Species Account

Thracia gracilis Jeffreys, 1865

Thracioidea : Thraciidae

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

To size: To 40mm. Shell Structure: Brittle. Equivalve: Inequivalve, RV more convex than LV. Equilateral: Inequilateral, beaks behind midline. Outline: Oval, anterior part longer and higher than posterior, dorsal anterior margin almost straight almost parallel to ventral margin to narrowly curving anterior margin. Ventral margin, which is straight. Posterior is rostrate, truncate.

Sculpture: Concentric lines, ridges with coarse granulations on posterior part (rostrum), remainder of shell finely granulated. Ligament: External and internal: External short, behind beaks; internal thick in a narrow, elongated, triangular resilifer below external. Hinge: Lithodesma broken off. Pallial Musculature: Angular, almost triangular to where lithodesma would be. Not confluent. Periostracum: Yellowish brown. Colour: Cream.

Distribution & Ecology

Recognised originally from Norway (Soot-Ryen 1941) and present in the northern North Sea. Confusion with T. phaseolina probably underestimates the true distribution.
Inhabits muddy sand at outer shelf depths.

Depth Range
Continental Shelf (to 200m)

Additional Information & Related Species

Additional Comments

syn Thracia rectangularis

Related Species


Listed are literature citing Thracia gracilis Jeffreys, 1865. Reference containing the species Type Description is highlighted.

Jefffreys J G 1865. British Conchology, vol. 3 Van Voorst, London. 394pp.
Soot-Ryen T 1941. Northern Pelecypods in the collection of Tromsø Museum I Order Anomalodesmacea Families Pholoadomyidae. Thraciidae and Periplomatidae. Tromsø Museums Arshefter Naturhistorisk Avd. Nr. 17. 61: 1-41, 10 pls.


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Record last modified: 14/04/2016