Lamella (gastropod)

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 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.

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.

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.{{cite journal}}: CS1 maint: multiple names: authors list (link) This article incorporates text from this source, which is under a CC BY 4.0 license.

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