<i>Microascus microspora</i> sp. nov. and <i>Tolypocladium terrae</i> sp. nov.; Two Novel Fungal Species Isolated from Soil in Korea

During an investigation of microfungi from various ecosystems in South Korea, two novel fungal species (KNUF-22-094^T and KNUF-23-321C^T) were discovered within the genera <i>Microascus</i> and <i>Tolypocladium</i>. The strain KNUF-22-094^T stands out among other <i>Microascus</i> species due to its distinctive conidiogenous cells and conidial size ranges. The conidiogenous cells of KNUF-22-094^T measured 2.3-4.3 × 2.0-3.6 µm, notably smaller than those of <i>M. rothbergiorum</i> (7.5-11.5 × 2.5-4.5 µm), <i>M. sparsimycelialis</i> (5.0-10.0 × 3.0-5.0 µm), which is considerably larger in both dimensions. For the conidial structures, conidia measured 2.6-4.8 × 2.6-4.4 µm, falling within a distinct range that is smaller than those of <i>M. rothbergiorum</i> (4.0-5.5 × 3.5-4.5 µm), <i>M. verrucosus</i> (5.0-7.0 × 4.5-6.0 µm), and <i>M. restrictus</i> (4.5-6.0 × 4.0-5.5 µm), but comparable in size to <i>M. murinus</i>, which tends to be more elongated (4.0-6.0 × 1.5-1.9 µm). The phialides of KNUF-23-321C^T are globose, with a notably broad length range of 3.7-22.5 µm and a width of 0.9-1.5 µm, making it one of the most variable in length compared to species like <i>T. album</i> (3.5-10 µm) and <i>T. endophyticum</i> (1.3 ± 0.2 µm, 4.1 µm on average). Phylogenetic analyses using a multi-locus sequences supported to confirm their distinctness under the genus <i>Microascus</i> and <i>Tolypocladium</i> species. Thus, these fungal strains isolated from soil in Korea are proposed as a novel species according to their characteristics and are named <i>Microascus microspora</i> sp. nov. and <i>Tolypocladium terrae</i> sp. nov. Detailed descriptions, illustrations, and phylogenetic data are provided to support the recognition of these new species.