Species Account

Thyasira (Thyasira) gouldi (Philippi, 1845)

Thyasiroidea : Thyasiridae

Tebble name: n/a
Smith & Heppell name: Thyasira gouldi (Philippi, 1845)

To size: To 10mm. Shell Structure: Thin. Equivalve: Equivalve. Equilateral: Equilateral. Tumidity: Moderate. Outline: Ovate, higher than long; anterior variable some with a distinct excavated lunule and a short subtruncate part giving a weakly angulate profile, others with a more steeply sloping rather straight margin; ventral rounded; posterior bisinuate, marginal sinus less prominent than posterior sinus. Contour: Auricle weakly projecting about half length of submarginal sulcus; posterior sinus prominent, posterior fold distinct but rounded. Larval shell distinct, large 205-270microns.

Sculpture: Smooth except for concentric growth lines and growth stops. Margin: Smooth. Ligament: External, sunken extending to half length of auricle. Hinge: Weak, a small cardinal peg in RV, LV with a corresponding depression. Pallial Musculature: Muscle scars obscure. Periostracum: Thin not persistent. Colour: Shell white. Additional Characters: 2 demibranchs.

Distribution & Ecology

A northern circum-arctic species extending sporadically into sheltered sea lochs and inlets around Shetland and Scotland. Its true distribution is probably unrealised due to confusion with T. flexuosa. Chemosymbiotic, in mud, muddy sand in sea lochs and sheltered bays and inlets. The gills have 2 demibranchs and are highly adapted to support bacterial symbiosis.
Gill anatomy – Dufour, 2005
Ecology in Scotland – Blacknell, 1973; Blacknell & Ansell, 1974,1975.

Depth Range
Continental Shelf (to 200m)

Additional Information & Related Species


Listed are literature citing Thyasira (Thyasira) gouldi (Philippi, 1845). Reference containing the species Type Description is highlighted.

Blacknell W M 1973. Aspects of the biology of Thyasira gouldi (Philippi) and its copepod parasite Axinophilus thyasirae (Bresciani & Ockelmann) PH.D Thesis; University of Stirling.
Blacknell W M & Ansell A D. 1974. The direct development of the bivalve Thyasira gouldi. Thalassia jugoslavia. 10: 23-43.
Blacknell W M & Ansell A D. 1975. Features of the reproductive cycle of an arctic bivalve from a Scottish sea loch. Publicazione della Stazione Zoologica di Napoli . 39: 26-52.
Dufour S C 2005. Gill anatomy and the evolution of symbiosis in the bivalve family Thyasiridae. Biological Bulletin. 208: 200-212.
Killeen I.J. & Oliver P.G 2002. The taxonomic and conservation status of Thysira gouldi (Philippi, 1844), the northen hatchet shell intest British waters. Journal of Conchology. 37: 391-402.
Ockelmann K 1958. The zoology of East Greenland: marine lamellibranchiata. Meddeleseler on Grønland. 122: 1-256.
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.
Philippi R A 1845. Bemerkungen über die Molluskenfauna von Massachusetts. Zeitschrift für Malakozoologie. 1845: 68-79.


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Record last modified: 17/05/2016