Pseudopyrenidium epipertusariae Etayo & Pino-Bodas, 2021

Etayo, J. & Pino-Bodas, R., 2021, Notes on lichenicolous Pleosporales, with two new species, Didymocyrtis azorica and Pseudopyrenidium epipertusariae (Phaeosphaeriaceae), Phytotaxa 494 (1), pp. 75-88 : 80-84

Pseudopyrenidium epipertusariae Etayo & Pino-Bodas , sp. nov. ( Fig 3 )

Mycobank MB 838955

Diagnosis: It differs from Pseudopyrenidium tartaricola by its larger perithecia, 250–300(–400) µm diam. thicker perithecial wall, (30–)40–50 µm, larger spores, (14–)18–26(–27) × 9–11 µm with 1–2 septa, then with 3–5 trasverse septa and anamorph Phoma -like. Additionally, both have different host genera, Pertusaria vs. Ochrolechia .

Type:— SPAIN. Navarre, Quinto Real, near of Fábrica de Armas and parking with a wood bridge, on Pertusaria pertusa on Fagus sylvatica , 775 m, 43º00’56’’N, 1º28’55’’W, 12 June 2018, J. Etayo 31748 (MAF-Lich.- holotype, hb. Etayo-isotype) (RP529).

Ascomata perithecia, solitary or aggregated in small groups, black, at first completely immersed finally erumpent, 150–200 µm diam., with central ostiole. Mycelium well visible around perithecia with brown hyphae, 4–5 µm thick. Ascomatal wall thin, composed of several rows of cells, brown to olive brown, with extracellular pigment, K-, 12–20 µm thick, slightly darker and thicker around ostiole to 30 µm thick, outer row with polygonal cells of thin wall, 5–10 µm diam. In upper part some external, brown periphyses are visible, 12–20 ×2–3 µm. Hymenium I-, K/I-with many paraphysoids. Paraphysoids of variable width, 1–2.5 µm, when wider clearly septate, branched with some anastomoses, abundant. Asci bitunicate, subcylindrical, only epiplasm KI+ orange, 95–115 × 10–12 µm, firstly with 8 juvenile spores, then with four mature ones. Ascospores ellipsoidal, soon golden brown, verruculose, (1–)3(–4) septate, rarely submuriform with one longitudinal septum, constricted at the septum, with one oil guttule per cell, obtuse ends, (15–)16–18(–19) × (6–)6.5–8(–10) µm. Conidiomata subspherical, solitary or aggregated in small groups, black, first immersed, finally sessile, 100–170 µm dbh, each with a single ostiole. Conidiomatal wall thin, composed of two rows of cells, dark brown, 5–7 µm thick, outer row with polygonal, thin-walled cells, 5–10 × 3–6 µm, with some small oil guttules inside. Ostiole central, surrounded by elongate cells with cylindrical to pyriform apices, brown, 7–10 × 3–5 µm. Conidiogenous cells lining the inner wall of the pycnidium, phialidic, hyaline, ampulliform to cylindrical, producing abundant conidia, 6–10 × 4.5–7 µm. Conidia hyaline to pale brown, unicellular, subspherical to ellipsoidal or pyriform with truncate base, with one large oil guttule, rarely several small ones, 5–8 × 3.5–5 µm.

Hosts and distribution: The species grows on blackened thalli of Pertusaria hymenea (Ach.) Schaerer (1836: 353) and dark violaceous thalli of P. pertusa , both in old, well-preserved Fagus forests in northern Spain (Guipúzcoa & Navarre). Species of Pertusaria in these woods are colonized by many species of lichenicolous fungi.

Discussion: So far only one species was known in the genus, P. tartaricola growing only on Ochrolechia . It has many features in common with P. epipertusariae but differs by its larger perithecia 250–300(–400) µm, a thicker perithecial wall (30–)40–50 µm and very variable but larger ellipsoidal ascospores, (14–)18–26(–27) × (7–)9–11(–13) µm, first with 1–2 septa, later with 3–5 transversal septa. No spores with 5 septa have been found in P. epipertusariae . Conidiomata have never been found in P. tartaricola ( Navarro-Rosinés et al. 2010, Navarro-Rosinés & Etayo 2018). Microscopical features of the anamorph remind Phoma s.lat. or Microsphaeropsis Sydow & P. Sydow (1916: 369) , genera including several lichenicolous species. So far, no lichenicolous species of those genera have been collected on Pertusaria . Phylogenetically this species is not related to Didymocyrtis ( Fig.1 ).

Specimens examined. SPAIN. Navarre, Urbasa mountains, way to Otxaportillo from the road, way to balsa de Mármol, Fagus wood, on Pertusaria hymenea on Fagus sylvatica , 950 m, 42º51’27’’N, 2º07’57’’W, 19 August 2017, J. Etayo 30789 (hb. Etayo), RP462. Navarre: Quinto Real, way to France just after the old fish hatchery, on Pertusaria pertusa on F. sylvatica , 940 m, 43º00’42’’N, 1º28’01’’W, 4 June 2017, J. Etayo 31750 (hb. Etayo). Guipúzcoa: Sª Aralar, way from Lizarrusti to Lareo reservoir, on P. pertusa on F. sylvatica , 760 m, 42º58’46’’N, 2º06’55’’W, 5 January 2017, J. Etayo & E. Ros 31122 (hb. Etayo), RP496.

Figures

FIGURE 1. Phylogeny of Pleosporales based on ITS rDNA and LSU rDNA. This is a 50% consensus majority tree from the Bayesian analyses. Branches supported with posterior probability ≥ 0.95 and bootstrap ≥ 70% are indicated in bold. Bootstrap and posterior probabilities values indicated at branches supported only in one analysis (ML or Bayesian analysis).

FIGURE 3. Pseudopyrenidium epipertusariae sp. nov. (holotypus teleomorph, hb. Etayo 31122 anamorph). A, B, habitus of perithecia immersed in thallus and apothecia of Pertusaria pertusa that turns violet with the parasite. C, longitudinal section of ascomatal wall (in KOH). D, section of hymenium with mature spores in an ascus. E, ascospores with 2–4 septa to submurales. F, habitus with immersed subspherical conidiomata on Pertusaria pertusa. G, conidiomatal wall in section and conidiogenous cells. H, I, conidia first hyaline, finally brownish. Scales A, B, G = 100 um; C, D, E, F, G, H & I = 10 µm.