Diloma arida

Diloma arida is a top shell, a marine gastropod mollusc in the family Trochidae.

Distribution

This top shell is endemic to New Zealand, including the Chatham, Auckland and Campbell islands.

Habitat

This species is common in the upper intertidal zone in sheltered rocky situations.

Shell description

The shell is solid, globose-conoid, with flattened sides and a subangulate periphery, smooth except for weak spiral lirae.

Coloration is purplish-black, sparsely spotted on the last whorl, in white or yellowish. The interior of the aperture is reddish-iridescent.

Maximum height is 19 mm, and width 17 mm.

References

• Powell A W B, New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979 ISBN 0-00-216906-1