Scytalidium rodionovae S. Q. Tong & Zhi. Y. Zhang 2025, sp. nov.

12.Scytalidium rodionovaeS. Q. Tong & Zhi. Y. Zhang sp. nov. Type. RUSSIA • Moscow, isolated from a rotting rope in the 1970s, living culture 3 C. Etymology. It was initially isolated by Rodionova et al. Description and illustration. Pavlov et al. (2018). Notes. Scytalidium rodionovae is phylogenetically closely related to S. album, S. assmuthi, S. aurantiacum, S. circinatum, S. terrigenum, and S. tongrenense (Figs 1, 2). The distinctions between S. rodionovae and S. album, S. assmuthi, and S. aurantiacum are detailed in the respective notes for S. album, S. assmuthi, and S. aurantiacum. Scytalidium rodionovae is distinguished from S. circinatum, S. terrigenum, and S. tongrenense by its known sexual morph, hyaline, ovoid, and septate chlamydospore-like cells (Sigler and Wang 1990; Jeong et al. 2025). Additionally, based on a pairwise comparison of ITS and LSU, S. rodionovae (ex-type 3 C) differs from S. circinatum (ex-type CBS 654.89) by 4 % (23 / 571 bp, four gaps) in the ITS and 1.1 % (7 / 628 bp, no gap) in the LSU; from S. terrigenum (ex-type KNUF- 23-236) by 7.8 % (44 / 559 bp, six gaps) in the ITS and 3.2 % (42 / 1299 bp, two gaps) in the LSU; from S. tongrenense (ex-type CGMCC 3.28994) by 9.7 % (53 / 548 bp, 11 gaps) in the ITS and 3.7 % (34 / 909 bp, one gap) in the LSU. Rodionova et al. (1974) identified strain 3 C as Geotrichum candidum based only on morphological characters. Pavlov et al. (2018) integrated morphological characteristics and phylogenetic analyses based on molecular data derived from 3 C to reclassify G. candidum into Scytalidium, naming it S. candidum. However, they overlooked the fact that 3 C does not belong to G. candidum. Here, we propose the new species Scytalidium rodionovae to accommodate the species for which 3 C is the ex-type. To date, the genome sequencing of strain 3 C has been completed (Polev et al. 2014). Studies have shown that this strain secretes a variety of enzymes capable of efficiently degrading cellulose, exhibits broad pH adaptability, and holds potential application value in lignocellulosic biomass conversion and green industrial processes (Lapin et al. 2002; Borisova et al. 2015).