Two Spot Keyhole Limpet

Fissurellidea bimaculata

Two Spot Keyhole Limpet

Fissurellidea bimaculata
Other Common Names
Two-spotted keyhole limpet
Other Common Names
Two-spotted keyhole limpet

At the Aquarium

Rocky Coast

Appearance

This limpet has a very large, fleshy mantle that is up to 3 times the length of its shell. The mantle can entirely cover the shell, the head, tentacles, and the foot. The mantle can come in various colors: including gray, yellow, red, or orange, and has papillae, or small bumps. The small shell covers its dorsal opening and just a bit of the mantle. The shell is usually whitish and has gray or brown ridges and a central opening that is about ⅓ the length of the shell, which can extend up to 0.8 inches in length, while the body is about 2.7 inches in length and 0.9 inches wide.

Habitat

Intertidal and shallow subtidal, to 98 feet, on compound tunicates or sponges, kelp holdfasts, or under rocks.

Diet

Sponges, compound tunicates, and possibly phytoplankton

Life History

Most sea snails in the Vetigastropoda grouping that these limpets belong to are broadcast spawners with a short, non-feeding larval stage.

IUCN Status

Not Evaluated

Ecosystem & Cultural Importance

This limpet’s predators include harlequin ducks.
Alaska to Baja California, Mexico
You may get lucky and find one of these limpets while tidepooling, typically hiding under rocks.
Young individuals have a shell about the same size as their body, but as the organism grows, the growth of its body far outpaces that of the shell.

Citations & Other Resources

  • Cunha, Tauana Junqueira, et al. inchesPutting keyhole limpets on the map: phylogeny and biogeography of the globally distributed marine family Fissurellidae (Vetigastropoda, Mollusca).inches Molecular phylogenetics and evolution 135 (2019): 249-269.
  • Dall, W. H. inchesDescriptions of sixty new forms of mollusks from the west coast of North America and the North Pacific Ocean, with notes on others already described.inches American Journal of Conchology 7.2 (1871): 93-160.
  • McLean, J. H. inchesShell reduction and loss in fissurellids: a review of genera and species in the Fissurellidea group.inches American Malacological Bulletin 2 (1984): 21-34.
  • Invertebrates of the Salish Sea