Hopkin's Rose Nudibranch

Okenia rosacea common name Hopkin's Rose Nudibranch, is a species of sea slug, specifically a dorid nudibranch, a marine gastropod mollusk in the family Goniodorididae. This species was described from Monterey Bay, California. It can be found along the coast of western North America from Oregon to Baja California.

Numerous lengthy papillae that taper into a rounded tip are present on the back of these pink sea slugs. Sometimes, the tips of these papillae are more or less white. Hopkinsiaxanthin, a xanthophyllic pigment that is most likely derived from feeding on the cheilostomatous bryozoan Integripelta bilabiate, is responsible for this pink tint. The mantle, foot, and head are combined into a single object with a lowered profile. There are no oral tentacles. The 20 gills are a little bit shorter and are located close to the anal papillae. The middle tooth of the taenioglossan radula is the largest and longest tooth in this family, and it ends in a hook-like tip, making it distinct from other radulae. The lateral teeth are little and have actually been simplified to a simple plate.