Dematipyriforma nilotica Abdel-Aziz &Abdel-Wahab, sp. nov.
Index Fungorum number: IF 900084; MycoBank number: MB 900084; Facesoffungi number: FoF 13401; Fig. 1
Etymology – Named after the River Nile where the fungus was collected.
Holotype – SUMCC H-12003
Saprobic on submerged date palm rachis in the River Nile. Sexual morph: Not observed. Asexual morph: Mycelium immersed and superficial, sub-hyaline to brown, septate, branched, smooth, 1.5–3.5 μm wide. Conidiophores absent or present, when present micronematous, mononematous, sub-hyaline to reddish-brown, flexuous, smooth, unicellular, 7–13 μm long, 2.5–4.5 μm wide. Conidiogenous cells holoblastic, integrated, intercalary or terminal, sub-hyaline to brown, determinate, ampulliform, clavate, subglobose, cylindrical, smooth, 1.5–8.5 μm long, 4.5–6.5 μm wide. Conidial secession rhexolytic. Conidia solitary or aggregated, effuse and heavily covered the surface of the wood, intercalary or terminal, smooth, or surrounded by fine fibers, pyriform, globose or subglobose, rounded at the apex, conidial cells are filled gradually with black material, black when mature, with brown to dark-brown basal cell, muriform, 6–9 cells, 3–5 transverse septa and 0–2 longitudinal or oblique septa, not or slightly constricted at the septa, 31–45×21–37 μm (x̄ =37×26.3 μm, n=50), basal cells are singles. Chlamydospores intercalary or terminal, dark-brown to black, smooth, form large, black muriform masses with irregular shapes.
Culture characteristics – Colonies on PDA reaching 30 mm diam after 3 weeks, at 25 °C, brown to reddish darkbrown, reverse brown to dark-brown. Conidial dimensions and shapes are similar to those found on natural wood.
Material examined – Egypt, Sohag City, the River Nile, on submerged date palm rachis, 14 August 2012, F. A. AbdelAziz, SUMCC H-12003, holotype, ex-type living culture, SUMCC 12103.
GenBank numbers – MT522157 (SSU), MT522156 (LSU).
Notes – Dematipyriforma nilotica differs from the other three species in having larger conidial dimensions that sometimes surrounded by fine fibres. Dematipyriforma nilotica is phylogenetically related with D. aquilaria, however, the first species have black and larger conidia (31–45×21–37 μm vs. 25–37×15–22 μm in D. nilotica and D. aquilaria respectively) and grow on decaying date palm rachis in freshwater habitat, while the latter species produce brown conidia and live as an endophyte. Chlamdydospores in D. aquilaria have perforative canal that is absent in D. nilotica. Both D. aquatica and D. nilotica have 3–5 continuous transverse septa with 0–2 longitudinal septa, however, conidia in the latter species are surrounded by fine fibres and are larger in size (27–38 × 15–26 μm vs. 31–45 × 21–37 μm for D. aquatica and D. nilotica respectively). A comparison of the 800 nucleotides of the LSU rDNA for D. aquatica and D. niloticashows 15 base pair differences (1.87%) that confirm they are two different species.
Figure 1 – Dematipyriforma nilotica (SUMCC H-12003, holotype). a–l Variously shaped conidia at different stages of maturity. a–d Conidia from natural date palm rachis. e–l Conidia from pure culture. m Chlamydospores in culture. b,d Conidia surrounded by fine fibers. a–b, g–i Gradual filling of the conidial rows by black material. Scale bars: a–m=10 µm