Sirius idoneus (Iredale, 1931)
Description: Protoconch of 2 smooth whorls. Teleoconch of 5 whorls, sculptured with 5 spiral cords, two at periphery strongest. Further 3 cords on base of body whorl. Axial sculpture of ribs forming beads at intersections with spiral cords. Umbilicus open, edged by anterior fasciole. Columella with low nodule bordering anterior canal. Outer lip expanded, thin. Colour fawn
Size: Up to 20.5 mm in length.
Distribution: Sydney Harbour, NSW.
Habitat: From harbour dredging.
Remarks: Only two specimens of this species are known, both picked out from dredge spoil from Sydney Harbour, when the dredge Triton was forming shipping channels. They are probably fossils.
Fig. 1: 4036-1 Sydney Harbour, Triton dredge. (C.166199)
Copyright Des Beechey 2007