Sclerococcum pseudobactrodesmium J. Ma & Y.Z. Lu, 2023

Ma, Jian, Liu, Ning-Guo, Tang, Xia, Xiao, Xing-Juan, Chen, Xue-Mei, Xiao, Yuan-Pin, Zhang, Ya-Zhou, Lu, Yong-Zhong & Boonmee, Saranyaphat, 2023, Sclerococcum pseudobactrodesmium sp. nov. from a terrestrial habitat in China, Phytotaxa 630 (1), pp. 69-79 : 73-76

Sclerococcum pseudobactrodesmium J. Ma & Y.Z. Lu , sp. nov. FIGURE 2

Index Fungorum number: IF 901087; Facesoffungi number: FoF 14772

Etymology: the specific epithet pseudobactrodesmium refers to this taxon morphologically similar to Bactrodesmium Holotype: HKAS 128890

Saprobic on decaying wood in a terrestrial habitat. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on substratum superficial, sporodochial, scattered, punctiform to pulvinate, yellow-brown to black, shining. Mycelium mostly immersed, composed of septate, branched, subhyaline to pale brown, smooth hyphae. Conidiophores up to 20 μm long, 3–4.5 μm wide, macronematous to semi-macronematous, fasciculate, short subcylindrical or monilioid, hyaline to pale brown, simple, rarely branched, septate, arising from basal hyphae. Conidiogenous cells 3–3.5 μm wide, holoblastic, mono- or polyblastic, terminal, integrated, subcylindrical to subspherical, hyaline to pale brown. Conidia 32–44 μm long, 11.5–15 μm wide (x = 38 × 13 μm, n = 30), solitary, clavate to ellipsoidal-clavate, occasionally pyriform or obovoid, sometimes broadly curved, 5–8-septate, predominantly 7-septate, with a conspicuous central pore at the septa, and a large sac-like at each cell, often bear a short frill of wall, pale brown to brown, smoothwalled.

Culture characteristics: Conidia germinating on PDA and germ tubes produced from polar cells of conidia within 18 hrs. Colonies on PDA are circular, with umbonate surface, edge entire, reaching 20 mm diam. after 40 days of incubation at 25 ℃, above-side brown to dark brown, reverse-side black. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown, smooth.

Material examined: China, Guizhou Province, Liupanshui City, Yushe National Forest Park, 26°46′ N, 104°78′ E,on decaying wood in terrestrial habitat, 25February2023, Jian Ma,LP1( HKAS128890 , holotype; GZAAS23-0058 , isotype), ex-type living culture CGMCC 3.25577 , GZCC 23-0055 ; Ibid., LP2 ( GZAAS 23-0059 ), living culture GZCC 23-0056 ; LP3( GZAAS23-0060 ), living culture GZCC23-0057 ; China, Guizhou Province, Liupanshui City, Yushe National Forest Park , 26°46′ N, 104°78′ E, on decaying wood in terrestrial habitat, 31 July 2022, Xing-Juan Xiao, YS38.1 ( GZAAS 23-0554 , paratype), living culture GZCC 23-0549 .

Notes: Morphologically, Sclerococcum pseudobactrodesmium resembles Bactrodesmium diversum , especially in its macronematous, fasciculate, short conidiophores, blastic terminal conidiogenous cells, and clavate to ellipsoidal-clavate conidia with a conspicuous central pore at the septa ( Réblová et al. 2020). However, multigene phylogeny reveals that our new species is nested within Sclerococcum ( Sclerococcaceae , Sclerococcales , Eurotiomycetes; Fig. 1 ), while Bactrodesmium diversum is classified under Savoryellales ( Sordariomycetes; Réblová et al. 2020). Furthermore, Sclerococcum pseudobactrodesmium is distinguished from other Sclerococcum taxa by its unique clavate to ellipsoidal-clavate conidia ( Thiyagaraja et al. 2022). We, therefore, introduce Sclerococcum pseudobactrodesmium as a new species.

Figures

FIGURE 1. Phylogenetic tree generated from ML analysis based on a combined LSU, ITS, mtSSU, and SSU sequence data. The bootstrap support (bs) values of ML equal to or greater than 75%, and Bayesian posterior probabilities (PP) equal to or greater than 0.95 are given near the nodes as ML/PP, respectively. Onygena corvina (CBS 281.48) and Trichocoma paradoxa CBS (78893-IFO 30659) were used as outgroup taxa. The newly generated sequences are indicated in black bold. “T” denotes ex-type strain.

FIGURE 2.Sclerococcumpseudobactrodesmium(HKAS128890,holotype).a,bColonies onthenaturalsubstrate surface.cSporodochium. d–k Conidiophores, conidiogenous cells, and conidia. l–n Conidia. o Germinating conidium. p, q Colonies on PDA from above and below. r Umbonate colony surface on PDA from the side. Scale bars: c = 50 µm, d–f, h–k = 20 µm, g, l–o = 10 µm.