Alvania pinguis

Alvania pinguis is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Rissoidae.

Description
The length of the shell attains 2 mm, its diameter 1.25 mm.

(Original description) The white shell consists of 4½ rounded but slightly flattened whorls, of which a very glossy protoconch occupies the first one and a half.

Sculpture: Fine spiral lines, three on the third and four on the body whorl above the aperture. The spirals are crossed by close-set longitudinal ribs as strong as the spirals. They die out on a level with, the posterior angle of the aperture, and the base has three spirals only. The columella is vertically arcuated. The aperture is diagonal-oval, a little angled where the outer lip joins the columella, behind which is a deep groove. The outer lip is thickened externally, especially where it joins the body whorl.

Distribution
This species occurs is endemic to New Zealand and occurs off Northland, off Great Barrier Island