Paraxerochrysium coryli Crous & Decock, sp. nov.

Index Fungorum number: MB841830; Facesoffungi number: FoF

Etymology. Name refers to the host genus Corylus from which it was isolated.

Mycelium consisting of hyaline, smooth-walled, branched, septate, 3 – 4(–7) μm diam hyphae. Reproductive structures consisting of solitary or short chains of chlamydoconidia, borne by retrogressive sympodial formation from hyphal tips, or as intercalary chlamydoconidia. Chlamydoconidia spherical, (7–)10 –15(– 20) μm diam, thick- and smooth-walled, guttulate, hyaline.

Culture characteristics — Colonies erumpent, spreading, surface folded, with sparse aerial mycelium and feathery, lobate margin, reaching 5 mm diam after 2 wk at 25 °C. On MEA sur- face dirty white, reverse pale luteous; on PDA and OA surface and reverse dirty white.

Typus. BELGIUM, Louvain-la-Neuve, from dry hazelnut, Corylus avellana (Betulaceae), Feb. 2021, C. Decock, 0234-8 (holotype CBS H-24853, culture ex-type CPC 41272 = CBS 148314 = MUCL 58103, ITS, LSU, rpb2 and tub2 sequences GenBank OK664748.1, OK663787.1, OK651178.1 and OK651216.1).

NotesParaxerochrysium is similar to Xerochrysium, as both genera are only known from their asexual morphs, and are characterised by having solitary or short chains of chlamydoco- nidia. Paraxerochrysium is distinct in that it lacks aleuroconidia (Pitt et al. 2013). Paraxerochrysium clusters with species of Bettsia, Xerochrysium and Xeromyces.

Based on a megablast search of NCBIs GenBank nucleotide database, the closest hits using the ITS sequence had highest similarity to Xerochrysium xerophilum (strain CBS 153.67, Gen- Bank NR_154476.1; Identities = 514/563 (91 %), 17 gaps (3 %)), Bettsia fastidia (strain CBS 454.91, GenBank MH862261.1; Identities = 460/509 (90 %), 30 gaps (5 %)), and Leiothecium ellipsoideum (strain CBS 147.75, GenBank MH860904.1; Identities = 490/556 (88 %), 30 gaps (5 %)). Closest hits using the LSU sequence are Xerochrysium dermatitidis (strain CBS 132.31, GenBank NG_058454.1; Identities = 822 /834 (99 %), two gaps (0 %)), Monilia medoacensis (strain CBS 222.32, GenBank MH866748.1; Identities = 821/ 835 (98 %), three gaps (0 %)), and Xerochrysium xerophilum (strain FRR 4958, GenBank KC989712.1; Identities = 820/834 (98 %), one gap (0 %)). Closest hits using the rpb2 sequence had highest similarity to Xerochrysium dermatitidis (strain CBS 132.31, GenBank JN121443.1; Identities = 622/699 (89 %), no gaps), Pseudopenicillium megasporum (strain CBS 256.55, GenBank JN121473.1; Identities = 538 /659 (82 %), no gaps), and Asper­ gillus koreanus (strain EML-GSNP1-2, GenBank KX216527.1; Identities = 416/510 (82 %), two gaps (0 %)). No significant hits were obtained when the tub2 sequence was used in blastn and megablast searches.

Species