Three new species of the sea fan genus Muricea (Cnidaria, Octocorallia, Plexauridae) from the northwest region of Mexico.

Twenty-one nominal species of Muricea have been reported in the Eastern Pacific with nine of them reported in the Mexican Pacific. We describe three new species of Muricea: Muriceaambarae sp. nov. and Muriceacacao sp. nov. , from rocky reefs on the central and the northern Gulf of California and the Pacific coast of Baja California Sur, and Muriceamolinai sp. nov. , from the Pacific coast of Baja California Sur. Muriceaambarae sp. nov. and M.cacao sp. nov. are taxonomically allied to the nominal species Muriceafruticosa Verrill, 1869 due to the morphological similarity of colony growth patterns and the phylogenetic closeness based on the mitochondrial MutS gene (mtMutS); but differ mainly in the calyx form and composition of sclerites. The main morphological differences between the new Muricea species are in their sclerite forms and color; M.ambarae sp. nov. has orange-colored colonies, thin leaf spindles and tuberculated blunt spindles, while M.cacao sp. nov. has dark brown colored colonies, strong spinous spindles and an absence of tuberculated blunt spindles. Muriceamolinai sp. nov. is phylogenetically close and morphologically similar to Muriceasquarrosa Verrill, 1869 in the growth form of the colony and tubular calyces; but has dark brown colored colonies and has calyces from the base to the branch tips. With these three new species, the total number of Muricea species reported in the Mexican northwest region increases to twelve and a total of 24 nominal species in the Eastern Pacific.