Muyocopron dipterocarpi Mapook, Doilom, Boonmee & K.D. Hyde, sp. nov., Index Fungorum number: IF 551617

Etymology: Named after the host genus Dipterocarpus, from which this species was collected.

Holotype: MFLU 15–1132

Saprobic on dried twigs of Dipterocarpus tuberculatus Roxb. Sexual morph: Ascomata 85–120 µm high × 225–270(–295) µm diam. (x̅ = 110 × 256.5 µm, n = 5), superficial, coriaceous, solitary or scattered, appearing as circular, scattered, flattened, brown to dark brown spots, covering the host, without a subiculum, with a poorly developed basal layer and an irregular margin. Ostiole central. Peridium (11–)15–30 µm wide, widest at the sides, outer layer comprising dark brown to black pseudoparenchymatous, occluded cells of textura angularis, inner layer comprising light brown cells of textura angularis. Hamathecium comprising 1.5–3 µm wide, cylindrical to filiform, septate, pseudoparaphyses. Asci (45–)50–70 × (15–)20–25(–30) µm (x̅ = 56.5 × 22 µm, n = 20), 8-spored, bitunicate, saccate or broadly obpyriform, pedicellate, straight or slightly curved, with small ocular chamber. Ascospores (12–)15–18 × (6–)7–9(–11) µm (x̅ = 16.5 × 9 µm, n = 30), irregularly arranged, overlapping in the ascus, hyaline, oval to obovoid with obtuse ends, aseptate, with granular appearance. Asexual morph: Undetermined.

Culture characteristics: Ascospores germinating on MEA within 24 hr. at room temperature and germ tubes produced from the ends of the ascospore. Colonies on MEA reaching 1 cm diam after 1 week, at 25 oC. Initially aerial mycelium white, slightly raised, in old cultures grayish to light brown, flattened on surface, dark to dark brown from below, light brown to white margin.

Material examined: THAILAND, Chiang Rai, Mae Lao, on dried twigs of Dipterocarpus tuberculatus (Dipterocarpaceae), 21 June 2014, M. doilom (MFLU 15–1132, holotype), ex-type culture MFLUCC 14–1103, BCC; ibid. (HKAS92523, isotype). 

Notes: Muyocopron dipterocarpi was collected from dried twigs of Dipterocarpus tuberculatus Roxb. The new species is similar to Muyocopron corrientinum (Spegazzini 1881), in having similar asci and ascospores. Our collection differs from Muyocopron corrientinum in having wider ascospores (x̅ = 9 vs 7.7 µm, Wu et al. 2011b). Furthermore, the species were associated with different host families and were collected from different continents. 

Fig. 3. Muyocopron dipterocarpi (holotype) a–c Superficial ascomata on substrate. d–e Squash mounts showing ascomata walls. f Section of ascoma. g Peridium. h Pseudoparaphyses. i–l Asci. m–q Unicellular ascospores. r Germination of ascospore. Scale bars: b = 500 µm, c = 200 µm, d, f, r = 50 µm, i–l = 20 µm, e, g, m–q = 10 µm, h = 5 µm.