Lamella (gastropod)

In malacology, a lamella (plural: lamellae) is a specific type of fold or tooth located on the inner boundary of the aperture.

Auriculella auricula with a strong and smooth parietal lamella

Types

One can discern following types:

• parietal lamella: positioned on the wall at hat forms the inner boundary of the aperture.
• columellar lamella: positioned on the columella (central axis) - sometimes only on juveniles.
• palatal lamella: positioned on the outer lip.

Auriculella perpusilla with a smooth palatal lamella

Functional Purposes

• defense: The lamella narrows the entrance to the shell, making it much harder for small predators (like beetles or specialized "snail-eating" larvae) to crawl inside and reach the snail's soft body.
• water retention: By narrowing the aperture, the lamella helps reduce evaporation, allowing the snail to survive dry periods by keeping moisture trapped inside the shell.
• structural guidance: It acts as a guide for the snail's body as it retracts or emerges, often ensuring the soft tissue is positioned correctly against the columella.

Identification in taxonomy

the parietal lamella is a key diagnostic feature (such as in the genus Auriculella ), .

• "valid" or "strong": a thick, obvious ridge.
• "obsolete": a ridge that is barely visible or has disappeared.
• branched": a complex lamella that splits into two or more ridges.

External links

Yeung N.W., Slapcinsky J., Strong E.E., Kim J.R. & Hayes K.A. (2020). "Overlooked but not forgotten: the first new extant species of Hawaiian land snail described in 60 years, Auriculella gagneorum sp. nov. (Achatinellidae, Auriculellinae)". ZooKeys. 950: 1–31. Retrieved 13 January 2026. This article incorporates text from this source, which is under a CC BY 4.0 license.