Thysanorea acropleurogena Réblová & Hern.-Restr., 2025

Réblová, Martina, Nekvindová, Jana, Bauchová, Lucie & Hernández-Restrepo, Margarita, 2025, Pleurophragmium parvisporum (Ascomycota): One name, seven stories – a case highlighting the need for verification of strains from public culture collections, IMA Fungus 16, pp. e 173033-e 173033 : e173033-

Thysanorea acropleurogena Réblová & Hern.-Restr. sp. nov.

Fig. 10

Etymology.

From Greek akros (apex), pleurá (side) and genēs (born, produced). Referring to the mode of conidium development, in which conidia are formed both terminally and laterally on the conidiogenous cells.

Typus.

PAPUA NEW GUINEA • Madang Province, foothills of Finisterre Range, 40.8 km along road to Lae ; 200 m a. s. l.; on unidentified wood; 2 Nov 1995; A. Aptroot 36665 ( holotype CBS H-25780 dried culture, ex-type culture CBS 215.96 ) .

Culture characteristics.

On CMD colonies 44–45 mm diam., circular, flat, margin entire, lanose, pinkish-brown to brown, darker at the margin, reverse dark brown. On MLA colonies 36–38 mm diam., circular, convex, margin entire, floccose to lanose, olivaceous-grey to mouse grey, dark olivaceous at the margin, reverse dark olivaceous. On OA colonies 40–41 mm diam., circular, flat, margin entire, lanose at the centre and on the inoculation block, cobwebby towards the periphery, with a well-defined grey-brown central zone, dark brown towards the periphery, with a diffuse lighter halo at the margin, reverse dark brown. On PCA colonies 40–42 mm diam., circular, flat, margin entire, lanose, grey-brown, cobwebby and dark brown towards the periphery, reverse dark brown. With a prominent submerged growth on all media. Sporulation on PCA, absent on CMD, MLA and OA.

Description in culture.

Colonies on PCA effuse. Sexual morph. Not observed. Asexual morph. Mycelium composed of subhyaline to pale olivaceous brown, septate hyphae, 1.5–2.5 µm wide. Conidiophores 98–145 × 3.5–4.5 µm, basal cells sometimes slightly inflated 5–6.5 µm wide, macronematous, mononematous, loosely scattered to densely fasciculate, mostly erect, straight to slightly flexuous, cylindrical, subtly undulate, unbranched to loosely branched in the upper part, pale to medium brown to pale olivaceous brown, darker at the base, smooth-walled, septate. Conidiogenous cells 23.5–28 (– 40) × 3.5–5 (– 5.5) µm, integrated, terminal, forming transverse septa during sympodial proliferation and often becoming intercalary, arranged either along most of the conidiophore length or restricted to the upper part, forming a rachis with numerous, closely spaced, minute denticles, polyblastic, cylindrical, pale brown to pale olivaceous brown, end cells tend to be paler, smooth-walled; conidiogenesis holoblastic-denticulate. Conidia (13.5 –) 15–21 × (3.5 –) 4–5.5 µm (mean ± SD = 17.2 ± 1.8 × 4.5 ± 0.3 μm), solitary, dry, acropleurogenous, subcylindrical to oblong or fusiform to fusiform-clavate, tapering towards both ends, truncate at the base 1–1.5 µm wide, with a conspicuous basal scar, straight or slightly curved, pale brown to pale olivaceous brown, darker at the base, dark olivaceous brown in mass, smooth-walled, (1 –) 3 - septate; conidial secession schizolytic.

Habitat and geographical distribution.

The species is a saprobe occurring on decaying wood and is currently known only from Papua New Guinea. No identical ITS sequences were recovered in the GlobalFungi database.

Notes.

Phylogenetic analyses (Fig. 2 ) revealed that T. acropleurogena forms a sister relationship to a subclade comprising three closely related species, T. hainanensis , T. sinensis , and T. wuzhishanensis . They belong to a subclade that also includes T. seifertii and T. cantrelliae . Among known species, T. acropleurogena is closest to T. obscura and T. seifertii in having lightly pigmented, subcylindrical to oblong, predominantly 3 - septate conidia. However, both species are readily distinguishable in conidial characters and having unbranched conidiophores. Thysanorea obscura differs from the new species in subhyaline to yellowish brown, larger conidia, 20–31 × 5–8 µm ( Matsushima 1983). Thysanorea seifertii produces similar pale brown, subcylindrical to clavate or oblong conidia, but these are considerably shorter, 7–15 × 1.5–3 µm ( Hernández-Restrepo et al. 2020). In addition, T. seifertii produces a phialidic synasexual morph in culture, a feature so far unique among Thysanorea species. In the phylogenetic tree, all three species are resolved as distinct lineages.

The original material, CBS H-6267 , from which the axenic culture was derived, consists of multiple twigs. However, we could not locate the target fungus. Several twigs are covered with aerial mycelium, while others carry fertile conidiophores of a dendryphiella-like fungus. Accordingly, a dried culture was designated as the holotype of T. acropleurogena .

Thysanorea acropleurogena appears to represent a rare species, confirmed thus far from a single collection on decaying wood. The absence of identical ITS sequences in the GlobalFungi database indicates that it has not yet been detected in environmental sequencing datasets, suggesting that the species may be geographically restricted or currently overlooked due to under-sampling.

Figures

Figure 2. Maximum likelihood phylogenetic tree of the Herpotrichiellaceae based on ITS – LSU – tub 2 DNA sequences. Names in bold indicate taxonomic novelties; strains with their accession numbers in bold and highlighted in violet colour were sequenced in this study; a ex-type of Cyphellophora vermispora, d ex-type of Thysanorea aquatica, e ex-type of Veronaea constricta. T, E, IN and AS denote ex-type, ex-epitype, ex-isoneotype, and authentic strains, respectively. Thickened branches indicate support ML BS = 100 % and PP values = 1.0. Branch support of nodes ≥ 70 % ML and ≥ 0.95 PP is indicated above or below branches. A hyphen (–) indicates values lower than 75 % ML BS or 0.95 PP.

Figure 10. Thysanorea acropleurogena (ex-type CBS 215.96). A Sporulating conidiophores B, C upper part of the conidiophore conidiogenous cells forming a rachis and attached conidia D – G conidiophores, conidiogenous cells and conidia H conidia I diversity of colony morphology on CMD, MLA, OA, and PCA, respectively (from left to right) after 4 wk. Images: on PCA (A – H). Scale bars: 300 µm (A); 10 µm (B – H); 1 cm (I).