Clanculus cruciatus (Linnaeus, 1758)
Algarve to Mediterranean. Grazer and deposit feeder in infralittoral rocky areas. The species exists for circa 16My. Original taxon: Trochus cruciatus.
On rocks in shallow water, Petit Paradis, eastern end of the cove, Anse de l’Arène, Cassis, Provence, S. France. 8-11mm.
 
Distinctive characteristics:
1: Basal cords smooth, whith interstitial areas are crossed by fine growth lines.
2: On the body, spiral sculpture is given by alignments of buttons; near the periphery of last whorl, a transition occurs between these rows and the smooth cords of basis.
3: Labial teeth more numerous and weaker than in corallinus.
4: The species does not show these big doubled columellar teeth, which are the very first distinctive feature of corallinus.
Synonyms: purpureus, rupestris… Many named variants.
Juvenile from 10m deep, Vignola bay, Marina di Davia, Corbara, NW. Corsica. 1,3mm.
Cl. corallinus (14-15) and Cl. cruciatus (16-17) in H. A. pilsbry: Manual of conchology, structural and systematic ser.1 vol.11, Philadelphia 1889, via BHL.
Monterosato reports two forms, “candida” and “rosea”, commonly found in the Gulf of Gabes, S. Tunisia.

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