In malacology, a lamella (plural: lamellae) is a specific type of fold or tooth located on the inner boundary of the aperture.
Types
One can discern following types:
- parietal lamella: positioned on the wall that 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.
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