh. Tongue is maroon, fork tips may be gray. It has enlarged rear fangs. The color of upper surface is extensively varied among individuals, including grey, green, yellow, orange, brown, and purple. A dark stripe extends from eye to base of jaw, and usually a reddish or black chevron sits on the nape, with its apex pointing toward the head. There are light bands along the vertebral ridge and dark squares on the sides of the bands; a light mid-dorsal stripe runs along the tail. Ventral surface is whitish anteriorly, gradually tinted with pinkish and may be mottled with black or white pigment in following part of body; the black spots aggregating on sides of the ventrals usually form a longitudinal stripe. The ventrals in anterior body may also have scattered quadrangular marks of black pigment which are irregularly arranged on sides. Anal scale is divided and subcaudals are paired.

此種蛇類體背底色個體間差異性很大，除了一般常見的褐色和灰褐色之外，還有偏紅、偏黃、偏灰、偏綠、偏橘與偏紫等等。

史丹吉氏斜鱗蛇、花尾斜鱗蛇(中國大陸)、紋尾斜鱗蛇

(1) "Opisthoglyphous snakes(後溝牙蛇 - opistho為後面之意，glyphos則為溝槽) ，有微毒，牠是利用上顎的後方一對擴大的牙齒來注入毒液。 這種毒牙在蛇閉合嘴吧時並不會垂直下降刺穿蛇的嘴，而是有隨著蛇的嘴開合而往後方斜向升降，蛇的嘴中有一對溝槽可以在閉合時收納這對毒牙。一般俗稱"rear-fanged snakes""。(Source)