Cryptoporus densiflorus , sp. nov. (Polyporaceae), from East Asia and a reassessment of species distributions in Cryptoporus

The genus Cryptoporus has historically been delimited primarily based on the distinctive veiled polypore morphology. Since its first report from North America, the genus has been regarded as monotypic, represented by Cryptoporus volvatus. Recently, two additional species were described from south and central China based on DNA sequence data. However, despite numerous records from Korea, Japan, and eastern China, no molecular phylogenetic studies have yet examined collections from these regions. The present study aims to clarify the species boundaries and geographic distribution of Cryptoporus in East Asia using integrative taxonomic approaches. Multilocus phylogenetic analyses were conducted using sequences from ITS, 28S, 18S, RPB2, and TEF1, together with species delimitation analyses. Our results demonstrate that East Asian collections represent a distinct lineage, herein described as a new species, Cryptoporus densiflorus. The new species is confirmed to occur in Korea and Japan and appears to be host-specific to Pinus densiflora. We reevaluate the geographic ranges of all currently accepted species and highlight that historical “C. volvatus” records in Asia include multiple taxa. These results indicate that Cryptoporus species exhibit strong geographic structuring and host association at the species level, thereby enhancing the taxonomic framework of the genus in East Asia.