Angular Unicorn

Acanthinucella spirata





A common sight especially during the winter (2), Acanthinucella spirata are predatory sea snails with a unique common name. They can be easily distinguished by a row of teeth on their blue-white aperture (2), the opening of the shell. Up to 4 cm long, they have broken brown bands that spiral around the shell with a light grey background (3). A. spirata lack a planktonic larval stage, instead freshly hatched A. spirata emerge from egg capsules as juveniles (1). This spatially restrictive reproductive method leads to low dispersal and is the main driver of their interaction with prey populations, chief among them that they cannot follow geographic variation in prey abundance (4). These predatory sea snails mainly feed on small mussels and barnacles (2).


(1) Hellberg, M. E., Deborah P. Balch, and Kaustuv Roy. "Climate-Driven Range Expansion and Morphological Evolution in a Marine Gastropod." Science 292, no. 5522 (2001): 1707-710. doi:10.1126/science.1060102.

(2) Hinton, Sam. Seashore life of southern California, New and Revised Edition. Univ Of California Press, 1987.

(3) Watanabe, James M. Molluscs.

(4) Wieters, Evie A., Steven D. Gaines, Sergio A. Navarrete, Carol A. Blanchette, and Bruce A. Menge. "Scales of Dispersal and the Biogeography of Marine Predator‐Prey Interactions." The American Naturalist 171, no. 3 (January 25, 2008): 405-17. doi:10.1086/527492.



  • rocky intertidal