Oidiosporium botulisporum Sastoque Cano & Stchigel, 2025

Oidiosporium botulisporum Sastoque Cano & Stchigel , sp. nov. MycoBank MB 847921. Fig. 5 View Fig .

Etymology: From Latin botulus -, sausage, and - spora, spore, because the shape of the thallic conidia.

Typus: Spain, Canary Islands, La Palma, Fuencaliente (Los Canarios), isolated from soil of Teneguía volcano, 15 Jul. 2008, coll. M. Calduch & A.M. Stchigel, isol. A.P. Sastoque (holotype CBS H-24247, culture ex-type FMR 18828 View Materials = CBS 149964 View Materials ) .

On oatmeal agar after 4 wk at 25 °C: Mycelium abundant, composed of hyaline to brown or reddish-brown, septate, branched, smooth- and thin- to moderately thick-walled hyphae when pigmented, 1–4.5 μm wide, often coiled ( Fig. 5F View Fig ). Conidiophores absent. Conidia holothallic, aseptate, hyaline or brown to reddish-brown, smooth- and thin-walled to moderately thick-walled, guttulate, subglobose, ellipsoidal, broadly fusiform, barrel-shaped or sausage-shaped, 8–23 × 4–8 μm, flattened at both ends but without visible scars, formed by remodelling of pre-existing hyphae sections, secession schizolytic ( Fig. 5G View Fig ), produced in short to long chains ( Fig. 5F–H View Fig ).

Culture characteristics (after 7 d at 25 ° C): Colonies on PCA 11–13 mm diam., flat and circular; margin filamentous and regular; surface sand (4B3) with a thin layer of greyish brown (6F3) aerial hyphae in the central area and yellowish white (4A2) margins; soluble pigment absent; reverse pale yellow (4A3) and light yellow in the centre (4A4). Colonies on OA 27–28 mm diam., flat and circular; margin filamentous and regular; surface champagne (4B4) with sparse dark grey (6F3), radiated and superficial mycelium and pale yellow (4A3) margins; soluble pigment violet brown (10F6) after 10 wk ( Fig. 6E View Fig ); reverse like surface. Colonies on CMA 13–14 mm diam., flat and circular; margin filamentous and regular; surface black (6F3) with sparse brownish grey (6F2) aerial mycelium and olive green (2F6) margins; soluble pigment absent; reverse greyish brown (5F3). Colonies on MEA 15–16 mm diam., flat and circular; margin filamentous and regular; surface with a thin layer of pearl white (3B1) and short aerial mycelium; reverse with olive grey (2F2) margins. Culture iconography after 4 wk of incubation on PCA, OA, CMA and MEA ( Fig. 5A–D View Fig , respectively). Minimum, optimum and maximum temperature of growth on PDA after 7 d: 15 °C, 25 °C and 37 ºC, respectively.

Notes: Oidiosporium botulisporum was placed in a fully supported clade close to the type species of the genera Carteria and Thermocarpiscus , but as a distinct genus ( Fig. 1 View Fig ). The new genus differs from the latter two by producing an asexual morph consisting of chains of holothallic conidia,

whereas C. arctostaphyli View in CoL and T. australiensis View in CoL lack asexual morphs ( Wang et al. 2019a, 2022).