Also known as Varicose Phyllidia, Warty Nudibranch, Yellow-warted Sea Slug
Varicose wart slugs glide openly across Indo-Pacific coral reefs, advertising potent chemical defenses through raised blue-gray ridges capped with vibrant yellow tubercles. Unlike typical dorid nudibranchs that breathe through an exposed feather-like gill circlet on the back, they conceal delicate respiratory leaflets beneath the outer skirt of their tough, leathery mantle. When threatened, epidermal glands discharge pungent isocyanopupukeanane terpenes derived from their sponge diet, a chemical weapon capable of killing nearby fish in confined waters.
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