A new species of the red alga Erythrotrichia (Erythropeltales, Rhodophyta) from Korea: Erythrotrichia johnawestii sp. nov. and observations in culture

Four species of Erythrotrichia (E. biseriata, E. reflexa, E. tetraseriata, E. carnea) have been reported in Korea, but phylogenetic studies have not been conducted on them. We analyzed two newly collected Erythrotrichia isolates using rbcL DNA sequences and determined their species status using four DNA-based species delimitation methods. One isolate (KNU-1) grouped with E. carnea in three methods: Assemble Species by Automatic Partitioning, both single-threshold and multiple-threshold general mixed yule coalescent, but grouped as a distinct species in the statistical parsimony network analysis. A second isolate (KNU-2) was considered a distinct species in all the above species-delimitation methods. We propose the name, Erythrotrichia johnawestii sp. nov., for this new species. The new species was different from E. carnea in lacking a thick outer cell wall layer and with a smaller cell size. Mature monosporangia produced raised openings that released monospores. Cell walls were not detected in newly released monospores but began to appear when the spore attached to the substratum and produced rhizoids. Sexual reproduction was not observed during the four-year culture period.