Lineatriton lineolus is a very slender salamander that is found primarily on dry land. The species can grow up to 38 mm SVL and 128 mm TL. In adult individuals, the tail is cylindrical and usually twice as long as the body and head. The front and forelimbs are short, with partially webbed hands and feet. This species has a rounded snout and stalked tongue.
L. lineolus can be distinguished from other wormlike salamanders by the long, narrow vertebrae it has. In all, the body contains fifteen elongated vertebrae.
This species is usually a dull black, with paler coloration marking the sides, (Dunn 1926) although Shannon and Werler (1955) have documented living specimens that were uniformally lead gray (Tanner and Dundee, 2000).
Lineatriton comes from the Latin words "linea," which literally translates as "feminine," and "triton," the name of the Roman sea god. "Linea" refers to the slender appearance of the salamander. The species name, lineola, is also from "linea," but in this context, it refers to the thin vertebral line some individuals have (Tanner and Dundee 2000).