Montagnula thevetiae Wanas., 2024

Wanasinghe, Dhanushka N., Nimalrathna, Thilina S., Qin Xian, Li, Faraj, Turki Kh., Xu, Jianchu & Mortimer, Peter E., 2024, Taxonomic novelties and global biogeography of Montagnula (Ascomycota, Didymosphaeriaceae), MycoKeys 101, pp. 191-232 : 191

Montagnula thevetiae Wanas. sp. nov.

Fig. 9

Etymology.

The specific epithet “thevetiae” refers to the host Thevetia peruviana from which the holotype was isolated.

Holotype.

HKAS 126964.

Description.

Saprobic on dead twigs of Thevetia peruviana . Teleomorph Ascomata 140-160 μm high × 150-190 μm diam., immersed, gregarious or rarely clustered, globose to subglobose, ostiolate. Ostiole 40-65 × 50-90 µm (x- = 50 × 78 μm, n = 6), papillate, central, straight, filled with hyaline to brown cells. Peridium 10-20 μm thin on the sides and can reach up to 30 μm near the apex, with an outer layer consisting of heavily pigmented cells that have thick walls and textura angularis arrangement, the inner layer consists of hyaline compressed rows of cells. Hamathecium of 2-3.5 μm broad, dense, branched, cellular pseudoparaphyses. Asci 110-160 × 25-35 µm (x- = 126.4 × 30.3 μm, n = 12), bitunicate, fissitunicate, cylindrical-clavate, pedicel 25-35 μm long, 8-spored, uni to biseriate, with a minute ocular chamber best seen in immature ascus. Ascospores 30-40 × 11.5-14 µm (x- = 37.3 × 12.8 μm, n = 20), ellipsoidal to narrowly oblong, straight to curved, with conically rounded ends, brown to dark brown, 1-septate, constricted at the septum, with large guttules in each cell, verruculose, surrounded by a thin mucilaginous sheath. Anamorph Undetermined.

Culture characteristics.

Ascospores germinated on PDA within 24 h. Following a two-week incubation period at 25 °C, the colonies on PDA medium reached a diameter of 4 cm. These colonies exhibit an irregular, flattened to slightly raised morphology and display various color sectors ranging from white, creamy orange to pale brown. The reverse side of the colonies appears creamy orange, with occasional dark patches that can be observed.

Habitat and distribution.

This species is found in terrestrial habitats of Yunnan, China, inhabiting dead woody twigs of Thevetia peruviana (this study).

Material examined.

China, Yunnan Province, Kunming city, Kunming Institute of Botany (25.142238°N, 102.750354°E, 1971 m), on dead twigs of Thevetia peruviana , 24 April 2022, L. Qinxian, K2B22-26-2 (holotype, HKAS 126964), ibid. (25.140859°N, 102.749045°E, 1968 m, K2B22-26 (HKAS 126963).

Notes.

Montagnula thevetiae is isolated from the dead twigs of Thevetia peruviana . The newly obtained sequences of this fungus formed a monophyletic clade closely related to Montagnula menglaensis . Morphologically, they share similarities in having 1-septate ascospores, although Montagnula thevetiae exhibits a darker pigmentation. On the other hand, Montagnula thevetiae differs from M. menglaensis by 15/1023 (1.46%) differences in the SSU region, 19/895 (2.12%) differences in the LSU region, 32/508 (6.3%) differences in the ITS region, 27/885 (3%) differences in the tef 1-α region, and 86/956 (9%) differences in the rpb 2 region.

Figures

Figure 9. Montagnula thevetiae (HKAS 126564, holotype). a, b ascomata on natural wood surface c vertical section through an ascoma d closeup of ostiole e pseudoparaphyses f-h asci j-l ascospores m, n culture characteristics on PDA (m = above, n = reverse). Scale bars: 100 μm (c); 50 μm (d, f-h); 10 μm (e, i-l).