Micrelenchus purpureus

Micrelenchus purpureus, common name the red opal top shell, is a species of medium-sized sea snail, a marine gastropod mollusc in the family Trochidae.

Description
The length of the shell varies between 16 mm and 32 mm. It grazes on seaweed.

Distribution
This marine species occurs off North Island and South Island, New Zealand.