Neognomoniopsis quercina Crous, sp. nov.

MycoBank number: MB 830857; IndexFungorum number: IF 830857; Facesoffungi number: FoF;

Etymology. Name refers to Quercus, the host genus from which this fungus was isolated.

Ascomata perithecial, sparsely formed on SNA, immersed to superficial, solitary or in groups of up to three, dark brown, globose, 200 – 250 µm diam, with solitary, central neck, straight to curved, apex pale brown, obtuse, 50 – 200 × 25 – 30 µm. Asci hyaline, uniseriate, inoperculate, subcylindrical with a long, tapered stalk, 40 – 55 × 6 –7 µm, with visible apical ring, containing eight multiseriate ascospores. Ascospores hyaline, smooth, guttulate, fusoid, widest at median septum, straight or slightly curved, ends subobtuse, lacking mucoid appendages, (17–)18 –19(– 24) × 2 µm.

Culture characteristics — Colonies flat, spreading, with sparse aerial mycelium and smooth, lobate margin, reaching 30 mm diam after 2 wk at 25 °C. On MEA surface sienna, reverse ochreous. On PDA surface sienna with patches of dirty white, reverse umber. On OA surface ochreous.

Typus. ITALY, Rome, on leaves of Quercus ilex (Fagaceae), 13 Apr. 2018, P.W. Crous, HPC 2333 (holotype CBS H-23965, culture ex-type CPC 35562 = CBS 145575, ITS and LSU sequences GenBank MK876399.1 and MK876440.1).

Notes — Members of Gnomoniaceae are characterised by ascomata that are generally immersed, solitary, without a stroma, or aggregated in leaves or woody tissues of predominantly hardwood trees from temperate zones in the Northern Hemisphere. Monod (1983) included 22 genera in the family, some of which were excluded by Castlebury et al. (2002). Species of Gnomonia typically have solitary, thin-walled, immersed perithecia with long necks and lack any stroma, and generally have ascospores that are medianly septate. However, Gnomo­nia was shown to not be monophyletic (Sogonov et al. 2005, 2008). Gnomoniopsis, which is mostly associated with either Fagaceae or Rosaceae, was originally described for species having ascospores that develop additional septa (Sogonov et al. 2008). One species to consider is Gnomonia quercus­ilicis, which was described from Quercus ilex in Italy, was listed as ‘doubtful’ by Monod (1983), having not found any material in PAD. However, based on the original description provided by Saccardo (1895), perithecia are 100 –110 mm diam, asci 45 – 50 × 12 –16 mm, and ascospores 1-septate, 20– 24 × 7– 8 mm, thus quite different from the present collection, which we describe here as new.

Based on a megablast search of NCBIs GenBank nucleotide database, the closest hits using the ITS sequence had highest similarity to Plagiostoma conradii (GenBank KX929768.1; Identities = 437/491 (89 %), 11 gaps (2 %)), Gnomoniopsis para­ clavulata (GenBank MH863162.1; Identities = 456/524 (87 %), 17 gaps (3 %)) and Discula quercina (GenBank GQ452263.1; Identities = 456/524 (87 %), 17 gaps (3 %)). Closest hits using the LSU sequence are Cryptodiaporthe aubertii (GenBank KX929803.1; Identities = 831/845 (98 %), 2 gaps (0 %)), Siro­ coccus castaneae (GenBank KX929769.1; Identities = 831/845 (98 %), 2 gaps (0 %)) and Ambarignomonia petiolorum (as Gno­ monia petiolorum, GenBank AY818963.1; Identities = 831/845 (98 %), 2 gaps (0 %)).