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UNGULINIDAE |
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Toralimysia excentrica Iredale, 1936 Description: Shell lightweight, well inflated. Shape sub-circular, umbo large, margins rounded, anterior more sharply than posterior. Lunule absent. Exterior with fine, irregular, commarginal ridges. Interior with indistinct, elongate muscle scars, pallial line continuous; margin smooth. Hinge strong, with 2 cardinal teeth in each valve, of which 1 is bifid (Fig. 2); lateral teeth not present. Ligament short, external. Shell colour white with thin fawn periostracum. Size: Up to 20 mm in height. Distribution: Endemic to Australia. Known from the middle reaches of Sydney Harbour, mainly west of the Harbour Bridge. The Atlas of Living Australia records a specimen from Moreton Bay, Queensland, and another from southern Tasmania, but the identification of these need confirmation. Habitat: Known from muddy substrates down to 8 m depth. Comparison: This species differs from the more common Zemysia tasmanica by being more inflated and having a sub-circular outline. Fig. 1: Sydney Harbour, NSW. PARATYPE C.172774 ex C47682 Fig. 2: Same specimen as Fig. 1. Hinge detail. |
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