Crassitoniella is a genus of minute sea snails, marine gastropod molluscs belonging to the family Eatoniellidae. First described by Winston Ponder in 1965, the genus is found in the waters of the South Pacific near Australia and New Zealand. Fossils of the species have been found on the coast of France.
In the original description, Ponder described the genus as below:
Members of the genus have minute shells and a straight peg that is in approximately same plane as rest of the species' operculum, and are smooth except for their single peripheral cord. Crassitoniella can be identified due to their unique opercular and radular features.
Crassitoniella was first described by Winston Ponder in 1965, naming Crassitoniella carinata as the type species. Phylogenetic analysis places Crassitoniella within the Cingulopsoidea superfamily, being closely related to Eatoniella, and more distantly to Skenella, Eatonina and Eatoniella.
Crassitoniella is found in the waters of the South Pacific, on the shores of southeastern Australia, New Zealand. Fossils of the Chattian fossil species C. europaea have been found near Saint-Paul-lès-Dax in southwestern France.
Members of the genus are often found between the lower littoral zone and sublittoral zone. Both C. carinata and C. flammea are known to live on algae.
Species within the genus Crassitoniella include: