Ophiostoma babimostense R. Jankowiak, 2025

Ophiostoma babimostense R. Jankowiak sp. nov.

Fig. 5 View Figure 5

Etymology.

The specific epithet “ babimostense ” refers to the name of locality in Poland, Babimost, where the fungus was isolated for the first time.

Type.

Poland • Lubuskie Province, Babimost , fallen shoots of Pinus sylvestris pruned by pine shoot beetles, Tomicus sp. , October 2023, coll. R. Jankowiak ( holotype KRAM F-60035 , ex-type culture CBS 152112 ) .

Description.

Sexual morph: not observed. Asexual morphs synnematous, pesotum-like and mononematous to micronematous (sporothrix-like type). Synnemata abundant on MEA and sterilised pine twigs, determinate, erect, single or in groups, arising from the agar, pine twigs or aerial mycelium and attached to substratum by brown, rhizoid-like hyphae, dark brown to black and becoming subhyaline to hyaline towards the conidiogenous apparatus, (127 –) 145.5–239 (– 315) μm long including the capitulum. Stipe dark brown to black at the bases, light brown or yellowish-brown at the centre and hyaline at the apex, (60 –) 86–153.5 (– 210) μm long, broadest towards the base, (16.5 –) 24–48.5 (– 81.5) µm down to (11.5 –) 18.5–44 (– 91) µm wide at the apex, cylindrical, smooth. Conidiophores branching divaricate or dichotomous with 2 (mostly) or 3 conidiogenous cells per branch point. Conidiogenous cells annellated, discrete, terminal, cylindrical, tapering towards apex, hyaline, smooth, (16.5 –) 27–42.8 (– 50) × (0.8 –) 0.9–1.5 (– 2) μm with. Conidia aseptate, hyaline, curved, obovate, (3 –) 3.5–4.5 (– 6) × (1 –) 1.5–2 (– 2.5) µm, accumulating in a terminal mucilagenous mass, hyaline, transparent and glassy when young, becoming white with age. Sporothrix - like type: conidiophores macronematous to micronematous, hyaline, produced as aerial mycelia, simple or irregularly or dichotomous branched, producing conidia from denticles in a sporothrix-like fashion. Conidiogenous cells hyaline, smooth, straight or curved, integrated or discrete, terminal or intercalary, cylindrical, tapering towards apex, (18.5 –) 20–43.5 (– 73.5) × (1 –) 1.5–2.5 (– 3) µm, apex becoming nodose from numerous denticles, often proliferating at the apex and giving rise to another nodose or a conidiogenous cell with nodose at the apex. Conidia solitary, abundant in cultures, more varied to the size and shape of conidia produced in synnemata, hyaline, aseptate, smooth, oblong, obovate, (3 –) 4–5.5 (– 8) × (1 –) 1.5–2 (– 3) µm.

Culture characteristics.

Colonies with optimal growth at 25 ° C on 2 % MEA, reaching 66 mm (± 0.59 mm) diam. in 14 d, with a radial growth rate of 0.24 mm / d, followed by 20 ° C ( 55 mm, ± 0.21 mm) diam. Colony olive-brown (1 E 5), with pale grey (1 B 1) aerial mycelia at the centre; with age, colonies become olive-grey (1 E 2); flat, with undulate margin, revers olive (1 F 4). Hyphae pale yellow (1 A 3) to olive-yellow (3 E 6) in colour ( Kornerup and Wanscher 1978), smooth, with or without granules, submerged in the medium and aerial mycelium abundant, often constricted at the septa, (1 –) 1.5–2.5 (– 3) µm wide.

Associated insect.

Tomicus spp.

Host tree.

Pinus sylvestris

Distribution.

Poland

Additional material examined.

Poland • Lubuskie Province, Babimost , from fallen shoots of Pinus sylvestris pruned by pine shoot beetles, Tomicus sp. , October 2023, coll. R. Jankowiak (culture CBS 152111 ) .

Notes.

The newly-described O. babimostense resides in the O. ulmi species complex. Ophiostoma babimostense is morphologically similar to many species of the O. ulmi complex. However, O. babimostense does not form a monophyletic clade with other species in the O. ulmi complex (Figs 1 View Figure 1 , 3 View Figure 3 , Suppl. material 1: figs S 1, S 2). This species fails to group consistently with any one member of the O. ulmi complex within the ITS - (Fig. 1 View Figure 1 ), TUB 2 - (Suppl. material 1: fig. S 1) and TEF 1 - (Suppl. material 1: fig. S 3) based trees. In addition, O. babimostense formed a distinct lineage basal to all other species in the O. ulmi complex in the combined analyses of the TUB 2 and TEF 1 datasets (Fig. 3 View Figure 3 ).