Species Account

Rangia cuneata (GB Sowerby I, 1831)

Mactroidea : Mactridae

Tebble name: n/a
Smith & Heppell name: n/a

To size: To 50mm. Shell Structure: Solid, thick. Equivalve: Equivalve. Equilateral: Slightly inequilateral, beaks slightly in front of midline. Tumidity: A little tumid, umbos prominent. Outline: Ovate-trigonal, slightly longer than high, posterior slope long, posterior more pointed than the broadly rounded anterior. Lunule and escutcheon not developed.

Sculpture: Of commarginal lines and weak undulations. Margin: Inner margin smooth. Ligament: Ligament internal in a prominent tear-drop shaped resilifer extending across the thick hinge plate. Hinge: Hinge plate thick, teeth strong; left valve with a small cardinal tooth anterior of the resilium, elongate anterior and posterior laterals with denticulate edges; right valve with a cardinal socket anterior of the resilium, with anterior and posterior lateral sockets. Pallial Musculature: Muscle scars distinct, adductor scars subequal. Pallial sinus short, rounded. Periostracum: Persistent, wrinkled in places and olive to light brown in colour. Colour: Shell off-white.

Distribution & Ecology

An alien species found only in Lincolnshire in a slightly brackish canalised river. In its native Gulf States of the USA it tolerates a wide range of salinities and therefore could be expected to become established in brackish waters in the UK. It is now established in The Netherlands and the eastern Baltic.

Depth Range

Additional Information & Related Species

Key Features & Similar Species

This is the only mactrid to be found in brackish waters in the UK but may be mistaken for Spisula solida, which is however more trigonal and equilateral in outline

Related Species


Listed are literature citing Rangia cuneata (GB Sowerby I, 1831). Reference containing the species Type Description is highlighted.

Rudinskaya L.V. & Gusev A.A. 2012. Invasion of the North American wedge clam Rangia cuneata (GB Sowerby I, 1831) (Bivalvia: Mactridae) in the Vistula Lagoon of the Baltic Sea.. Russian Journal of Biological Invasions. 3: 220-229.
Sowerby G.B. I 1832 (1821-34). The genera of recent and fossil shells, for the use of students, in conchology and geology. London. Part 36.
Verween A, Kerckhof F., Vincx M. & Degraer S. 2006. First European record of the invasive brackish water clam Rangia cuneata (GB Sowerby I, 1831) (Mollusca: Bivalvia) . Aquatic Invasions. 1(4): 198-203.
Willing M.J. 2015. Two invasive bivalves, Rangia cuneata (GB Sowerby I, 1831) and Mytilopsis leucophaeta (Conrad, 1831), living in freshwater in Lincolnshire, Eastern England.. Journal of Conchology. 42 (2): 189-192.


  • Conchological Society of Great Britain & Ireland
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  • MarBEF
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Record last modified: 11/04/2016