Calliotropis regalis

Calliotropis regalis, or the regal spiny margarite, is a species of sea snail, a marine gastropod mollusk in the family Eucyclidae.

In older literature, this species was always synonymized with Margarita regalis Verril & Smlith, 1880 or with Trochus ottoi Philippi, 1844 or with Solariella ottoi Philippi, 1844, all synonyms of Calliotropis ottoi (Philippi, 1844).

Description
The size of an adult shell varies between 6 mm and 18 mm.

Distribution
This species is distributed in European waters along the British Isles and the Faroes, in the Mediterranean Sea, in the Northwest Atlantic Ocean from Nova Scotia to North Carolina.