Pseudophialocephala cuneata N.G. Liu, M.S. Calabon, E.B.G. Jones, K.D. Hyde, sp. nov.      Fig. 35

MycoBank number: MB 559313; Index Fungorum number: IF 559313; Facesoffungi number: FoF 10603;

Etymology – wedge-shaped, referring to the shape of the conidia

Holotype – MFLU 19–2852

Saprobic on decaying wood. Sexual morph: Undetermined. Asexual morph: Colonies on natural substate effuse, white, velvety. Mycelium mostly immersed, composed of hyaline, branched, septate and constricted at the septa, guttulate hyphae, 1.5–3 μm wide. Conidiophore determinate, macronematous, composed of stipe and penicillate heads. Stipe up to 300 μm long, 5–7 μm wide at base, 3.5–4.5 μm wide at tip, macronematous, mononematous, erect, straight, or broadly curved, subcylindrical, wider at base, septate, median brown, thick-walled, branched at the apex, terminated by a penicillate head. Penicillate heads composed of 1–2 series of metulae terminating in groups of conidiogenous cells. Conidiogenous cells monophialidic, discrete, determinate, terminal, clustered at the apex of secondary metulae, hyaline, thin-walled, cylindrical, with inconspicuous openings, with minute collarettes. Conidia 2.5–4 μm long, 2–3.5 μm at widest (x̄ = 3.5 × 2.5 μm, n = 30), acrogenous, aggregated in slimy and white masses, acrogenous, solitary to catenate, hyaline, cuneate, rhomboid or shield-shaped, asepate, smooth.

Culture characteristics – Conidia germinated within 48h. Germ tubes produced from one angle. Mycelia superficial, decumbent, irregular, with entire edge, yellowish brown at center, pale brown at circumference from above.

Material examined – THAILAND, Phrae Province, Rong Kwang, on decaying wood, 10 January 2018, N.G. Liu, N016 (MFLU 19–2852, holotype); ex-type living culture, GZCC 20−0005.

GenBank numbers – ITS: MN999924, LSU: MN901120, SSU: MN901150.

Notes – Pseudophialocephala cuneata was previously placed in Vibrisseaceae as Phialocephala humicola GZCC 20-0005 as it clustered with Ph. humicola CBS 601.66 on the phylogenetic analysis of Hyde et al. (2020). With the inclusion of other taxa from different classes of Ascomycota, phylogenetic analysis of combined LSU and ITS placed the novel species basal to other Pseudophialocephala taxa with low bootstrap support (Fig 33, 34). In addition, the morphology of the isolate supports the inclusion in Pseudophialocephala as it resembles the generic description in having a conidiophore composed of stipe and penicillate heads (Fig. **). The conidial shape of P. cuneata are cuneate, rhomboid, or shield-shaped and it is totally different from other Pseudophialocephala species wherein conidia are cylindrical, ellipsoidal, and oblong. Therefore, based on morphology and two-locus phylogenetic analysis, the strain GZCC 20-0005 is introduced as a novel taxon from Pseudophialocephala, P. cuneata.  Pseudophialocephala cuneata is the second species of Pseudophialocephala reported from Thailand, P. humicola as the other species observed from decaying Pinus kesiya needles (Tokumasu et al. 1990).

Figure 35 – Pseudophialocephala cuneata (MFLU 19–2852: Holotype) a–c Conidiophores and conidia. d Conidiogenous cells and conidia. e–j Condia. Scale bars: a–c = 50 µm, d = 10 µm, e–j = 3 µm.