Species Account

Pholadidea loscombiana Turton, 1819

Pholadoidea : Pholadidae

Tebble name: Pholadidea loscombiana Turton
Smith & Heppell name: Pholadidea loscombiana Turton, 1819

To size: To 40mm. Shell Structure: Rather thin, brittle. Mesoplax of two small triangular pieces. Equivalve: Equivalve. Equilateral: Inequilateral, beaks in front of midline. Tumidity: Inflated. Outline: Subelliptical anterior much higher, posterior slightly extended, rounded, developing a tube-like, chitinous siphonoplax in adults; anterior beaked with a large pedal gape this closing by a callum in adults. Contour: With a strong oblique median sulcus.

Sculpture: Behind the median sulcus, of co-marginal ridges and; in front of weak radial riblets and co-marginal ridges, weakly imbricate. Callum smooth. Margin: Inner margin smooth. Ligament: Ligament internal, small, on a chondrophore. Hinge: Umbonal reflection strong, rising above the umbo. Pallial Musculature: Pallial sinus deep extending to below beaks; ventral adductor scar prominent. Apophysis small. Colour: Shell dirty white.

Distribution & Ecology

A borer into soft sedimentary rocks, mud, clay and peat. From low intertidal and offshore. Restricted to south and south west coasts.

Depth Range
Continental Shelf (to 200m)

Additional Information & Related Species

Key Features & Similar Species

When young, may be confused with small Zirphaea crispata but that species is heavier shelled and gapes widely on all margins whereas P. loscombiana does not gape posteriorly. When adult P. loscombiana is the only British species to develop a siphonoplax and callum.

Related Species


Listed are literature citing Pholadidea loscombiana Turton, 1819. Reference containing the species Type Description is highlighted.

Turton W 1819. A conchological dictionary of the British Islands London. 272pp, 28pls.


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Record last modified: 22/03/2016