Epitonium christyi (Iredale, 1936)
Description: Shell moderately broad for genus; whorls disconnected, joined only by axial ribs. Whorls rounded, with 11-13 axial ribs per whorl. Ribs tall, rolled back, peaked below suture, aligned from whorl to whorl. Interspaces with numerous spiral threads, crossed by finer axial threads. Aperture oval, outer lip with normal rib externally. Umbilicus open. Colour white, with broad, tan band at middle of whorls. Operculum unknown.
Size: Up to 21 mm in length.
Distribution: Australia and Japan. In Australia, known only from Port Stephens and Sydney Harbour. In Japan, known from off Minabe, Kii Peninsula, in 70 m (Nakayama, 2003).
Habitat: Known from empty shells from beach washup and down to 13 m. Rare.
Comparison: See "Identification of the NSW species of Epitonium" in the introduction to this family.
Remarks: In the original description Iredale described this species as having the whorls "not separate", but in the type and all other specimens they are disconnected, joined only by the axial ribs (Fig. 2).
Fig. 1: HOLOTYPE Sydney Harbour, dredge Triton (C.060648)
Fig. 2: HOLOTYPE Detail of sculpture and suture
Copyright Des Beechey 2008