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RISSOIDAE |
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Voorwindia umbilicata Ponder, 1985 Description: Shell short and wide, spire outline convex. Protoconch of 1¼ whorls with junction to teleoconch well defined. Teleoconch of about 3 rounded whorls. Whorls with exceedingly fine spiral microsculpture barely visible with light microscope. Aperture ovate, anterior canal broad, not channelled posteriorly; outer lip thin, thickened by smooth varix externally; inner lip reflected towards narrow umbilicus. Shell colourless transparent when fresh, becoming opaque white with age. Size: Up to 2.3 mm in length. Distribution: Endemic to Australia: Hervey Bay, southern Queensland, southwards to Eden, NSW. Habitat: "Found in sheltered bays and estuaries on the northern half of the NSW coast where it is associated with seagrass" (Ponder, 1985). Most specimens are empty shells from beach washup or dredged down to 20 m. Common. Comparison: This is similar to Powellisetia simillima (May, 1916), differing by its broader, umbilicate shell. Although the shells are very similar, there are substantial differences in the animals of Voorwindia and Powellisetia. Synonymy: Laseron (1950) misidentified this species as Notosetia simillima (May, 1916) Fig. 1: Off Chinamans Beach, Middle Harbour, NSW (C.337640) |
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