Ground color translucent greyish-white. A median band of brilliant cadmium orange occurs between oral tentacles and passes between rhinophores (where it is narrowest), to anterior of cardiac region; an opalescent blue line occurs dorsally on either oral tentacle, becoming broader & bifurcating proximally, inner portion of blue line extends between rhinophores, on either side of orange line, and continues dorso-medially to tip of tail; outer portion of these blue lines extend dorso-laterally to tip of tail. A narrow, opalescent blue line extends posteriorly along dorsal margin of foot, from foot corners to tip of tail. Cerata in 5-11 groups, tipped with white, with a subterminal band of cadmium orange, cores usually light burnt umber to deep brown, but variable depending upon food source. Rhinophores weakly perfoliate, with 8-24 lamellae, clavus opalescent white to very pale blue. Distinguished from Hermissenda crassicornis which has cerata with reddish-orange tips, & a bluish-white longitudinal band on anterior surface of each ceras. May be distinguished from the much rarer Emarcusia morroensis which has smooth rhinophores and lacks opalescent blue lines on body.
Typically about 25mmm in length, but may exceed 70mm.
Washington, to Bahia de Los Angeles, Baja California, Mexico.
Preys on a variety of hydroids. Previously considered a junior synonym of Hermissenda crassicornis.
LINDSAY, T., & Á. VALDÉS. 2016. The model organism Hermissenda crassicornis (Gastropoda: Heterobranchia) is a species complex. PLoS ONE 11(4): e0154265. PDF
MACFARLAND, F. M. 1966. Studies of opisthobranchiate mollusks of the Pacific coast of North America. Memoirs of the California Academy of Sciences 6:1-546, pls. 1-72. PDF
McDONALD, G. R. 1983. A review of the nudibranchs of the California coast. Malacologia 24(1-2):114-276. PDF
SOUTHERN CALIFORNIA ASSOCIATION OF MARINE INVERTEBRATE TAXONOMISTS. 2018. A taxonomic listing of benthic macro- and megainvertebrates from infaunal & epibenthic monitoring and research programs in the southern California bight, edition 12, 1 July 2018, xviii + 167 pp. PDF
Body | aeolidiform |
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Cerata | unbranched |