Species Account

Yoldiella incala Allen, Sanders & Hannah, 1995

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 5mm. Shell Structure: Thin, fragile. Equivalve: Equivalve. Equilateral: Moderately inequilateral, the beaks lie approximately 40% of dorsal margin length from anterior. Tumidity: Rather compressed. Outline: Elongate-oval: dorsal margin crimped either side of the umbo, dipping down to give a small notch; postero-dorsal margin long, straight (or slightly concave), gently sloping with a dorsal margin – posterior margin junction; antero-dorsal margin shorter and gently sloping; lower posterior margin obliquely truncated, weakly rostrate in larger specimens; anterior margin broadly rounded; ventral margin long, deeply rounded. Umbo relatively narrow, but prominent, projecting just above the dorsal margin, situated anterior of midline. Contour: Thin, laterally compressed.

Sculpture: Weak striations. Margin: Smooth. Ligament: Amphidetic, attached internally to the underside of the beak without a projecting chondrophore or resilifer. Relatively short. Hinge: Taxodont: long, v-shaped with up to 8 well-developed chevron-shaped teeth on either side of the ligament. Periostracum: Silky, pale straw-coloured. Colour: Translucent white. Additional Characters: The hind-gut forms a simple, rounded loop on the right side of the body.

Distribution & Ecology

Southern part of Rockall Trough to northwest of Rosemary Bank in depths ranging from 1270 to 2900m.
Western European Basin (including Rockall Trough) from latitudes of 44°N to 58°N, and at depths of 1913-2170m.

Depth Range
Bathyal (500 - 2000m)
Abyssal Rise (2000 - 4000m)

Additional Information & Related Species


Listed are literature citing Yoldiella incala Allen, Sanders & Hannah, 1995. Reference containing the species Type Description is highlighted.

Allen, J.A., Sanders, H.L. & Hannah, F. 1995. Studies on the deep-sea Protobranchia (Bivalvia); the subfamily Yoldiellinae. Bulletin of the British Museum of Natural History. 61: 11-90.
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