Cratera cuarassu is a species of land planarian belonging to the subfamily Geoplaninae.

[1] It is known from specimens found in Desengano State Park, Brazil.

The ventral side is a light ivory color, becoming a brown-beige at the front end.

[2] It is distinguished from other members of Cratera by its coloration along with the peculiar shape of the male organs; specifically, a short, wide penis papilla that projects vertically downwards from the male atrium roof, and the possession of a large intra-penial cavity.

[2] The specific epithet, cuarassu, is derived from the Tupi language words cuara, "hole, cave", and assu, "large"; this is in reference to the species' large intra-penial cavity.