Imbira flavonigra is a species of land planarian belonging to the subfamily Geoplaninae.

Imbira flavonigra is a flatworm that can reach up to 135 mm in length when crawling.

[2] It can additionally be distinguished from other members of Imbira via its internal anatomy; I. flavonigra has a short esophagus, a bell-shaped pharynx, and a long, fork-shaped, sinuous, tubular prostatic vesicle.

[2] The specific epithet is derived from the Latin words flavus (yellow) and niger (black), in reference to the species' dorsal color.

[2] Imbira flavonigra is only known from its type locality, within the municipality of Maquiné in Rio Grande do Sul, Brazil.