Halokirschsteiniothelia hunanensis Y.X. Shu, W. Dong & K.D. Hyde, in Dong et al., Fungal Diversity [13] (2025)
Index Fungorum number: IF 903172; MycoBank number: MB 903172; Facesoffungi number: FoF 17148; Fig. 1
Etymology – the specific epithet “hunanensis” refers to Hunan Province, China, from where the holotype was collected.
Holotype – MHZU 24-0872
Saprobic on decaying wood submerged in freshwater habitats. Sexual morph: Ascomata 115–160 µm high, 120–150 µm diam. x̄ = 150 × 135 µm, n = 5), solitary or scattered, superficial, subglobose, with a poorly developed, black, carbonaceous, ostiolate in the center. Peridium uneven in width, 8–15 µm thick, composed of 1–3 layers of dark brown, thick-walled cells of textura angularis in outer layer, and several layers of hyaline, thin-walled cells of textura angularis inwardly. Pseudoparaphyses 1.5–2.5 µm thick, cellular, septate, irregularly branched. Asci 60–90 × 20–30 µm (x̄ = 73 × 26 µm, n = 10), bitunicate, 8-spored, broadly clavate, short pedicellate. Ascospores 20–30 × 7–10 µm (x̄ = 24.8 × 8.2 µm, n = 30), fusiform with rounded ends, 1-septate, constricted at the septum, apical cell slightly larger than the basal cell, brown to dark brown, becoming paler at the apices, smooth-walled. Asexual morph: undetermined.
Culture characteristics – conidia germinating on MEA within 36 h, colony reaching up to 15 mm on PDA after 20 days at room temperature, white from above, dark green from below, surface short villous, dry, edge neatly.
Material examined – China, Hunan Province, Loudi City, on decaying wood submerged in freshwater habitats in a reservoir, 30 September 2022, Y.X. Shu, Hn6 (MHZU 24-0872, holotype); ex-type culture, ZHKUCC 24-1526.
GenBank accession numbers – LSU: PQ639961, tef1-a: PQ642444.
Notes – our multigene phylogenetic analysis of a combined LSU and tef1-a sequence dataset indicates that H. hunanensis is sister to H. maritima (Fig. 2). Halokirschsteiniothelia hunanensis can be easily distinguished from H. maritima based on the morphological comparison of their holotype. Halokirschsteiniothelia hunanensis has larger asci (60– 90 × 20–30 µm vs. 35–60 × 8–14 µm), larger ascospores (20–30 × 7–10 µm vs. 15–19 × 5–6 µm), and darker ascospores (dark brown at maturity in H. hunanensis vs. pale brown at maturity in H. maritima) (Hawksworth 1985). In addition, the comparison of DNA sequence data between H. hunanensis ZHKUCC 24-1526 and H. maritima CBS 221.6 reveals a difference of 0.80% (7 out of 876) and 4.09% (38 out of 929) in nucleotide variations within the LSU and tef1-a, respectively. Therefore, H. hunanensis is established as a new species.
Figure 1 – Halokirschsteiniothelia hunanensis (MHZU 24-0872, holotype). a Ascomata on host surface. b Section through ascoma. c Structure of the ostiole. d Peridium. e Pseudoparaphyses. f–h Asci. i Immature bitunicate asci. j–m Ascospores. n Germinated ascospore. o, p Colony on MEA (from front and reverse). Scale bars: b = 100 µm, c, f–n = 20 µm, d, e = 5 µm.
Figure 2 – Maximum likelihood consensus tree inferred from the combined LSU and tef1-a multiple sequence alignments. Bootstrap support values for maximum likelihood (ML, first value) equal to or greater than 70% and Bayesian posterior probabilities from MCMC analyses (BYPP, second value) equal to or greater than 0.95 are given near the nodes. The scale bar indicates expected changes per site. The tree is rooted to Glonium circumserpens CBS 123343 and Glonium stellatum CBS 207.34. Ex-type strains are indicated with “T”. The newly generated sequence is indicated in red.