Genetic diversity and haplotype distribution of P achymeniopsis gargiuli sp. nov. and P . lanceolata ( H alymeniales, R hodophyta) in K orea, with notes on their non‐native distributions

The red alga P achymeniopsis lanceolata , formerly known as G rateloupia lanceolata , is a component of the native algal flora of northeast A sia and has been introduced to E uropean and N orth A merican waters. It has been confused with a cryptic species collected from K orea and I taly. Our analyses of rbc L, cox 3 and ITS from P . lanceolata and this cryptic species has revealed two distinct entities, forming a clade, which were clearly separated from its congeners and positioned with other A sian species. Here, we describe the cryptic species as P . gargiuli sp. nov., a species that differs from others by molecular sequence and subtle anatomical characters. We hypothesize that P . gargiuli may have been recently dispersed by anthropogenic vectors, possibly at or near the same time as was P . lanceolata . Our cox 3 data set revealed that one haplotype of P . gargiuli, shared between K orea and I taly, and two haplotypes of P . lanceolata , commonly occurring in K orea and USA , are invasive haplotypes. This is the first report of the utility of the mitochondrial coding cox 3 sequences in red algae.