Dematipyriforma aquatica Abdel-Aziz &Abdel-Wahab sp. nov.
Index Fungorum number: IF 900081; MycoBank number: MB 900081; Facesoffungi number: FoF 13400; Fig. 1
Etymology – Named after the aquatic habitat, where this fungus was collected.
Holotype – SUMCC H-12001 (Sohag University Microbial Culture Collection)
Saprobic on submerged wood in the River Nile. Sexual morph: Not observed. Asexual morph: Mycelium immersed and superficial, sub-hyaline to brown, septate, branched, smooth, 1.5–4 μm wide. Conidiophores absent or present, when present micronematous, mononematous, subhyaline to brown, flexuous, smooth, unicellular, 7–15 μm long, 1.5–4 μm wide. Conidiogenous cells holoblastic, integrated, intercalary or terminal, sub-hyaline to brown, determinate, ampulliform, clavate, subglobose, smooth, 5–8 μm long, 5–6 μm wide. Conidial secession rhexolytic. Conidia solitary or aggregated, effuse and heavily covered the surface of the wood, intercalary or terminal, smooth, pyriform or subglobose, rounded at the apex, black, with brown to dark-brown basal cell, muriform, 4–10 cells, 3–5 transverse septa and 0–2 longitudinal septa, not or slightly constricted at the septa, 27–38×15–26 μm (x̄ =32.2×20.9 μm, n=50), apex and basal cells are singles. Chlamydospores intercalary or terminal, catenated, straight, or curved, brown to dark brown, smooth, granulate, phragmoseptate.
Culture characteristics – Colonies on PDA reaching 25 mm diam after 3 weeks, at 25 °C, dark-brown to black, reverse dark-brown to black. Conidial dimensions and shapes are similar to those found on natural wood.
Material examined – Egypt, Sohag City, the River Nile, on submerged wood, 14 August 2012, F. A. Abdel-Aziz, SUMCC H-12001, holotype, ex-type living culture, SUMCC 12101.
GenBank numbers – MT522154 (SSU), MT522155 (LSU)
Notes – Combined phylogenetic analyses of SSU and LSU rDNA placed the three new species of Dematipyriforma with the type species D. aquilaria with high statistical support as distinct new taxa. The three new species differ from D. aquilaria in having black conidia vs. pale grey olivaceous to pale brown in the latter species. Dematipyriforma aquilaria was isolated as an endophyte from a trunk of Aquilaria crassna in Laos (Sun et al. 2017), while the three new species are freshwater taxa. Conidia of D. aquilaria are evenly pigmented, while the three new species have black conidia with basal cells that are lighter. Chlamydospores of D. aquilaria have thick walls with axial perforative canals, these canals are absent in the three new species. A comparison of the 590 nucleotides of the D1/D2 region of the LSU rDNA of the three new species of Dematipyriforma with D. aquilarias hows 14 base pair differences (2.37%) which justifies the erection of the three new species following the guidelines of Jeewon and Hyde (2016).
Figure 1 – Dematipyriforma aquatica (SUMCC H-12001, holotype).a–j, l–p Variously shaped conidia at different stages of maturity. k Chlamydospores in culture. a–j Conidia from natural wood. g–j, l–p Conidia from pure culture. Scale bars: a–p=10 µm