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Semicassis angasi (Iredale, 1927)

Description: Shell light in weight, whorls rounded. Spire whorls with spiral ribs and grooves crossed by dense axial riblets. Body whorl smooth, with weak spiral threads on shoulder and spiral grooves at base. Columella and columellar shield strongly plicate; shield margin with lobe extending onto anterior fasciole. Umbilicus and false umbilicus open. Outer lip reflected, toothed along inner edge. Colour white, fawn or pink.

Size: Up to 54 mm in length.

Distribution: Restricted to Australia, from the Kimberley, WA, to Sydney, NSW.  The Sydney record is based on a single fresh dead specimen collected in Camp Cove, Sydney Harbour, by Ashley Miskelly in 2015. The next northernmost record is Trial Bay in northern NSW.   The Australian Museum collection hold specimens dredged from below the sea floor in Sydney Harbour, but these are probably subfossil.

Habitat: In northern Australia, uncommon at low tide level down to 70 m. Rare in NSW, subtidal.

Synonyms: Xenogalea angasi knighti Thornley, 1954 was described as "differing in colour, more rounded and not shouldered, smoother everywhere, and the ridging and cancellation of the upper whorls are less prominent", but these features fall within the range of variation of the species. Also Phalium denisi Salmon, 1948.

Remarks: Abbott (1968) considerd this species to be a subspecies of the western Pacific species Semicassis glabratum (Dunker 1852).

Figs. 1,2: Off Iluka, NSW, in 45-65 m (C.154302)

 

Copyright Des Beechey 2000