Wongia rhachidophora 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-

Wongia rhachidophora Réblová & Hern.-Restr. sp. nov.

Fig. 12

Etymology.

From Greek rhachis (spine, axis) and phoros derived from phora (bearing). Referring to the fertile, rachis-like upper part of the conidiophore, which bears conidia along its length.

Typus.

INDIA • Bangalore, Arboretum of Forestry Department ; on dead leaf of Bambusa sp. ; Jun 1973; W. Gams ( holotype CBS H-11671 dried culture, ex-type culture CBS 531.73 , paratype CBS H-5414 ) .

Culture characteristics.

On CMD colonies 45–51 mm diam., circular, flat, powdery, sienna, margin paler, cinnamon to fawn, diffuse, fimbriate to slightly lobate, reverse brown with different tones of dark brick, brick to sienna in concentric zones. On MLA colonies 65–67 mm diam., circular, flat, margin entire to fimbriate, velvety to powdery, centre rosy buff, cinnamon to saffron towards the periphery, reverse brown. On OA colonies 58–60 mm diam., circular, flat, margin entire to fimbriate to floccose, velvety, with concentric brown zones of different tones such as fulvous, sienna to cinnamon, ochreous towards the margin, reverse dark brown (umber) in the centre with ochreous margin. On PCA colonies 53–54 mm diam., circular, flat, margin entire fimbriate to diffuse, velvety to sandy, centre fulvous to ochreous, isabelline towards the margin, with numerous exudates at the centre, reverse of the same colour. Sporulation abundant on all media.

Description in culture.

Colonies on OA effuse. Sexual morph. Not observed. Asexual morph. Mycelium composed of hyaline to pale brown, smooth hyphae, verrucose close to the conidiophore base, 1–2 μm wide. Conidiophores up to 63 μm long, 2.5–3.5 μm wide at the base, macronematous, mononematous, solitary, erect, straight to slightly flexuous, cylindrical, unbranched, pale brown to brown-orange. Conidiogenous cells 13–52 × 3–4 μm, integrated, terminal, sometimes forming transverse septa during sympodial proliferation and becoming intercalary, polyblastic, denticulate, cylindrical to subcylindrical, tapering, pale brown to brown, smooth-walled; conidiogenesis holoblastic-denticulate. Conidia 8.5–18.5 × 3–5.5 μm (mean ± SD = 14.2 ± 2.4 × 4.0 ± 0.4 μm), solitary, dry, acropleurogenous, oblong-ellipsoidal to ellipsoidal-clavate, rounded at the apex, slightly tapering towards the base, truncate at the base, 0.5–1 μm wide, smooth-walled, 0–3 septate, hyaline when young, subhyaline to pale brown when mature, pale grey-brown in mass; conidial secession schizolytic.

Habitat and geographical distribution.

The species is a saprobe, currently known from two records, including a dead leaf of Bambusa sp. in India (this study) and a sample isolated from soil in a pine rock land ecosystem in the coastal savanna biome in Miami, USA (GlobalFungi). Occurrences are associated with MAT ~ 24.4 ° C and MAP ~ 1441 mm / year.

Notes.

In the phylogenetic analyses, W. rhachidophora was placed within a species complex comprising also W. bambusae , W. bandungensis , W. fusiformis , and W. suae (Fig. 3 ). Among these, W. fusiformis is readily distinguished by its 1–2 (– 3) - septate, fusiform to clavate, mid-brown conidia, often with paler end cells, measuring 14–18 × 4–5 µm ( Bao et al. 2021). Wongia rhachidophora is also well differentiated within this complex by its 3 - septate, uniformly brown conidia, 8.5–18.5 × 3–5.5 μm. In conidial size and shape it most closely resembles W. fusiformis , but the two are resolved as distinct lineages. The remaining three species are particularly difficult to separate morphologically, as they share 1–2 (– 3) - septate, hyaline to pale brown, oblong to ellipsoidal-clavate conidia. The conidia of W. suae , 8–11 × 3–4 µm ( Zhang et al. 2023 a), and W. bambusae , 8–13 × 3–5 µm ( Yu et al. 2024), overlap in size, making them almost indistinguishable without molecular data. The conidial length of W. bandungensis slightly overlaps with the former two species, but extends to a longer upper range, 11.3–14 × 4.3–5.2 µm ( Manawasinghe et al. 2024). A detailed phylogenetic comparison of W. rhachidophora with morphologically similar taxa of this species complex is provided in the Results chapter.

Wongia rhachidophora appears to be a rare saprobe, with a disjunct distribution between Oceania and subtropical North America. Its presence in a pine rock land biome underscores its adaptability to soil of seasonally dry savannas. However, given the limited records, it is unclear whether this species is truly rare and geographically restricted, or more widespread but overlooked in global fungal diversity surveys.

Figures

Figure 3. Maximum likelihood phylogenetic tree of the Papulosaceae based on ITS – LSU – SSU – rpb 2 – tef 1 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. T and I denote ex-type and ex-isotype 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 12. Wongia rhachidophora (ex-type CBS 531.73). A – C Sporulating conidiophores D – G conidiophores, conidiogenous cells and conidia H – K conidia L diversity of colony morphology on CMD, MLA, OA, and PCA, respectively (from left to right) after 4 wk. Images: on OA (A – K). Scale bars: 50 µm (A, C); 100 µm (B); 10 µm (D – K); 1 cm (L).