Common Names in English:
Two-Spot Keyhole Limpet
Shell with a dorsal opening at or near the apex, or with a slight indentation at the anterior margin (such an indentation is present only in the rare and subtidal Arginula bella; it marks the place where a groove on the interior of the shell, beginning at the apex, reaches the margin )
Species Fissurellidea bimaculata
This keyhole limpet has a large brown, red, orange, or yellow mantle which covers so much of the shell that the animal looks very much like a nudibranch at first. The body is much larger than the shell, which only covers the area around the dorsal opening (aperture ) and may be mostly covered by mantle. The opening in the small shell is about 1/3 the shell length. Shell length to 2 cm (usually 1.6 cm or less), and has gray or brownish radiating ridges dorsally , smooth white ventrally. Animal length to at least 3 cm. When free from the animal the shell has a shallow groove around the margin and the ends may turn up slightly (see photo). I do not know why it is called the two-spot keyhole limpet.
Typically found in water with a depth of 0 to -47 meters (0 to -154 feet).
Biome: Marine .
Predators include harlequin ducks.
- Whittaker & Margulis,1978
- C. Linnaeus, 1758
- (Hatschek, 1888) Cavalier-Smith, 1983
- Grobben, 1908
- (C. Linnaeus, 1758) Cuvier, 1795
- Ponder & Lindberg, 1996
- Salvini-Plawen, 1980
- Order: order_Pleurotomariina/Fissurellidae/Fissurellidea_ ()
- Superorder: Vetigastropoda () - Salvini-Plawen, 1980
- Subclass: Orthogastropoda () - Ponder & Lindberg, 1996
- Phylum: Mollusca () - (C. Linnaeus, 1758) Cuvier, 1795 - Molluscs
- Superphylum: Eutrochozoa ()
- Infrakingdom: Lophotrochozoa ()
- Branch: Protostomia () - Grobben, 1908
- Subkingdom: Bilateria () - (Hatschek, 1888) Cavalier-Smith, 1983
- Kingdom: Animalia () - C. Linnaeus, 1758 - animals
Status: Accepted Name
Last scrutiny: 30-Dec-2004
Other keyhole limpets here do not have a shell which is so small in comparison to the body, nor is the aperture equal to about a third of the shell length. Be careful not to mistake it as a dorid nudibranch (the apex looks much like the anus and gills of a dorid but is surrounded by a small, mostly hidden shell and is just behind the head instead of on the posterior end of the body as seen in dorids). (Ref. 109953)
Members of the genus Fissurellidea
ZipcodeZoo has pages for 1 species and subspecies in this genus:
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- Annual report - Western Society of Malacologists. Pomona, Calif., Western Society of Malacologists. url p. 23.
- Discovery reports. London; Cambridge University Press. url p. 85.
- Memoirs of the San Diego Society of Natural History. 1 1931 San Diego, Calif.: The Society, 1931-1989. url p. 848, p. 849.
- Shells and sea life. Phoenix, AZ: Miranda Enterprises, url p. 113.
- Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed January 17, 2012.
- Cowles, Dave. Key to Invertebrates Found At or Near The Rosario Beach Marine Laboratory (a campus of Walla Walla University) Fidalgo Island, Anacortes, WA.
- Global Biodiversity Information Facility. Accessed January 27, 2008. http://www.gbif.org Mediated distribution data from provider.
- Ruggiero M., Gordon D., Bailly N., Kirk P., Nicolson D. (2011). The Catalogue of Life Taxonomic Classification, Edition 2, Part A. In: Species 2000 & ITIS Catalogue of Life: 2011 Annual Checklist (Bisby F.A., Roskov Y.R., Orrell T.M., Nicolson D., Paglinawan L.E., Bailly N., Kirk P.M., Bourgoin T., Baillargeon G., Ouvrard D., eds). DVD; Species 2000: Reading, UK.
Accessed through GBIF Data Portal January 30, 2008:
- Institute of Marine and Coastal Sciences, Rutgers University, Gwaii Haanas Invertebrates
- Biodiversity Heritage Library NamebankID: 2682601
- Catalogue of Life Accepted Name Code: ITS-69655
- Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 69655
- Zipcode Zoo Species Identifier: 505912
- Cowles, Dave. Key to Invertebrates Found At or Near The Rosario Beach Marine Laboratory (a campus of Walla Walla University) Fidalgo Island, Anacortes, WA May 2009. [back]
- Mean = 45.470 meters (149.180 feet), Standard Deviation = 117.550 based on 15 observations. Ocean depth information for each observation from British Oceanographic Data Centre. [back]