Favorinus elenalexiae, a new species (Opisthobranchia: Aeolidiidae) from the eastern Pacific Ocean

A new species of Nudibranchia, belonging to the genus Favorinus Cray, 1850, is described. It differs from other species of that genus mainly by its rhinophoral ornamentation: Favorinus elenalexiae new species has three large, overlapping flanges with the upper margins free, like three cups, in almost all the species the rhinophores are papillated or lamellated. The external anatomy, radula, and reproductive system are described and compared with those of other species of the genus. A table comparing summarizing the differences amongst the species of the genus Favorinus is included.