Species Account

Thyasira dunbari Lubinsky, 1976

Thyasiroidea : Thyasiridae

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

To size: To 6mm. Shell Structure: Thin shelled. Equivalve: Equivalve. Equilateral: Equilateral (large shells becoming expanded anteriorly). Tumidity: Moderate. Outline: Rhomboidal; anterior dorsal margin sloping steeply, rather long and with a short truncation before the anterior junction; ventral rounded, posterior weakly biangulate but scarcely sinuous; posterior subacute; posterior dorsal slope rather straight and angled close to the beak. Contour: Posterior area flattened, in some weakly sunken; auricle absent, submarginal sulcus distinct margin sharp.

Sculpture: Smooth with growth lines and stops only. Margin: Inner margin smooth. Ligament: External, deeply sunken about half the length of submarginal sulcus. Hinge: Hinge plate narrow lacking distinct teeth but some with cardinal thickening in RV. Pallial Musculature: Muscle scars obscure. Periostracum: Not persistent. Colour: Shell white. Additional Characters: 2 demibranchs.

Distribution & Ecology

An arctic species whose southerly extension is unclear due to confusion with T. equalis. It is likely that it reaches Iceland, Faroes and northern Norway. The morphology is very similar to that of T. equalis and like it we suspect it to be only partially chemosymbiotic. Gill has 2 demibranchs. Common in arctic muddy sediments but also known from the Hakon-Moseby mud volcano. Development is probably direct as indicated by large larval shell.

Depth Range
Continental Shelf (to 200m)
Continental Margin Zone (200 - 500m)
Bathyal (500 - 2000m)

Additional Information & Related Species


Listed are literature citing Thyasira dunbari Lubinsky, 1976. Reference containing the species Type Description is highlighted.

Lubinsky I 1976. Thyasira dunbari n. sp. (Bivalvia: Thyasiridae) from the Canadian Arctic Archipelago. Journal of the Fisheries Research Board of Canada. 33: 1667-1670.
Oliver P G & Killeen I J 2002. The Thyasiridae (Mollusca: bivalvia) of the British continental shelf and North Sea Oilfields. Studies in Marine Biodiversity and Systematics from the National Museum of Wales. BIOMOR Reports. 3: 1-73.
Payne C.M. & Allen J.A. 1991. The morphology of deep-sea Thyasiridae (Mollusca: Bivalvia) from the Atlantic Ocean. Philosophical Transactions of the Royal Society of London Series B. 334: 481-566.
Włodarska-Kowalczuk M 2007. Molluscs in Kongsfjorden (Spitsbergen, Svalbard): a species list and patterns of distribution and diversity. Polar Research. 26: 48-63.


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Record last modified: 17/05/2016