Abrothallus canariensis Pérez-Ortega, van den Boom & 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 : 208-209

Abrothallus canariensis Pérez-Ortega, van den Boom & Suija , sp. nov.

Mycobank MB#809366; Fig. 3

Diagnosis:—Lichenicolous fungus on Pseudocyphellaria aurata similar to Abrothallus secedens but differs by having bigger ascospores, 16–(17.8)–25 × 6–(7)–9.5 μm, and 4-spored asci.

Type:— SPAIN. Canary Islands: Tenerife, Península de Anaga, Chinobre, on Erica sp. , on Pseudocyphellaria aurata , 12 May 2007, B. & P. van den Boom 37849 (holotype MA, isotype hb. v. d. Boom).

Mycelium immersed, K/I–. Ascomata superficial on thallus of Pseudocyphellaria aurata , black, ascomata covered with greenish-bluish pruina especially when young, flat; 270–(330)–520 μm wide, up to 190 μm high; ascomata are usually surrounded by a black rim. Epihymenial layer of dark yellowish brown granules, K+ emerald greenish, N+ violet; hymenium hyaline or yellowish, 55–75 μm high, K+ emerald green in the upper part; exciple ca. 15–45 μm wide in vertical section; hypothecium light to dark brown, especially in the upper part, hypothecial cells irregularly rectangular to sinuose, covered with brown pigment, 4.5–8 × 3–7 μm. Asci bitunicate, clavate, 36.5–55 × 9–12.5 μm, with 4(–6) ascospores. Ascospores 2-celled, light brown (young) to dark brown (overmature), verruculose, 16–(17.8 ±1.99)–25 × 6–(7 ±0.79)–9.5 (upper cell)/5–(6.3 ±0.94)–8.5 (lower cell) μm (n=30), l/w (upper cell) ratio = 2.34–2.65; split in two asymmetric part-spores. Interascal filaments unequally dichotomosly branched, ca. 2–3 μm wide, the tip not or only slightly widened. Anamorph not observed.

Etymology:—The epithet canariensis refers to the the area (Canary Islands) where the species is known so far.

Notes:—In our phylogenetic analysis, the newly described species turned to be sister to Abrothallus secedens , from which it differs in a high number of positions in its DNA sequences (26 in ITS, 27 in TEF-α). Both species show high morphological and anatomical similarities and share the same host genus ( Pseudocyphellaria ). The most important distinguishing character is the size of ascospores, 16–(17.8)–25 × 6–(7)–9.5 μm in A. canariensis and 12.8– (15.6)–9.6 × 4.8–(6.2)–9.6 μm in A. secedens . In addition, the number of ascospores within the ascus is a disdinctive character although due to their tendency to split in part-spores, counting can sometimes be problematic.

Figures

FIGURE 3. Abrothallus canariensis (holotype). a: green pruinose ascomata; b: cross-section of the ascoma; c: detail of the exciple (DIC); d: young ascus (DIC); e: mature ascus with ascospores (DIC); f: young ascospore (DIC); g: part-spores (DIC). Scale bars: a: 250 μm; b: 100 μm; c–g: 10 μm