Antiopella barbarensis is a commonly found nudibranch on the Pacific coast inhabiting tide pools of La Jolla, California.[6] Populations also expand to some parts of Costa Rica.
Behrens 1991 gives the distribution as "San Francisco Bay to Baja California, Gulf of California, Mexico".[7]
^Cooper, J.G. (1863). On new or rare Mollusca inhabiting the coast of California. Proc. Calif. Acad. Sci. 3(1): 56-60
^Turgeon, D.; Quinn, J.F.; Bogan, A.E.; Coan, E.V.; Hochberg, F.G.; Lyons, W.G.; Mikkelsen, P.M.; Neves, R.J.; Roper, C.F.E.; Rosenberg, G.; Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D. (1998). Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. 2nd ed. American Fisheries Society Special Publication, 26. American Fisheries Society: Bethesda, MD (USA). ISBN1-888569-01-8. IX, 526 + cd-rom pp.