<i>Anthracophyllum sontraense</i> (Omphalotaceae, Agaricales), A New Species from Danang, Vietnam

During the collection of macrofungi resources in Son Tra Nature Reserve, Danang, Vietnam, two fungal specimens of the genus <i>Anthracophyllum</i>, designated as M34295 and M3457, living on dead still-attached branches of <i>Mussaenda frondosa</i> L. at an elevation around 360 m above the sea level were recorded. The morphological characteristics of the specimens shared some common characteristics with <i>Anthracophyllum</i> spp. However, the specimens possessed some distinct characteristics from other <i>Anthracophylllum</i> species. The phylogenetic analyses based on the combined internal transcribed spacer (ITS) and Large Subunit (LSU) molecular markers of ribosomal <i>RNA</i> genes revealed that the two specimens clustered in a single clade at species level with all tested <i>Anthracophyllum</i> species with strong bootstrap support of 99%. Among <i>Anthracophyllum</i> genus, our specimens seemed closest to <i>A. archeri</i> in morphological and genetic characteristics. Based on the combination of morphological approaches and multilocus phylogenetic analyses, we introduced <i>Anthracophyllum sontraense</i> sp. nov. as a new species. <i>A. sontraense</i> was characterized by its skewed bell-like basidiome with the color of dark blue to midnight blue, 1.0 - 1.5 cm diam, stipeless, light pink lamellae, sparse, occasionally branching. Basidiospores broadly ovoid to subglobose, 6-7 × 5.5-6 µm. To our knowledge, this is the first record of <i>Anthracophyllum</i> fungus in Vietnam.