Marioniopsis arborescens

Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Nudibranchia
Family: Tritoniidae
Genus: Marioniopsis
Species: Marioniopsis arborescens

Marioniopsis arborescens is a tritoniid nudibranch with a row of tree-like branching gills along each side of its back. It was formerly known as Marionia arborescens.

It feeds on soft corals and is often well camouflaged against its prey, with a mottled brown, green or white body.

In the Philippines it is found on reefs and rubble slopes near soft corals, often only noticed when the branching gills stand out.