Neocucurbitaria acerina Wanas., Camporesi, E.B.G. Jones & K.D. Hyde, in Wanasinghe, Phookamsak, Jeewon, Li, Hyde, Jones, Camporesi & Promputtha, Mycosphere 8(3): 410 (2017)
Index Fungorum number: IF552833; Facesofungi number: FoF 02903
Etymology: Name reflects the host genus Acer.
Holotype: MFLU 16–2710
Endophytic or saprobic on Acer campestre, trees and shrubs in terrestrial habitat. Sexual morph: Ascomata 250–350 µm high 300–450 µm diam. (x̄ = 329.6 × 399.7 µm, n = 10), black, superficial to semi-immersed, confluent, gregarious, sometimes scattered beneath the host periderm or on decorticated wood, fully or partly erumpent, globose, uniloculate, with an ostiole. Ostiole 50–70 µm long 70–100 µm diam., centrally located, slightly sunken, short and broad papillate, inconspicuous at the surface, black, smooth, filled with hyaline periphyses. Peridium 25–30 µm wide at the base, 50–70 µm wide in sides, thick, comprising 6–10 layers, outermost layer heavily pigmented, thin-walled, comprising blackish to dark brown amorphous layer, middle layer heavily pigmented, thick-walled, comprising blackish to dark brown loosely packed cells of textura angularis, inner layer composed 3–4 layers, reddish-brown to hyaline, cells towards the inside lighter, flattened, thick-walled cells of textura angularis. Hamathecium comprising numerous, 2–2.5 µm (n = 40) wide, filamentous, branched septate, pseudoparaphyses. Asci 100–110 × 10–12 µm x (x̄ = 105.8 × 10.6 µm, n = 40), 8-spored, bitunicate, fissitunicate, cylindrical, short-pedicellate, apex rounded with a minute ocular chamber. Ascospores 15–20 × 6–9 µm (x̄ = 19.4 × 7.1 µm, n = 50), overlapping uniseriate, muriform, mostly ellipsoidal, 6−8 transverse septa, with a longitudinal septum, deeply constricted at the middle septum, slightly constricted at remaining septa, initially hyaline, becoming pale brown at maturity, symmetrical, slightly paler ends, conical and narrowly rounded at the ends. Asexual morph: Undetermined.
Material examined: ITALY, Forlì-Cesena, Fiumicello di Premilcuore, on dead aerial twigs of Acer campestre, 20 November 2013, Erio Camporesi, IT1527 (MFLU 16–2710, holotype), isotype in BBH, living culture, MFLUCC 16–1450.
GenBank Numbers: ITS: KY563073; LSU: KY563076; SSU: KY563079
Note: In this study, we introduce a novel taxon as a possible sexual morph of Pyrenochaeta quercina from Italy on Acer campestre based on a combined gene analysis of ITS, LSU, and SSU sequence data. The novel species resembles Cucurbitaria in having semi-immersed, globose ascomata with a central ostiole, short-pedicellate asci with a minute ocular chamber, and overlapping uniseriate, pale brown, muriform ascospores. However, there are differences as Neocucurbitaria acerina has mostly solitary ascomata, ostiole with hyaline periphyses, smaller asci (<110 × 12 μm) and smaller ascospores (<20 × 9 μm) with 1-longitudinal septum, while Cucurbitaria species have gregarious ascomata, ostiole without periphyses, larger asci (>150 × 12 μm) and larger ascospores (>20 × 9 μm) with more than a 1-longitudinal septum (Wanasinghe et al. 2017).