Colpomenia wynnei sp. nov. (Scytosiphonaceae, Phaeophyceae): a new species of marine algae from northeast Asia

The taxonomic distinctiveness and distribution of the brown alga Colpomenia phaeodactyla are debatable. The type locality of this species is Puerto Penasco, Mexico, and its distribution includes northeast Asia. We analyzed two gene sequences of specimens of so-called C. phaeodactyla from Korea, Japan and Mexico, in combination with morphological observations of the specimens. Analyses of 71 cox3 and 23 rbcL sequences resulted in similar trees in which specimens under the name C. phaeodactyla consisted of two distinct clades. One clade comprised samples from Korea and Japan, and the other clade, from the Gulf of California, was identical to C. durvillei. Additional observations of the morphology and anatomy of the specimens agreed with the molecular data. On the basis of these results, we describe the new species C. wynnei for plants from Korea and Japan. Colpomenia wynnei was distinguished by finger-like sacs with adventitious branchlets when mature and was much contorted, the height of ascocysts being shorter than plurilocular sporangia. Both cox3 and rbcL sequence data strongly supported the monophyly of C. wynnei, C. bullosa and C. durvillei, all being characterized by having elongate thalli. Based on both cox3 and rbcL data sets, we herein propose to synonymise C. phaeodactyla with C. durvillei.