Green Giant' nudibranch
updated May 2020
seen? This large chunky hard nudibranch is sometimes seen among coral rubble
and reefs on our Southern islands. Usually several are seen at the
same time, and then none for a while. It does look rather jolly and
is large! It was previously known as Ceratosoma sinuatum.
Features: 6-8cm long. The body is stiff, narrow with a short, broad tail. The front of the body generally pointed. The body edge has regular
undulating lobes along the edge of the mantle from front to end. The
lobes are armed with glands that secrete distasteful substances to
discourage predators. There is a large horn-like lobe in front of the feathery
usually green, with small yellow bumps, sometimes with tiny blue spots. The gills have tiny yellow spots.
Like other members of the Family Chromodorididae, the Ceratosoma nudibranch
absorbs the toxic chemicals in their sponge food and incorporate these
chemicals into the mantle glands. According to Bill
Rudman, most species of Ceratosoma have a long 'horn' that
stick out and curves towards the head. This acts as a defensive lure
attracting and sacrificed to potential predators. This 'horn' contains
most of the distasteful chemicals stored from the sponges that they
What does it eat? It is eats sponges.
Large lobe in front of gills.
Sisters Island, Jul 06
Semakau, Feb 09
gills with yellow spots.
Green Giant' nudibranchs on Singapore shores
|Other sightings on Singapore shores
Releasing white fluid when alarmed.
Pulau Hantu, Aug 15
Photo shared by Marcus Ng on flickr.
Tanah Merah, Jul 09
Photo shared by James Koh on flickr.
Pulau Hantu, Aug 15
Photo shared by Marcus Ng on facebook.
- Tan Siong
Kiat and Henrietta P. M. Woo, 2010 Preliminary
Checklist of The Molluscs of Singapore (pdf), Raffles
Museum of Biodiversity Research, National University of Singapore.
Helmut, 2001. Nudibranchs
and Sea Snails: Indo-Pacific Field Guide
IKAN-Unterwasserachiv, Frankfurt. 321 pp.
- Wells, Fred
E. and Clayton W. Bryce. 2000. Slugs
of Western Australia: A guide to the species from the Indian to
West Pacific Oceans.
Western Australian Museum. 184 pp.
Neville. 2001. 1001
Nudibranchs: Catalogue of Indo-Pacific Sea Slugs. Neville
Coleman's Underwater Geographic Pty Ltd, Australia.144pp.
Neville, 1989. Nudibranchs
of the South Pacific Vol 1. 64 pp.
- Humann, Paul
and Ned Deloach. 2010. Reef
Creature Identification:Tropical Pacific New World Publications.
Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral
Reef Animals of the Indo-Pacific: Animal life from Africa to Hawaii
exclusive of the vertebrates
Sea Challengers. 314pp.