[1][3][4] The specific name viejas is a Spanish expression meaning "pretty young women", in reference to three biologist who had studied this species.

The snout is long, subacuminate in dorsal view, and rounded in lateral profile.

The fingers and the toes have lateral fringes and round terminal discs but no webbing.

[2] Pristimantis viejas occurs in sub-Andean forests at elevations of 565–1,880 m (1,854–6,168 ft) above sea level.

[1] Pristimantis viejas is a common and adaptable species that seems to benefit from a degree of disturbance to forest habitats.