Cippumomyces mortalis Crous, Overton & Ricci, sp. nov.

MycoBank number: MB 841837; Index Fungorum number: IF 841837; Facesoffungi number: FoF 15610;

Etymology. Name refers to the association of gravestones and death = mors.

Conidiomata aggregated in a brown stroma, visible on surface via exuding mucoid spore droplets (on OA and SNA). Mycelium consisting of brown, verruculose, branched, septate, 3 − 6 μm diam hyphae, encased in mucoid sheath, forming chains of intercalary conidiomata, globose to ellipsoid, 30 − 70 μm diam, with dividing walls dissolving, forming longer conidiomata that can be up to 250 μm wide, and 30 − 50 μm tall; wall of 2 − 3 layers of brown, verruculose textura angularis; open via ir- regular rupture. Conidiogenous cells arising from basal layer of conidioma, brown, cylindrical, giving rise to a conidium that is hyaline, globose, encased in thick mucoid sheath; conidium content dividing into several globose endoconidia, hyaline, smooth, 5 − 10 μm diam, with 2, 4, 8 or multiple endoconidia; original conidial wall dissolving at maturity, but endoconidia, 3 − 5 × 2.5 − 5 μm, remain encased in mucoid sheath. Conidia hyaline, smooth, thin-walled, ellipsoid to globose, encased in thick mucoid sheath. Mature conidia become brown, verrucu- lose, muriformly septate, and frequently anastomose; conidia exude in a mucoid droplet.

Culture characteristics — Colonies erumpent, spreading, with sparse aerial mycelium and smooth, lobate margin, reach- ing 4 − 6 mm diam after 7 d at 25 °C. On MEA and PDA surface and reverse isabelline; on OA surface brown vinaceous. Good growth and sporulation also observed on Acidified Rose-Bengal Agar, but the mucoid sheath tends to be less well-developed, the endoconidia less clustered, and conidiogenous cells not observed.

Typus. USA, Clinton County Pennsylvania, on tombstone, adjacent to Lock Haven University Campus, 14 Oct. 2020, G.M. Ricci (holotype CBS H-24893, culture ex-type CPC 41588 = CBS 148452, ITS, LSU, actA, cmdA, rpb2, tef1 (first part) and tub2 sequences GenBank OK664755.1, OK663794.1, OK651139.1, OK651180.1, OK651195.1 and OK651218.1; ibid., culture CPC 41587 = CBS 148453, ITS, LSU, actA, cmdA, rpb2, tef1 (first part) and tub2 sequences GenBank OK664756.1, OK663795.1, OK651140.1, OK651146.1, OK651181.1, OK651196.1 and OK651219.1).

Notes — Cippumomyces adds yet another slow-growing yeast-like genus to the Neoantennariellaceae. It is characterised by forming a stroma containing conidiomata that are initially linked in chains in a mycelial network, with conidiomatal walls that dissolve at maturity, forming larger conidiomata. Primary conidia formed on conidiogenous cells are globose, and give rise to endoconidia. At first sight, the primary conidia containing propagules are rather reminiscent of asci with ascospores, but as these were found to form on stalks, that were interpreted as conidiogenous cells forming from the inner wall of conidiomata, they are regarded as primary conidia. Endoconidia vary in number and increase in number at maturity.

Based on a megablast search of NCBIs GenBank nucleotide database, the closest hits using the ITS sequence of CPC 41587 had highest similarity to Ramimonilia apicalis (strain CBS 118327, GenBank NR_144959.1; Identities = 437/474 (92 %), seven gaps (1 %)), Neocatenulostroma germanicum (strain CBG, GenBank MK622897.1; Identities = 435/492 (88 %), 21 gaps (4 %)), and Aulographina pinorum (strain CBS 302.71, GenBank GU214622.1; Identities = 482/547 (88 %), 24 gaps (4 %)). The ITS sequences of CPC 41587 and 41588 were identical (535/535 nucleotides, no gaps). Closest hits using the LSU sequence of CPC 41587 are Readerielliopsis fuscoporiae (strain CBS 139900, GenBank NG_058161.1; Identities = 691/728 (95 %), five gaps (0 %)), Readerielliopsis guyanensis (as Readeriella guyanensis; strain CBS 117550, GenBank FJ493211.1; Identities = 691/728 (95 %), five gaps (0 %)), and Nothophaeotheca mirabibensis (strain CBS 146980, GenBank NG_076740.1; Identities = 694/ 732 (95 %), nine gaps (1 %)). The LSU sequences of CPC 41587 and 41588 were identical (721/721 nucleotides, no gaps). No significant hits were obtained when the actA, cmdA, rpb2, tef1 (first part) and tub2 sequences were used in blastn and megablast searches. The actA, rpb2, tef1 (first part) and tub2 sequences of CPC 41587 and 41588 were identical (558/558, 817/817, 422/422 and 410/410 nucleotides, no gaps).