Mimic Dorid, Baptodoris mimetica

Mimic Dorid, Baptodoris mimetica. Underwater photograph taken in Monterey Bay, California, February 2022. Photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Mimic Dorid, Baptodoris mimetica (Gosliner, 1991), is a member of the Discodoridae Family of Nudibranchs. The genus Baptodoris is one of thirty genera in the Discodoridae Family, and there are five species in the Baptodoris genus. In Mexico they are known as Nudibranquio Mimético. The genus name Baptodoris comes from the Greek words meaning “immersed Doris” Doris was a sea nymph in Greek mythology. This species  derives its specific name from its resemblance to the White-spotted Doris, Doriopsilla albopuncta, which it mimics.

Morphology:  The Mimic Dorid has an oval outline and a high profile. It is bright lemon yellow in color and covered with small oblique white spots, which are uniformly scattered over the dorsal surface. Their rhinophores are brown and their gills are translucent white. The dorsal surface is textured with caryophillidia (sensory tubercles surrounded by tiny spicules). The head is well developed with paired labial tentacles and the foot is broad and bilabiate anterior. The posterior end of the foot is rounded and extends beyond the posterior of the notum. Mimic Dorids reach a maximum of 3.6 cm (1.4 inches) in length. The Mimic Dorid is distinguished from the similar White-spotted Dorid, Doriopsilla albopuncta, which is less rigid, has tentacles under its mantle, and holds its gills more horizontally.

Habitat and Distribution: Mimic Dorids reside on and under rocks within the intertidal zone to depths up to 20 m (65 feet).  The Mimic Dorid is a subtropical Eastern Pacific species. It has a limited distribution in Mexican waters of the Pacific Ocean, being found from San Martin Island, Baja California northward along the central and northwest coasts of the Baja Peninsula.

Diet: Mimic Dorids feed primarily on sponges.

Predators: Mimic Dorids are preyed upon by other nudibranchs.

Reproduction: Mimic Dorids 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:  Any parasitic, commensal, and mutualistic relationships of Mimic Dorids with other species has not been documented.

Human Interactions:  Mimic Dorids 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.