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Sea Slugs & Nudibranchs

Diverse & varied

Sea Slugs and Nudibranchs



Index

Sea Slugs



Side-Gilled

Side-Gilled Slugs

Umbrella Shells

Umbrella Shells

Head-shield Slugs

Head-shield Slugs

Pteropods

Pteropods

Sap-Sucking Slugs

Sap-Sucking Slugs

Sea Hares

Sea Hares

Nudibranchs



Phanerobranch Dorids

Side-Gilled Slugs

Cryptobranch Discodorids

Cryptobranch Discodorids

Cryptobranch Chromodorids

Cryptobranch Chromodorids

Radula-less Dorids

Radula-less Dorids

Arminids

Arminids

Dendronotids

Sap-Sucking Slugs

Aeolids

Aeolids

Nudibranchs are found in all areas of reefs, on seaweeds, on the ocean floor and even swimming in the ocean currents. Some feed on other nudibranchs, others bryozoans, jellyfish, corals, sponges, ascideans, fish mucous, and seaweed.

Those that feed on animals with stinging cells, can absorb the stinging cells without triggering the firing mechnism. Any predator is not so protected and in biting into the nudibranch, causes all the stinging cells to fire their poisonous darts. Sponge eaters absorb and concentrate the sponge toxins in their bodies.

Those with stinging cells and toxins are often brightly coloured to warn of their danger. Those living on seaweeds are often extremely cryptic. Sediment living species often live within the sediment and only come out at night to feed.

The classification followed here is that in "Nudibranch & Sea Slug Identification", by T. M. Gosliner, A. Valdés & D. W. Behrens (2nd edition, 2018). Images with a species number are detailed in this guide. A review of the guide can be found on the reviews page on this web-site. Many details of sea slugs and nudibranchs can be found there and online in the Slug Site.

Side-Gilled & Basal-Shelled Sea Slugs



These groups are closely related to nudibranchs. Many have small internal shells, which may disappear in the adults.

Some Pleurobranchus species grow up to 60cm long. Many produce acidic secretions as a defence mechanism.

Bethellina delicata
Bethellina delicata
Euselenops luniceps
Euselenops luniceps mating
Euselenops luniceps mating
Pleuorbranchus brockii
Pleurobranchus grandis
Pleurobranchus grandis
Pleurobranchus forskalii juvenile
Pleurobranchus forskalii juvenile
Pleurobranchus grandis
Pleurobranchus grandis
Parasitic copepods on Pleurobranchus

Side-Gilled Slugs

Side-Gilled Slugs

These groups are closely related to nudibranchs. Many have small internal shells, which may disappear in the adults.

Some Pleurobranchus species grow up to 60cm long. Many produce acidic secretions as a defence mechanism.

Bethellina delicata
Bethellina delicata
Euselenops luniceps
Euselenops luniceps mating
Euselenops luniceps mating
01-Pleuorbranchus brockii
Pleurobranchus grandis
Pleurobranchus grandis
Pleurobranchus forskalii juvenile
Pleurobranchus forskalii juvenile
Pleurobranchus grandis
Pleurobranchus grandis
Parasitic copepods on Pleurobranchus