Two new encrusting species from the genus Phymatolithon (Hapalidiales, Corallinophycidae, Rhodophyta) from Korea

Abstract

ABSTRACTThe genus Phymatolithon currently includes 21 taxonomically accepted species. Of these, only P. repandum has been reported from Korea. Here, we document two new species, namely P. dosungii sp. nov. and P. koreanum sp. nov., from Korea using both molecular and morpho-anatomical analyses. Both species have unique DNA sequences. Phylogenetic analyses of rbcL sequence data and the concatenated psbA and COI-5P dataset revealed that the two species belong in Phymatolithon. The sequence divergences between P. dosungii and P. koreanum were 9.9%–10.2% for rbcL, 7.9%–8.0% for psbA and 10.2%–10.6% for COI-5P. Phymatolithon dosungii is morpho-anatomically characterised by having encrusting and orbicular thalli; raised, mound-like tetra/bisporangial conceptacles with roofs that are four to five cells thick, bearing mostly palisade-like cells; tetra/bisporangial conceptacles with 13 to 28 pores surrounded by five to six rosette cells; and lacking buried conceptacles. Phymatolithon koreanum is morpho-anatomically characterised by having encrusting and amorphous thalli; raised, mound-like tetra/bisporangial conceptacles with roofs that are three to four cells thick bearing rounded to squarish cells; tetra/bisporangial conceptacles with 17 to 20 pores surrounded by five to seven rosette cells; and lacking buried conceptacles.