Species Account

Kelliola symmetros (Jeffreys, 1876)

Galeommatoidea : Montacutidae

Tebble name: n/a
Smith & Heppell name: Axinodon symmetros (Jeffreys, 1876)

Notes on Nomenclature

Here previously as Axinodon symmetros.

To size: To 1.3mm. Shell Structure: Thin, fragile. Equivalve: Equivalve. Equilateral: Slightly inequilateral, beaks a little behind midline. Tumidity: Not inflated. Outline: subovate, slightly extended anteriorly; anterior dorsal margin sloping into broadly rounded anterior margin; posterior dorsal margin indistinct, sloping into broadly rounded posterior margin, this slightly less expanded than anterior margin; ventral margin weakly curved.

Sculpture: Weak, of indistinct commarginal lines most obvious on lateral margins. Margin: Inner margin smooth. Ligament: Internal, short, attached to a shallow resilifer situated beneath and posterior of the beaks. Hinge: Right valve with a single, projecting, cardinal peg, immediately anterior to this tooth a slight depression; left valve with a short, weak, marginal flange in a posterior lateral position. Pallial Musculature: Scars weakly impressed, indistinct but adductor muscles subequal, pallial line entire. Periostracum: Insignificant. Colour: Shell off-white, translucent.

Distribution & Ecology

Known from the North Atlantic as far south as the Bay of Biscay. It is commensal, living attached to the spines of the echinoid Aeropsis. The gills are not modified for hosting bacteria and is presumed to be a suspension feeder

Known only from abyssal depths, 3202-4165m

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

Additional Information & Related Species

Key Features & Similar Species

Such small species of the Montacutidae are difficult to identify if not associated with their host. At bathyal depths the only other echinoid associate is Kelliola symmetros but it is not so expanded anteriorly and is hosted by the echinoid Aeropsis.

Related Species


Listed are literature citing Kelliola symmetros (Jeffreys, 1876). Reference containing the species Type Description is highlighted.

Jeffreys J G 1876. New and peculiar Mollusca of the Kellia, Cyprina and Corbula families, procured in the Valorous expedition. Annals and magazine of natural History. (4) 18: 490-499.
Oliver P.G. 2012. Taxonomy of some Galeommatoidea (Mollusca, Bivalvia) associated with deep-sea echinoids: A reassessment of the bivalve genera Axinodon Verrill & Bush, 1898 and Kelliola Dall, 1899 with descriptions of new genera Syssitomya gen. nov. and Ptilomyax gen. nov. . European Journal of Taxonomy. 12: 1-24.


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Record last modified: 17/05/2016