Phyllidia varicosa

Singapore's Splendour

The unravelling of shore life at low spring tide. Slugs galore. Colourful gems of the sea. Like most gems, these gems were painstakingly uncovered under rocks or in areas away from view. Their flamboyant colours are indications of their unpleasant taste; nice to see but bad to eat.

Nudies . Nudibranchs have a few natural predators. They are toxic although they do not produce their own toxins but rather they recycle from their prey. Instead of the well-sheltered but cumbersome shell that protects most molluscs, Nudibranchs (“naked gills”) have evolved by advertising their toxicity instead. The chemical defence comes in vivid colours and they resemble the colourful slugs if not for the exposed gills. Some are able to ingest nematocysts (stinging cells) of hydroids and other cnidarians without firing them hence are able to utilize them in their arsenal. They are omnivorous, feeding too on sponges, corals and tunicates. The striking colourful appearance of nudibranchs are obviously aposematic , serving to warn potential predators of their repugnant taste.

Comprising of 4 main types (Suborders), the most common is the Harlequin nudibranchs (Doridaceans or dorids) which is characterized by a pair or tentacles (rhinophores) and decorative, flower-like and exposed, external gills which are sited towards the posterior. The species Phyllidiids, however, lack the conspicuous gills.

The Tubercular nudibranchs (Aeolidaceans or aeolids) have tapering bodies numerous finger-like appendages or cerata; the Side-gilled nudibranchs (Dendrotaceans) has gills on the sides of its back and sheaths on each tentacle and the Veiled nudibranchs (Arminaceans) has longitudinal ridges on its back and enlarged fleshy lobe on its head.

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