Species Account

Silicula fragilis Jeffreys, 1879

Nuculanoidea : Siliculidae

Tebble name: n/a
Smith & Heppell name: Silicula fragilis Jeffreys, 1879

To size: To 5mm. Shell Structure: Thin, fragile. Equivalve: Equivalve. Equilateral: Inequilateral, beaks situated to the anterior of midline, approximately 30% of total length from anterior end. Tumidity: Flattened. Outline: Elongate, rounded rectangular: length of shell approximately twice the height; shell gaping anteriorly and posteriorly and along the dorsal margin; antero-dorsal margin short, gently sloping; anterior end well rounded, sometimes with a slight point; postero-dorsal margin very long, slightly concave, slightly sloping, with a sharp dorsal margin - posterior margin junction; posterior end angled, straight and truncated and forming a distinct junction with the ventral margin; ventral margin gently rounded. Umbo narrow, pointed and projecting slightly above the dorsal margin.

Sculpture: Virtually smooth , with extremely fine, regularly spaced concentric lines. Margin: Smooth. Ligament: Opisthodetic, narrow curved, angled posteriorly, attached internally to the underside of the beak without a projecting chondrophore or resilifer. Hinge: Taxodont: long, broadening away from the umbos. Very long, thin overlapping teeth, usually 4 posterior and 3 anterior. Periostracum: Glossy, very pale straw coloured, slightly iridescent, almost transparent. Colour: Transparent. Additional Characters: Gut loop: The hind-gut forms a rounded loop on both sides of the body.

Distribution & Ecology

A deep water species known from several Atlantic deep-sea basins (West European, North American and Argentine) in depths ranging from 1500 to 4400m.

Depth Range
Abyssal Rise (2000 - 4000m)
Abyssal Plain (4000m +)

Additional Information & Related Species

Related Species

Nuculanoidea : Siliculidae


Listed are literature citing Silicula fragilis Jeffreys, 1879. Reference containing the species Type Description is highlighted.

Allen J A & Sanders H L 1973. Studies on deep-sea Protobranchia (Bivalvia); the families Siliculidae and Lametilidae). Bulletin of the Museum of Comparative Zoology, Harvard. 145: 263-310.
Jeffreys J.G. 1879. On the Mollusca procured during the ‘Lightning’ and ‘Porcupine’ Expeditions, 1868-70. (Part II). Proceedings of the Zoological Society of London. 1879: 553-588.
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.


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Record last modified: 22/03/2016