Mating Activity - Nembrotha rutilans

January 18, 2001
From: Ken Knezick

[Note added 4 March 2008: This is the new species Nembrotha aurea - see message #21419]

Thank you for your ID of my Ceratosoma sinuata. I greatly appreciate the knowledge base represented by this list.

Thought you would enjoy the accompanying photo, taken near Padar Island, Indonesia (part of Komodo National Park).

I watched these two individuals find one another and begin mating. After exhausting my film, I surfaced, had lunch, returned two and a half hours later, and they were still colorfully engaged.

Color me jealous!

Knezick, K., 2001 (Jan 18) Mating Activity - Nembrotha rutilans. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Ken,
Apart from being a very colourful photo, this shot has some valuable scientific information. There are a number of very similarly coloured 'species' of Nembrotha which have been considered good species by some and perhaps just colour varieties by others. For example compare Nembrotha rutilans with Nembrotha purpureolineata, Nembrotha megalocera, Nembrotha sp. 1 and Nembrotha sp. 2.

In your photo, one of the animals has 5 relatively thin brown lines and the other has 3 broad dark brown bands. I am not sure that this solves everything, but it certainly shows that quite major colour differences can occur in one species.

The Forum is both a place to get things identified and a place to share information and interesting photos. Over the last few years we have gained a lot of interesting information on the biology of these amazing animals, which is of scientific value. So apart from nice photos of interesting animals, if you have photos of animals 'doing things' such as feeding, breeding, laying eggs etc they would be very welcome,
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Jan 18). Comment on Mating Activity - Nembrotha rutilans by Ken Knezick. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Nembrotha aurea

Related messages

  1. Nembrotha aurea being eaten by Robostra luteolineata [2]
    From: Colin Ogden, April 15, 2008
  2. Nembrotha aurea being eaten by Robostra luteolineata [1]
    From: Colin Ogden, April 15, 2008
  3. Re: Nembrotha rutilans, N. aurea & N. purpureolineata
    From: Colin Ogden, April 15, 2008
  4. Nembrotha rutilans, N. aurea & N. purpureolineata
    From: Bill Rudman, March 4, 2008
  5. Nembrotha purpureolineata - juvenile
    From: Wyatt Ang, July 13, 2007
  6. Nembrotha purpureolinata - feeding?
    From: Colin Ogden, March 29, 2006
  7. Nembrotha purpureolineata mating
    From: Roberto Sozzani, May 4, 2005
  8. Nembrotha purpureolineata from Mozambique
    From: Charles Rowe, February 7, 2005
  9. Nembrotha purpureolineata on an unusual path
    From: Valda Fraser, August 15, 2003
  10. Nembrotha purpureolineata from Indonesia
    From: Jim Bartlett, November 28, 2002
  11. Nembrotha purpureolineata feeding?
    From: Scott Johnson, October 25, 2002
  12. Nembrotha purpureolineata from Komodo
    From: Walabha Sinbul, August 7, 2002
  13. Nembrotha purpureolineata from Japan
    From: Yasuhiro Shirai, May 30, 2002
  14. Nembrotha purpureolineata? from Sulawesi
    From: Mary Jane Adams, May 11, 2002
  15. Nembrotha? from Japan
    From: Ken-Ichi Ohno, May 10, 2002
  16. Nembrotha purpureolineata from Westn Australia
    From: Kirk Gibson, April 1, 2001
  17. Nudibranchs of Southern Africa
    From: Yvonne Rozsenich, February 10, 2001
  18. Nembrotha from Philippines
    From: Erwin Koehler, March 14, 2000
  19. Nembrotha purpureolineata from South Africa
    From: Valda Fraser, December 20, 1999

Show factsheet and all related messages