nudibranchs text index | photo index
Phylum Mollusca > Class Gastropoda > sea slugs > Order Nudibranchia
Polka-dot nudibranch
Jorunna funebris
Family Discodorididae
updated May 2020
Where seen? This distinctive elegantly-spotted nudibranch is regularly encountered on many our shores. Sometimes lots are seen. On coral rubble near reefs.

Features: 1- 6cm long. Fleshy oval body, white with black circular markings. These markings are actually made up of tiny raised black bristles on the skin (called caryophyllidia). In fact, the entire body is covered with bristles, which are mostly white, giving the animal a fuzzy appearance. It has black-tipped rhinophores and black edging on feathery gills on the back.

What does it eat? It is said to eat a blue sponge (Neopetrosia sp.). Indeed, on Pulau Sekudu, we have seen large Polka-dot jorunna nudibranchs near these sponges, sometimes in pairs, and sometimes appearing to have just having laid a ribbon-like egg mass. Elsewhere, we have also seen these nudibranchs near blue sponges.

Sentosa, Mar 05

Black edged gills

The spots are actually arrangements
of tiny black bristles.


With egg mass near
blue jorunna sponge

Pulau Sekudu, Jul 05


Ate up a lot of the blue jorunna sponge
Pulau Sekudu, Aug 23
Photo shared by Chay Hoon on facebook.


With egg mass
Pulau Sekudu, Jul 05

Underside


Chomping on a blue sponge?
Pulau Semakau, Jan 09

Chomping on a blue sponge?
South Cyrene, Feb 11

Ate something large?
Pulau Semakau, Mar 08


Mating
Pulau Semakau, Feb 08

Mating
Tanah Merah, Aug 11

Tiny, about 1cm. Several seen.
Sentosa, Jan 06

Polka-dot nudibranchs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores


Tanah Merah, Aug 09
Photo shared by James Koh on his blog.

Sentosa Tg Rimau, Oct 15

Photo shared by Loh Kok Sheng on facebook.


Sisters Island, Feb 08
Photo shared by Toh Chay Hoon on her flickr.

Terumbu Selegie, Jun 11

Photo shared by Neo Mei Lin on her blog.

Mating?
Cyrene Reef, Mar 18

Photo shared by Marcus Ng on facebook.


Pulau Semakau East, Nov 14

Photo shared by Loh Kok Sheng on facebook.

Pulau Semakau, Nov 09

Photo shared by James Koh on flickr.


Terumbu Raya, Jun 18

Photo shared by Gina Tan on facebook.

Terumbu Raya, Mar 11
Photo shared by Russel Low on facebook.


Beting Bemban Besar, Apr 10
Photo shared by Loh Kok Sheng on his flickr.

Terumbu Bemban, Jun 10
Photo shared by Toh Chay Hoon on her blog .


Terumbu Pempang Tengah, May 11

Photo shared by Liana Tang on facebook.

Terumbu Pempang Darat, Jun 10
Photo shared by James Koh on his blog.

Terumbu Pempang Laut, Apr 11
Photo shared by Loh Kok Sheng on his blog.


Pulau Biola, Dec 09
Photo shared by Loh Kok Sheng on his flickr.

Pulau Biola, Jan 22
Photo shared by Toh Chay Hoon on facebook.


Pulau Sudong, Dec 09
Photo shared by Loh Kok Sheng on his flickr.

Terumbu Berkas, Jan 10
Photo shared by Loh Kok Sheng on his flickr.

Terumbu Salu, Jan 10
Photo shared by Loh Kok Sheng on his flickr.


Pulau Salu, Apr 21
Photo shared by Toh Chay Hoon on facebook.

Pulau Senang, Jun 10
Photo shared by Loh Kok Sheng on his flickr.
 


Pulau Berkas, Feb 22
Photo shared by Loh Kok Sheng on facebook.

Pulau Berkas, May 10
Photo shared by Loh Kok Sheng on his flickr.
 

Polka dotted nudibranch from Loh Kok Sheng on Vimeo.


Polka-dot nudibranch at Sentosa from Loh Kok Sheng on Vimeo.


Links
References
  • 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.
  • Chou, L. M., 1998. A Guide to the Coral Reef Life of Singapore. Singapore Science Centre. 128 pages.
  • Debelius, 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.
  • 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.
  • Humann, Paul and Ned Deloach. 2010. Reef Creature Identification: Tropical Pacific New World Publications. 497pp.
  • Gosliner, 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.
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