Tonatia maresi is a bat distributed in South America. The adult female used as the holotype reference in the paper had dark gray-brown fur above and a grayer, paler underside. The species roosts in hollow trees.
The adult female holotype has dark gray-brown dorsal fur, with patches of reddish hair tips. Shoulder hairs have white tips, and hairs behind the ears and around the neck base have white bases. White tips on the crown form a pale stripe between the ears; the underside is grayer and paler than the back.
The paper says this species roosts in hollow trees, forming groups of its own species or mixed groups with other bat species.
An extinction-risk assessment has not been added yet.