Family Dendronotidae – Dendronotid Nudibranchs

Giant Nudibranch, Dendronotus iris, a representative of the Dendronotidae Family of Nudibranchs.

Nudibranchs of the Dendronotidae Family are known as Dendronotids with “Dendro” meaning tree stemming from their numerous branched papillae found around the rhinophores. They are Sea Slugs in the Phylum Mollusca and the Order Nudibranchia. They are soft-bodied gastropods that lose their shells during their larval phase. These nudibranchs have “naked gills” exposed on their backs that are utilized to separate these Chromodorids 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. These cerrata function as gills that assist with digestion, and they can incorporate stinging cells, from their prey, that they utilize for defense.

These 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. All nudibranchs have rhinophores (horn-like projections) on their heads that are chemosensory organs that help them to locate food and potential mates. Nudibranchs lack complex eyes but have photoreceptors that sense light and dark. Despite their inability to see color, nudibranchs are some of the most brightly colored of all animals. They derive the pigments for their color from the food they eat.

Dendronotids are Aeolids with elongated bodies with numerous branching cerata on the lateral edges of the dorsum. The cerata act as secondary gills and contain extensions from the digestive gland which vary by species. These cerata generally get smaller toward the posterior of the animal. The head has an oral veil having up to five pairs of velar processes. The lamellate rhinophores are retractable and are surrounded by a sheath and branched papillae. Dendronotids reach a maximum length of 30 cm (12 inches).

The Dendronotids are found worldwide, in tropical, temperate, and polar waters. They are found on hard surfaces and soft substrates within the intertidal zone to depths up to 3,000 m (9,840 feet). They feed primarily on hydroids, but also consume polychaeta worms, polyp-state jellyfish, and tube-dwelling anemones. In turn they are preyed upon by sea stars and other nudibranchs.

There are thirty-four species in the Dendronotidae Family of which at least two species are found along the west coast of Mexico.