Species Account

Parathyasira subcircularis (Payne & Allen 1991)

Thyasiroidea : Thyasiridae

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

To size: To 8mm. Shell Structure: Thin, fragile. Equivalve: Equivalve. Equilateral: Equilateral. Tumidity: Not inflated. Outline: Ovate-rhomboidal but rather rounded: anterior dorsal margin depressed; Anterior broadly rounded; ventral rounded; posterior margin subtruncate scarcely sinuous; posterior dorsal margin long sloping steeply. Contour: Submarginal sulcus long, edges angled, no auricle; posterior area a little flattened, sulcus very shallow.

Sculpture: Of concentric lines and growth stops; overall with microscopic radiating raised striations that have a slightly granular appearance. Margin: Inner margin smooth. Ligament: External, deeply sunken scarcely visible. Hinge: Hinge plate weak, indistinct cardinal protuberance in RV, corresponding depression in LV. Pallial Musculature: Muscle scars obscure. Periostracum: Thin, pale straw coloured. Colour: Shell white. Additional Characters: 2 demibranchs.

Distribution & Ecology

A lower bathyal and abyssal species recorded from the Atlantic margin.

Depth Range
Bathyal (500 - 2000m)
Abyssal Rise (2000 - 4000m)

Additional Information & Related Species


Listed are literature citing Parathyasira subcircularis (Payne & Allen 1991). Reference containing the species Type Description is highlighted.

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.


  • Conchological Society of Great Britain & Ireland
    Provides resources for understanding, identifying, recording, and conserving molluscs
    Check List of European Marine Mollusca
  • MarLIN
    The Marine Life Information Network for Britain and Ireland (MarLIN) provides information for marine environmental management, protection and education. It is a centre of excellence in spatially based and time-series marine biological information and supports good stewardship in the marine environment.
  • NBN Gateway
    National Biodiversity Network's Gateway. Use it to explore UK biodiversity data, as contributed by participating data providers.
  • BivAToL
  • MarBEF
  • Malacological Society
  • Unitas Malacologica
  • Census of Marine Life
  • MarBEF
    MarBEF, a network of excellence funded by the European Union and consisting of 94 European marine institutes, is a platform to integrate and disseminate knowledge and expertise on marine biodiversity, with links to researchers, industry, stakeholders and the general public.

Record last modified: 26/11/2015