Cyphellophora guangxiensis L.X. Mi, K.D. Hyde & D.M. Hu, 2025

Mi, Li-Xue, Song, Hai-Yan, Hyde, Kevin D., Eungwanichayapant, Prapassorn D., Mapook, Ausana, Chen, Mu-Sen & Hu, Dian-Ming, 2025, Morphological and phylogenetic characterization of a new Cyphellophora (Chaetothyriales, Cyphellophoraceae) species associated with Tetradium ruticarpum from Guangxi Province, China, Phytotaxa 704 (3), pp. 239-254 : 243-246

Cyphellophora guangxiensis L.X. Mi, K.D. Hyde & D.M. Hu sp. nov. Fig. 3

Index Fungorum number: IF903758 Faces of fungi number: FoF 17680

Etymology: The name reflects the type location, “ Guangxi ”, China.

Holotype: HFJAU10461

Endophytic from the healthy root of Tetradium ruticarpum . Sexual morph: Undetermined. Asexual morph: Hyphomycetes. Mycelium densely branched, 1–2.5 μm wide, hyaline, subhyaline to pale brown, septate, constrictions at the septa, smooth-walled, with inflated cells, sometimes with excrescences in older hyphae, guttulate in young hyphae, many oil droplets in older ones. Conidiophores mononematous, indistinct, absent or rarely reduced to a short cell basal to the conidiogenous cells. Conidiogenous cells 3.4–13.5 × 2–3.5 μm (x̅ = 8 × 2.8 µm, n = 35) monophialidic, short cylindrical to flask-shaped, intercalary, lateral or terminal, sometimes arising at short side branches of hyphae, with an inconspicuous short flaring collarette, sub-hyaline to pale olivaceous brown, thin-walled. Conidia one-celled, guttulate or non-guttulate, hyaline to pale brown, smooth-walled, broadly ovate or ellipsoidal, 2.5–4 × 2–3 μm (x̅ = 3 × 2.5 µm, n = 50), aggregating in a slimy mass at the apex of the phialide.

Culture characteristics: Colonies slowly grow on PDA at 25° C and reach 30 mm in diameter after 39 days, spreading with moderate to sparse aerial mycelium, consisting of woolly-velvety texture, pale olivaceous grey in the center, margin entire; reverse olivaceous black. No diffusible pigment was produced.

Material examined: CHINA, Guangxi Province, Hechi City, from healthy roots of Tetradium ruticarpum ( Rutaceae ), 24.8667°N 109.0333°E, 9 Sept. 2023, Lixue Mi, dry culture ( HFJAU 10461, holotype), ex-type living culture: JAUCC 6546; ibid, 24.8831°N 109.0432°E, 100 m asl, 12 Oct. 2024, Lixue Mi, dry culture ( HFJAU 10462, paratype), living culture: JAUCC 6547.

Notes: The multi-locus phylogenetic analysis showed that Cyphellophora guangxiensis clustered as a sister taxon to C. deltoidea with 82.8% ML bootstrap support in the SH-aLRT test, 93% in the UFB method, and a Bayesian probability of 0.82 ( Figure 1 ). Similarly, the ITS single-locus phylogenetic analysis also supports C. guangxiensis as a distinct lineage, with even stronger support (SH-aLRT/UFB/BPP = 95.3/99/1.0) ( Figure 2 ). Morphologically, C. guangxiensis differs from its closely related species in conidia shape and size. Cyphellophora guangxiensis produces broadly ovate to ellipsoidal, aseptate conidia measuring 2.5–4 × 2–3 μm, whereas C. deltoidea has distinctly triangular spores that are slightly smaller, measuring as 2.6–3.2 μm ( Marchisio et al. 2011; Crous et al. 2023); C. clematidis has larger, aseptate, ellipsoid conidia measuring (3–)4–5(–6.5) × (1.5–)2(–2.5) μm ( Crous et al. 2019). In addition, C. neerlandica differs from C. guangxiensis by its subcylindrical, significantly larger conidia [(27–)30–33(–36) × 2 μm] with three septa ( Crous et al. 2023). Therefore, the observed genetic divergence, in combination with its distinct morphological characteristics, prompted us to describe our isolate as a new species, C. guangxiensis in Tetradium ruticarpum from China.

Figures

FIGURE 1. Maximum likelihood (ML) phylogenetic tree of Cyphellophora based on combined ITS, LSU, and tub2 sequences, with Shimodaira–Hasegawa-like approximate likelihood ratio test (SH-aLRT) (left), ultrafast bootstrap (UFB) (middle), and Bayesian posterior probabilities (BPP) values (right) near the corresponding node. Thickened branches indicate branch support with SH-aLRT/UFB/BPP = 100/100/1. Only one of SH-aLRT ≥ 80 or UFB ≥ 95 for ML and BYPP ≥ 0.90 for BI are indicated along branches (SH-aLRT/UFB/BPP). Newly generated sequences are highlighted in red. Ex-type strains are highlighted in bold.

FIGURE 2. Maximum likelihood (ML) phylogenetic tree of Cyphellophora based on only ITS sequences, with Shimodaira–Hasegawalike approximate likelihood ratio test (SH-aLRT) (left), ultrafast bootstrap (UFB) (middle), and Bayesian posterior probabilities (BPP) values (right) near the corresponding node. Thickened branches indicate branch support with SH-aLRT/UFB/BPP = 100/100/1. Only one of SH-aLRT ≥ 80 or UFB ≥ 95 for ML and BYPP ≥ 0.90 for BI are indicated along branches (SH-aLRT/UFB/BPP). Newly generated sequences are highlighted in red bold. Ex-type strains are highlighted in black bold.

FIGURE 3. Cyphellophora guangxiensis (HFJAU10461, holotype), a Host. b, c Colony on PDA after 39 days (surface and reverse). d Hyphal. e–h Conidiogenous cells and conidia. i–k Conidia. Scale bars: d–i = 10 μm; j–k = 5 μm.