Species Account

Asperarca nodulosa (Müller, 1776)

Arcoidea : Arcidae

Tebble name: n/a
Smith & Heppell name: Bentharca nodulosa (Müller, 1776)

To size: To 15mm. Shell Structure: Solid opaque. Equivalve: Equivalve. Equilateral: Inequilateral, beaks at about 1/4 length of dorsal margin from anterior. Tumidity: Not inflated. Outline: Trapezoidal, posterior greatly expanded, umbos low; dorsal margin long, straight; posterior margin almost straight, sloping obliquely; ventral and anterior margins continuous gently curved or with a shallow sinus; anterior roundly pointed. Contour: Posterior angle prominent, rounded; median area flat or slightly concave; dorsal area narrow, flat.

Sculpture: Strong of radial and comarginal ribs and ridges; comarginal dominant over median area intersected by radial and nodulose; posterior dominated by radial riblets these nodulose to spiny, anterior dominated by radial riblets these nodulose. Margin: Inner margin smooth. Ligament: Duplivincular, v-shaped ligament bands arising from posterior of dorsal area at first, then between beaks. Hinge: Taxodont, teeth, small, in two series separated by a short edentulous space, set on a narrow straight hinge plate; up to 7 anterior and 14 posterior teeth all angled obliquely. Pallial Musculature: Adductor scars unequal, anterior a little smaller than posterior. Periostracum: Thin, hyaline to pale straw coloured frills or bristles usually only persistent at margins. Colour: White, older shells brownish or greyish.

Distribution & Ecology

Attached by a thin byssus to deep-sea corals, stones and gravel. Mostly at the shelf edge and upper slope but occasionally deeper to bottom of slope. Along the entire western seaboard.

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

Additional Information & Related Species

Key Features & Similar Species

Being equivalve, strongly nodulose or imbricate distinguish this from all Bathyarca species with which it occurs. Bentharca asperula has a weak sculpture and is restricted to abyssal depths.

Related Species


Listed are literature citing Asperarca nodulosa (Müller, 1776). Reference containing the species Type Description is highlighted.

La Perna R 1998. On Asperarca Sacco, 1898 (Bivalvia, Arcidae) and two new Mediterranean species. Bollettino Malacologico. 33: 11-18.
Müller O F 1776. Zoologiae Danicae Prodromus, seu Animalium Daniae et Norvegiae Indigenarum, characteres, nomina, et synonyma imprimis popularum Havniae (Copenhagen): Typis Hallageriis. 281pp.
Olabarria C. 2005. Patterns of bathymetric zonation of bivalves in the Porcupine Sea Bight and adjacent abyssal plain, NE Atlantic. Deep-Sea Research I. 52: 15-31.
Oliver G & Allen J A 1980. The Functional and Adaptive Morphology of the Deep-Sea Species of the Arcacea (Mollusca: Bivalvia) from the Atlantic. Philosophical Transactions of the Royal Society of London Series B. 291: 45-76.


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Record last modified: 22/03/2016