Species Account

Musculus (Modiolarca) subpictus (Cantraine, 1835)

Mytiloidea : Mytilidae

Tebble name: Musculus marmoratus (Forbes)
Smith & Heppell name: Modiolarca tumida (Hanley, 1843)

Notes on Nomenclature

Here previously as Modiolarca tumida (Hanley, 1843). Modiolarca is distinct from Musculus hence use of subgenus.

To size: To 20mm. Shell Structure: Thin but not fragile. Equivalve: Equivalve. Equilateral: Strongly inequilateral beaks close to the anterior margin. Tumidity: Inflated, umbos prominent. Outline: Modioliform, rhomboidal; ligament margin short, angled to posterior dorsal margin; posterior drawn out, narrowly rounded; ventral and anterior margins a broad curve but often depressed adjacent to non ribbed area. Contour: Posterior angle distinct extending from umbos to margins.

Sculpture: Radially ribbed except for smooth median area; 20-35 flat posterior ribs often faint, interspaces narrow; 15-18 prominent anterior ribs; Overall with comarginal lines and growth stops. Margin: Crenulate where radial ribs meet margin. Ligament: Deeply inset extending for most of the posterior dorsal margin. Hinge: Hinge plate narrow, dysodont teeth posterior of ligament obscure, otherwise smooth. Pallial Musculature: Mostly obscure. Periostracum: Thin persistent. Light green to greenish brown often with scattered blotches and spots of brown, pinkish brown or purplish brown. Colour: White, internally lustrous.

Distribution & Ecology

Widely distributed around all coasts. Mostly recorded from the intertidal and sublittoral but also to moderate shelf depths.
Often embedded in the tests of ascidians but not exclusively and can be found attached by the byssus in kelp holdfasts, crevices and on coarse offshore substrates.

Depth Range
Continental Shelf (to 200m)

Additional Information & Related Species


Listed are literature citing Musculus (Modiolarca) subpictus (Cantraine, 1835). Reference containing the species Type Description is highlighted.

Bodger P M & Allen J A 2008. The ecology and lifecycle of a population of Modiolarca tumida (Hanley, 1843) (Bivalvia: Mytilidae) of the coast off northeastern England. Journal of Molluscan Studies. 74: 97-101.
Cantraine F J 1835. Diagnoses ou descriptions succinctes de quelques espèces nouvelles de mollusques. Bulletins de l'Académie Royale des Sciences et Belles-lettres de Bruxelles. 2 (11): 38-411.


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Record last modified: 22/03/2016