DNA sequencing of type material of Polyopes constrictus and Dermocorynus occidentalis (Halymeniales, Rhodophyta) supports Polyopes capensis sp. nov. and Polyopes occidentalis (Hollenberg) comb. nov.

Abstract

Characterized by its expansive crust, short upright blades, and reproductive structures characteristic of Halymeniaceae, the northeast Pacific species Dermocorynus occidentalis was originally classified in that genus with the morphologically similar generitype, D. montagnei. To determine if the generic placement of D. occidentalis was correct, four short rbcL gene amplicons from one of two syntype specimens of D. occidentalis, Hollenberg #650, were sequenced yielding 722 base pairs. The sequenced specimen is herein designated as the lectotype of D. occidentalis. A phylogenetic analysis of this and other rbcL gene sequences of selected Halymeniales, which included the generitype species of Dermocorynus, D. montagnei, fully resolved D. occidentalis in a clade with nine Polyopes spp. This clade included a complete rbcL gene sequence obtained from one of the specimens on the lectotype sheet of Fucus constrictus, the basionym of P. constrictus, the generitype of Polyopes from Australia. We also present the complete mitochondrial and plastid genomes obtained from the P. constrictus lectotype. These results support the transfer of D. occidentalis to Polyopes as P. occidentalis (Hollenberg) comb. nov. In addition, specimens identified as P. constrictus from South Africa were resolved in a clade well separated from the Australian P. constrictus. Consequently, we describe the South African specimens as Polyopes capensis sp. nov.