Opuscula Philolichenum, 11: 120-XXXX
Total Page：16
File Type：pdf, Size：1020Kb
Opuscula Philolichenum, 13: 177–183. 2014. *pdf effectively published online 12December2014 via (http://sweetgum.nybg.org/philolichenum/) Myriospora westbergii (Acarosporaceae), a new discovery from the Galapagos Islands, Ecuador 1 2 KERRY KNUDSEN AND FRANK BUNGARTZ ABSTRACT. – Myriospora westbergii is described from the Galapagos Islands where it is considered to be endemic. It differs from other species of Myriospora by its emergent apothecia with a distinctly elevated thalline margin that increasingly blackens from the inside. The species is most similar in general appearance to M. hassei, a lichenicolous lichen parasitic on Acarospora socialis which occurs along the coast of California. The new species is clearly distinguished from M. hassei by its unusual apothecial anatomy and ontogeny and in having orange pruina occasionally covering the apothecial disc and margin. The epicortex in Acarosporaceae is discussed. Myriospora westbergii is the 28th species of Acarosporaceae we have reported from South America. KEYWORDS. – Acarosporales, epinecral layer, lichenicolous lichens, parasites. INTRODUCTION The genus Myriospora Nägeli ex Uloth represents the former Acarospora smaragdula group and is characterized by usually brown or gray areoles or squamules with slender paraphyses (usually 1–2 µm), a tall hymenium (100–200 µm), and a photobiont layer interrupted by hyphal bundles (Arcadia & Knudsen 2012; Knudsen 2005, 2007b; Roux & Navarro-Rosinés 2011; Westberg et al. 2011). The type of the genus is M. smaragdula (Wahlenb. ex Ach.) Nägeli ex Uloth. The genus is distributed throughout the northern hemisphere (Knudsen 2007b, 2011; Magnusson 1929; Schiefelbeinet al. in press; Westberg et al. 2011). Myriospora smaragdula was recently reported from South America (Knudsen et al. 2012). The genus currently contains nine species, with only M. smaragdula being relatively common throughout the range of the genus (Arcadia & Knudsen 2011; Knudsen 2007a; Magnusson 1929; Westberg et al. 2011). The genera Silobia M. Westb. & Wedin and Trimmatothelopsis Zschacke are considered synonyms of Myriospora (Arcadia & Knudsen 2012; Roux & Navarro-Rosinés 2011; Westberg et al. 2011). This study is part of the lichen inventory of the Galapagos Islands by the Charles Darwin Foundation (Bungartz et al. 2013). Here we describe the new species Myriospora westbergii from the Galapagos Islands. It is currently known only from the steep basalt cliffs of Cerro Gavilan, a volcanic crater in the highland of Santiago Island. MATERIAL AND METHODS Herbarium collections of the Galapagos Lichen Inventory are deposited at CDS; other Galapagos specimens from historical collections were also reviewed at several herbaria (B, CAS, COLO FH, H, S), but no material of the new species was found among these collections. For comparison, non-Galapagos material of Myriospora from FH, UCR, and hb. Knudsen & Kocourková was studied. 1 KERRY KNUDSEN – Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences, Prague, Kamýcká 129, Praha 6 – Suchdol, CZ–165 21,Czech Republic – e-mail: [email protected] 2 FRANK BUNGARTZ – Biodiversity Assessment, Charles Darwin Foundation (AISBL), Puerto Ayora, Santa Cruz, Galapagos, Ecuador; postal address: Avenida Juan Gonzales N35-26 y Juan Pablo Sanz, Quito, Ecuador. – e-mail: [email protected] or [email protected] 177 All specimens were examined with a Zeiss Stemi DV4 dissecting microscope and a Zeiss Imager A1 compound microscope equipped with differential interference contrast. Macro-photographs were taken with a Nikon D800 and/or D300, 62 mm Nikkor Micro Lens and R1C1 macro flash directly in the field, or using a Novoflex macro-table to take images of herbarium specimens; for photographic magnifications higher than 1:1 an extension tube was used. For micro-photographs the compound microscope was equipped with a phototube for the Nikon D300. Photos in the laboratory were taken with ControlMyNikon v5.0Pro. All photographs were databased with the program IDimager 5 using the Darwin Core XML schema to embed collection and identification information as XMP metadata (http://owl.phy.queensu.ca/~phil/exiftool/TagNames/DarwinCore.html). Photos were processed with Photoshop CS6. TAXONOMIC SECTION Myriospora westbergii K. Knudsen & Bungartz, sp. nov. Mycobank #811043. FIGURES 1A-C, 2A-E. TYPE: ECUADOR. GALAPAGOS ISLANDS: ISLA SANTIAGO: summit of Cerro Gavilan, inner N- and NE-exposed crater rim, 12º20′0″S, 90º47′3″W, 840 m, humid zone N- and NE-exposed, steep basalt cliffs of crater rim with ferns (Pityrogramma calomelanos var. calomelanos, Polypodium tridens, Dryopteris palmata, Adianthum concinnum, Blechnum polypodioides), 23.iii.2006, growing on lava rock in crevices, A. Aptroot 65667 (CDS 32258!, holotype). DIAGNOSIS. – Similar to Myriospora hassei, but distinguished by emergent apothecia that are occasionally covered with coarse orange pruina and, when mature, develop a distinctly elevated thalline margin, which increasingly blackens from the inside. ETYMOLOGY. – The species is named in honor of lichenologist and taxonomist Martin Westberg (b. 1969) of Sweden for his excellent revision of the genus Myriospora and continuing work on the Acarosporaceae of Fennoscandia. DESCRIPTION. – Thallus of dispersed to closely adjoining, circular to irregular areoles, individual areoles broadly attached, ca. (0.3–)0.7–1.0(–2) mm in diameter, subsquamulose, indistinctly lobate along the margin; surface whitish to pale brown, dull, even to irregular, but not conspicuously verrucose, epruinose. Cortex differentiated into a ca. 25 µm thick epicortex of prosoplectenchymatous conglutinated cells, hyphae irregularly interwoven, not distinctly orientated, not becoming necrotic, subtended by a eucortex, divided into an outer, ca. 5–15 µm thick, prosoplectenchymatous, deep brown-pigmented part, and an inner, ca. 30–45 µm thick, prosoplectenchymatous, hyaline part (all layers devoid of crystals), the outer pigmented part often fading or indistinct in the thallus areoles, but strongly pronounced and best developed in the thalline margin of the apothecia; photobiont layer discontinuous, especially towards the center of the areoles interrupted by bundles of hyaline hyphae (ca. 10–20 µm wide), which conspicuously divide this layer into ‘islands’ or ‘packets’ of photobiont cells (ca. 20–60 µm wide); photobiont cells trebouxioid, ca. 8–12 µm in diameter; medulla of loosely interwoven hyphae, continuous with attachment hyphae below. Apothecia one (or rarely two) per areole, at first immersed, but soon emergent and pseudolecanorine, with a distinctly elevated thalline margin, though not becoming sessile; disc at first punctiform to urceolate, soon dilating, expanding and becoming concave to barely convex, deep reddish brown, epruinose or rarely covered by a coarse, orange, crystalline pruina (K–, crystals dissolving); margin at first inconspicuous, barely elevated, concolorous with the thallus surface, pigmentation pale due to the thick hyaline epicortex, at maturity the epicortex of the prominent margin increasingly abraded, the margin thus darkened to almost blackened. Thalline exciple well developed, conical, at the base ca. 250–350 µm wide and filled with clusters of photobiont cells surrounded by densely interwoven hyphae, towards the apex tapering, ca. 50 μm wide, photobiont cells and medullary hyphae disappearing, apical part distinctly stratified into an innermost hyaline part, a central, deep brown layer and the outer, hyaline epicortex; 178 Figure 1, type locality (A) and thallus morphology of Myriospora westbergii (B, C). A, summit of Cerro Gavilan, Isla Santiago, Galapagos (the photo shows the outer slope of the crater, the specimen was collected on the other side, on the steep N- to NE exposed walls of the inner crater). B, thallus of the holotype (A. Aptroot 65667, scale 15 mm). C, thallus of the paratype (Bungartz 4762, scale 15 mm). proper exciple reduced, barely differentiated from the innermost, hyaline part of the thalline exciple; epihymenium ca. 21–30 µm wide, apices of paraphyses in a diffuse pale orange brown pigment; hymenium ca. 125–150 µm high, not inspersed, paraphyses at mid-level ca. 1.5 µm wide, apically not significantly wider, not conspicuously swollen. Asci clavate, ca. 30 8 µm, polysporous (more than 100 spores per ascus); ascospores hyaline, non-septate, oblong (3.5–)4(–4.5) ca. 2 µm (n = 35); subhymenium and hypothecium not distinctly differentiated, laterally extending into the proper exciple, in the center up to 200 µm thick, sparsely inspersed with tiny oil drops (ca. 1–2 µm in diameter). Pycnidia punctiform, urceolate to flask-shaped, wall unpigmented, sometimes adjoining, ostiole colored by a diffuse, brown pigment, conidigenous cells ca. 10 1 µm, conidia subglobose, ca. 2 1.5 µm (n = 20). CHEMISTRY. – All spot tests negative, no secondary metabolites detected. 179 Figure 2, anatomy of Myriospora westbergii. A, overview of the apothecium (scale 100 µm). B, apothecial section showing the hypothecium that laterally transitions into an thin layer of hyphae forming a barely distinct proper exciple, and the well developed conical thalline exciple (th-exp) that is apically differentiated into a thick epicortex (e), pigmented outer layer (pl) and hyaline inner layer (hl) (scale 100 µm). C, thallus section close to the margin of a subsquamilose areole showing the differentiation of the hyaline epicortex (e) from the eucortex with an outer, ±discontinous pigmented leayer (pl) and an inner