Phylogenetic classification of arbuscular mycorrhizal fungi: new species and higher-ranking taxa in Glomeromycota and Mucoromycota (class Endogonomycetes) Author Tedersoo, Leho Mycology and Microbiology Center, University of Tartu, 2 Liivi, 50409 Tartu, Estonia & Department of Zoology, College of Science, King Saud University, 12371 Riyadh, Saudi Arabia Author Magurno, Franco 0000-0002-3117-8149 Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Jagiellońska 28, 40 - 032 Katowice, Poland Author Alkahtani, Saad 0000-0001-7381-5110 Department of Zoology, College of Science, King Saud University, 12371 Riyadh, Saudi Arabia Author Mikryukov, Vladimir 0000-0003-2786-2690 Mycology and Microbiology Center, University of Tartu, 2 Liivi, 50409 Tartu, Estonia text MycoKeys 2024 2024-08-09 107 249 271 journal article 10.3897/mycokeys.107.125549 Endogonomycetes Doweld emend. Tedersoo Type order. Endogonales Jacz. & P. A. Jacz. Description. Fruiting body absent, rarely present - hypogeous or on debris, globose, irregular, sometimes resupinate, 1–20 mm in diam., may be composed of aggregated zygosporangial clusters. Reproductive structures as zygosporangia (in Endogone , Jimgerdemannia ) or chlamydospores (in Vinositunica , Densospora ), aggregated in the fruiting body or as chlamydospores on extraradical hyphae (in Planticonsortium ). Chlamydospore wall continuous, multilayered, with dense subtending hyphae, lacking septa. Hyphae filamentous, coenocytic, sometimes with secondary septa, rarely yeast-like (in Bifiguratus ). Forms a monophyletic group in Mucoromycota, as the least inclusive clade covering accessions UDB 025468, UDB 28692, EUK 1201418, EUK 1203196, EUK 1602762, EUK 1202520, EUK 1203766, EUK 1107335 and EUK 1602357 (Suppl. material 3 ). Notes. Endogonomycetes harbours currently 17 orders and two unassigned, potentially order-level groups represented by sequences EUK 1604020 and EUK 1603073 ( GSMc plot G 3308, Juniperus communis coppiced grassland soil in Atla, Estonia , 58.30122 ° N , 21.93600 ° E ); and EUK 1602478 ( GSMc plot G 4627, mixed forest soil in Tudusoo, Estonia , 59.11368 ° N , 26.75944 ° E ).