Aplysiopsis enteromorphae
(Cockerell & Eliot, 1905)

Family: Hermaeidae


West coast of Nth America [Alaska to Mexico]


Locality: Scott Creek State Beach, Davenport,  California, USA, Pacific, 4 November 2009, Rocky intertidal, in a set of shallow pools, feeding on what I think is Cladophora. Length: 5-10 mm. Photographer: Ken-ichi Ueda.

The head is pigmented black except for a translucent whitish patch surrounding each eye. The body and cerata are translucent with the viscera showing through. In the cerata the branching digestive gland rages in colour from green to dark blackish brown depending on the algal food being eaten, and there is a white tip to each bluntly pointed ceras. Usually there are brown to purple lines running up the cerata.

The biology of this is species has been extensively studied in Oregon by Cynthia Trowbridge (1993a, b) It can grow to 30 mm in length but is usually between 10-20 mm. Animals grow very rapidly after larval settlement and can produce eggs within 3 or 4 days of metamorphosis. They feed on filamentous green algae of the genera Chaetomorpha, Cladophora, Urospora and Rhizoclonium.

Trowbridge found them in two distinct habitats -  on filamentous green algae in high intertidal pools on the open coast, and on green algal mats in bays and estuaries. This species was named Aplysiopsis smithi By Marcus (1961) but as Behrens (1991) noted,  Cockerell & Eliot's Phyllobranchopsis enteromorphae, is a much earlier name.

  • Cockerell, T. D. A. and C. N. E. Eliot (1905). Notes on a collection of Californian nudibranchs. The Journal of Malacology 12(3): 31-53.
  • Gonor, J. J. (1961). Observations on the biology of Hermaeina smithi, a sacoglossan opisthobranch from the west coast of North America. The Veliger 4(2): 85-98.
  • Marcus, E. (1961). Opisthobranch mollusks from California. Part One. The Veliger 3: 1-85
  • Trowbridge, C. D. (1993a). Population structure of two common species of Ascoglossan (= Sacoglossan) Opisthobranchs on the central coast of Oregon, USA. The Veliger 36(2): 99-106.
  • Trowbridge, C. D. (1993b). Feeding ecology of the ascoglossan opisthobranch Aplysiopsis enteromorphae (Cockerell & Eliot): patterns of distribution and impact on tidepool-dwelling green algae. Journal of Experimental Marine Biology and Ecology 169: 233-257.

Authorship details
Rudman, W.B., 2009 (November 24) Aplysiopsis enteromorphae (Cockerell & Eliot, 1905). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/aplyente

Related messages

  1. Aplysiopsis enteromorphae from California
    From: Ken-ichi Ueda, November 26, 2009

Show factsheet and all related messages