Integrative systematics approaches revealed that the rare red alga Schimmelmannia (Shimmelmanniaceae, Acrosymphytales) from Japan is a new species: The description of S. benzaiteniana sp. nov

SUMMARY The rare red alga Schimmelmannia (Schimmelmanniaceae, Acrosymphytales) from Japan was taxonomically re‐examined in this study. Japanese Schimmelmannia has previously been identified as S. plumosa (Setchell) I.A.Abbott. However, Japanese Schimmelmannia and S. plumosa have approximately 5 and 1.9% of genetic distance in mitochondrial cox1 and chloroplast rbcL sequences, respectively. They also differ morphologically in the numbers of periaxial cells and auxiliary cell branches indicating that they are distinct species. Based on molecular phylogenetics and morphology, S. benzaiteniana is distinguishable from other Schimmelmannia species, except for S. bollei Montagne which lacks a detailed description. Since S. bollei has been reported only from the North Atlantic coast of Africa, we assumed that it is distinct from the Japanese species. We, therefore, described the Japanese species as a new species, S. benzaiteniana.