Triplosphaeria guizhouensis L. L. Liu & Z. Y. Liu 2023, sp. nov.

Triplosphaeria guizhouensis L.L. Liu & Z.Y. Liu, sp. nov. Figure 2.

Index Fungorum number: IF 900370; Facesoffungi number: FoF 10694

Etymology: In reference to the host location, Guizhou province, where the holotype was collected.

Saprobic on decaying submerged wood in freshwater habitats. Asexual morph: Colonies on natural substrate effuse, consisting of individual conidium scattered over the substrate surface, conspicuous, brown to black. Mycelium mostly immersed, consisting of branched, septate, smooth, subhyaline to pale brown hyphae. Conidiophores absent. Conidiogenous cells monoblastic. Conidia solitary, straight or slightly curved, conidia body 18.9–23 × 8–9 μm (x = 21 × 8.5 μm, n = 15), composed of three or four columns of cells, 5–7-septate in each column, guttulate, smooth-walled or sometimes verrucose on the base cell, with 3–4 setose appendages. Appendages (4.7–) 12.6–18.9 (–21.5) long, 1–1.5 μm wide, divergent, pale brown to brown, 2–4-septate, straight or slightly flexuous, smooth-walled. Sexual morph: Undetermined.

Cultural characteristics: Conidia germinating on WA and germ tubes produced from appendages within 12 h. Colonies on PDA growing slowly, reaching 20–25 mm DIAM. after one month at 25°C, under dark condition, circular, consisting of a matted felt with velutinous appearance, umbonate, surface of the colony mouse grey, in reverse brown.

Material examined: CHINA, Guizhou Province, Chishui City, Chishui river basin, 28°25′N, 106°0′E, at an altitude of 204 m, on submerged decaying wood in a stream, 16 July 2019, L.L. Liu, CS1-18-1 (GZAAS 20–0407, holotype), ex-type living culture GZCC 19–0512.

Notes: Triplosphaeria guizhouensis shares similar morphological characteristics with the tetraploa -like anamorph in having cylindrical conidia with columns of cells and apical appendages (Tanaka et al., 2009). Phylogenetic analyses of combined LSU, ITS, SSU, tef1-α, and β-tubulin sequence data indicates that the new strain (GZAAS20-0407) nested within the Tetraplosphaeriaceae, and was resolved as a monophyletic clade with the genus Triplosphaeria (FIGURE 1). Triplosphaeria guizhouensis can be distinguished from other Triplosphaeria species in having conidia with ¾ columns and ¾ setose appendages. Moreover, the conidia of T. guizhouensis on the host plant differs from those of Triplosphaeria produced under culture conditions in having smaller conidia and shorter appendages (TABLE 2). Triplosphaeria sp. formed smaller conidia on the host plant also (TABLE 2) (Tanaka et al., 2009). In phylogenetic analysis, T. guizhouensis is sister to Tetraplosphaeria sp. (HHUF 27481) (Figure 1). Morphologically, T. guizhouensis is well distinguishable from Triplosphaeria sp. by quite smaller conidia (18.9–23 × 8–9 µm vs. (26–) 31.5–46 × 14–23 µm) and shorter appendages ((4.7–) 12.6–18.9 (–21.5) µm vs. 36–90µm). The teleomorph of T. guizhouensis is unknown, however based on anamorph form and molecular data, it clearly belongs to Triplosphaeria.