AbstractPteronotus gymnonotus (Wagner, 1843) is a medium-sized mormoopid commonly called the big naked-backed bat because of its wing membranes attached on the dorsal midline of the body, giving the appearance of a naked dorsum, and its large size in comparison to the other two species of naked-backed Pteronotus. The species is distributed across most of the Neotropical mainlands, ranging from southeastern Mexico through Central and South America south to northeastern Bolivia and central Brazil. P. gymnonotus has been considered as an uncommon species in most parts of its geographic distribution but there are some reports of more numerous local populations. It is an aerial insectivore that forages in open areas and gallery forests. Like other mormoopids P. gymnonotus usually forms large colonies roosting preferentially in hot and humid caves. It is currently listed as “Least Concern” according to the International Union for Conservation of Nature and Natural Resources Red List.