[2][3][1] The adult male frog measures 15.3–17.7 mm in from nose to rear end.

The skin of the head and dorsum is black with large yellow blotches behind the eyes.

[3] Scientists named this frog for Thomas Defler, a primatologist who worked in Colombia for 32 years and founded the Estación Biológica Caparú.

[3] This semi-arboreal frog inhabits lowland primary forest that remains wet year-round.

[3] The IUCN classifies this frog as least concern of extinction due to its presumed large range, which includes at least one protected park: Parque Nacional Natural Yaigojé Apaporis [es].