Palicella lueckingii Rodr. Flakus, 2018

Rodriguez-Flakus, Pamela, 2018, Palicella lueckingii (Lecanorales, Ascomycota), a new lichen species inhabiting Araucaria from the extratropical South America, Phytotaxa 344 (1), pp. 24-30 : 26-27

Palicella lueckingii Rodr. Flakus , sp. nov. ( Fig. 2 )

MycoBank no. 824257

Diagnosis:—Differs from its relative P. glaucopa (Hook. f. & Taylor) Rodriguez Flakus & Printzen in having smaller ascospores, comparatively thicker thallus, epruinose apothecia, the inner part of exciple not inspersed by oil droplets, and presence of thiophanic acid as a major metabolite.

Type:— CHILE. IX Región, de la Araucanía, Malleco, Reserva Nacional Malalcahuelo, very close to Lonquimay Vulcan, 38°25′14.5′′S, 71°32′38.9′′W, 1431 m, Valdivian temperate forest, on bark of Araucaria araucana , 22 November 2011, P. Rodriguez Flakus 2124 & R. Vargas ( CONC — holotype, FR — isotype).

Etymology:—The epithet is named in honor of Dr. Robert Lücking, prominent German lichenologist, who has made an outstanding contribution to the knowledge of Neotropical lichens.

Description:— Thallus greyish to pale yellow, crustose, very thick, (0.3–) 0.6–1.3 mm high, cracked-areolate, split into elevated areoles of different size, 0.4–1.5(–3.0) mm in diam., surface smooth to rough, isidia and soredia absent. Photobiont chlorococcoid, cells 8–11 μm diam. Apothecia usually numerous, rounded to irregular in shape, sessile with constricted base, 0.2–0.6(–0.8) mm in diam., when well-developed sometimes growing in groups. Disc black, matte or shiny, epruinose, flat to moderately convex (in old apothecia), usually P+ orange. Margin concolorous with disc, persistent, shiny. Exciple laterally 15–20 μm, basally 50–60 μm wide, colourless inside, not inspersed by crystals or oil droplets, I–, outer layer dark pigmented by Cinereorufa -green ( Meyer & Printzen 2000), and additional undetermined brown pigment, K+ green, N+ purple-red, composed of highly conglutinate radiate hyphae,1–2 μm wide, in which apically widened to 5 μm. Hypothecium colourless, 45–50 μm high. Subhymenium colourless, ca. 15 μm high. Hymenium colourless, inspersed by oil droplets, 45–55 μm high, strongly agglutinated. Epihymenium greenish black, mainly because of Cinereorufa -green pigment (the same as in the exciple), 8–10 μm thick. Paraphyses colourless, branched and anastomosed, 1–2 μm wide, strongly apically thickened, pigmented caps not evident, apical cells 3–6 μm wide. Asci 8-spored, clavate, with K/I+ blue tholus resembling a transitional form between Lecanora - and Lecidella - type, usually with a small region at the top with non-amyloid reaction, 35–45 × 10–15 μm. Ascospores colourless, simple to 1-septate, broadly ellipsoid, without epispore, (8–)10.4– 12.9 –15.6(–17) × (4–)4.7– 5.3 –5.9(–6.5) μm, length-width ratio (1.8–)2.0– 2.4 –2.8(–3.0) μm (n=26). Pycnidia not seen.

Chemistry:—Atranorin (minor to trace), pannarin (minor; on disc), thiophanic acid (major). Thallus K–, P–, C+ orange, KC+ orange, UV+ pale yellowish; apothecial disc K–, P+ rust orange to yellowish, C–, KC–.

Ecology and distribution:—So far, Palicella lueckingii is known only from the type locality in Chile, where it grows exclusively on the bark of Araucaria araucana in the Malalcahuelo National Reserve in humid Valdivian temperate forest.

Remarks:—The new species is characterized by small ascospores, thick thallus, epruinose apothecia, not inspersed inner part of exciple, and production of atranorin, pannarin and thiophanic acid as secondary metabolites. Palicella lueckingii is rather similar to the epruinose forms of P. glaucopa , a common species growing on Nothofagus spp. bark in the southern part of Argentina and Chile. Both species have similar black and marginate lecideoid apothecia reacting P+ rust-orange. Palicella glaucopa , however, can be easily distinguished by its larger ascospores, (9.0–)15.9–19.5– 23.0(–32.0) × (4.8–)5.5–6.5–7.4(–9.5) μm, inner part of exciple composed of loosely arranged narrow hyphae and strongly inspersed by oil droplets, much thinner thallus (0.04–0.15 mm), larger apothecia, (0.3–)0.5–0.7–1.0(–1.4) mm, and different chemistry ( Rodriguez Flakus & Printzen 2014a). The key characters to separate Palicella lueckingii from other known species of Palicella are presented in Table 1.

Figures

FIGURE 2. Palicella lueckingii (Rodriguez Flakus 2124). A habit: A, thick thallus with black marginate apothecia, B, section through apothecium showing hyaline exciple; C, asci showing amyloid Lecanora/Lecidella-like ascus apex (mounted in K/I); D, ascospores. Scales: A = 1000 μm, B = 50 μm, C–D = 10 μm.