Sea Slugs are known to regenerate body parts that have been lost either through accident, attack or autotomy. If anyone has any recent references or observations they would be very welcome. Discussions and reports on regeneration are found in many parts of the Forum. A search of the Forum for regeneration should find most of them.

See also pages on Autotomy and Abnormalities

Authorship details
Rudman, W.B., 2001 (January 16) Regeneration. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

Re: Damaged Elysia crispata

September 2, 2006
From: Denis Riek

Concerning message #17684:

Dear Bill,
This poor Elysia sp was found this week at Hastings Point. It was moving over algae on rock reef in shallow water. Although not much more than a head it was making fairly good progress, moving in a jerking fashion. It was still very much alive when returned to the water after six days at home in a bowl.

Locality: Hastings Point. Northern New South Wales, 1 metre, Australia, Pacific, 23 August 2006, On algae on rock reef. Length: 6 mm. Photographer: Denis Riek.


Riek, D.W., 2006 (Sep 2) Re: Damaged Elysia crispata. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Denis,
Your photo alongside well illustrates what Nick Curtis said about these animals surviving as long as the percardial region was intact. The lump in the middle of the animal is the heart and pericardial region which also contains the kidney opening and the anus. This means the main body organs are still intact and operating, allowing the animal to regenerate its lost half. - but please don't ask me to try and identify it.

Best wishes,
Bill Rudman

Rudman, W.B., 2006 (Sep 2). Comment on Re: Damaged Elysia crispata by Denis Riek. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Re: Regeneration in Elysia ornata

January 20, 2001
From: Kathe R. Jensen

Dear Bill,

In reply to Satoru's message, I have a few references to autotomy and regeneration in sacoglossans. It seems that in the Oxynoidae the tail and parapodial lobes can be autotomized and regenerated. In the Limapontioidea the cerata can be autotomized and regenerated. I have also observed partial regeneration of rhinophores in several species, and sometimes partial regeneration of part of parapodia in Elysia spp..

• Di Marzo, V., Vardaro, R.R., De Petrocellis, Villani, G., Minei, R. & Cimino, G. 1991. Cyercenes, novel pyrones from the ascoglossan mollusc Cyerce cristallina. Tissue distribution, biosynthesis and possible involvement in defense and regenerative processes. Experientia, 47: 1221-1227.
• Di Marzo, V., Marin, A., Vardaro, R.R., De Petrocellis, L., Villani, G. & Cimino, G. 1993. Histological and biochemical bases of defense mechanisms in four species of Polybranchioidea ascoglossan molluscs. Marine Biology, 117: 367-380.
• Warmke, G. & Almodovar, L.R. 1972. Observations on the life cycle and regeneration in Oxynoe antillarum Morch, an ascoglossan opisthobranch from the Caribbean. Bulletin of Marine Science, 22: 67-74.

Kathe Jensen

Jensen, K.R., 2001 (Jan 20) Re: Regeneration in Elysia ornata. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Kathe,
With luck someone will know of some studies on nudibranchs as well.
Bill Rudman

Regeneration in Elysia ornata

January 18, 2001
From: Satoru Hori

Dear Bill

I found Elysia ornata whose rhinophores were lost. I took this sea slug in my tank because I wanted to know how long it could live without rhinophores. In my tank, I cultivated a type of sea weed that Elysia ornata ate. That sea weed is shown in the photo.

To my surprise, rhinophores were regenerated after a month. I would like to know more about the regeneration rhinophores and cerata. Could you tell me the references on regeneration of sea slugs.

Thank you.
Satoru Hori

Hori, S. , 2001 (Jan 18) Regeneration in Elysia ornata. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Satoru,
Thanks for the interesting information on regeneration in Elysia ornata. I am afraid I can't help with any recent references on regeneration in sea slugs. If anyone out there knows of some I would be very grateful for the information.

There were some French & German studies published about 1900. There was also a paper by Child (1905) which showed that aeolids could regenerate the head if it was cut off in front of the nerve ring, and regenerate the posterior part of the body as long as more than half the body remained.
[Child, C. (1905) Regeneration in Nudibranchs. Science, 21]

Hopefully someone can help us with some recent references.
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Jan 18). Comment on Regeneration in Elysia ornata by Satoru Hori . [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from