Sphon’s Red-Cross Chromodorid, Felimida sphoni

Sphon’s Red-Cross Chromodorid, Felimida sphoni. Underwater photographs taken from within Zihuantanejo Bay, Guerrero, March 2026. Photographs courtesy of Ron Woheau, Zihuantanejo.

Phylogeny: Sphon’s Red-Cross Chromodorid, Felimida sphoni (Ev. Marcus, 1971), is a member of the Chromodorididae Family of Nudibranchs. The genus Felimida is one of eighteen genera in  the Chromodorididae Family, and there are twenty-eight  species in the Felimida Genus. They are also known as the Sphon’s Chromodorid and the and in Mexico as Chromodóridae de Cruz Roja de Sphon. The genus name Felimida is thought to be derived from the Latin word for cat, but no one seems to know why.

Morphology:  Sphon’s Red-Cross Chromid has an elongated oval profile. They are vibrantly colored with a white dorsal surface with a distinct purple or reddish cross-shaped mark and blue and yellowish banding composed of elongated spots. The gills and rhinophores are white with purple tips. The mantle has a continuous white margin with a red bar just above that has a yellow bar composed of interrupted yellow spots. They are small in stature reaching a maximum of 3.5 cm (1.4 inches) in length.

Habitat and Distribution:  Sphon’s Red-Cross Chromodorid is found on and under rocks. They reside intertidally and can be found at depths up to 18 (60 feet). Sphon’s Red-Cross Choromodorids are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from the west coast of the Baja Peninsula.

Diet:  Sphon’s Red-Cross Chromodorids primarily prey on Psammocinia sponges.

Predators: Sphon’s Red-Cross Chromodorids are preyed upon by crabs, sea stars, polychaete worms and other nudibranchs. Other potential predators are deterred by this species’ ability to secrete chemical defenses that make it taste bad or even toxic. Sphon’s Red-Cross Chromodorids obtain this toxin from the sponges that they eat.

Reproduction:  Sphon’s Red-Cross Chromodorids are simultaneous hermaphrodites. They reproduce sexually by hypodermic insemination. This occurs when both mating partners dart their penis toward each other to induce one to act as a male and the other as the female. The victorious one to penetrate the body wall is the dominant male. The eggs are laid as a mass on the bottom stratum. The eggs hatch into veliger larva and later metamorphose into adults.

Ecosystem Interactions:  Very limited information regarding interspecies relationships for Sphon’s Red-Cross Chromodorids has been documented.

Human Interactions:  Sphon’s Red-Cross Chromodorids have no direct impact on human activities. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

Synonyms:   Chromodoris sphoni