Rough Keyhole Limpet (Diodora aspera)

Description: The rough keyhole limpet has a hole in the top point of their shell. They are often brown to gray in color with some faint patterns. As their name suggests, the outside of this species’ shell has a rough texture and often has barnacles growing on it. Rough keyhole limpets can grow large, sometimes up to 7.6 cm across! Unlike many other species of limpet, it is possible to see the mantle or flesh of the limpet when the tide is out. If you look closely you may even see a set of antennae.

Habitat: Rough keyhole limpets range from Alaska to Nicaragua. They live on rocks in the low intertidal and subtidal zones (down to 40 m). At Haystack Rock they are usually found in the lower intertidal zone at the western part of the north wall or at The Needles.

Diet: Grazing on rocks, rough keyhole limpets eat bryozoans, algae, and sponges.

Tide Pool Tidbits:

• When their predator, the ochre star, is nearby, the rough keyhole limpet with extend its large mantle over its shell to stop the ochre from being able to grab onto it.

• The hole in the top of their shell is used for exhaling and disposing of waste.

References: The New Beachcomber’s Guide to the Pacific Northwest by J Duane Sept, Animal Diversity Web