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RISSOIDAE |
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Powellisetia simillima (May, 1916) Description: Shell short and wide, spire outline straight. Protoconch of 1 whorl, with well-defined junction to teleoconch. Teleoconch of up to 3 whorls; spire whorls rounded, last whorl sometimes with weak angulation on periphery. Whorls smooth, or with irregular axial growth zones that produce a pattern of alternating opaque and translucent axial bands. Aperture ovate, with weak posterior sinus and shallow excavation anteriorly; inner lip reflected over narrow umbilical slit; out lip thickened externally with weak varix. Shell colourless transparent when fresh, becoming opaque with age. Size: Up to 2.0 mm in length. Distribution: Endemic to Australia: Laurieton, NSW, southwards to south-western Tasmania. Habitat: Subtidal, 64-366 m. Uncommon. Comparison: This is similar to Pusillina (Haurakia) angulata, but is shorter and broader, and has a less sinuate outer lip. There are anatomical differences described by Ponder (1985, p. 62). Synonymy: None. Fig. 1: 1.6 km east of Malabar outlet, NSW (C.396116) Fig. 2: Original figure from May, 1916
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