Triseptata sexualis Boonmee & Phookamsak, 2020

Boonmee, Saranyaphat, Calabon, Mark S., Phookamsak, Rungtiwa, Elgorban, Abdallah M. & Hyde, Kevin D., 2020, Triseptata sexualis gen. et sp. nov. in Latoruaceae (Pleosporales), Phytotaxa 447 (4), pp. 252-264 : 257-258

Triseptata sexualis Boonmee & Phookamsak , sp. nov. ( Figs. 2 , 3 )

Index Fungorum number: IF557184, Facesoffungi number: FoF 07230

Etymology:—The specific epithet “ sexualis ” referring to sexual morph.

Holotype:— MFLU 11–0002

Saprobic on dried branches of an unidentified plant. Sexual morph: Ascostromata (108–)148–157 µm high × (120–)157–198 µm diam. (x = 145 × 172 µm, n = 5), immersed to slightly erumpent, visible as black spots, single or clustered, scattered or gregarious, uni- to multi-locular, globose to subglobose, with or without basal stroma, dark brown, obscure ostiole. Peridium 16–26 µm wide, composing several layers of textura angularis, with compressed of dark brown cells. Hamathecium comprising 1.5–2 µm wide, cylindrical, branched, septate, anastomosed, hyaline pseudoparaphyses. Asci 43–60 × 7–9 µm (x = 52 × 8 µm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical-clavate, sessile, apically rounded. Ascospores 11.5–15 × 4–5 µm (x = 13 × 4.5 µm, n = 20), 1–2-seriate, partially overlapping, ellipsoid-fusiform, straight or slightly curved, regularly 3–septate, darkened and constricted at the septa, the second cell from the top slightly wider than the others, asymmetrical ends, light brown to brown, smooth-walled. Asexual morph: hyphomycetous conidia-like structures in culture. Conidiophores and conidiogenous cells absent. Conidia (12–)16–23 µm diam. (n = 30), superficial, globose to subglobose, multiseptate, brown to dark brown, smooth-walled.

Culture characteristics:—Conidia germinating on WA within 12 hrs. Colonies growing on malt extract agar (MEA), reaching 18 mm in 2 weeks at 28°C, effuse, dentate and lobate edges, darkly brown. Mycelium superficial and partly immersed, branched, septate, pale brown to brown, smooth-walled, chlamydospores produced in culture and induced with plant tissues within 90 days.

Material examined:— THAILAND, Chiang Mai, Jom Thong , elev. 800–1000 msl., N18 o 31’ E 98 o 29’, on dead branches of an unidentified plant, 16 November 2010, R. Phookamsak, ITN04: MFLU 11–0002 , holotype ; ex-type living culture, MFLUCC 11–0002 = BBC 52152 .

Notes:—Phylogenetic analysis of a combined LSU, ITS and SSU sequence dataset ( Fig. 1 ) indicates that our new taxon Triseptata sexualis (MFLUCC 11–0002) forms a well-resolved single lineage basal to the sister clade of Latoruaceae with 99% MLBS and 1.00 BYPP support.

Figures

FIGURE 1. Phylogram obtained from RAxML based on analysis of a combined dataset of LSU ITS and SSU sequence data. Bootstrap values for RAxML ≥ 55% BS and BYPP ≥ 0.95 are given on the branches. The tree is rooted to Dothidea insculpta CBS 189.58 (Dothideaceae, Dothideales). The type species of each genus are in bold and new taxa in blue.

FIGURE 2. Triseptata sexualis (MFLU 11–0002, holotype). a Appearance of ascomata and habit on dried branches substrate. b, c Section of ascomata. d Peridium. e Pseudoparaphyses. f–h Asci. i–l Ascospores. Scale bars: a = 500 µm, b, c = 100 µm, d, f-h = 20 µm, e, i–l = 5 µm.

FIGURE 3. Triseptata sexualis (MFLUCC 11–0002, ex-type). a Germinating ascospore.b, c Colonies on MEA from surface and reverse. d Aerial mycelium in culture. e, f Development of conidia in culture. g–i Close up of conidia–like structures. Scale bars: a = 5 µm, d = 10 µm, f = 10 µm, g–i = 20 µm.