Abrothallus ertzii Suija & Pérez-Ortega, 2015

Suija, Ave, Ríos, Asunción De Los & Pérez-Ortega, Sergio, 2015, A molecular reappraisal of Abrothallus species growing on lichens of the order Peltigerales, Phytotaxa 195 (3), pp. 201-226 : 211-212

Abrothallus ertzii Suija & Pérez-Ortega , sp. nov.

Mycobank MB#809369; Fig. 6

Diagnosis:—Lichenicolous fungus growing on Lobaria pulmonaria which differs from the rest of Abrothallus species by having clavate asci with eight two-celled ascospores with dimensions of 9–(10.3)–11.5 × 3–(3.6)–4.5 which easily split into part-spores.

Type:— CANADA. British Columbia: Wells Gray Provincial Park, Dawson Falls, forest, elev. 800 m, on trunk of Thuja plicata , on Lobaria pulmonaria , 22 July 2008, D. Ertz 12517 & P. Diederich (holotype BR-LICH 6512-13).

Mycelium immersed, K/I–. Ascomata superficial on the thallus of Lobaria pulmonaria , black, often covered with a greenish pruina, plane to convex, 140–(240)–360 μm wide, 85–122 μm high, w/h ratio = 1.5–2.3. Hymenium hyaline in lower part, greenish in upper part, ca. 50 μm high, covered with dark red-brown crystals, K ± greenish, N–; exciple ca. 60 μm wide in vertical section, composed of paraphysis-like hyphae; hypothecium medium brown, hypothecial cells rectangular, covered with dark brown pigment, 6.5–11.7 × 3.7–7.7 μm (n=9). Asci bitunicate in structure, clavate to broadly clavate, 27.5–36.5 × 10–12.5 μm, with eight ascopores. Ascospores 2-celled, medium brown, verruculose, asymmetric, strongly constricted at septum, separating into part-spores but mostly outside the ascus, 9–(10.3 ±0.8)– 11.5 × 3–(3.6 ±0.4)–4.5 μm (upper cell)/ 2.3–(2.9 ±0.4)–3.6 (lower cell) μm (n=20), l/w (upper cell) ratio = 2.2–3.8. Interascal filaments dichotomously branched, 1–1.5 μm wide, the tip only slightly widened, 1.5–1.8 μm. Anamorph not observed. No visible damage observed.

Etymology:—The species is dedicated to Damien Ertz ( Belgium), renowed researcher of lichen-forming and lichenicolous fungi and collector of the type specimen.

Notes:—The new species is known from two provinces in Canada, British Columbia and Quebec. Abrothallus ertzii is the third Abrothallus species known from the lichen genus Lobaria . The recently described species, A. halei and A. macrosporus , both have 4-celled ascospores with dimensions of 9–(10.7)–14 × 3–(4)–5 μm ( Suija et al. 2011) and 18.5–24 × 7–9 μm ( Etayo 2010), respectively. In our phylogenetic tree, the morpho-anatomically similar, but geographically and molecularly distinct specimen on Lobaria pulmonaria (IVL-5491), forms a separate lineage which we treat here as Abrothallus sp. 3 . Further material is needed to make conclusions about its taxonomic identity.

Zopf (1896) listed three Abrothallus species on Lobaria pulmonaria — A. parmeliarum , A. viduus Körb. and A. lobariellus (Nyl.) Zopf (both last names = Dactylospora lobariella (Nyl.) Hafellner ). Zopf’s (1896) description of A. parmeliarum on L. pulmonaria states that the species has at first sunken pruinose apothecia with 2-celled ascospores, 10–17 × 4–5 μm. However, none of the known species on Lobaria spp. adheres to this description.

Additional specimens examined: — CANADA. Quebec: Gaspesie, ca. 15 km E of Gaspe, Parc National Forillon, ca. 4 km NE of the village D’Aiguillon, “La Chute” walk, deciduous woods, beside walking trail above water fall, elev. 100 m (48º51’N 64º16’W), bark of Acer saccharum , on thallus of Lobaria pulmonaria , growing together with Dactylospora lobariella , Phoma lobariae and Plectocarpon lichenum , 18 August 1997, D. Triebel & G. Rambold 6115 (M-0044152).

Figures

FIGURE 6. Abrothallus ertzii (holotype). a: ascomata on the thallus of Lobaria pulmonaria; b: section of the hymenium; c: ascus with ascospores. Scale bars: a = 500 μm; b = 25 μm; c = 10 μm