Agassiz’s Nudibranch, Felimare agassizii
Agassiz’s Nudibranch, Felimare agassizii. Underwater photograph taken in Zihuatanejo Bay, Guerrero, December 2019. Photograph and identification courtesy of Maude Jette, Dive Zihuatanejo, www.Divezihuatanejo.com.
Phylogeny: Agassiz’s Nudibranch, Felimare agassizii (Bergh, 1894), is a member of the Chromodorididae Family of Nudibranchs. The genus Felimare is one of sixteen genera in the Chromodorididae Family, and there are forty-four species in the Felimare Genus. In Mexico they are is known as Nudibranquio de Agassiz. This species was named in honor of the Harvard biologist Alexander Agassiz.
Morphology: Agassiz’s Nudibranch is a marine gastropod that displays a rectangular profile and a slightly flattened head. Their body is blue-black in color and their dorsal side is covered with numerous small yellow dots and elongated white oval spots. They have three body stripes along the margin, yellow on the outside, narrower navy blue or black in the middle and light green. They have a maximum of 7.9 cm (3.1 inches) in length.
Habitat and Distribution: Agassiz’s Nudibranch is found on and under rocks in the intertidal zone to depths up to 18 m (60 feet). Agassiz’s Nudibranch is 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: Agassiz’s Nudibranchs feed almost exclusively on demosponges.
Predation: Agassiz’s Nudibranchs are preyed upon by crabs, fish, other sea slugs and sea stars.
Reproduction: Agassiz’s Nudibranchs are simultaneous hermaphrodites (having both male and female reproductive organs at the same time). Reproduction is sexual, with internal fertilization. The eggs are laid as a sticky string on the surface of the reef or other hard surface. Neither parent tends or protects the eggs. The eggs hatch into planktonic larva and then settle to the bottom to begin benthic life.
Ecosystem Interactions: The parasitic, commensal, and mutualistic relationships of Agassiz’s Nudibranchs is poorly studied and has not been documented.
Human Interactions: Agassiz’s Nudibranchs 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 agassizii, Chromodoris aegialia, Glossodoris aegialia, Hypselodoris aegialia and Hypselodoris agassizii.