Cladosporium aulonemiae P. P. Costa, A. W. C. Rosado & O. L. Pereira, sp. nov.

MycoBank: MB824721

Systematic position: Fungi, Ascomycota, Pezizomycotina, Dothideomycetes, Dothideomycetidae, Cladosporiales, Cladosporiaceae

Etymology:—Name refers to the genus Aulonemia, from which the species was isolated.

Colonies on PDA attaining 47 mm diam, dull green to dark herbage green, grey olivaceous to citrine scarce aerial mycelium, velvety, furrowed; reverse olivaceous grey. On MEA attaining 40 mm diam, grey olivaceous, greenish glaucous, pale olivaceous grey woolly central mycelium; velvety, slightly radially furrowed; reverse olivaceous grey. On OA attaining 45 mm diam, grey olivaceous, dull green at the margin; reverse greenish-grey, velvety, flat. On SNA attaining 19 mm diam, greenish glaucous to grey olivaceous, flat, and sparse; reverse similar to surface. Mycelium sparsely formed, 2.38–4.55 µm wide, septate, sometimes slightly swollen and constricted at the septum, medium to dark brown, irregularly rough-walled, sometimes walls thickened, usually covered by polysaccharide-like material, and formation of stromatic hyphal aggregations. Conidiophores macronematous, solitary, 37.14–228.51 × 2.31–4.53 µm, arising terminal and laterally from hyphae, erect or somewhat flexuous, sometimes bent, cylindrical, sometimes narrowed, several times distinctly geniculate-sinuous towards the apex due to accentuated zig-zag-like sympodial proliferation, loci then localized on small lateral shoulders, up to 37 µm long, frequently dichotomously branched towards the apex, occasionally with prolongations at the apex, brown at the base and becoming paler towards the apex, septum conspicuous, sometimes refractive,1–5 septate, walls irregularly rough-walled, thickened at the base, sometimes micronematous, lateral, 15.67–32.28 × 2.78–3.75 µm, short to medium scars 1–2 rarely 5, brown, loci somewhat protuberant, cylindrical, cylindrical attenuated. Conidiogenous cells integrated, terminal and intercalary, cylindrical, cylindrical-oblong, sometimes geniculate-sinuous, proliferation sympodial, 14.32–47.88 × 2.29–4.13 µm, conidiogenous loci at the apex (1–4) or in lateral shoulders (3–13), loci somewhat thickened and darkened. Ramoconidia rarely present, cylindrical, 19.08–27.7 × 3.08–3.51µm, 0–2 septa, pale brown, large base, somewhat thickened. Secondary ramoconidia oblong, oblong-ellipsoid, 2–5 distal hila, narrowed base, 8.26–17.98 × 2.53–4.23 µm, 0–1 septate, pale brown. Conidia numerous, catenate, acrogenous, branching in all directions, subglobose, ellipsoid, aseptate, rarely once septate, medium to dark brown, 4.59–7.9 × 2.77–4.96 µm, small terminal conidia, obovoid to globose, 3.63–5.59 × 2.90–4.06 µm, hila somewhat protuberant. Microcyclic conidiogenesis occurs.

Type:— Brazil. Minas Gerais: Araponga, at “ Parque Estadual Serra do Brigadeiro ”, isolated from decayed leaf of Aulonemia amplissima (Poaceae), March 15, 2016 (holotype VIC 44413, ex-type culture COAD 2269).

GenBank: MT373119 (ACT), MT680198 (TEF1-α), MZ318427 (rDNA-ITS)

Additional specimens examined: — BRAZIL. Minas Gerais: Araponga, at “Parque Estadual Serra do Brigadeiro”, isolated from decayed leaves of Aulonemia amplissima (Poaceae), 15 March 2016 (living culture COAD 2270 and COAD 2271).

Notes:— Cladosporium aulonemiae is phylogenetically close but distinct from C. rugulovarians. Although morphologically different, they have in common the presence of long conidiophores dichotomously branched towards the apex. Both belong to the C. cladosporioides species complex and form a basal sister clade in this complex. Perhaps this is the reason why C. aulonemiae possesses some features differentiated from their group and similar to species of C. herbarum species complex. Loci formation in close succession on small to large lateral shoulders results in a marked zig-zag-like growth. Similar conidiogenous cells are reported in C. arthropodii and C. sinuosum, belonging to the C. herbarum species complex. However, both species produce solitary and ornate conidia, characteristic of the C. herbarum species complex. In the sympodial loci of C. aulonemiae, besides the solitary and slightly rough conidia, short conidia chains or new conidiogenous cells with equal sympodial proliferation are also formed. Another unusual feature is the polysaccharide-like material produced in C. antarcticum and C. variabile (both belonging to the C. herbarum species complex). The material appears to adhere to the hypha in these species, enveloping these structures. However, in C. aulonemiae, it has more loosely adhered. It appears as a brownish smudge around the fungal structures and is also dispersed in the medium where the lamina was mounted.