Xenopleopunctum guizhouense J. Y. Zhang, Y. Z. Lu & K. D. Hyde, 2025

Zhang, Jing-Yi, Hyde, Kevin D., Yang, Ming-Fei, Sun, Ya-Ru, Xiao, Xing-Juan, Meng, Ze-Bin, Bao, Dan-Feng & Lu, Yong-Zhong, 2025, Discoveries of Dothideomycetes (Fungi) associated with pteridophytes in China, IMA Fungus 16, pp. e 167717-e 167717 : e167717-

Xenopleopunctum guizhouense J. Y. Zhang, Y. Z. Lu & K. D. Hyde sp. nov.

Fig. 8

Etymology.

The species epithet refers to its collecting site.

Diagnosis.

Differs from X. sporodochiale in having larger conidia (46.5–66.5 × 22–32.5 µm vs. 35–45 (– 47.8) × 18.3–25.5 µm) with diverse shapes.

Holotype.

HKAS 129707 .

Description.

Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on natural substrate superficial, effuse, scattered to gregarious, sporodochial, punctiform, brown to black. Mycelium mostly superficial, composed of branched, septate, hyaline to brown hyphae. Conidiophores micro- to macronematous, mononematous, cylindrical, brown, often reduced to conidiogenous cells. Conidiogenous cells monoblastic, integrated, terminal, cylindrical, thick-walled, brown, 4–6.5 µm ( x ̄ = 5.1 µm, n = 20) wide. Conidia acrogenous, cylindrical to oval to irregular ellipsoidal, muriform, constricted at septa, brown to dark brown, sometime slightly darked at the upper part, 46.5–66.5 × 22–32.5 µm ( x ̄ = 53.5 × 26.3 µm, n = 30), often with a cylindrical to subglobose, hyaline or subhyaline to pale brown basal cell, 8.5–14 × 6–15 µm.

Culture characteristics.

Conidia germinating on WA within 15 h and germ tube produced from the base of conidia. Colonies growing on PDA under natural light, reaching ca. 36 mm diameter after one month at 26 ° C, circular with entire margin, flat with a protuberance in the center, dry, velvety, white to taupe brown in concentric circles from center towards margin in the front; pale brown in the center, followed by brown to pale brown in concentric circles towards the edge, not producing pigmentation in culture.

Material examined.

CHINA • Guizhou Province, Tongren City , Jiangkou County, 27°46'38"N, 108°45'22"E 522 M, on dead petiole of Woodwardia japonica , in a distributed forest, 21 May 2022, J. Y. Zhang, F 37 ( HKAS 129707 , holotype; GZAAS 23-0675 , isotype), ex-type living culture KUNCC 23-13881 ; • ibid., F 34 ( HKAS 147018 = GZAAS 23-0825 , paratype), living culture, KUNCC 23-13880 ; • ibid., F 38-1 ( HKAS 129708 , paratype), living culture, KUNCC 23-13882 .

Additional sequence.

KUNCC 23-13881 : ITS ( PV 862373); KUNCC 23-13880 : ITS ( PV 862374); KUNCC 23-13882 : ITS ( PV 862375).

Notes.

Three collections representing a new species, Xenopleopunctum guizhouense , form an independent lineage that is sister to X. sporodochiale with strong support value (100 % ML / 1.00 PP, Fig. 1 ). Xenopleopunctum guizhouense and X. sporodochiale share a similar morphology in having sporodochial, punctiform colonies, integrated, monoblastic, brown conidiogenous cells, and muriform, brown conidia with a hyaline or subhyaline to pale brown basal cell. However, Xenopleopunctum guizhouense differs from X. sporodochiale in having larger conidia (46.5–66.5 × 22–32.5 µm vs. 35–45 (– 47.8) × 18.3–25.5 µm) with diverse shapes (cylindrical to oval to irregular ellipsoidal vs. oval to ellipsoidal). Additionally, a comparison of nucleotide base pairs of ITS, LSU, RPB 2, SSU, and tef 1-α between X. guizhouense (F 37 - KUNCC 23-13881 ) and X. sporodochiale (C 22 - HKAS 129694 ) shows 27 / 469 bp (6 %, including 4 gaps), 12 / 857 bp (1 %, with 2 gaps), 60 / 1062 bp (6 %, 0 gaps), 2 / 1022 bp (- %, 0 gaps), and 50 / 908 bp (6 %, with 1 gap) differences, confirming they are distinct species.

Figures

Figure 1. Phylogram generated from maximum likelihood analysis based on combined LSU, RPB 2, SSU, and tef 1 - α sequence data in Dothideomycetes. Bootstrap support values for maximum likelihood (ML) greater than 60 % and Bayesian posterior probabilities (PPs) greater than 0.90 are indicated near the nodes as ML / PP. The tree is rooted with three species of Arthoniomycetes, including Dendrographa decolorans (Ertz 5003), Lecanactis abietina (Ertz 5068), and Roccella fuciformis (Tehler 8171). The new taxa and new combinations are shown in blue.

Figure 8. Xenopleopunctum guizhouense (HKAS 129707, holotype). A The host; B Host substrate; C, D Colonies on the host substrate; E, F Mycelium and conidiogenous cells (arrows indicating conidiogenous cells); G – O Conidia; P, Q Pure culture from above and below. Scale bars: 20 μm (E – O).