Atrina fragilis
species of mollusc
Atrina fragilis, the fan mussel, is a species of large saltwater clam, a marine bivalve mollusc in the family Pinnidae, the pen shells.
The fan mussel, Atrina fragilis is one of the largest (30 to 48 cm long) and rarest bivalve molluscs occurring in northern European waters and the only member of the family Pinnidae to inhabit UK waters. It is one of the largest (30 to 48 cm long) European bivalve molluscs. It is one of the rarest species of marine mollusc in the United Kingdom — so rare that surveys of nearly 9,000 sites around Britain between 1987 and 1998 found none. The fan mussel has a larval stage that is very difficult to identify due to the rarity of the specimen. Atrina fragilis is greatly affected by the industrialization of the fishing industry, and it has impacted the distribution of the rare species.
Description
The shell of the fan mussel tapers to a point at the umbos, and is very brittle. It is yellowish to dark brown with blackish patches. The two valves are equal and triangular in outline, with prominent gapes. The shell surface has a sculpture of concentric lines and 8 to 12 ribs, which may have fluted spines.
“Atrina fragilis” enters the record as species of mollusc. Crown Archives preserves that source wording while asking what Atrina, fragilis and species can confirm, complicate or overturn.
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Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated May 10, 2026. The linked authority identifier is Q3016868. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1987 and 1998.
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This entry incorporates text from “Atrina fragilis” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.