Hystricella bicarinata

Hystricella bicarinata is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Geomitridae, the hairy snails and their allies.
Two subspecies are recognised, one extant and one known only as a fossil.

Description

This minute species exhibits a rather globular form with a short, slightly conical spire. The spire comprises five squarish whorls, each featuring two central carinae, the upper of which is rather obtuse. The aperture is entire and round, with a distinct peristome. The umbilicus is small. A notable characteristic is the surface, which is covered with a granular epidermis.

Distribution

This species is endemic to the island of Porto Santo in the Madeira archipelago, Portugal. They are terrestrial and are found under rocks in grasslands. They have a very limited range, confined to about ten square kilometers but are abundant within that area.