Ovicillium pseudoattenuatum Y. Wang & D. X. Tang, 2025

Wang, Yao, Tang, De-Xiang, Chen, Hui, Li, Qi-Rui, Loinheuang, Chanhom & Shen, Xiang-Chun, 2025, Phylogenetic evidence reveal a close relationship between Amphichorda and Ovicillium in Bionectriaceae (Hypocreales), MycoKeys 117, pp. 337-352 : 337-352

Ovicillium pseudoattenuatum Y. Wang & D. X. Tang sp. nov.

Fig. 3

Etymology:

“ Pseudoattenuatum ” refers to morphologically resembling Ovicillium attenuatum, but phylogenetically distinct.

Type.

Laos • Vientiane City, Mekong Riverside Park (17.96°N, 102.60°E, 674 m above sea level), from soil on the forest floor, 11 August 2024, Yao Wang (holotype as dried culture GMB 3007 ); ex-type culture GMBC 3007 .

Description.

Sexual morph: Undetermined. Asexual morph: Colonies on PDA reaching 23–25 mm in diameter in 7 days at 25 ° C, white to pinkish; reverse yellowish. Hyphae branched, smooth-walled, septate, hyaline, 1.2–2.8 μm wide. Conidiophores hyaline, smooth-walled, with single phialide or whorls of 2–5 phialides or verticillium-like directly from hyphae, up to 500 μm long. Phialides terminal or lateral, straight, somewhat inflated base, attenuated from the middle, sometimes undulated near the tip, 16.0–37.5 × 1.5–2.4 (X ̄ = 26.8 × 2.0, n = 50) μm. Conidia smooth-walled, hyaline, ellipsoidal to cylindrical, 3.2–4.0 × 1.7–3.2 (X ̄ = 3.7 × 2.3, n = 50) μm, aggregated in large globose to subglobose heads. Crystals absent. Chlamydospores absent.

Other material examined.

Laos • Oudomxay Province, Muang Xay District, Nam Kat Yorla Pa Resort (20.71°N, 102.11°E, 708 m above sea level), from soil on the forest floor, 14 August 2024, Yao Wang (living culture GMBC 3008 ) .

Substrate.

Soil.

Distribution.

Laos.

Notes.

Ovicillium pseudoattenuatum , isolated from forest floor soil, forms a distinct phylogenetic lineage within the Ovicillium genus. Multilocus phylogenetic analyses reveal its close relationship with O. attenuatum and O. sinense , supported by strong statistical values (BS IQ / BS RAx / PP = 82 % / 79 % / 0.93). Morphologically, while sharing the characteristic undulated phialide tips with O. attenuatum , O. pseudoattenuatum differs significantly in microscopic dimensions: it possesses smaller phialides (16.0–37.5 × 1.5–2.4 μm vs 25–50 × 1.7–3.3 μm) and more compact conidia (3.2–4.0 × 1.7–3.2 μm vs 3.5–5 × 2.5–3.8 μm). Distinct from O. sinense , which exhibits even smaller reproductive structures (phialides 16.2–25.8 × 1.7–2.4 μm; conidia 2.1–2.9 × 1.1–1.7 μm), O. pseudoattenuatum is further characterized by its unique ellipsoidal to cylindrical conidial morphology, a diagnostic feature distinguishing it from all known Ovicillium species (Table 3 ).

Figures

Figure 3. Morphology of Ovicillium pseudoattenuatum A, B Colony obverse and reverse on PDA medium C – I Conidiophores, phialides and conidia J Conidia. Scale bars: 10 mm (A – B); 100 μm (C); 50 μm (D – E); 25 μm (F – I); 10 μm (J).