Phylogenetic assessment and taxonomic revision of Scytalidium (Helotiales, Leotiomycetes) Author Tong, Shuo-Qiu https://orcid.org/0009-0006-9422-5551 College of Life Sciences, Institute of Agro-bioengineering, Guizhou University, Guiyang 550025, China Author Yang, Yi-Fan https://orcid.org/0009-0004-5897-8236 College of Life Sciences, Institute of Agro-bioengineering, Guizhou University, Guiyang 550025, China Author Li, Peng https://orcid.org/0009-0000-9175-6599 College of Life Sciences, Institute of Agro-bioengineering, Guizhou University, Guiyang 550025, China Author Wu, Yong-Jun 0000-0002-6732-8276 College of Life Sciences, Institute of Agro-bioengineering, Guizhou University, Guiyang 550025, China Author Sun, Bing-Da 0000-0003-0272-6422 China General Microbiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China Author Zhang, Zhi-Yuan 0000-0003-2031-7518 College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang 550025, China text IMA Fungus 2025 2025-10-14 16 e 164608 e 164608 journal article 312645 10.3897/imafungus.16.164608 b4bb0c4c-775d-4eb6-9e9c-964e77874d4f PMC12541464 41132763 9. Scytalidium guizhouense S. Q. Tong & Zhi. Y. Zhang sp. nov. Fig. 4 Type. CHINA • Guizhou , Guiyang , Huaxi District , Shiban Town , 26.46°N , 106.65°E , soil , 8 July 2022 , Shuo-Qiu Tong ( holotype HMAS 354097 , dried culture; ex-type CGMCC 3.28992 , ibid ., SQT 08 and SQT 09) . Etymology. The epithet refers to the type location. Description. Culture characteristics (14 days at 25 ° C): Colony on PDA attaining 48–55 mm diam., flat, margin lobate edge, ash gray (1 B 2) to dull green (30 E 3). Reverse ash gray (1 B 2) to jade green (27 E 3). Colony on SNA attaining 20–26 mm diam., flat, margin radially striate with lobate edge, white (1 A 1). Reverse white (1 A 1). Mycelium consisting of hyaline, smooth-walled, branched, septate, 1–2.5 μm diam hyphae. Conidiophores erect, hyaline, smooth, solitary, terminal, lateral, subcylindrical, straight to flexuous, unbranched, 0–2 - septate, reduced to conidiogenous cells, 12.5–43 × 1–3 μm. Conidia solitary, catenate, hyaline, smooth-walled, oblong or ellipsoidal to globose, subcylindrical to cylindrical, not constricted at septa, segments 6.5–12 × 5–7 μm (avg. 8.9 × 5.9 μm, n = 30). Chlamydospore-like cells dark brown, oblong or ellipsoidal to subglobose, ellipsoidal, 0–1 - septate, thick-walled, smooth, solitary or catenate, 7.5–13 × 4.5–6.5 μm (avg. 10.5 × 5.4 μm, n = 30). Fertile hyphae borne laterally on simple conidiophores, fragmenting into arthroconidia. Arthroconidia hyaline to brown, smooth, cuboidal to oblong or cylindrical, 3–7.5 × 2–3 µm (avg. 5.3 × 2.7 μm, n = 30). Sexual morph unknown. Scytalidium guizhouense (from holotype HMAS 354097 ) a, b upper and reverse views of cultures on PDA and SNA after 14 d at 25 ° C c conidia and conidiophores d, f arthroconidia e chlamydospore-like cells g arthroconidia and chlamydospore-like cells. Scale bars: 10 μm (c – f); 20 μm (g). Geographical distribution. Guizhou Province , China . GenBank numbers. SQT 08 – SQT 09, ITS : PV 890023 – PV 890024 , LSU : PV 890030 – PV 890031 . Notes. Phylogenetic analysis showed that two new isolates ( CGMCC 3.28992 and SQT 09) clustered in a single subclade with strong support (100 / 1) (Figs 1 , 2 ). Morphologically, S. guizhouense differs from other species in Scytalidium by its production of conidia, arthroconidia, and chlamydospore-like cells, and an unknown sexual morph (see notes of key). Scytalidium guizhouense was isolated from soil in a pepper cultivation area and is likely to have a saprophytic lifestyle.