The genus is known only from the Brazilian Paleocene Itaboraí Basin, in Rio de Janeiro.

[3] The most characteristic feature of the genus is its two spiral furrows on the body whorl.

[3] The generic name Brasilennea originally intended to imply that it is a Brazilian genus that is very similar and related to the African genus Ennea.

[2] This is no longer the case, however: while the genus was originally classified in the family Streptaxidae,[2] Brasilennea was then later transferred to the family Cerionidae.

[3] Species within the genus Brasilennea include: