Neothyrostroma encephalarti Crous, in Crous et al., Persoonia 43: 257 (2019)

MycoBank number: MB 832864; Index Fungorum number: IF 832864; Facesoffungi number: FoF 09670;

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

Conidiomata sporodochial, black, erumpent in agar and superficial on leaves in nature, solitary, 200 – 500 µm diam (in culture). Conidiophores arising from brown stroma, subcylindrical, hyaline, smooth, branched, septate, up to 50 µm tall, 4 – 5 µm wide. Conidiogenous cells subcylindrical, hyaline, smooth, terminal and intercalary, 10 – 30 × 4 – 5 µm, proliferating percurrently at apex. Conidia solitary, brown, smooth, fusoid-ellipsoid, apex acutely rounded, base truncate, 2 – 3 µm diam, distoseptate, with 3 – 5 horizontal septa, and 3 – 5 oblique or vertical septa, (20 –)21– 24(– 27) × (8 –)9 –10(–11) µm.

Culture characteristics — Colonies flat, spreading, with moderate aerial mycelium and smooth, lobate margin, reaching 25 mm diam after 2 wk at 25 °C. On MEA surface pale olivaceous grey, reverse olivaceous grey. On PDA surface and reverse olivaceous grey. On OA surface dirty white to smoke grey.

Typus. SOUTH AFRICA, Limpopo Province, Tzaneen, on leaves of Encephalartos sp. (Zamiaceae), 2010, P.W. Crous, HPC 2486 (holotype CBS H-24162, cultures ex-type CPC 35999, CPC 35998 = CBS 146037.

GenBank Accession Numbers: CPC 35998 – ITS: MN562104, LSU: MN567612 and tef1: MN556830; CPC 35999 – ITS: MN562105, LSU: MN567613 and  tef1: MN556831.

Notes — Neothyrostroma is reminiscent of the genus Thyrostroma, which was recently treated by Marin-Felix et al. (2017). The two genera are distinct phylogenetically, and Neothyrostroma can also be distinguished morphologically in having distoseptate conidia. Based on a megablast search of NCBIs GenBank nucleotide database, the closest hits using the ITS sequence of CPC 35998 had highest similarity to Angustimassarina sp. DP-2019a (voucher MFLU 18-0057, GenBank MN244197.1; Identities = 427/461 (93 %), 8 gaps (1 %)), Exosporium stylobatum (strain AN122R, GenBank MH397653.1; Identities = 416/450 (92 %), 8 gaps (1 %)), and Lophiostoma corticola (strain Z26, GenBank MK907710.1; Identities = 438/474 (92 %), 11 gaps (2 %)). The ITS sequences of CPC 35998 and 35999 are identical (545/545 bases). Closest hits using the LSU sequence of CPC 35998 are Alfoldia vorosii (as Dothideomycetes sp. DGK-2019a, strain REF117, GenBank MK589355.1; Identities = 863/883 (98 %), 4 gaps (0 %)), Amorocoelophoma cassiae (voucher C259, GenBank MK347956.1; Identities = 857/883 (97 %), 5 gaps (0 %)), and Angustimassarina coryli (strain MFLUCC 14-0981, GenBank MF167432.1; Identities = 854/881 (97 %), 6 gaps (0 %)). The LSU sequences of CPC 35998 and 35999 are identical (883/883 bases). Closest hits using the tef1 sequence had highest similarity to Alfoldia vorosii (as Dothideomycetes sp. DGK-2019a, strain REF117, GenBank MK599321.1; Identities = 438/466 (94 %), no gaps), Parathyridaria percutanea (strain UTHSC DI16-292, GenBank LT797111.1; Identities = 433/462 (94 %), no gaps), and Splanchnonema platani (strain CBS 221.37, GenBank DQ677908.2; Identities = 435/466 (93 %), no gaps).