Epitonium antisoa (Iredale, 1936)
Description: Shell slender for genus, fairly constant in height to width ratio; whorls connected. Whorls rounded, with about 16 axial ribs. Ribs usually very fine, thin, low, occasionally thickened; not peaked, continuous from whorl to whorl. Interspaces between axial ribs with 7-13 spiral threads, restricted to lower three-quarters of whorls. Aperture oval, outer lip with thick rib externally. Umbilicus open behind columellar callus. Colour white. Operculum unknown.
Size: Up to 19 mm in length.
Distribution: Australia and South Africa. In Australia, known from only two lots; Zilzie Point, Keppel Bay; Sydney Harbour.
Habitat: Queensland specimens are empty beach shells. Sydney Harbour specimens are empty shells obtained by the dredge Triton.
Comparison: This species is distinctive in the NSW fauna because of its very fine, sparse, axial ribs and strong spiral threads. See also "Identification of the NSW species of Epitonium" in the introduction to this family.
Remarks: Kilburn (1985) has recognised this species from South Africa, taken in 30-50 m.
Fig. 1: HOLOTYPE Sydney Harbour, dredge Triton (C.060654)
Fig. 2: HOLOTYPE Detail of sculpture
Copyright Des Beechey 2008