Dictyochaeta jiangxiensis J.E. Huang, X.Y. Yan, H.Y. Song & D.M. Hu, 2023

Yan, Xin-Yi, Huang, Jun-En, Song, Hai-Yan, Gao, Yang, Hu, Hai-Jing, Zhai, Zhi-Jun, Yan, Jun-Qing, Huo, Guang-Hua & Hu, Dian-Ming, 2023, A new species of Dictyochaeta (Sordariomycetes, Chaetosphaeriales, Chaetosphaeriaceae) from freshwater habitats in China, Biodiversity Data Journal 11, pp. 97439-97439 : 97439

Dictyochaeta jiangxiensis J.E. Huang, X.Y. Yan, H.Y. Song & D.M. Hu sp. nov.

Materials

Type status: Holotype. Occurrence: occurrenceID: B23E3165-B465-54BD-ADAE-FB318AEB9F70; Taxon: scientificName: Dictyochaeta jiangxiensis; acceptedNameUsage: Dictyochaeta jiangxiensis J.E. Huang, X.Y. Yan & D.M. Hu; kingdom: Fungi; phylum: Ascomycota; class: Sordariomycetes; order: Chaetosphaeriales; family: Chaetosphaeriaceae; genus: Dictyochaeta; specificEpithet: jiangxiensis; taxonRank: species; verbatimTaxonRank: species; scientificNameAuthorship: J.E. Huang, X.Y. Yan & D.M. Hu; Location: continent: Asia; country: China; stateProvince: Jiangxi Province; county: Jishui county; locality: Dingjiang ; verbatimLatitude: 27.127397 N; verbatimLongitude: 115.276527 E; Identification: identifiedBy: J.E Huang, X.Y. Yan; Record Level : type: PhysicalObject ; language: en; rightsHolder: Dian-Ming Hu ; institutionID: HFJAU 3175; collectionID: HJ0108-1; institutionCode: the Herbarium of Fungi , Jiangxi Agricultural University (HFJAU); collectionCode: Fungi ; ownerInstitutionCode: the Herbarium of Fungi , Jiangxi Agricultural University (HFJAU); basisOfRecord: PreservedSpecimen

Description

Saprobic on decaying submerged wood. Sexual morph Undetermined. Asexual morph Hyphomycetous. Colonies effuse, aggregate, spreading very widely, glistening white to transparent spots and short dark brown hairs. Mycelium composed of partly immersed and partly superficial, brown to dark brown, septate. Setae of the upper layer sterile, brown to black, usually associated with the conidiophores and together these can form small clusters originating from a knot of superficial hyphae, 200-420 × 4.6-7.2 μm, cylindrical, straight or slightly flexuous, septate, smooth, thick-walled, base swollen 9-12 μm wide, tapering to terminal. Conidiophores of the lower layer always fertile, mononematous, macronematous, erect or flexuous, unbranched, 26-60 × 3.5-5 μm (av. = 48.3 × 4.0 µm, n = 20), 3-8-septate, smooth, thin-walled, base brown 4.8-7.5 µm, apex pale brown with single phialide. Conidiogenous cells monophialidic (15-) 24-34 × 3.6-5 μm (av. = 27.6 × 4 µm, n = 20), subcylindrical, light brown, narrowing below the collarette. Collarettes light brown, funnel-shaped, 2.2-4.9 μm at the opening, 0.8-1.1 μm at deep. Conidia accumulating at the heads white, 23-32 × 2.5-3.2 μm (av. = 26.1 × 2.9 µm, n = 30), hyaline, unicellular, thin-walled, smooth, abundant guttulate, falcate to subclavate, rarely straight, narrowly rounded at the both ends, with 6-11 μm long hair-like appendages at both ends, smooth (Fig. 2 ).

Culture characteristics

Conidia germinating on PDA within 12 h. Colonies growing on PDA, reaching 20-30 mm diam. after 3 weeks at 28°C, circular, white to pale grey mycelium with hyaline margin, centre lightly raised, pale brown to dark brown in reverse, with smooth margin.

Material examined

CHINA, Jiangxi Province, Jian, Dingjiang, on submerged wood in a stream, 9 April 2018, J.E. Huang (HFJAU 3175, Holotype); ex-type living culture (JAUCC 2824).

Etymology

' Dictyochaeta jiangxiensis ' refering to the host location, Jiangxi Province, where the holotype was collected.

Notes

Dictyochaeta jiangxiensis is a distinct species in the genus as supported by molecular phylogenetic analysis and it clusters with D. brevis , but the latter has smaller conidia (7.5-11.4 µm long, 2.0-2.9 μm wide; Lin et al. (2019)). We found that there was 8% nucleotide difference of ITS sequences and about 2% nucleotide difference between the LSU sequences of Dictyochaeta jiangxiensis sp. nov. JAUCC2824 and Dictyochaeta brevis MFLU 19-0216. Morphologically, D. jiangxiensis matches Dictyochaeta well, especially the setae surrounded by several conidiophores and conidia with setulae at both ends. D. jiangxiensis is similar to D. fuegiana ( Chaetosphaeria fuegiana ), D. occidentalis , C. siamensis ( Dictyochaeta siamensis ) and C. lignicola ( Dictyochaeta lignicola ) in having multi-septae and a single phialide at the apex, subcylindrical conidiogenous cells with funnel-shaped collarette and guttulate conidia with hair-like appendages. However, D. fuegiana ( Chaet. fuegiana ) has smaller conidia (15-23 × 2-2.5 μm) without hair-like appendages at both ends ( Spegazzini 1923). C. lignicola also has smaller conidia (13-15 μm long, 4.5-5.5 μm wide) and has no setae ( Luo et al. 2019). D. occidentalis has wider conidia (24-32 × 3-4 μm; Whitton et al. (2000)) with degenerated appendages. C. siamensis has mono- or polyphialidic conidiogenous cells and samller conidia (8-17 × 2-5 μm; Tibpromma et al. (2018)).

Figures

Figure 2. Dictyochaeta jiangxiensis (HFJAU 3175, holotype). a Colonies on submerged wood; b, c Setae and conidiophores; d, e Conidiophores and phialides with a developing conidia; f, g Apex and base of setae; h, i Conidia; j, k Colony on PDA from above and below. Scale bars: a = 200 μm, b, c = 50 μm, d-h = 5 μm.