Ceratosoma brevicaudatum from Melbourne, Australia

April 6, 2010
From: James Bailey

I have attached a photo of a common Sea Slug that I find in the rock pools at Brighton Beach in Melbourne, Australia. Sea slugs fascinate me, and I feel somewhat disappointed I can't put a name to this one. Thanks in advance.

Locality: Brighton Beach, Brighton, Melbourne, Australia, in shallow rock pool, Victoria, Port Phillip Bay, 05 April 2010, Rock pools. Length: No length available.. Photographer: Myself.

James Bailey

silverwolf.lupinewilderness@hotmail.com

Bailey, J.P., 2010 (Apr 6) Ceratosoma brevicaudatum from Melbourne, Australia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/23446

Dear James,

This is Ceratosoma brevicaudatum. Most species of Ceratosoma are found in the warm tropical waters of the Indo-West Pacific and as you will see with Ceratosoma trilobatum they usually have a long recurved dorsal 'horn' which sticks up from the body behind the gills. This horn has an interesting defensive function because it is where the animal stores distasteful and noxious chemicals its has removed from its sponge food. The horn appears to act as a sacrificial lure, tempting fish to take a bite. When or if they do they get a mouth full of nasty chemicals which teach them to leave Ceratosoma alone. As the 'hom' has no other function, the slug can live quite happily without it.

It seems that Ceratosoma brevicaudatum represents an early stage in the evolution of the dorsal horn. In the close-up alongside I have ringed the swollen 'bump' which is found in this species. It is packed full of noxious chemicals and is usually more brightly coloured thyan the rest of the body - again acting as a lure. If you look at some of the other messages on thsi species, which are attached to the Fact Sheet, you will see that in juveniles the horn is even more brightly coloured.

The name brevicaudatum means 'short tail' in Latin, which is a reference to this very short dorsal horn.

Best wishes,
Bill Rudman

Rudman, W.B., 2010 (Apr 6). Comment on Ceratosoma brevicaudatum from Melbourne, Australia by James Bailey. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/23446

Factsheet

Ceratosoma brevicaudatum

Related messages

  1. Ceratosoma brevicaudatum laying eggs
    From: Leanne & David Atkinson, April 10, 2007
  2. Ceratosoma brevicaudatum from Western Australia
    From: Bruce Potter, January 30, 2007
  3. Ceratosoma brevicaudatum from Port Philip Bay
    From: Bill van Eijk, March 25, 2006
  4. Ceratosoma brevicaudatum mating
    From: Leanne & David Atkinson, January 21, 2006
  5. Juvenile Ceratosoma brevicaudatum from W. Australia
    From: Chris Cunnold, October 25, 2005
  6. Re: Ceratosoma brevicaudatum from Botany Bay
    From: Nicholas Missenden, May 31, 2005
  7. Ceratosoma brevicaudatum from Botany Bay
    From: Nicholas Missenden, May 27, 2005
  8. Ceratosoma brevicaudatum feeding
    From: John Chuk, March 8, 2004
  9. Ceratosoma brevicaudatum laying eggs
    From: Leanne & David Atkinson, February 17, 2004
  10. Ceratosoma brevicaudatum feeding
    From: Nerida Wilson, February 17, 2004
  11. Ceratosoma brevicaudatum feeding
    From: Leanne & David Atkinson, February 11, 2004
  12. Ceratosoma brevicaudatum feeding
    From: Leanne & David Atkinson, January 21, 2004
  13. Ceratosoma brevicaudatum feeding
    From: Sue Newson, November 18, 2003
  14. Ceratosoma brevicaudatum from eastern Australa
    From: Sue Newson, May 14, 2003
  15. Ceratosoma brevicaudatum from Port Stephens, NSW
    From: Ian Simpson, December 11, 2002
  16. Ceratosoma brevicaudatum from South Australia
    From: Stuart Hutchison, February 22, 2002
  17. Ceratosoma amoena and ? from Nelson Bay, NSW
    From: David Harasti, April 25, 2001
  18. Re: Feeding in Ceratosoma brevicaudatum
    From: Des Paroz, October 27, 2000
  19. Feeding in Ceratosoma brevicaudatum
    From: Des Paroz, October 20, 2000
  20. Colour variation in Ceratosoma brevicaudatum
    From: Stuart Hutchison, September 14, 2000
  21. Ceratosoma brevicaudatum from Sydney
    From: A. Lumnitzer & D. Piotrowska, June 9, 2000
  22. Ceratosoma brevicaudatum from Sydney
    From: Akos Lumnitzer, June 2, 2000

Show factsheet and all related messages