Two Unrecorded <i>Apiospora</i> Species Isolated from Marine Substrates in Korea with Eight New Combinations (<i>A. piptatheri</i> and <i>A. rasikravindrae</i>)

Although <i>Apiospora</i> Sacc. has previously been considered a sexual morph of <i>Arthrinium</i> species on the basis of phylogenetic, morphological, and ecological diagnoses, a recent study delimited these as different species. Recently, 14 species, including eight new species, of marine <i>Arthrinium</i> have been reported from Korea. Six known species have previously been renamed as species in the genus <i>Apiospora</i> (<i>A. arundinis</i>, <i>A. marii</i>, <i>A. piptatheri</i>, <i>A. rasikravindrae</i>, <i>A. sacchari</i>, and <i>A. saccharicola</i>). However, the eight new species of marine <i>Arthrinium</i> (<i>Ar. agari</i>, <i>Ar. arctoscopi</i>, <i>Ar. fermenti</i>, <i>Ar. koreanum</i>, <i>Ar. marinum</i>, <i>Ar. pusillispermum</i>, <i>Ar. sargassi</i>, and <i>Ar. taeanense</i>) are yet to be studied, and thus the taxonomic status of these species remains to be clarified. In this study, we conducted phylogenetic analyses using the internal transcribed spacer, 28S large subunit ribosomal RNA gene, translation elongation factor 1-alpha, and beta-tubulin regions to confirm the phylogenetic position of these eight species. Based on these analyses, we re-identified the eight <i>Arthrinium</i> species as new combinations in <i>Apiospora</i>. Additionally, among the six known <i>Apiospora</i> species, two (<i>A. piptatheri</i> and <i>A. rasikravindrae</i>) have not previously been recorded in Korea. On the basis of morphological and molecular analyses, we report these as new species in Korea. Herein, we present scanning electron micrographs detailing the morphologies of these species, along with phylogenetic trees and detailed descriptions.