Tubeufia dictyospora Y.Z. Lu, Boonmee & K.D. Hyde
Index Fungorum number: IF 554900; Facesoffungi number: FoF 04755
Etymology: “dictyospora” referring to dictyospores of this fungus.
Holotype: MFLU 17–1114
Saprobic on submerged decaying wood in a freshwater stream. Sexual morph Undetermined. Asexual morph Hyphomycetous, dictyosporous. Conidiophores lacking. Conidiogenous cells holoblastic, monoblastic, integrated, cylindric, apical, pale brown. Dictyospores acrogenous, carbonaceous, friable, solitary, variable in shape, globose to subglobose, ovoid to irregular, indistinctly dictyoseptate, verrucose, size in holotype: 95–185 μm long, 60–85 μm wide (x̄ = 145 × 70 μm, n = 20); size in paratype: 60–100 μm long, 60–70 (–80) μm wide (x̄ = 75 × 65 μm, n = 20), pale brown when young, dark brown to black when matured. (Lu et al. 2018)
Culture characteristics: Conidia germinating on water agar and producing germ tubes within 24 h. Colonies growing on PDA, circular, with flat surface, edge filiform, reaching 35 mm in 4 weeks at 28 °C, brown to dark brown in PDA media. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown.
Material examined: THAILAND, Chiang Mai, Mae Taeng, Mushroom Research Center, on decaying wood in a mountain, 25 January 2017, Yong-Zhong Lu, MRC15 (MFLU 17–1114, holotype), ex-type living cultures, MFLUCC 17–1805, TBRC 8895. THAILAND, Krabi, Muang, Nongtalay, Khao Hang Nak, on submerged decaying wood in a freshwater stream, 16 December 2015, Saranyaphat Boonmee, HN02–3 (MFLU 17–1173, paratype), living culture, MFLUCC 16–0220.
Notes: Morphologically, Tubeufia dictyospora resembles T. chlamydospora in colony features on decaying woody substrate but can be distinguished by conidial morphology. The conidia of T. dictyospora are obviously longer than T. chlamydospora (95–185 μm vs. 65–100 μm) and lack secondary conidia. Tubeufia chlamydospora resembles Artocarpomyces paradoxus in having conidia that are variable in shape, globose to subglobose, ovoid to irregular, verrucose, and can also be distinguished by conidiophore morphology (Subramanian 1994). Phylogenetically, T. dictyospora is closely related to T. machaerinae with high bootstrap support (Lu et al. 2018). We noted that our two newly obtained isolates of T. dictyospora were phylogenetically slightly apart from each other. Following the recommendation of Jeewon and Hyde (2016) for delimitation of new species, we looked into pair wise dissimilarities of DNA sequences and noted that there are 1, 3 and 1 base pair differences in their LSU, RPB2 and TEF1α, respectively, which may explain a close phylogenetic relatedness between them and their slight phylogenetic divergence. Although most conidia of MFLU 17–1173 are morphologically globose to subglobose and in the holotype MFLU 17–1114 they are irregular, we identified these two isolates as Tubeufia dictyospora as their ITS sequence data are identical and those few base pair differences in LSU, RPB2 and TEF1α sequence data are not enough to indicate they are different species. (Lu et al. 2018)
Freshwater distribution: Thailand (Lu et al. 2018)
Fig 1 Tubeufia dictyospora (MFLU 17–1114, holotype). a Colony on decaying wood. b–j Conidia. k Germinating conidium. l, m Colony on PDA from above and below. Scale bars: a = 200 µm, b–k = 50 µm (Lu et al. 2018)