Intertidal Invertebrates of the Monterey Bay Area, California

Compiled & photographed by Gary McDonald, Long Marine Laboratory, University of California, Santa Cruz

Eubranchus rupium (Moller, 1842)               
Green Balloon Aeolid
Mollusca: Gastropoda: Opisthobranchia: Nudibranchia: Aeolidina: Eubranchidae
Geographic Range: Homer, AK, to Bahia de los Angeles, Baja California, Mexico. Synonyms: Eubranchus olivaceus
Back to: Aeolidina Back to: Intertidal Invertebrates of the Monterey Bay Area
Buckhorn Cove, Mendocino Co., CA; 23 June 2009; 11mm total length; Brenna Green.

Description: Ground color pale translucent yellow-green to yellow-white, an irregular network of reddish-brown lines occurs on dorsum, along with a faint, irregular, dorso-medial band of olive green. A few opaque white dots occur on head and dorsal surface of tail. Cerata slightly frosted with white and bear an indistinct, subterminal band of reddish-brown to olivaceous green, cores deep olivaceous green. Oral tentacles translucent yellow-white with a subterminal band of brownish to olivaceous green, and encrusted with white dots which are more concentrated distally. Rhinophores smooth, colored as oral tentacles. Foot corners rounded. May be distinguished from Eubranchus rustyus which has specks of brownish to light grey or greenish over body & lacks dorso-medial band of olive green.
Size: Typically less than 12mm in length.
Notes: Feeds on hydroids such as on Laomedea flexuosa, Obelia spp., & Plumularia sp. Very rare in the Monterey Bay area.

Asilomar, Monterey Co., CA; 5 May 1973; 7mm total length.

Last Updated: