Dendronotus albus

Dendronotus albus is a shell-less marine sea slug belonging to the family Dendronotidae. It is found along the west coast of North America, from Alaska to Baja California, Mexico. The species was first described from shallow waters at Point Pinos in Monterey Bay, California.

Its taxonomic history is tangled. Robilliard correctly identified two species of Dendronotus in the northeastern Pacific and named one Dendronotus diversicolor. However, D. albus and D. diversicolor were later treated as the same species by Stout et al. in 2010, likely because their study specimens did not include both forms. In fact, Robilliard had consistently used the name D. albus for what is now called Dendronotus robilliardi, and he redescribed the true D. albus as D. diversicolor.

This species reaches a maximum length of 73 mm. It differs from D. robilliardi in having only four pairs of large cerata (with two extra, small cerata in larger animals), whereas D. robilliardi is smaller but has five to seven pairs. The body and cerata are translucent white, with opaque white and orange-yellow tips on the cerata, though the orange-yellow is sometimes absent.

Its diet consists mainly of the hydroids Abietinaria greenei, Hydrallmania distans, and Abietinaria amphora. In contrast, D. robilliardi is said to prefer the hydroid Thuiaria argentea in the family Sertulariidae.