颈棱蛇（学名：Macropisthodon rudis）为游蛇科颈棱蛇属的爬行动物，俗名“伪蝮蛇”。

雄性长60～80厘米，雌性长约1米；头部呈三角形，颈部明显；头背为黑褐色，上下唇淡橘红色；体背为棕褐色，背中线两侧具有黑褐色斑块28～33个，腹部为深褐色，杂有黑色花纹。

Macropisthodon rudis, also known as red keelback, false habu, and false viper, is a species of snake in the Colubridae family. It is found in southwest, south, and east China and in ******. One subspecies, Macropisthodon rudis multiprefrontalis Zhao and Jiang 1981 from Sichuan, is recognized, in addition to the nominotypical one.