Morphology and phylogenetic analysis of two new deep-sea species of Chrysogorgia (Cnidaria, Octocorallia, Chrysogorgiidae) from Kocebu Guyot (Magellan seamounts) in the Pacific Ocean

Abstract. Two new species of Chrysogorgia Duchassaing & Michelotti, 1864 collected from Kocebu Guyot in the Magellan seamounts of the Pacific Ocean are described and illustrated: Chrysogorgia ramificanssp. nov. collected from a depth of 1831 m and Chrysogorgia binatasp. nov. collected from a depth of 1669 m. Chrysogorgia ramificanssp. nov. belongs to the Chrysogorgia “group A, Spiculosae” with rods distributed in body wall and tentacles, and C. binatasp. nov. belongs to the “group C, Squamosae typicae” with rods and/or spindles not present but only scales. Chrysogorgia ramificanssp. nov. differs from congeners by its main stem with 2/5R branching sequence at the bottom forming two large bottlebrush-shaped branches with 1/3R branching sequence at the top. Chrysogorgia binatasp. nov. is similar to C. scintillans Bayer & Stefani, 1988, but differs by its larger polyps, larger sclerites in the body wall, and different scales in the upper part of polyps. The mtMutS genetic distances between C. ramificanssp. nov. and C. binatasp. nov. and congeners are in the range of 0.33%–2.28% and 0.33%–2.94%, respectively, while the intraspecific distances are in the range of 0–0.16%. Molecular phylogenetic analysis indicates that C. ramificanssp. nov. is clustered with C. monticola Cairns, 2007 and C. binatasp. nov. is clustered with C. chryseis Bayer & Stefani, 1988, both with high support indicating close relationships.