Nigropunctata shiwandashanensis C. T. Lu, K. Habib & Q. R. Li, 2025

Nigropunctata shiwandashanensis C. T. Lu, K. Habib & Q. R. Li sp. nov.

Fig. 4 View Figure 4

Etymology.

The specific epithet “ shiwandashanensis ” refers to Shiwandashan National Nature Reserve, where the holotype specimen was collected.

Type.

China • Guangxi Zhuang Autonomous Region, Shiwandashan National Nature Reserve ( 21°58'17.88"N, 108°2'52.22"E), altitude: 315 m, on dead culms of bamboo, 22 September 2024, Changtao Lu, 2024 SWS 82 ( GMB 4903 , holotype; GMBC 4903 , ex-type) GoogleMaps ; ibid KUN-HKAS 146985 , isotype GoogleMaps .

Description.

Saprobic on dead culms of bamboo. Sexual morph: Ascomata 610–1180 µm wide, 490–730 µm high, immersed, solitary, scattered, appearing as small black dots, in cross-section globose to subglobose with a flattened base. Ostioles centric, slightly papillate, black, covered with black, thick-walled clypeus. Peridium 8–12.5 µm thick, comprised of two layers; outer layer composed of thick-walled, dense, dark brown cells of textura angularis; inner layer hyaline cells of textura angularis. Paraphyses 2.5–7.3 µm (x ̄ = 6.1 µm, n = 30) wide, longer than the asci, numerous, filamentous, contain white intracellular material. Asci 167–220 × 10–24 µm (x ̄ = 195.5 × 17.5 µm, n = 30), 8 - spored, unitunicate, cylindrical, short-pedicellate, apically rounded, with a J +, discoid apical apparatus, 1–2 µm high, 3–5 µm wide (x ̄ = 1.5 × 4 µm, n = 30). Ascospores 15–24 × 5.5–9 µm (x ̄ = 19.7 × 7.0 µm, n = 30), uniseriate, unicellular, brown to dark brown, oblong to broadly ellipsoidal, surrounded by 2–5 µm (x ̄ = 3.7 µm, n = 30) thick mucilaginous sheath, with a straight germ slit along the entire spore length. Asexual morph: Undetermined.

Culture characteristics.

Ascospores germinated on PDA within 36 hours. Colonies grow fast, reaching 2 cm in 1 week at 24–27 ° C. Colony surface white, velvety to hairy, thin, nearly circular; reverse, pale yellowish.

Paratype.

China • Guangxi Zhuang Autonomous Region, Shiwandashan National Nature Reserve ( 21°59'37.26"N, 108°2'44.36"E), altitude: 326 m, on dead culms of bamboo, 22 September 2024, Changtao Lu, 2024 SWS 109 ( GMB 4952 , GMBC 4952 ) GoogleMaps .

Notes.

In the phylogram (Fig. 1 View Figure 1 ), Nigropunctata shiwandashanensis and N. hydei form a sister clade with strong support value (91 BS / 1 PP). Morphologically, N. shiwandashanensis can be distinguished from N. hydei by its larger ascomata (613–1180 × 490–730 µm vs. 485–575 × 400–520 µm), thinner peridium (8.3–12.5 µm vs. 16.5–31 µm), larger asci (167–220 × 10–24 µm vs. 150–185 × 11.5–16.5 µm) and longer ascospores (15–24 × 5.5–9 µm vs. 13.5–18 × 7–10 µm). In addition, the ascospores of N. hydei lack a germ slit ( Samarakoon et al. 2023), whereas N. shiwandashanensis possesses a full-length, straight germ slit. Comparative analysis of nucleotide base pairs showed that Nigropunctata shiwandashanensis differs from N. hydei by 10.5 % (51 / 487) in the ITS locus, 2.6 % (25 / 946) in the LSU locus and 7.5 % (71 / 951) in the rpb 2 gene. Comparison with other morphologically similar species is presented in Table 2 View Table 2 .