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RISSOIDAE |
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Rissoina (Rissoina) iredalei Laseron, 1950 Description: Shell with spire convex. Protoconch of 1 smooth whorl, with distinct junction with teleoconch. Teleoconch of 3¾-5¼ moderately convex whorls, shouldered below deeply impressed suture. Axial sculpture of narrow, widely and irregularly spaced axial grooves; spiral sculpture of deep grooves covering entire surface. Aperture lens or D-shaped, with broad anterior canal and narrow posterior canal; outer lip expanded, not thickened and smooth internally, with weak varix externally; inner lip callused, thickened at top and bottom. Colour translucent fawn when fresh, aging to opaque white. Size: Up to 6.0 mm in length. Distribution: Endemic to Australia; Tweed Heads, NSW, southwards and around southern Australia to south-western WA, including Bass Strait. Habitat: On the continental shelf, at depths of 20-150 m. Moderately common. Comparison: The unusual sculpture of widely-spaced axial grooves makes this species distinctive within the genus. Synonymy: Rissoina axiscalpta Cotton, 1952, from South Australia, is the same species (NEW SYNONYM). Fig. 1: Off Jervis Bay, NSW, in 37 m (C.395971) |
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