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RISSOIDAE |
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Attenuata praetornatilis (Hedley, 1912) Description: Shell stout, solid, spire convex. Protoconch of 1¼ whorls, with weak spiral threads, and distinct junction with teleoconch. Teleoconch up to 3½ whorls; whorls concave or straight sided on upper half, with 2 strong spiral cords on lower half; last whorl with about 5 weaker cords on base. Aperture nearly circular, anterior canal broad, without posterior channel. Outer lip of aperture with strong varix externally. Umbilicus closed or a narrow slit. Colour opaque white. Size: Up to 2.8 mm in length. Distribution: Endemic to Australia: Clarence River, NSW, southwards to Tasmania. Habitat: On the continental shelf, 26-183 m. Uncommon. Comparison: This is very similar to Attenuata archensis, differing only in the number of spiral cords. There are specimens which have a weak spiral cord on the top half of the whorls, being intermediate in sculpture between A. praetornatilis and A. archensis, so the two may be extreme sculptural forms of a single species. Attenuata imbrex has a much taller spire. Synonymy: None. Fig. 1: Off Hallidays Point, NSW, in 118 m (C.396018) Fig. 2: Original figure from Hedley, 1912
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