It contains several species adapted to human-disturbed environments,[1] including the only invasive land planarian native to the Neotropical realm, Obama nungara, which has been accidentally introduced in Europe.

The hundreds of eyes distributed along the body are of two types: monolobulated, which are simple and circular, and trilobulated, which have three lobes.

[4] Morphologically the genus can be divided in two subgroups depending on the shape of the penis papilla, which may be symmetrical or asymmetrical.

The group with an asymmetrical penis papilla includes 10 species (O. anthropophilla, O. carbayoi, O. carrierei, O. decidualis, O. josefi, O. ladislavii, O. marmorata, O. nungara, O. otavioi and O. ruiva) and seems to form a monophyletic clade within Obama.

[5] The name Obama is formed by a composition of the Tupi words oba (leaf) and ma (animal), being a reference to the body shape of species in this genus.