Sirius badius (Tension-Woods, 1878)
Description: Protoconch of 1¼ whorls, with 4 spiral keels. Teleoconch up to 3 whorls. Spire whorls usually shouldered, with cord on shoulder, 2-3 spiral threads above and 3-4 cords below. Last whorl rounded, with 6 spiral cords on base.. Axial sculpture of dense riblets, forming beads or lamellae at intersections with spiral cords on shoulder and below. Umbilicus a narrow or broad slit. Columella with large nodule bordering anterior canal. Aperture semicircular, outer lip expanded, thin. Colour white, with lamellate fawn periostracum.
Size: Up to 5 mm in length.
Distribution: Endemic to Australia: Swain Reefs, Queensland, southwards to Tasmania.
Habitat: Occasionally collected as empty beach shells, but moderately common subtidally down to 384 m.
Synonymy: Sirius meracus Iredale, 1936 was described by the author as "easily distinguished [from Sirius badius] by its smaller size, its more pronounced sculpture and its narrow umbilical fissure", but it falls within the range of variation of Sirius badius (NEW SYNONYM). Sirius meracus chrestus Iredale, 1936 is based on a shell of S. badius with 3 teleoconch whorls, rather than the typical 2¾, in which the last quarter whorl is expanded and loosely coiled (NEW SYNONYM) (Fig. 3). Sirius meracus desponsus is based on a relatively short and broad specimen of S. badius (NEW SYNONYM).
Fig. 1: 4037-1 16 miles east of Wollongong, NSW, in 183 m (C.017994)
Fig. 2: 4038-1 30 km SW of Cape Everard, Victoria, in 119 m (C.360538)
Fig. 3: 4039-1 Holotype of Sirius meracus chrestus. Off Cape Pillar, Tasmania, in 100 fathoms (183 m) (C.029056)
Copyright Des Beechey 2007