Global diversity of the <i>Tylopilus alboater</i> complex (<i>Boletaceae</i>, <i>Boletales</i>): new genus and species, and typification of the name <i>Boletus alboater</i>

Recognition of <i>Tylopilus alboater</i> once relied heavily on the morphological features of the basidiomata, which resulted in considerable confusion due to morphological stasis and plasticity. In this study, we examined specimens morphologically identified as <i>T. alboater</i> from Asia, North America, and Australia using phylogenomics and multi-locus sequence data. To clarify its phylogenetic placement within <i>Boletaceae</i>, we conducted a phylogenomic analysis based on 45 genomes (including three newly sequenced <i>T. alboater</i> genomes) comprising representatives from the eight subfamilies of <i>Boletaceae</i>. Additionally, we constructed a concatenated dataset (nrLSU + <i>tef1-α</i> + <i>rpb1</i> + <i>rpb2</i>), incorporating representative species from all genera within the subfamily to which <i>T. alboater</i> belongs, to infer its phylogeny. Our phylogenomic analysis revealed that specimens morphologically identified as <i>T. alboater</i> exhibit polyphyly, clustering entirely within the subfamily <i>Boletoideae</i>. Our multi-locus phylogenetic analyses further indicated that these specimens represent eight distinct species distributed across five generic lineages within the subfamily <i>Boletoideae</i>, including one new genus, <i>Neoporphyrellus</i>, proposed in this study, as well as one new species, <i>N. sinoalboater</i>, and two new combinations, <i>N. alboater</i> and <i>N. atronicotianus</i>. The remaining five species are nested in four known genera, including two new species of <i>Abtylopilus</i>, <i>Ab. indonesiensis</i> and <i>Ab. australiensis</i>, and three known species belonging to <i>Anthracoporus</i>, <i>Indoporus</i>, and <i>Tylopilus</i>, respectively. These findings highlight the taxonomic complexity of the <i>T. alboater</i> complex and emphasize the importance of integrating phylogenomic and multi-locus approaches for accurate fungal systematics. Color photos of fresh basidiomata, line drawings of microscopic features, and detailed descriptions of the new taxa are presented.