Lijiangomyces laojunensis Meng & Jayaward., 2025

Lijiangomyces laojunensis Meng & Jayaward. sp. nov.

Fig. 3 View Figure 3

Etymology.

The species epithet “ laojunensis ” refers to the type locality “Laojun Mountain National Nature Reserve” in Yunnan Province of China.

Holotype.

KUN-L 88703.

Description.

Sexual morph: Ascomata hysterothecia, (0.8 –) 0.88–1.05 (– 1.1) × (0.4 –) 0.47–0.78 (– 0.8) mm (x – = 0.97 × 0.63, n = 10), superficial, solitary, dispersed, sessile, non-stromatic, obovoid to broadly shell-shaped or irregularly rounded, with a broadly open or slit-like disc. Margin black, vertically erect, fragile, with a yellowish-brown, slightly depressed disc surface appearing below the rim of the lateral wall. Peridium 70–100 μm thick, carbonaceous, black laterally and apically, transitioning to grayish near the base. Hymenium 350–400 μm high, hyaline to slightly yellowish, densely packed with hamathecium. Paraphyses 1–2 μm wide, unbranched, hyaline, non-anastomosed, non-septate. Hypothecium 35–50 μm thick, slightly yellowish. Asci (120 –) 122.6–168.7 (– 190) × (13 –) 13.4–16.5 (– 18) μm (x – = 145.7 × 14.9, n = 10), bitunicate, 8 - spored, elongated to clavate, rounded apex, without apical thickening of ascal wall, K-, I-. Ascospores (20 –) 20.9–28.8 (– 37.5) × (9 –) 10.1–15.4 (– 17.5) (x – = 24.8 × 12.8, n = 30) μm, K-, I + reddish brown, then turning to dark blue, uniseriate, arranged obliquely and parallelly, hyaline, thin-walled, smooth, fusiform to ellipsoidal, aseptate at immature, becoming muriform at maturity with 4–7 transverse septa and 1–2 longitudinal septa, sometimes slightly constricted at the median septum, rounded at the ends in aged ascospores. Asexual morph: Not observed.

Material examined.

China • Yunnan Province, Lijiang City, Laojun Mountain National Nature Reserve , 26°39'N, 99°43'E, 3900 m elev., on the bark of Abies fabri ( Pinaceae ), 10 Apr 2022, Qing-feng Meng, ljs- 52 (holotype KUN-L 88703 ) GoogleMaps .

Notes.

Lijiangomyces laojunensis closely resembles Ostreola consociata (the type species of Ostreola ) and O. sessilis , in having cylindrical asci and uniseriate muriform ascospores. However, the new species is distinguished by its ascomatal morphology, which is broadly shell-shaped or irregularly rounded with a widely opened disc, in contrast to Ostreola species which have conchiform to hatchet-shaped ascomata with a narrow slit-like opening. Furthermore, the ascospores of the new species are hyaline and larger in size (20.9–28.8 × 10.1–15.4 μm), in contrast, brown and smaller ascospores (14–22 × 6–8 μm) are the characteristic feature of Ostreola ( Darker 1963) .

Phylogenetic analysis places this species as a sister clade to Mytilinidion , however, it can be distinguished by its obovoid to broadly shell-shaped or irregularly rounded ascomata (vs. globoid to obovoid, erect, conchate, or dolabrate), and hyaline and muriform ascospores (vs. hyaline to dark brown and transversely septate) ( Boehm et al. 2009 b; Jayasiri et al. 2018).