• Size:  Notoacmea scutum ranges from 2.5-6 cm. long. Its height is usually less than one-third its width.
• Range:  It can be found from Alaska to California
• Habitat:  Notoacmea scutum resides on rocky beaches, and is common on mid- and low intertidal and shallow subtidal zones.
• Misidentification:  It is often thought of as a subspecies to Atlantic Plate Limpet, but is anatomically different which indicates that it's a distinct species. It can also be mistaken Notoacmaea persona, or mask limpet, but is flatter and with nearly center apex.
• Life History: Notoacmea scutum are broadcast spawners, resulting in external fertilization by males releasing sperm and females releasing eggs into the water.  Spawning is most abundant and generally occurs during April thru June.  Larval types are known as trochophores and feeding veligers.
• Natural History:  By grazing on algae and diatoms, Notoacmea scutum may shove aside and cause early mortality of newly settled barnacles.
• Predators:  Pisaster spp. is its most fierce predator, but can be chemically detected from a distance by receptors along the mantle edge.
• Links: Western Fisheries
• Suggested Reading:  Mash, Kaye. (1975). How Invertebrates Live. Elsevier-Phaidon, New York, New York.

This page prepared by Shannon Peterson, Spring 1999.