Species Account

Yoldiella annenkovae (Gorbunov, 1946)

Nuculanoidea : Nuculanidae

Tebble name: n/a
Smith & Heppell name: n/a

Notes on Nomenclature

Nuculanidae in place of Yoldiidae
Killeen & Turner (2009) use Nuculanidae instead of Yoldiidae in agreement with Ockelmann & Warén (1998) who explan that the distinguishing characters between these two families has never been well documented. Until the Yoldiidae can be clearly distinguished from the Nuculanidae we shall treat them under the single family Nuculanidae.

To size: To 2.5mm. Shell Structure: Thin, fragile. Equivalve: Equivalve. Equilateral: Almost equilateral, beaks at midline or very slightly behind the midline. Tumidity: Moderately inflated. Outline: Oval: pointed at the anterior end and obliquely, though almost vertically, truncated at the posterior end. The antero- and postero-dorsal margins are gently curved, and the ventral margin is shallowly curved to almost straight. The umbo is centrally placed, narrow, prominent, projecting above the dorsal margin.

Sculpture: Virtually smooth, with only very faint, closely spaced concentric lines. Margin: Smooth. Ligament: Amphidetic, attached internally to the underside of the beak without a projecting chondrophore or resilifer. Relatively long, arched, widest below the centre of the beaks and pointed at each end. Hinge: Taxodont, very narrow, gently curved hinge plate, with 5-6 blunt, chevron-shaped teeth either side of the umbo. Periostracum: Silky, straw-coloured. Colour: Translucent white. Additional Characters: The hind-gut forms a narrow loop on both sides of the body. It is curved with the dorsal and ventral sides relatively close together, tapering towards the anterior end, and is highly visible through the shell.

Distribution & Ecology

Known only from west of Shetland to northeast of Shetland in depths ranging from 725 to 1623m (mostly in 900-1000m).

Widely distributed from scattered localities over the Polar Basin in depths from 698 to 3270m:
off Franz Josef Land, east of Svalbard, west of the Lofoten Islands, Norway, Laptev Sea, Siberia, southeast and northeast of the Faroes, the North Canadian Basin.

Depth Range
Bathyal (500 - 2000m)

Additional Information & Related Species


Listed are literature citing Yoldiella annenkovae (Gorbunov, 1946). Reference containing the species Type Description is highlighted.

Gorbunov 1946. New and interesting species of Mollusca and Brachiopoda from the Arctic Ocean. Dreifuiuschaia Ekspeditia Glavseomorputi na Ledokol’nom Parakholi ‘G. Sedov’ 1937-1940 . 3: 308-322.
Killeen I.J. & Turner J. 2009. Yoldiella and Portlandia (Bivalvia) from the Faroe-Shetland Channel and Rockall Trough, Northeast Atlantic. Journal of Conchology. 39 (6): 733-778.


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Record last modified: 22/03/2016