Flabellinidae Family of Nudibranchs
Phylogeny: Flabellinidae Nudibranchs of the Flabellinidae Family are Aneolids that belong to the Phylum Mollusca. They are in the Class Gastropoda and the Order Nudibranchia. These Nudibranchs fall into two main classifications, the Aeolids and the Dorids. The Aeolids have a mantle that forms a series of finger-like projections (cerrata) along the entire back of the animal. The Aeolids that have an elongated high tapering profile with a pointed tail and long tapering oral tentacles. They have smooth or bumpy rhinophores. The anterior corners of the foot are rounded or form short tentacles. The mantle has a ridge that runs down the middle of the dorsal surface. The cerata, set in rows or clusters, are long and tapering and can be raised on lobes. The Dorids have a thick mantle on their back (dorsal surface) that extends over the foot; their gills consist of feathery plumes that encircle the anus.
Distribution: Flabellinidae Nudibranchs are found worldwide, in tropical and temperate waters, however, these nudibranchs are best represented in colder waters. There are between thirty-four and seventy-four members in the Flabellinidae Family of which at least eight species are found along the west coast of Mexico. They are found on, or under, rocks, in crevasses, and on vertical and overhanging surfaces. Most are found intertidally or subtidally at depths up to 30 m (98 feet), either because it is the actual depth limit, or because most observations are made by SCUBA divers.
Morphology: The Flabellinidae Nudibranchs are soft-bodied gastropods All nudibranchs have rhinophores (horn-like projections) on their heads that are chemosensory organs that help them to locate food and potential mates. They lose their shells during their larval phase. Nudibranchs lack complex eyes, but have photo-receptors that sense light and dark. Despite their inability to see color, the Aeolid Nudibranchs are some of the most brightly colored of all animals. They derive the pigments for their color from the food they eat.
Ecosystem Roles: The Flabellinidae Nudibranchs feed exclusively on hyroids. In turn they are preyed upon by other nudibranchs. They can store stinging cells (nematocysts) that they obtain from the food they eat in cnido-sacks that are located at the end of their cerata as a defense mechanism.