Abstract
This study re-evaluates the species diversity and taxonomy of the genera Canistrocarpus, Dictyota, and Rugulopteryx in Korea using an integrative approach combining molecular data and morphological observations. Phylogenetic analyses based on psbA, cox1, and rbcL gene sequences identified nine lineages including eight Dictyota and one Rugulopteryx. Morphological assessments corroborated these molecular findings. Of the seven species listed in recent national checklists, only two were confirmed, while the remaining species were misidentifications. Three novel species are described: Dictyota haenyeosa sp. nov., Dictyota sumbisoria sp. nov., and Dictyota taewakia sp. nov. Additionally, molecular evidence confirmed that the species historically identified as D. dichotoma in Korea corresponds to D. spathulata, a species described from Japan. This revision of Dictyota taxonomy highlights the importance of molecular tools in resolving long-standing misidentifications. The updated checklist for Korean Dictyota and Rugulopteryx includes D. bartayresiana, D. coriacea, D. haenyeosa sp. nov., D. pfaffii, D. spathulata, D. sumbisoria sp. nov., D. taewakia sp. nov., and R. okamurae. The genus Canistrocarpus is absent from the Korean flora. The Korean Dictyota and Rugulopteryx flora is predominantly endemic to the Eastern Asian region (Korea and Japan), with species such as D. coriacea, D. haenyeosa sp. nov., D. spathulata, D. sumbisoria sp. nov., D. taewakia sp. nov., and R. okamurae. Exceptions include the widely distributed, potentially introduced species D. pfaffii and D. bartayresiana, both originally described from the Caribbean. Rugulopteryx okamurae, while endemic to Korea and Japan, has also been introduced to the Atlantic and Mediterranean regions over the past two decades.