Aquapteridospora submersa R.J. Xu, Q. Zhao & Boonmee, 2024

Xu, Rong-Ju, Li, Jun-Fu, Zhou, De-Qun, Boonmee, Saranyaphat, Zhao, Qi & Chen, Ya-Ya, 2024, Three novel species of Aquapteridospora (Distoseptisporales, Aquapteridosporaceae) from freshwater habitats in Tibetan Plateau, China, MycoKeys 102, pp. 183-200 : 183

Aquapteridospora submersa R.J. Xu, Q. Zhao & Boonmee sp. nov.

Fig. 4

Etymology.

Referring to the fungus’s habitat "decaying wood submerged in freshwater habitats".

Holotype.

HKAS 128980.

Description.

Saprobic on decaying wood submerged in freshwater. Sexual morph: Undetermined. Asexual morph: Colonies on the natural substrate effuse, glistening, pale brown to brown, scattered or in small groups. Mycelium mostly superficial, consisting of branched, septate, smooth, pale brown to brown hyphae. Conidiophores 376-708 × 5-12 μm (x̄ = 451 × 7 μm, n = 20), macronematous, mononematous, solitary, erect, straight or slightly flexuous, unbranched, smooth, cylindrical, multi-septate, tapering towards apex, brown to pale brown. Conidiogenous cells polyblastic, monoblastic, terminal, becoming intercalary, cylindrical, pale brown, integrated, with several sympodial proliferations, conspicuous denticles, bearing tiny, protuberant, circular scars. Conidia 19-22 × 6-8 μm (x̄ = 21 × 7 μm, n = 20), solitary or acropleurogenous, fusiform, smooth, 2-3-septate, rounded at apex, truncate at base, slightly constricted at septa, hyaline when young, sub-hyaline to pale brown when mature, two big guttulate when young. Conidial secession schizolytic.

Culture characteristics.

Conidia were germinated on PDA within 48 hours. Germ tubes produced from each end. Colonies grown on PDA, circular, flat, superficial, raised, with dense, pale mycelium in the centre. Grey brown from above, dark brown from below.

Material examined.

China, Xizang, Linzhi City , Motuo County, on submerged decaying wood, 677 msl, 29°19'43"N, 95°21'19"E, 13 July 2022, R.J. Xu, LJN-15 (HKAS 128980, holotype), ex-type living culture (KUNCC 10446) . Xizang, Linzhi City, Motuo County, Gelin Village , on submerged decaying wood, 677 msl, 29°19'43"N, 95°21'19"E, 12 July 2022, R.J. Xu, LJN-15-5, (HKAS 128981), living culture (KUNCC 10444) .

Notes.

Phylogenetic analyses show that Aquapteridospora submersa (KUNCC 10446, KUNCC 10444), formed a sister grouped with A. yadongensis (KUNCC 10445 and KUNCC 10488) and was close to A. lignicola (MFLUCC 15-0377) with 75% ML/0.96 PP, Fig. 1 . However, the comparison of conidial characteristics and nucleotides shows that A. submersa differs from A. yadongensis (see the notes of A. yadongensis ). Indeed, A. submersa differs from A. lignicola in having long conidiophores (376-708 vs. 70-200 μm) and conidia without a conspicuous sheath ( Yang et al. 2015). Aquapteridospora submersa is introduced here as a new species.

Figures

Figure 1. Maximum likelihood (ML) tree is based on combined LSU, TEF 1 - α and ITS sequence data. ML bootstrap support values equal to or greater than 70 % and Bayesian posterior probabilities (PP) equal to or greater than 0.95 given above the nodes, shown as " ML / PP ". The tree is rooted with Pseudostanjehughesia aquitropica (MFLUCC 16 - 0569) and P. lignicola (MFLUCC 15 - 0352). New species are indicated in red and type strains are in bold.

Figure 4. Aquapteridospora submersa (HKAS 128980, holotype) a colonies on the substratum b-d conidiophores, conidiogenous cells with conidia e-g conidiogenous cells with developmental conidia h-k conidia l germinating conidium m, n culture on PDA. Scale bars: 50 μm (b-d); 20 μm (e-g); 10 μm (h-l).