Dematipyriforma globispora Abdel-Aziz &Abdel-Wahab sp. nov.
Index Fungorum number: IF 900083; MycoBank number: MB 900083; Facesoffungi number: FoF 13865; Fig. 1
Etymology – Named after the shape of the globose shape of the conidia.
Holotype – SUMCC H-12002
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, 2–4 μm wide. Conidiophores absent or present, when present micronematous, mononematous, subhyaline to brown, flexuous, smooth, unicellular, 6–12.5 μm long, 1.5–4.5 μm wide. Conidiogenous cells holoblastic, integrated, intercalary or terminal, sub-hyaline to brown, determinate, clavate, smooth, 4–6.5 μm long, 2.5–4.5 μm wide. Conidial secession rhexolytic. Conidia solitary or aggregated, effuse and heavily covered the surface of the wood, intercalary or terminal, smooth, globose or subglobose, rounded at the apex, black, with brown to dark-brown basal cell, muriform, with irregular transverse, longitudinal and oblique septa and form mass of cells, not constricted at the septa, sometimes surrounded by network of hyphae, 17–37×15–30 μm (x̄ =27.7×20.9 μm, n=60), smaller buds are produced from conidia that are yellow–brown to brown in color, muriform, 11–19.2×7.1–14.5 μm. Chlamydospores intercalary or terminal, catenated, straight, or curved, brown to black, smooth, form large, black muriform masses similar to conidia but much larger in size 37–120×17–30 μm.
Culture characteristics – Colonies on PDA reaching 20 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-12002, holotype, ex-type living culture, SUMCC 12102.
GenBank numbers – MT522158 (SSU), MT522153 (LSU).
Notes – Dematipyriforma globispora differs from the other three species in having smaller conidia, that are mostly globose, sometimes surrounded by networks of hyphae and produce buds that are pale-brown to brown. Dematipyriforma globispora and D. aquatica are phylogenetically related, however, they differ in their morphology. Conidial cells in D. globispora are arranged irregularly and conidia are globose with small buds and surrounded by network of hyphae. Conidia in D. aquatica are pyriform or subglobose with 3 to 5 continuous transverse septa. Rhexoacrodictys nigrospora produce similar conidia with overlapping dimensions, however, conidia of D. globispora are surrounded by network of hyphae with brown buds. Mycelium in R. nigrospora are narrow (1–2 μm wide) with verruculose or finely echinulatewalled (Boonmee et al. 2021), while hyphae in D. globispora are 2–4 μm wide and smooth. A comparison of the 805 nucleotides of the LSU rDNA for D. globispora and R. nigrosporashows 11 base pair differences (1.36%) that confirm they are two different species.
Figure 1 – Dematipyriforma globispora (SUMCC H-12002, holotype).a–g, i–l Variously shaped conidia at different stages of maturity. h Chlamydospores in culture. a–e Conidia from natural wood. f–g, i–l Conidia from pure culture. c–d Conidia are surrounded by network of hyphae. e, l Conidia with small buds. Scale bars: a–l=10 µm