sea slugs text index | photo index
Phylum Mollusca > Class Gastropoda > sea slugs > Order Notaspidea
Forskal's sidegill slug
Pleurobranchus forskalii
Family Pleurobranchidae
updated Oct 2016
Where seen? This humungous slug is sometimes seen, near reefs and seagrass areas. Sometimes seen buried just beneath the sand. On Cyrene, large numbers have been seen at some times of the year. According to Dr Bill Rudman, it is often found in quite large populations in shallow lagoons, reef crests and pools and sea grass beds.

Features: 20-30cm. The large slug has a body texture of flat polygonal bumps with faint white lines forming circles. Colour variable from completely dark to shades of brown and orange. It has a pair of tubular rhinophores on its head. The large single gill is found on the right side between the mantle and the foot. The underside is smooth and unmarked. The slug appears to secrete a slime that feels acidic and is hard to rub off your hand.

What does it eat? Although it is not known what this species eats, other species of Pleurobranchus are reported to feed on ascidians.

What eats it? According to Dr Rudman, chitinous plates identified as the jaw plates of this sea slug had been found in the stomach of a turtle.

Baby slugs: They have been seen laying egg masses in white or pink frilly ribbons.

Tanah Merah, Jun 09

Pair of tubular rhinophores.

Cyrene Reef, Jul 11

GIlls on the side.

Bumps in a circular pattern.

Many were seen in areas thick with Green gum drop ascidians.
Cyrene Reef, Jul 11

Laying egg ribbons.
Cyrene Reef, Jul 11

Forskal's sidegill slugs on Singapore shores

Photos of Forskal's sidegill slugs for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Cyrene Reef, Nov 07
Photo shared by Loh Kok Sheng on his blog.

Cyrene Reef, Oct 08
Photo shared by Tan Sijie on his blog.

Pulau Semakau East, Jan 16
Photo shared by Loh Kok Sheng on facebook.

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

Pulau Semakau, Aug 11
Photo shared by Lok Kok Sheng on his blog.

Beting Bemban Besar, Mar 17
Photo shared by Richard Kuah on facebook.

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.
  • Debelius, Helmut, 2001. Nudibranchs and Sea Snails: Indo-Pacific Field Guide IKAN-Unterwasserachiv, Frankfurt. 321 pp.
  • Coleman, Neville. 2001. 1001 Nudibranchs: Catalogue of Indo-Pacific Sea Slugs. Neville Colemanis Underwater Geographic Pty Ltd, Australia.144pp.
  • Humann, Paul and Ned Deloach. 2010. Reef Creature Identification: Tropical Pacific New World Publications. 497pp.
  • Kuiter, Rudie H and Helmut Debelius. 2009. World Atlas of Marine Fauna. IKAN-Unterwasserachiv. 723pp.
  • 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.
FREE photos from wildsingapore tagged with Notaspidea. Make your own badge here.
links | references | about | email Ria
Spot errors? Have a question? Want to share your sightings? email Ria I'll be glad to hear from you!
wildfactsheets website©ria tan 2008