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UNGULINIDAE |
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Microstagon adamsi (Angas, 1868) Description: Shape higher than wide, umbo on midline. Anterior-dorsal margin slightly concave, margin otherwise smoothly rounded. Lunule absent. Exterior glossy with microscopic commarginal ridges. Interior with elongate muscle scars, pallial line continuous, margin smooth. Hinge strong, with 2 cardinal teeth in each valve, of which 1 is bifid. Ligament short, internal. Shell colour white or pink. Periostracum thin, shiny, usually absent. Size: Up to 12 mm in height. Distribution: Endemic to Australia. Southern Qld, southwards and around southern Australia to south-western WA, including Tasmania. Habitat: Lives in sand on exposed and semi-exposed coasts, down to 85 m. This is one of the most common shells washed up on Sydney beaches. Synonymy: A second species of Microstagon was described from NSW - Microstagon jacksonensis (Angas, 1868). It is supposedly smaller, more oblique and pinkish. Until the type material is examined (they are in the Natural History Museum in London) a firm conclusion cannot be reached whether it is a valid species or a form of M. adamsi. Huber (2015) synonymised Microstagon and Numella; the latter was a much more euphonious name in the present author’s opinion. Fig. 1: Cronulla Beach, Sydney, NSW (C.68659) |
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