Species Account

Altenaeum dawsoni (Jeffreys, 1864)

Galeommatoidea : Montacutidae

Tebble name: n/a
Smith & Heppell name: Mysella dawsoni (Jeffreys, 1864)

To size: To 1.5mm. Shell Structure: Solid. Equivalve: Equivalve. Equilateral: Inequilateral, beaks close to posterior margin. Tumidity: Moderate. Outline: Obliquely oval, extended anterior ventrally; posterior gently curving to more narrow posterior ventral margin, anterior more rounded. Contour: Prodissoconch very large, its margins weakly elevated.

Sculpture: Prodissoconch granular, adult shell almost smooth with weak concentric striations and stronger growth stops. Margin: Inner margin smooth. Ligament: Internal, small set in a shallow resilifer on the hinge plate beneath the beaks. Hinge: RV with two cardinal teeth, the anterior relatively massive, the posterior variably developed but usually small, anterior lateral tooth long, prominent, bounded by a groove dorsally, posterior lateral tooth much weaker. LV with two very weak cardinal teeth the anterior almost obsolete, anterior lateral marginal in position, more prominent than posterior lateral. Pallial Musculature: Pallial line entire. Colour: Shell white.

Distribution & Ecology

Described from apparently live collected material off the northeast coast of Scotland but is primarily a boreal subarctic species.

Depth Range
Continental Shelf (to 200m)

Additional Information & Related Species

Key Features & Similar Species

The two large cardinal teeth in the RV give a similarity to species of Kurtiella but in Altenaeum the ligament is on the hinge plate and not beneath the umbos and there are lateral teeth present.

Related Species


Listed are literature citing Altenaeum dawsoni (Jeffreys, 1864). Reference containing the species Type Description is highlighted.

Backeljau T, Meyer M de, Janssens L, Proesmans R 1984. The systematics and distribution of Altenaeum dawsoni (Jeffreys, 1864) with special reference to some new records from northern Norway (Mollusca, Bivalvia: Condylocardiidae?). Sarsia. 69: 205-209.
Daan R, Duineveld GCA, Lavaleye MSS & Mulder M 2001. Four marine mollusc species new to the Dutch recent fauna. Basteria. 65: 93-99.
Jefffreys J G 1864. British Conchology, vol. 2 Van Voorst, London. 479pp.
Spaink G 1972. Altenaeum nortoni nov. gen nov. spec. (Lamellibranchia: Condylocardiidae) from the Pleistocene of the southern North Sea Basin. Basteria. 36: 143-147.
Van Aartsen JJ 1996. Galeommatacea and Cyamiacea Part II. La Conchiglia. 281: 27-53, + 61.


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Record last modified: 17/05/2016