Idas simpsoni (Marshall, 1900)
Mytiloidea : Mytilidae
To size: To 40mm. Shell Structure: Thin. Equivalve: Equivalve. Equilateral: Inequilateral beaks at about 1/5 of shell length from anterior. Tumidity: A little inflated, umbos low but shell expansion greatest behind umbos. Outline: Submodioliform, elongate, with anterior distinctly more narrow than posterior; dorsal and ventral margins of about equal length, ventral subparallel to dorsal; ventral margin long slightly to distinctly incurved, dorsal margin gently curved, anterior dorsal margin sloping downwards making rounded anterior projecting, posterior broadly curved. Contour: Posterior angle distinct but rounded; median area a little depressed.
Sculpture: Smooth with a few growth lines, larger shells with a few radial lines on the median depression. Margin: Inner margin smooth. Ligament: Large, on a wide sunken, resilifer behind the beaks extending about 2/3 the length of the posterior dorsal margin. Hinge: Hinge plate narrow apparently smooth in large shells but in smaller shells with a few small dysodont teeth behind the ligament and 1-3 irregular crenulae below the beaks. Pallial Musculature: Anterior adductor scar only a little smaller than posterior, this with a small dorsal extension (byssus retractor scar). Periostracum: Persistent, glossy golden yellow to olive-brown in larger shells. Colour: White.
Distribution & Ecology
Continental Shelf (to 200m)
Additional Information & Related Species
Mytiloidea : Mytilidae
Listed are literature citing Idas simpsoni (Marshall, 1900). Reference containing the species Type Description is highlighted.
Bolotin J., Hrs-Brenko M., Tutman P., Glavic N., Kozul V., Skaramuca B., Lucic D. & Dulcic J. 2005. First record of Idas simpsoni (Mollusca: Bivalvia: Mytilidae) in the Adriatic Sea. Journal of the Marine Biological Association of the United Kingdom. 85: 977-978.
Marshall J T 1900. On a British species of Myrina, with a note on the genus Idas. Journal of Malacology. 7: 167-170.
Oliver PG & Holmes AM 2009. Idas lamellosus Verrill, 1881 (Bivalvia: Mytiloidea) a woodfall mussel new to the fauna of the northeast Atlantic. Journal of Conchology. 39 (6): 705-708.
Southward E C 2008. The Morphology of bacterial symbioses in the gills of mussels of the genera Adipola and Idas (Bivalvia: Mytilidae). Journal of Shellfish Research. 27(1): 139-146.
Warén A 1991. New and little known Mollusca from Iceland and Scandinavia. Sarsia. 76: 53-124.
Warén A. & Carrozza F. 1990. Idas ghisotti sp.n., a new mytilid bivalve associated with sunken wood in the Mediterranean. Bollettino Malacologico. 26: 19-24.
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