Abrothallus boomii Pérez-Ortega & Suija, 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 : 206-208

publication ID

https://doi.org/ 10.11646/phytotaxa.195.3.1

persistent identifier

https://treatment.plazi.org/id/9B012A03-6A69-904B-0BD8-F97012D0FDA3

treatment provided by

Felipe

scientific name

Abrothallus boomii Pérez-Ortega & Suija
status

sp. nov.

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

Mycobank MB#809372; Fig. 2 View FIGURE 2

Diagnosis:—The new species differs from all the rest of Abrothallus species by the host selection ( Nephroma ), and from the rest of Abrothallus species on Nephroma by having 6-spored asci and semi-immersed pycnidia with hyaline conidia in dimensions of 7–(9.2)–10.5 × 5.5–(6.54)–8 μm.

Type:— PORTUGAL. Beira Alta: N of Guarda, W of Pinhel, between Malta and Vila Franca das Naves along byway of N226 road, N of Ervas Tenras, Pinus - Quercus forest along vineyand on S slope with acidic outcrops and roadside Fraxinus trees, on vertical rocks, 18 June 2009, B. & P. v. d. Boom 43228 (holotype MA).

Mycelium immersed, K/I–. Ascomata superficial on thallus of Nephroma tangeriense , black, especially young ascomata covered with greenish pruina, convex, more rarely flat, mature apothecia often tuberculate; 285–(360)–520 μm wide, up to 250 μm high; host thallus around ascomata black. Epihymenial layer with dark greenish granules, K+ emerald greenish, N ± pink violet; hymenium hyaline to greenish, K+ emerald green, 55–75 μm high, basal part of interascal tissue is composed of prismatic cells forming a paraplectenchymatic tissue similar to the hypothecium; interascal filaments appear only in the upper part of the interascal tissue, unequally dichotomosly branched, ca. 2–2.5 μm wide, the tip not or only slightly widened. Exciple only present in young ascomata, 35–55 μm wide; hypothecium light brown to greenish, hypothecial cells irregularly prismatic, with a greenish pigment K+ emerald green, 5.5–11 × 4–7 μm. Asci bitunicate, clavate, 42–55 × 9–14 μm, (4–)6(–8) spored. Ascospores usually 2-celled, but mature ascospores sometimes with 2–3 septa, light to dark brown, verruculose, asymmetric with a larger upper cell, usually soleiform in shape, slightly to heavily constricted at septum, 11.5–(14.8 ±1.83)–20.5 × 5.5–(6.1 ±0.4)–7 (upper cell)/4– (4.7 ±0.43)–6 (lower cell) μm (n=30), l/w (upper cell) ratio = 2.04–3.05. Anamorph present, pycnidial. Pycnidia immersed, later slightly erumpent, ca. 200 μm wide; pycnidial wall K+ green, N ± violet, especially around the ostiole. Conidiogenous cells holoblastic, lining the cavity of pycnidia, 7–(11.3 ±0.82)–13.1 × 3.5–(4.3 ±0.72)–5.8 μm. Conidia simple, hyaline, obpyriform with truncated end, 7–(9.2 ±0.82)–10.5 × 5.5–(6.54 ±0.75)–8 μm (n=30).

Etymology:—The new species is named after Pieter van den Boom, renowed lichenologist, author of a long list of research articles and indefatigable collector of lichens and lichenicolous fungi. We thank him for his unvaluable help in sending us his collections of Abrothallus .

Notes:— Abrothallus boomii is known only from type locality in Portugal. The host of the species likely corresponds to Nephroma tangeriense , a frequent species in the west of the Iberian Peninsula.

The new species is closely related and anatomically similar to A. nephromatis , also described in this study. The ascospores are roughly the same size in both species, although slightly larger in A. boomii . The most notable differences between both species are the size of conidia, as A. boomii has much wider conidia (5.5–(6.54)–8 μm) than A. nephromatis (2.9–(3.8)–5.6 μm). However, asexual morph was not found in many of examined specimens on Nephroma spp. , and therefore the common presence of 6- or even 4-spored asci is another diagnostic character of A. boomii .

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