The genus is monotypic, containing the sole species Tropidoclonion lineatum, commonly known as the lined snake.

[4][5] Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Tropidoclonion.

The lined snake is olive green to brown with a distinctive tan or yellow stripe running down the middle of the back from head to tail.

[7] On the belly, it has a double row of clean-cut black half-moon spots running down the middle.

[9] The lined snake is semifossorial, spending most of its time hiding under rocks, leaf litter, logs, or buried in the soil.