Plocamopherus imperialis
Angas, 1864

Order: NUDIBRANCHIA
Suborder: DORIDINA
Family: Polyceridae
Subfamily: Triophinae

DISTRIBUTION

Known from temperate southeastern Australian waters and northern New Zealand.

PHOTO

Green Pk, Woolgoolga, northern New South Wales, Australia, Nov 1982. Length approx 70mm. Lower photo showing a magnified view of one of the posterior lateral bulbs on the side of the body. PHOTOS: Bill Rudman.

RELATED TOPIC

Plocamopherus tilesii

Species of Plocamopherus have a series of paired papillae down the upper (mantle) edge of the body. Some of these papillae usually have a large bulb at the tip. When disturbed, the bulbs, and other patches on the side of the body, luminesce, producing flashes of light down each side of the body. How they do this and whether light-producing bacteria are involved is unknown.

Species of Plocamopherus also are able to extend the posterior end of their body/foot into a vertical "paddle". When disturbed they can also swim by vigorously flapping their body from side to side like a stranded fish. The paddle-like shape of the posterior end of the body provides necessary propulsion, just like a fish, to propel the slug through the water.

Although it is often found crawling over brown algae, it most probably feeds on arborescent bryozoans, but I know of no direct observations on its feeding habits.

Reference:
• Angas, G.F. (1864). Description d'espèces nouvelles appartenant à plusieurs genres de Mollusques Nudibranches des environs de Port-Jackson (Nouvelles-Galles du Sud), accompagnée de dessins faits d'après nature. Journal de Conchyliologie, 12: 43-70

Authorship details
Rudman, W.B., 1998 (December 21) Plocamopherus imperialis Angas, 1864. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/plocimpe

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