seen? These nudibranchs with tough skin are often encountered,
especially on our Southern shores, among coral rubble and on reefs.
It is believed that these nudibranchs are commonly seen because they
can roam around in the open with impunity due to the nasty stuff they
secrete to deter predators. Their colourful patterns probably also
warn of this feature.
What are phyllid nudibranchs? Phyllid nudibranchs are thick slugs with a body covered in warts or
bumps. They don't have flower-like gill structures on their backs.
The gills are hidden under the mantle skirt and are made up of a row
as many as 100 leaflets, along the length of the body on either side
of the foot. Their short rhinophores are often overlooked among all
the bumps on their bodies. The different genus are identified by the
position of the anus (in the middle of its back for Phyllidia species), and shape of the oral tentacles.
What do they eat? Phyllids eat sponges. They lack a
radula and don't rasp the sponge. Instead, digestive juices are secreted
into the sponge and the partially digested sponge is sucked up. Sort
of like a sponge slurpee. Some species may insert a large feeding
organ called the pharyngeal bulb deep into the sponge to eat it.
Members of the Family Phyllidiidae absorb the toxic chemicals in their
sponge food and incorporate these chemicals in their own defence.
They produce a milky white substance. This is lethal to other nudibranchs
especially if they are kept in the same tank.
Human uses: Although colourful,
phyllids are not popular in the aquarium trade as they produce a powerful
toxin that can kill off the entire tank. The toxins produced are so
strong that the water from the aquarium may have an acrid smell. The
properties of these toxins are currently being studied for possible
applications such as in human medicine and anti-fouling uses.
phyllid: milky substance
secreted when disturbed.
Sisters Island, May 07
of the Varicose phyllid
look like the orange blobs on its body.
St. John's Island, May 05
Gills on the
the length of the body
St. John's Island, Jan 06
|Some Phyllid nudibranchs on Singapore shores
|More Phyllid nudibranchs on Singapore shores
Pulau Hantu, Apr 21
Photo shared by Jianlin Liu on facebook.
Phyllidia elegans (underside) |
- J. van Alphen,
N. J. de Voogd and B. W. Hoeksema Differential
feeding strategies in phyllidiid nudibranchs on coral reefs at
Halmahera, northern Moluccas Coral Reefs Volume 30, Number
1 (2011), 59.
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
Colemanís Underwater Geographic Pty Ltd, Australia.144pp.
Neville, 1989. Nudibranchs
of the South Pacific Vol 1. 64 pp.