Sporothrix europaea R. Jankowiak & H. Solheim, 2025

Sporothrix europaea R. Jankowiak & H. Solheim sp. nov.

Fig. 6 View Figure 6

Etymology.

The specific epithet “ europaea ” (Latin) refers to the European continent, where this fungus was isolated in Norway and Poland.

Type.

Norway • Ås , from Anisandrus dispar infesting Quercus robur , June 2016, coll. T. Aas, ( holotype KRAM F-60036 , culture ex-type CBS 151676 ) .

Description.

Sexual and asexual morphs produced on the sterilised beech twigs and on the surface of malt agar in Petri dishes. Sexual morphs: ascomata perithecial, abundant, superficially or partly embedded in the agar, single or in groups. Perithecial bases globose, (86 –) 105–160 (– 193) μm diam., black, with brown hyphal hairs, 30–84 μm long and 1.3–2.4 μm wide at the base. Perithecial necks black, straight or curved, (257 –) 336–456 (– 530) μm long, (8.5 –) 9.5–13 (– 14.5) μm diam. at the apex and (22 –) 26–39 (– 57.5) μm at the base. Ostiolar hyphae present, pale brown, septate, straight or curved, simple, tips blunting or strongly thickened, 10–19 in number, (14 –) 29–42.5 (– 48.5) μm long, 0.5–1.5 μm at the apex and 1–2.5 μm at the base. Asci evanescent. Ascospores one-celled, hyaline, allantoid in side view (3 –) 3.5–4 (– 5) x (0.5 –) 1–1.5 (– 2) μm, elliptical in front view (2.5 –) 3–4 (– 5) × (1 –) 1–1.5 (– 1.5) μm, sometimes with residual sheath up to 2 μm thick, accumulated in white-colour mass at the tip of the neck. Asexual morph Sporothrix - like: conidiophores hyaline, micronematous, simple or branched and bearing several conidiogenous cells, borne on upright undifferentiated hyphae. Conidiogenous cells cylindrical, terminal or intercalary, straight or curved, tapering towards the apex, (3.5 –) 15–36 (– 50.5) μm long, (0.5 –) 1–2 (– 2) μm wide at the base, the apical part swollen, (1 –) 2–3 (– 3) μm long, (1.5 –) 2–4 (– 5.5) μm wide, with multiple conidiogenous loci as denticles, born by sympodial proliferation. Conidia of two types: 1) abundant in cultures, hyaline, unicellular, smooth, variable in shape and size, guttuliform to fusiform, curved, often asymmetric, pointed at the base, (3 –) 3.5–5 (– 7) × (0.5 –) 1–1.5 (– 2.5) μm, formed directly on denticles; 2) sparse in cultures, directly on the side of submerged hyphae in malt agar, subhyaline to lightly pigmented, unicellular, smooth, subglobose to broadly obovate, (2.5 –) 3–4 (– 5.5) × (2 –) 2–3 (– 4) μm diam., formed singly.

Culture characteristics.

Colonies with optimal growth at 25 ° C on 2 % MEA reaching an average of 47 mm (± 0.07 mm) after 14 days, with radial growth rate 1.68 (± 0.24) mm / d, growth somewhat slower at 30 ° C ( 40 mm diameter); white (3 A 1), flat, floccose, growing in a circular pattern with entire margins, reverse yellowish-white (3 A 2). Hyphae greenish-grey (1 B 7) in colour, smooth, with granules, submerged in the medium and aerial mycelium abundant, (0.5 –) 1–1.5 (– 3) µm wide.

Associated insects.

Anisandrus dispar , Ips cembrae , Scolytus intricatus , Scolytus rugulosus , Xyleborinus saxesenii , Xyleborus monographus .

Host trees.

Fagus sylvatica , Larix decidua , Prunus domestica , Quercus robur

Distribution.

Norway, Poland

Additional specimen examined.

Poland • Prószków , from Xyleborus monographus infesting Quercus robur , May 2013, coll. P. Wieczorek, (culture CBS 149830 = CMW 60554 ) ; Norway • Ås , Anisandrus dispar on Quercus robur , June 2016, coll. T. Aas, (culture CBS 151675 ) .

Notes.

This species is phylogenetically distinct from the other Sporothrix species, based on phylogenetic analysis of combined TUB 2 and CAL sequence data (Fig. 4 View Figure 4 ). Sporothrix europaea is phylogenetically closely related to S. fusiformis and S. lunata described by Aghayeva et al. (2004). However, S. europaea has smaller ascomatal bases and necks compared to S. fusiformis (86–193 μm and 257–530 μm vs. 121–273 μm and 301–1168 μm). In turn, S. europaea has larger ascomatal bases (86–193 μm vs. 60–178 μm) and longer necks (257–530 μm vs. 162–700 μm) compared to S. lunata ( Aghayeva et al. 2004) . In addition, S. europaea has two conidial types, guttuliform to fusiform and subglobose to obovate, whereas those in cultures of S. fusiformis are only guttuliform to fusiform.

Spotothrix lunata has lunate conidia flattened at one side or curved with a blunt base ( Aghayeva et al. 2004). The cultures of S. europaea grow on 2 % MEA between 5 ° C and 35 ° C, whereas S. fusiformis and S. lunata did not growth below 10 ° C and above 30 ° C ( Aghayeva et al. 2004).

Sporothrix europaea was represented by five isolates collected from Poland. It corresponds to Sporothrix sp. 4 in the study of Jankowiak et al. (2019 b). Sporothrix europaea was isolated from hardwoods in association with different bark beetles.