Paraneoaraneomyces guizhouensis Y. Wang & H. Chen sp. nov.

Fig. 3

Etymology.

The specific epithet refers to Guizhou Province, China, where the holotype was collected.

Type.

China, • Guizhou Province, Guian New District (26°23'48"N, 106°27'08"E, alt. 1235 m), isolated from the rhizosphere soil of Gaultheria leucocarpa var. yunnanensis, May 2025, Yao Wang (holotype a dried culture GMB 3009); ex-type living culture GMBC 3009.

Description.

Colonies on PDA reaching 35–40 mm in diameter in 30 days at 25 ° C, white, slightly raised at center, plicate, nearly circular with regular margin; reverse pale yellow. Hyphae hyaline, smooth, branched, septate, 1.0–2.2 μm wide. Phialides arising from aerial or vegetative hyphae, solitary or occasionally in whorls, straight to slightly curved, tapering toward the apex, base slightly enlarged, smooth, hyaline, 28.0–69.0 × 0.8–1.9 μm (x ̄ = 56.0 × 1.3, n = 50). Conidia formed at phialide apices, often aggregated in small globose heads, cymbiform to reniform, smooth-walled, aseptate, 3.5–7.0 × 1.5–2.5 μm (x ̄ = 4.9 × 2.0, n = 50). Sexual morph not observed.

Other material examined.

China, • Guizhou Province, Guian New District (same locality and habitat as the holotype), May 2025, Yao Wang (living culture GMBC 3010).

Substrate.

Rhizosphere soil.

Distribution.

Known only from Guizhou Province, China.

Notes.

In the six-locus phylogeny (ITS, SSU, LSU, tef - 1 α, rpb 1, and rpb 2), strains GMBC 3009 (ex-type) and GMBC 3010 of Paraneoaraneomyces guizhouensis formed a distinct clade sister to P. sinensis, with strong statistical support (100 % / 100 % / 1; Figs 1, 2). Jeewon and Hyde (2016) suggested that nucleotide differences exceeding 1.5 % in ITS and protein-coding genes may indicate species-level divergence. BLASTn comparisons of sequences from the ex-type strain with those of P. sinensis were conducted for ITS, tef - 1 α, and rpb 2 (as rpb 1 data for P. sinensis are unavailable). The results revealed 3 / 531 bp (0.56 %) divergence in ITS, below the suggested threshold; 17 / 937 bp (1.81 %) in tef - 1 α; and 42 / 1004 bp (4.18 %) in rpb 2, with the latter two exceeding the recommended cut-off. These molecular differences are supported by clear morphological discontinuities. Paraneoaraneomyces guizhouensis produces longer phialides (28.0–69.0 × 0.8–1.9 μm, x ̄ = 56.0 × 1.3 μm vs. 19.0–34.0 × 0.5–1.5 μm, x ̄ = 27.0 × 1.1 μm in P. sinensis) and larger conidia (3.5–7.0 × 1.5–2.5 μm, x ̄ = 4.9 × 2.0 μm vs. 3.0–5.5 × 1.0–1.5 μm, x ̄ = 4.3 × 1.4 μm; Zhang et al. 2023). Additionally, phialides in the new species occasionally arise in whorls (Fig. 3 J), a feature not observed in P. sinensis. The combination of phylogenetic evidence, multi-locus genetic divergence (particularly in protein-coding genes), and consistent morphological differences supports the recognition of P. guizhouensis as a distinct species.