Paraconiothyrium zingiberacearum Tennakoon, C.H. Kuo & K.D. Hyde, sp. nov.

MycoBank number: MB; Index Fungorum Number: IF; Facesoffungi number: FoF 10802, FIGURE XX

Etymology: The species name reflects the host family Zingiberaceae, from which the holotype was collected.

Holotype: MFLU 18-0091

Saprobic on dead stem of Hedychium coronarium J. Koenig (Zingiberaceae). Sexual morph: Ascomata 100–170 μm high × 120–220 μm diam. ( = 150 × 180 µm, n = 10), solitary or clustered, coriaceous, immersed to semi-immersed, erumpent, visible as black dots on the host surface, unilocular, globose to sub-globose, brown to dark brown. Peridium 20–30 μm wide, outermost layer comprising reddish brown to dark brown, thick-walled, loosely packed cells of textura angularis, inner layer composed hyaline, flattened, thin-walled cells of textura angularis. Hamathecium comprising 1.5–3 μm wide, cylindrical to filiform, septate, cellular, pseudoparaphyses. Asci 50–60 × 5.5–7 μm (= 53 × 6.5 μm, n = 20), 8-spored, bitunicate, fissitunicate, clavate to cylindrical, short pedicellate, rounded at the apex and with a shallow ocular chamber. Ascospores 11–14 × 2.5–4 μm (= 12.5 × 3 μm, n = 30), overlapping, 1–2-seriate, light brown, 1-septate, broadly fusiform with acute ends, straight or slightly curved, guttulate, rough-walled, without a mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics: Colonies on PDA, 10–12 mm diam. after three weeks at 25 °C, colonies from above: medium dense, circular, flat, surface smooth with crenate edge, velvety, with smooth aspects, white to cream at the margin, cream to grey in the centre; reverse: white at the margin, light brown to yellowish in the centre.

Material examined: Taiwan, Chiayi, Ali Shan Mountain, Fanlu Township area, Dahu forest, on dead stem of Hedychium coronarium (Zingiberaceae), 05 August 2017, D. S. Tennakoon, NSP002a (MFLU 18-0091, holotype); ex-type living culture, MFLUCC 18-0559. ibid. NSP002b (NCYU 19-0320, Paratype); ex-paratype living culture, NCYUCC 19-0230.

GenBank numbers: LSU: XXXX; ITS: XXXX.; tub2: XXXX

Notes: According to the multi-gene phylogenetic analyses, our collection (MFLU 18-0091 and NCYU 19-0320) is grouped with Paraconiothyrium estuarinum with strong statistical support (89% ML, 0.96 BYPP, Fig. XX). The asexual morph of Paraconiothyrium estuarinum was introduced by Verkley et al. (2004) from an estuarine sediment polluted with industrial discharges in Brazil. However, our collection did not sporulate even after 2 months’ incubation period and, hence could not be compared with the asexual morph of Paraconiothyrium estuarinum (CBS 109850) (Verkley et al. 2004). Therefore, we compared the base pair differences between our collection and Paraconiothyrium estuarinum. There are 10 base pair differences (2.21%) across 451 nucleotides across the tub2 gene region and 11 base pair differences (2.17%) across 506 nucleotides across the ITS (+5.8S) gene region. Phylogeny also indicates that the clade containing our collection and Paraconiothyrium estuarinum provides sister lineage to P. cyclothyrioides (Fig. XX). The sexual morph of Paraconiothyrium cyclothyrioides differs from our collection in having olive-brown, 3-septate, cylindrical to ellipsoidal with obtusely rounded ends, whereas our collection has light brown, 1-septeate, broadly fusiform ascospores with acute ends (Hyde et al. 2020). Therefore, based on significant morphology and phylogeny evidence, we introduce our collection as a new species, Paraconiothyrium zingiberacearum from dead stem of Hedychium coronarium (Zingiberaceae).

Fig. XX Paraconiothyrium zingiberacearum (MFLU 18-0091, holotype). a Appearance of ascomata on substrate. b Vertical section through ascoma. c Peridium. d Pseudoparaphyses. e –g Asci. i–m Ascospores. n A germinating ascospore. o Colonies from above (on PDA). p Colonies from below (on PDA). Scale bars: b = 50 µm, c = 10 µm, d–h = 20 µm, i–n = 6 µm.