Coryphellina marcusorum, (Spanish common name: Eolidáceo de Marcus)[2] is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Flabellinidae.

[3] This species was described from Isla San Diego, Baja California, Mexico.

Coryphellina marcusorum is thought to occur in two disjunct populations in the waters of central and south America: one group on the west coast of central America in the eastern Pacific Ocean[4] and as far east as the Galapagos Islands[2] and the other on the east side of the continent in the Caribbean Sea and in the western Atlantic Ocean down to Brazil.

[5] Coryphellina marcusorum has a mainly translucent pink or orange body colour.

[5] A comparison with other Flabellinidae species from Mexico is given in the description of Orienthella fogata.