Arca (Tetrarca) tetragona Poli, 1795
Arcoidea : Arcidae |
| Tebble name: | Arca tetragona Poli |
| Smith & Heppell name: | Arca tetragona Poli, 1795 |
To size:
To 40mm.
Shell Structure:
Strong but not thick, opaque.
Equivalve:
Equivalve.
Equilateral:
Inequilateral, beaks about 1/4 of dorsal margin length from anterior.
Tumidity:
Becoming greatly expanded.
Outline:
Trapezoidal, dorsal margin very long straight, posterior margin oblique straight, ventral margin straight or sinuate with a prominent byssal gape, anterior margin rounded.
Contour:
Dorsal area flat, becoming very wide. Posterior carina sharp, median area flattened or depressed.
Sculpture:
Primary sculpture of closely spaced radial riblets these interrupted by growth stops and overall nodulose; posterior area with a few broad ribs these also nodulose.
Margin:
Inner margin weakly crenulated in correspondence to riblets.
Ligament:
Duplivincular, initially between beaks but extending over the whole of the dorsal.
Hinge:
Taxodont: Of numerous small teeth in two series, set on a narrow straight hinge plate; anterior teeth mostly vertical small up to 30 in number; posterior teeth larger, mostly oblique up to 15 in number although those closest to the centre may be eroded or lost.
Pallial Musculature:
Anterior adductor slightly smaller than posterior, both with a weak myophoric flange.
Periostracum:
Of simple dark brown, short bristles, those on the posterior carina longer.
Colour:
White to dull pale brown.
Distribution & Ecology
Depth Range
Intertidal
Continental Shelf (to 200m)
Additional Information & Related Species
Juvenile Description
Key Features & Similar Species
Related Species
Arcoidea : Arcidae
References
Listed are literature citing Arca (Tetrarca) tetragona Poli, 1795. Reference containing the species Type Description is highlighted.
|
Poli J X 1795. Testacea Utriusque Siciliae eorumque historia et anatome. vol. 2 Parma, Regio Typographeio. i-lxxvi. 75-264, pls 19-39. |
Resources
- Conchological Society
of Great Britain & Ireland
Provides resources for understanding, identifying, recording, and conserving molluscs - CLEMAM
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.
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