Parabambusicola zhenxiongensis L. S. Han & D. Q. Dai 2026, sp. nov.

Parabambusicola zhenxiongensis L. S. Han & D. Q. Dai sp. nov. Fig. 4 Etymology. Named after the locality where the holotype was collected, Zhenxiong (China). Holotype. GMB-W 1138. Description. Saprobic on dead culms of bamboo, dome-shaped areas on the host surface. Sexual morph: Ascomata 500–650 μm diam., 150–210 μm high, raised, immersed, solitary or clustered together, black, subglobose to globose in surface view, with pore-like opening and a flat base, coriaceous, uni-loculate. Peridium 5–15 μm wide, poorly developed at the base intermixed with host tissue, composed of brown cells of textura angularis. Hamathecium 1–2.5 µm wide, filamentous, septate, branched pseudoparaphyses. Asci 105–140 × 30–40 µm (x ̄ = 118 × 34.5 µm, n = 20), 8 - spored, bitunicate, clavate, subsessile to shortly pedicellate, apically rounded, with a small ocular chamber. Ascospores 45–55 × 9.5–12 µm (x ̄ = 50 × 10.5 µm, n = 20), overlapping 2–3 - seriate, hyaline, fusiform, rounded at both ends, slightly constricted at the median septum, 3–6 - septate, wrapped by a thin sheath. Asexual morph: Undetermined. Culture characteristics. Ascospores germinate on PDA, with colonies reaching 30 mm diam. after 25 days in the dark at 25 ° C. Colonies are dense, circular, with regular margins; the color is dark brown at the center, gradually becoming pale gray toward the margin on the upper surface, and dark brown on the reverse, without producing pigment on the agar medium. Material examined. China • Yunnan Province, Zhaotong City, Zhenxiong Town, (27°36'06"N, 104°50'36"E, 1705 m), on dead culms of unidentified Bambusoideae (Poaceae), 29 July 2021, L. S. Han & D. Q. Dai, DDQ 02076 (GMB-W 1138, holotype) GMBCC 1138, ex-type; • ibid. (MHZU 24-0630, isotype), ZHKUCC 24-1166, ex-isotype; • ibid. DDQ 02076-1 (GMB-W 1139), living culture GMBCC 1139. Notes. Phylogenetic analyses based on combined gene regions (ITS, LSU, SSU, and tef 1 - α) showed that the new isolates (GMBCC 1138 and GMBCC 1139) clustered with P. bambusina (H 4321, KT 2637, and KH 139), P. hongheensis (KUMCC 21-0410, ex-type), and P. zhaotongensis (GMBCC 1147, ex-type, and GMBCC 1148) with 92 % ML statistical support. Morphologically, the new collections differ from P. bambusina and P. zhaotongensis by having ascospores with rounded ends, while P. bambusina and P. zhaotongensis have ascospores with acute ends (Tanaka and Harada 2003; Tanaka et al. 2015; this study). Additionally, the collections have shorter ascospores than those of P. zhaotongensis (45–55 µm vs. 55–65 µm). Furthermore, the new isolates can be distinguished from P. hongheensis by having a wider range of septa (3–6 - septate vs. 4–5 - septate) and smaller ascospores (45–55 × 9.5–12 µm vs. 50–55 × 12–15 µm) (Xie et al. 2022). Hence, P. zhenxiongensis is introduced as a new species based on multigene analyses and morphological comparisons.