Clypeococcum lichenostigmoides Flakus, Etayo & Rodr. Flakus, sp. nov.

Index Fungorum number: IF 900422; MycoBank number: MB 900422; Facesoffungi number: FoF 14177; Fig. 1

Etymology – The epithet refers to the strongly developed vegetative hyphae of the species, radially spreading over the host thallus, giving the appearance of a member of the genus Lichenostigma.

Diagnosis – The new species differs from other species of Clypeococcum by having strongly developed vegetative hyphae radially spreading over the host thallus, 4–8-spored asci, dark greenish-grey to brown, 1-septate, strongly verrucose ascospores of size 10–(x=18.6±2.1)–24 × 8–(x=9.8±0.6)–11 μm, and its host selection (Lecanora rupicola group).

Lichenicolous. Growing on saxicolous lichen of Lecanora rupicola species complex (thallus C+yellow) in humidity high, Andean vegetation and break the host thallus detaching from the substrate. Sexual morph: Mycelium well developed, composed of pale to dark brown, usually verrucose, vegetative hyphae, immersed and radially spreading over the host thallus, (1.5–)3–4 µm wide, often developing 1–5×0–2 septate, dark brown conidia (7–35×4–10 μm). Pseudothecia globose to subglobose, black, matt, ostiolate, 150–250 µm diam., 150–200 µm high, immersed, arising singly or aggregated in groups, covered by black, common clypeus. Clypeus forming a rounded, convex, black patch, in section dark brown, 40–50 µm high. Pseudothecial wall proso- to paraplectenchymatous in transversal section, 15–30 µm wide, composed of several layers of narrowly elongated to almost isodiametric, dark-brown, pigmented cells, K + greyish brown, N + slightly reddish-brown. Hymenium hyaline, I–, K/I–. Pseudoparaphyses persistent, hyaline, filiform, scarcely branched and anastomosing, 1.5–2.5 µm thick, slightly constricted at the septum. Asci bitunicate, subcylindrical, short-stalked, with evident tholus, I–, K/I– (endoascus K/I+orange), 60–110×15–23 µm, 4–8-spored. Ascospores broadly ellipsoid, 1–septate, with almost equal cells or with larger upper cell, constricted at the septum, with torus-like structure (stronger pigmented at the septum), walls 0.5–2.0 µm wide, dark greenish grey to brown, guttulate, strongly verrucose, with thin gelatinous coat, 10–(x = 18.6 ± 2.1)–24 × 8–(x = 9.8 ± 0.6)–11 μm, l/b ratio 1–(x = 1.9 ± 0.3)–3 (n = 54). Asexual morph: Undetermined.

Material examined – Bolivia, Cochabamba Department, Tiraque Province, Parque Nacional Carrasco, Camino de los Nubes-Cotany Alto road, 17° 17′ 28″ S, 65° 44′ 05″ W, 4146 m, open high Andean vegetation, on saxicolous Lecanora rupicola species complex, 2 December 2014, A. Flakus 26078 (KRAM-L 73247 holotype, LPB isotype); Department La Paz, Nor Yungas Province, Pongo, S slope, rocky stream with grasslands and Polylepis sp., 16° 19′ 26″,67° 57′ 18″, 3700 m, on grey Lecanora rupicola on rocks, 25 May 2011, J. Etayo 26875, 26876 (LPB, herb. Etayo).

GenBank number – LSU: OR133231

Notes – Our phylogenetic analyses (Fig. 2) based on LSU dataset confirmed the phylogenetic placement of our collection (KRAM-L 73247) in Polycoccum (Polycoccaceae) grouped with P. clauzadei and several species of Clypeococcum. Ertz et al. (2015) mentioned the phylogenetic placement of P. clauzadei within Clypeococcum and consider as a wrong identification. Further phylogenetic analyses are required to clarify the phylogeny of P. clauzadei.

Figure 1 – Clypeococcum lichenostigmoides (KRAM-L 73247; holotype). a–b Habit of ascomata and vegetative hyphae radially spreading over the thallus of Lecanora rupicola. c section of two aggregated pseudothecia covered by thick common clypeus (mounted in distilled water). d Section of single pseudothecium showing prosoplectenchymatous wall (mounted in LPCB). e Pseudothecial wall with dark brown vegetative hyphae proliferating from its basal part (mounted in LPCB). f Pseudothecial wall with dark brown vegetative hyphae proliferating from its apical part (mounted in LPCB). g 4–8-spored asci mounted in Lugol’s solution pretreated by 10% KOH. h Branched and anastomosing pseudoparaphyses (mounted in LPCB). i Vegetative hyphae (mycelium) immersed in the host thallus (mounted in LPCB). j–k Vegetative hyphae mounted in LPCB. (j With visible septation, k Showing verrucose walls). l–m Conidia produced by vegetative hyphae (l mounted in 10% KOH m mounted in LPCB). n Ascospores mounted in distilled water (upper row) and LPCB (lower row). Scale bars: a=500 µm, b=250 µm, c–d=50 µm, e, f, i=25 µm, g, h, j–n=10 µm

Figure 2 – Phylogenetic reconstruction of the systematic position of Clypeococcum lichenostigmoides within Polycoccaceae inferred from ML analyses of nuLSU rDNA dataset. Laurera megasperma (Trypetheliaceae) was used as outgroup. Bold branches represent either bootstrap values≥than 70 and/or Bayesian posterior probabilities≥than 0.95