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LIMIDAE |
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Divarilima sydneyensis (Hedley, 1904) Description: Shape very inequilateral, posterior and ventral margins rounded, anterior margin absolutely straight from umbo almost to ventral margin. Anterior region infolded creating a wide, concave, wrinkled region Hinge line straight, short, with auricle at posterior end, flat region above bisected by triangular ligament pit. Interior smooth, polished, two muscle scars posteriorly sometimes visible, exterior ribs showing through. Exterior with numerous, very fine radial ribs, microscopically rugose, diverging from midline. Periostracum fawn to dark brown, absent in beach specimens. Shell translucent, white. Size: Up to 10 mm in height. Distribution: Known from eastern Australia, northern New Zealand and Kermadec Islands. In Eastern Australia, from Swain Reefs, Qld, southwards to Sydney. Habitat: Lives attached by a byssus under stones intertidally and subtidally, down to 77 depth. Most commonly found in beach washup. Synonymy: This small species with its distinctive shape and sculpture was first described as Lima brunnea Hedley, 1901, but that name was preoccupied, and Hedley renamed it in 1904 as Lima sydneyensis. The original name L. brunnea was not an obvious choice as beach specimens are white, and it is not until live taken specimens are seen, some of which have a dark brown periostracum, that Hedley’s first choice of name is appreciated. Fig. 1: Kurnell, Botany Bay, NSW. Beach washup (C.359453) Fig. 2: Green Point, Watsons Bay, Sydney Harbour. Dredged 9-14.5 m (C.222353) |
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