Chromodoris splendida: a stylish sea slug endemic to New South Wales

The beauty and diversity of terrestrial and aquatic organisms never ceases to amaze me. A few days ago I posted a blog about a strange-looking sea creature, Glaucus atlanticus. Although small, the beautiful Blue Dragon looks almost intimidating and somewhat sinister. It's like the Darth Vader of the nudibranchs. Today we have a blog about a related sea creature, but with a look completely opposed to G. atlanticus. Its scientific name is Chromodoris splendida, although it’s best known as the Splendid chromodoris. This is also a nudibranch. Although related, both sea slugs could not be more dissimilar. C. splendida is extraordinarily colorful. Its charming appearance is evocative of the popular Japanese cultural expression known as Kawaii. C. splendida is cute, delicate, “groovy”, and undeniably adorable.

Jason Shelley

Chromodoris splendida, a stunningly beautiful sea slug, is endemic to New South Wales, Australia.

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This nudibranch is small, about 2 to 5 cm. long. It has a milk-white mantle with a thin gold rim. Its mantle is covered with large red polka dots; in the frontal section has two purple-red sensory prominences called rhinophores, and in the posterior region, a gill rosette composed of 9 to 12 white plume-like gills with a purple-red trim.

Jason Shelley

Chromodoris splendida is a stunningly beautiful sea slug endemic to New South Wales, Australia. Posterior view, showing detail of the gill system.

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This enchanting little slug is endemic to eastern Australia being present only in coastal and marine areas of New South Wales and southern Queensland. It was first described in 1864 by English explorer, naturalist and painter George F. Angas, an accomplished watercolor painter, who was appointed Secretary of the Australian Museum in Sydney and made a significant contribution to the knowledge of the nudibranchs of Australia. For most snails and bivalves (double shelled mollusks), the hard shell is the main defence against predators. Nudibranchs, however, lack a shell and have evolved various strategies to avoid becoming prey of fish and birds. In some cases they use camouflage to blend with their surroundings, others, such a Chromodoris splendida use distinct, brilliant coloration to warn potential predators of a distasteful flavor. The pretty red dots of the Splendid chromodoris are, in fact, an anti-predator adaptation known as aposematism (warning colouration). It advertises that the species contains foul tasting toxins and noxious acid secretions. Predators recognize the benefit of not attempting to eat such an unpleasant tasting morsel.

Jason Shelley

Chromodoris splendida. The bright red dots warn potential predators about a distasteful flavor.

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The photographs shown in this blog were taken by Jason Shelley in waters off the Kurnell Peninsula, Botany Bay National Park, Sydney, Australia, where Chromodoris splendida is a fairly common occurrence.