Alvania vermaasi van Aartsen 1975

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

Type of larval development: direct (non planktotrophic)

Shell 1.8-2.2 mm high, moderately solid, with a protoconch of little more than one whorl and teleoconch of 3 to 3.5 whorls. Sculpture of protoconch Sculpture of protoconch with a very characteristic pattern of zig-zag spiral threads. Teleoconch sculpture of spiral cords, narrower than interspaces and rounded, flexuous axial ribs. Aperture with outer lip slightly thickened externally, smooth inside. Colour pale buff with a subsutural series of brown spots. This species somewhat resembles the common North Atlantic Alvania punctura (Montagu, 1803) but differs in having a paucispiral protoconch, proportionally higher spire and more rounded cords, not forming projections at their intersection with the spiral cords.

Strait of Gibraltar, from low tide to ca. 100 m depth; Gorringe seamount, rare at 485 m (probably transported downslope).