Alvania stephanensis

Alvania stephanensis is an extinct species of minute sea snail, a marine gastropod mollusc or micromollusk in the family Rissoidae.

Description
The length of the shell attains 1.64 mm, its diameter 0.98 mm.

Distribution
Fossils of this species were found in Oligocene strata in Aquitaine, France; age range: 28.4 to 23.03 Ma