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Phylum Mollusca > Class Gastropoda > sea slugs > Order Sacoglossa > Elysia species
Ornate leaf slug
Elysia ornata
Family Plakobranchidae
updated Oct 2019
Where seen? Often mistaken for leafy seaweed, this slug is seen on all our shores. However, it appears to be seasonal. Sometimes seen in large numbers, at other times, none is to be seen.

Features: 4-6cm. Body long with a pair of very large 'wings' (called parapodia). The overall body colour of the slug may be shades of green, yellow or even white. It is believed that the colour depends on how much and what seaweed is in the animal's digestive system. But all have a black margin on the edge of the parapodia, with an orange or yellow margin next to the black. There is a pair of long thick tentacles with tips in the same colour banding as the body edge. The body may have black spots. It may also have white spots, which are glands that secrete a white substance that may repel predators. The parapodia are often held in ruffles so that the animal resembles seaweed.

What does it eat? This slug is believed to eat the Hairy green seaweed (Bryopsis sp.) Indeed, leaf slugs are commonly seen there is a bloom of this green feathery seaweed on the shores. See details in the Family Elysiidae for more about how the slug eats and uses the seaweed's chloroplasts.

St. John's Island, Jun 07

Pulau Sekudu, Apr 06

Sentosa, Jan 05
Baby Sacoglossa: These slugs are simultaneous hermaphrodites, that is, each animal has both male and female reproductive organs at the same time. They practice internal fertilisation. When two slugs mate, they may both act as males, extending the penis (usually a white tube that emerges from the side of the neck). Some may insert the penis into the female genital pore, others may simply pierce the partner anywhere in the body. They lay eggs in ribbons.

Mating slugs
St. John's Island, May 05

The white bits are the reproductive organs.

Also seen among Sargassum seaweeds.
St John's Island, Oct 11

Sentosa, Apr 04

Just mated?

Recently laid egg strings?
Pulau Jong, Jan 23
Photo shared by Lok Kok Sheng on facebook.

Ornate leaf slugs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Punggol, May 21
Photo shared by Richard Kuah on facebook.

Changi, May 11

Photo shared by Loh Kok Sheng on his blog.

Chang Lost Coast, Jun 22

Photo shared by Loh Kok Sheng on facebook.

East Coast, May 08
Photo shared by Loh Kok Sheng on his blog.

East Coast, NSRCC, Nov 20

Photo shared by James Koh on flickr.

Tuas, Mar 15
Photo shared by Marcus Ng on facebook.

Labrador, Dec 06

Photo shared by Wai on her blog.

Lazarus Island, Nov 20

Photo shared by Jianlin Liu on facebook.

Lazarus Island, Feb 11

Photo shared by Loh Kok Sheng on flickr.

Cyrene Reef, Nov 09
Photo shared by James Koh on flickr.

Pulau Jong, Apr 11
Photo shared by Toh Chay Hoon on her blog.

Terumbu Selegie, Jun 11

Photo shared by Neo Mei Lin on her blog.

Pulau Hantu, Apr 21
Photo shared by Richard Kuah on facebook.

Pulau Semakau, Aug 14

Photo shared by Loh Kok Sheng on his blog.

Beting Bemban Besar, Mar 17

Photo shared by Richard Kuah on facebook.

Terumbu Raya, Feb 14

Photo shared by Russel Low on facebook.

Terumbu Bemban, May 21

Photo shared by Toh Chay Hoon on facebook.

Terumbu Pempang Laut, Mar 24

Photo shared by Tommy Arden on facebook.

Raffles Lighthouse, Nov 16

Photo shared by Jianlin Liu on facebook.

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

Pulau Salu, Apr 21
Photo shared by Loh Kok Sheng on facebook.

Pulau Sudong, Dec 09
Photo shared by Toh Chay Hoon on her flickr.

Pulau Biola, Dec 09

Pulau Biola, May 10

Elysia ornata @ Tanah Merah 06Dec2009 from SgBeachBum on Vimeo.

Links References
  • K. R. Jensen. Sacoglossa (Mollusca: Gastropoda: Heterobranchia) from northern coasts of Singapore. 10 July 2015. The Comprehensive Marine Biodiversity Survey: Johor Straits International Workshop (2012) The Raffles Bulletin of Zoology 2015 Supplement No. 31, Pp. 226-249.
  • 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.
  • Kathe R. Jensen. 30 Dec 2009. Sacoglossa (Mollusca: Gastropoda: Opisthobranchia) from Singapore. The Raffles Bulletin of Zoology, Supplement 22: 207-223.
  • 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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