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Phylum Mollusca > Class Gastropoda > sea slugs > Order Nudibranchia
Sponge nudibranch
Atagema spongiosa
Family Discodorididae
updated May 2020
Where seen? Resembling a large 'holey' sponge, this well camouflaged nudibranch is sometimes seen our undisturbed Northern shores among coral rubble. Appears to be seasonally common. It was formerly known as Trippa spongiosa.

Features: 8-12cm long. Boday heavy with a hump in the middle, it looks like a dull sponge with regular dark coloured 'holes' on the sides, a row of large 'holes' like portholes along the sides, large ones with and additional two or more rows of smaller 'holes'. Body resembles coral rubble in colour and texture, 'holes' may have fine ring of bright pink on a broader smooth blue margin. Gills large feathery, rhinophores smooth, large when fully extended. The underside of the body is dark to deep purple. When disturbed, it can drop off parts of its body. Its egg mass looks like rosette of frilly ribbon.

Well camouflaged.
Pulau Sekudu, Jul 08

Pulau Sekudu, Jul 08


Feathery gills.


Pulau Sekudu, May 08

Feathery gills.


Laying eggs.
Chek Jawa, Jun 05


Feathery gills.

Sponge nudibranchs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Changi Loyang, May 21
Photo by Jianlin Liu on facebook.

Chek Jawa, Jul 16
Photo shared by Marcus Ng on flickr.

Pulau Ubin, Jul 17
Photo shared by Loh Kok Sheng on facebook.

Pulau Sekudu, Jun 17
Photo by Loh Kok Sheng on facebook.

Pasir Ris Park, May 21
Photo by Vincent Choo 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.
  • 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.
  • Coleman, Neville. 2001. 1001 Nudibranchs: Catalogue of Indo-Pacific Sea Slugs. Neville Coleman's Underwater Geographic Pty Ltd, Australia.144pp.
  • Coleman, Neville, 1989. Nudibranchs of the South Pacific Vol 1. 64 pp.
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