Distoseptispora subtropica M. G. Liao & Jian Ma, 2025

Distoseptispora subtropica M. G. Liao & Jian Ma sp. nov.

Fig. 6 View Figure 6

Type.

China • Fujian Province, Nanping City, Wuyishan National Nature Reserve , 27°43′N, 117°41′E, on decaying wood of an unidentified broadleaf tree, 16 October 2023, YF. Hu (holotype HJAUP M 2528 ; ex-type living culture HJAUP C 2528 ) GoogleMaps .

Etymology.

In reference to the subtropical climate in which the species was collected.

Description.

Saprobic on dead branches in a terrestrial habitat. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on natural substrate effuse, scattered, dark brown to black, hairy. Mycelium partly superficial, partly immersed in the substratum, composed of branched, septate, smooth, pale brown to brown hyphae. Conidiophores macronematous, mononematous, solitary or in groups, unbranched, erect, straight or slightly flexuous, cylindrical, smooth, 5–10 - septate, brown to dark brown and paler towards the apex, 125–262 × 6–10.5 µm (x ̄ = 181.7 × 6.7 µm, n = 12). Conidiogenous cells monoblastic or ployblastic, integrated, terminal, cylindrical, pale brown, smooth, determinate or sometimes with cylindrical, enteroblastic percurrent extensions. Conidia acropleurogenous, solitary, dry, straight or slightly curved, obclavate, rostrate, verrucose, 5–10 - euseptate, pale brown to brown, 64–147 × 12–15 µm (x ̄ = 90.1 × 13.3 µm, n = 23), tapering to 2.5–4.5 µm near the apex, 4.5–7 µm wide at the truncate base.

Culture characteristics.

Colonies on PDA reaching 57–58 mm diam. after 4 weeks in an incubator under dark conditions at 25 ° C, circular, surface velvety, with yellow to pale brown and denser mycelium at the center, becoming dark brown at the ring with a pale edge, reverse brown at the central parts with a dark brown inner ring and an outer pale brown halo.

Additional specimen examined.

China • Fujian Province, Nanping City, Wuyishan National Nature Reserve , 27°43′N, 117°41′E, on decaying wood of an unidentified broadleaf tree, 16 October 2023, Y. F. Hu (paratype HJAUP M 2535 ; living culture HJAUP C 2535 ) GoogleMaps .

Notes.

Strains HJAUP C 2528 and HJAUP C 2535 grouped together with 94 % ML / 0.81 BI support. Comparisons of their nucleotide sequences revealed differences of 12 nucleotides (1.9 %, including five gaps) in the ITS region, 7 nucleotides (1.2 %, including three gaps) in the LSU region, and 13 nucleotides (1.3 %, including two gaps) in the TEF 1 region. Based on the criteria established by Jeewon and Hyde (2016), nucleotide differences greater than 1.5 % in the ITS region may suggest a new species. However, aside from slight differences in conidial length (64–147 µm vs. 53–86 µm), there were no significant morphological distinctions. Therefore, we propose to identify these two strains as the same new species, Distoseptispora subtropica . Phylogenetic analyses show that D. subtropica ( HJAUP C 2528 and HJAUP C 2535 ) forms a sister clade to D. aquamyces R. Zhu & H. Zhang ( KUNCC 21–10732), with 93 % ML / 0.81 BI support. A BLASTn search of GenBank reveals that the sequences of D. subtropica ( HJAUP C 2528 ) and D. aquamyces ( KUNCC 21–10732) share 99 % similarity (568 / 575, two gaps) in ITS, 99 % similarity (571 / 574, three gaps) in LSU, 99 % similarity (1035 / 1040, three gaps) in RPB 2, and 99 % similarity (912 / 919, no gaps) in TEF 1. Moreover, D. subtropica is significantly different from D. aquamyces ( Zhang et al. 2022) by having larger conidiophores [125–262 × 6–10.5 µm vs. (78 –) 91–198 × 4–7 µm], and acropleurogenous, obclavate, larger conidia (64–147 × 12–15 µm vs. 30–95 × 7–12 µm).