Nigropunctata xiaohensis X. Zhou, K. Habib & Q. R. Li, 2024

Zhou, Xin, Habib, Kamran, Zeng, Wenyu, Ren, Yulin, Shen, Xiangchun, Kang, Jichuan & Li, Qirui, 2024, Addition of three new species of Xylariomycetidae fungi on bamboo from Southern China, MycoKeys 109, pp. 109-129 : 109-129

Nigropunctata xiaohensis X. Zhou, K. Habib & Q. R. Li sp. nov.

Fig. 5

Etymology.

The specific epithet “ xiaohensis ” refers to the geographical location, Xiaohe Village, where the holotype specimen was collected.

Type.

China • Guizhou Province, Guiyang City, Huaxi District, Xiaohe Village , (25 ° 33 ' 10.46 " N, 105 ° 38 ' 22.57 " E), altitude: 120 m, on bamboo, 1 June 2023, Xin Zhou, Wenyu Zeng, 2023 XHC 1 ( GMB 4503 , holotype, no culture was obtained); ibid KUN-HKAS 134921 , isotype .

Description.

Saprobic on decaying bamboo culms. Sexual morph: Ascomata 320–380 × 340–400 μm (x ̄ = 352.7 × 360 μm, n = 10), immersed, solitary or scattered, appearing as small black dots, solitary, in cross-section globose to subglobose with a flattened base. Ostioles centrally, slightly, papillate, black, flush with the surface of the host. Peridium 15–25 µm thick, comprised of several layers, composed of thick-walled, dense, brown to hyaline, cells of textura angularis. Paraphyses 2.8–4.3 μm (x ̄ = 3.6 μm, n = 20) wide, longer than the asci, numerous, filamentous, curving, contain white intracellular material. Asci 85.5–140 × 11–18.5 μm (x ̄ = 120.2 × 15.5 μm, n = 20) 8 - spored, unitunicate, cylindrical, short-pedicellate, apically rounded, with a J +, discoid apical ring, measures 1.3–2.4 μm high, 3.5–5.0 μm wide (x ̄ = 1.8 × 4.4 μm, n = 10). Ascospores 11–21 × 6.5–10.5 μm (x ̄ = 17.8 × 8.1 μm, n = 30), L / W 2.2, uniseriate, unicellular, ellipsoid to broadly ellipsoid, dark brown to black, with rounded ends, covered with a thick mucilaginous sheath measuring 5–8 µm (x ̄ = 6.2 µm, n = 10), with a germ slit extending across the entire spore. Asexual morph: Undetermined.

Paratype.

China • Guizhou Province, Guiyang City Huaxi District, Xiaohe Village (25 ° 33 ' 20.34 " N, 105 ° 38 ' 32.23 " E), altitude: 120 m, on bamboo, 4 June 2023, Xin Zhou, Wenyu Zeng, 2023 XHC 340 ( GMB 4552 , paratype) .

Notes.

In the phylogram (Fig. 2 ), Nigropunctata xiaohensis formed a separate clade in Nigropunctata s. str. Morphologically, N. xiaohensis resembles N. complanate R. Sugita & Kaz. Tanaka ( Sugita et al. 2024) as both share similar size ascospore. However, N. complanate is distinguished by thick clypeus (75–90 μm high, 270–410 μm diam.), larger asci (130–175 × 13–20 μm), and an inverted hat-shaped apical ring. The ITS sequences analysis of N. complanate and N. xiaohensis reveals a sequence length of 496 base pairs, with an 84.3 % identity, and 9.1 % gap presence. Nigropunctata nigrocircularis Samarak. & K. D. Hyde differs in having larger ascomata (450–535 × 455–560 μm), longer asci (125–170 μm) and smaller ascospore averaging 15.5 × 6.4 μm with a 3–4.5 μm mucilaginous sheath ( Samarakoon et al. 2022). The type species of the genus, N. bambusicola Samarak. & K. D. Hyde differs in having smaller ascomata measuring 285–315 × 260–340 μm, smaller discoid-inverted hat-shaped ascal apical rings (1.7–2 × 4–4.8 μm), and ascospores measuring 13.5–17 × 5.5–9.5 μm, with a 2–6 μm mucilaginous sheath ( Samarakoon et al. 2022). A recently reported new species from China, N. khalidii Y. P. Wu & Q. R. Li , differs by possessing larger ascomata (608–782 × 762–830 μm vs. 320–380 × 340–400 μm in N. xiaohensis ), larger asci (146–173 × 8.6–13.6 µm vs. 85.5–140 × 11–18.5 μm in N. xiaohensis ), and slightly smaller ascospores (14.8–18 × 6.3–9 µm) lacking a germ slit ( Li et al. 2024).

Figures

Figure 2. Molecular phylogenetic analysis of Nigropunctata and related taxa based on a combined ITS, LSU, tub 2 and tef 1 α sequences. Bootstrap support values for maximum likelihood (ML) greater than 75 % and Bayesian posterior probabilities (BPP) greater than 0.95 are displayed above or below the respective branches (ML / BI). The newly described species are marked red. Holotype and ex-type materials are in bold.

Figure 5. Nigropunctata xiaohensis (GMB 4503, holotype) A material B ascoma on the surface of host C cross-section of ascoma D, E longitudinal sections of ascomata F peridium G paraphyses H – J asci K a wedge-shaped, J + apical ring bluing in Melzer’s reagent L, M ascospores N ascospores with germ slits. Scale bars: 0.5 mm (C, D); 100 μm (E); 10 μm (F – N).