Neohelicosporium guizhouense X. Y. Ma, J. Ma & Y. Z. Lu, 2025

Neohelicosporium guizhouense X. Y. Ma, J. Ma & Y. Z. Lu sp. nov.

Fig. 2 View Figure 2

Etymology.

The epithet “ guizhouense ” refers to Guizhou Province, where the fungus was collected.

Holotype.

HKAS 128908 View Materials

Description.

Saprobic on decaying wood in terrestrial habitats. Sexual morph Undetermined. Asexual morph Hyphomycetous, helicosporous. Colonies on natural substrate superficial, effuse, gregarious, white. Mycelium mostly immersed, partly superficial, composed of pale brown to brown, branched, septate, guttulate, smooth. Conidiophores 56.5–165 μm long, 4–6.5 μm wide (x ̄ = 118.5 × 5.5 μm, n = 20), macronematous, mononematous, procumbent, aggregated, cylindrical, tapering towards the tip, straight or slightly flexuous, branched, septate, smooth- and thick-walled, brown at the base and hyaline towards the apex. Conidiogenous cells 9–16.5 μm long, 3.5–6 μm wide (x ̄ = 12.5 × 4.5 μm, n = 30), holoblastic, mono- to poly-blastic, integrated, intercalary or terminal, hyaline, smooth-walled, cylindrical or subcylindrical, becoming truncate towards the apex after conidial secession with tiny tooth-like protrusions, mostly bearing one (rarely two) tiny conidiogenous loci. Conidia solitary, acropleurogenous, helicoid, tapering towards the ends, developing on tooth-like protrusions, 20.5–27.5 μm diam. and conidial filament 3.5–5 μm wide (x ̄ = 23.5 × 4 μm, n = 30), 78–109.5 μm long (x ̄ = 88 μm, n = 30), indistinctly multi-septate, slightly constricted at septa, tightly coiled up to 3 times, becoming loosely coiled or uncoiled in water, guttulate, hyaline, smooth-walled.

Culture characteristics.

Conidia germinating on PDA within 13 h and germ tubes arising from the terminal ends and the middle of the conidium. Colonies reached 26 mm diam. after 33 days of incubation at 25 ° C, irregular, with flat, brown to black mycelia on the surface, in reverse pale brown to black with undulate margin.

Material examined.

China • Guizhou Province, Qiannan Buyi and Miao Autonomous Prefecture, Libo County, Maolan Nature Reserve , on decaying wood in a terrestrial habitat, 10 April 2022, Jian Ma, MN 4.1 ( HKAS 128908 View Materials , holotype), ex-type living culture GZCC 23-0078 ; China, Guizhou Province, Sandu Shui Autonomous County, Yao Renshan National Forest Park , on decaying wood in a terrestrial habitat, 10 April 2022, Jian Ma, YS 17.4 ( GZAAS 23-0550 , paratype), living culture GZCC 23-0545 ; China, Hainan Province, Ledong Li Autonomous County, Jianfengling National Forest Park , on decaying wood in a forest, 28 December 2021, Jian Ma, JB 2 ( HKAS 128876 View Materials , paratype), living culture GZCC 23-0023 .

Notes.

In the phylogenetic tree (Fig. 1 View Figure 1 ), three strains of Neohelicosporium guizhouense ( GZCC 23-0078 , GZCC 23-0023 , and GZCC 23-0545 ) formed a distinct lineage and were sister to N. wuzhishanense ( GZCC 23-0278 , GZCC 23-0279 , and GZCC 23-0326 ), supported by 100 % ML and 1.00 PP. A comparison of LSU, ITS, tef 1 - α, and rpb 2 sequences between the ex-type strain of N. guizhouense ( GZCC 23-0078 ) and N. wuzhishanense ( GZCC 23-0326 ) revealed 2 / 837 bp (0.2 %, including one gap), 26 / 773 bp (3.4 %, including one gap), 21 / 885 bp (2.4 %, without a gap), and 35 / 914 bp (3.8 %, including one gap) nucleotide base differences, respectively, which strongly support them as two distinct species. Morphologically, Neohelicosporium guizhouense ( HKAS 128908 ) differs from N. wuzhishanense ( HKAS 128903 ) by its distinct conidiogenous cells (tooth-like vs. tooth-like and / or bladder-like), smaller conidial filaments (3.5–5 μm vs. 4.5–6 μm), and different coiled states in water (loosely coiled vs. tightly coiled). Therefore, we designate the three isolates ( GZCC 23-0023 , GZCC 23-0078 , and GZCC 23-0545 ) as a new species, Neohelicosporium guizhouense .