Genetic diversity hotspot of the amphi-Pacific macroalga Gloiopeltis furcata sensu lato (Gigartinales, Florideophyceae)

Genetic diversity patterns around the North Pacific received attention for marine organisms and have been used to infer biodiversity “hotspots” in the region. We conducted a phylogeographic study of the red alga Gloiopeltis furcata, investigating cryptic species diversity and comparing population genetic structure in the north Pacific. A phylogenetic tree and haplotype networks were constructed on the basis of 201 mitochondrial COI-5P sequences and 149 plastid rbcL sequences from G. furcata specimens. Eight distinct cryptic lineages (A–H) were identified within G. furcata. These lineages showed high genetic diversity and complex geographic distributions. All eight lineages of G. furcatasensulato were present in the NW Pacific; however, only a single lineage (A) was present in the NE Pacific, suggesting that the NW Pacific is a center of genetic diversity for G. furcatasensulato. Habitat discontinuities of G. furcatasensulato in the high rocky intertidal zone may have been responsible for the high level of genetic differentiation of G. furcatasensulato in the NW Pacific by impeding genetic exchange between adjacent populations. Our phylogenetic diversity suggests that the NW Pacific, especially Jeju Island, was a genetic diversity hotspot involving species diversity of Gloiopeltis.