Alvania interrupta

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

Description
This species is characterized by its irregularly-placed spiral ribs, these being crowded anteriorly, but almost absent posteriorly, so that spire-whorls have only two distinct ribs close to suture below. There are, however, traces of faint flattish ribs with linear interstices between these and suture above, and a distinct groove crosses ribs just below suture.

Distribution
Fossils of this marine species were found in Tertiary strata in New Zealand