Acarospora malouina Øvstedal & K. Knudsen, 2018

Øvstedal, Dag O., Lindblom, Louise, Knudsen, Kerry & Fryday, Alan M., 2018, A new species of Acarospora (Acarosporaceae, Acarosporales, lichenized Ascomycota) from the Falkland Islands (Islas Malvinas), Phytotaxa 340 (1), pp. 86-92 : 88-90

Acarospora malouina Øvstedal & K. Knudsen sp. nov. Mycobank no 824038

Diagnosis: Morphologically similar to Acarospora gwynnii , but differs in molecular characters, chemistry and ecology.

Type:— FALKLAND ISLANDS, Saunders Island, north shore 200 m west of rockhopper penguin rookery,–51.308309° –60.122618°, 51 m., saxicolous on boulders, 5 November 2015. A.M. Fryday 11351 (holotype MSC!). ( Figs 2 , 3 )

Thallus of contiguous squamules, 0.3–3 cm in diameter, 300–560 μm thick, indeterminate; squamules up to 2 mm wide, rugulose, fissured, continuously dividing. often forming large clusters of small squamules with 1 or 2 apothecia; upper surface glossy yellow, lower surface pale brown with a central stipe; epicortex thin, less than 10 μm thick or almost absent, of gelatinized thin hyphae, cortex red-brown throughout, 20–60 μm thick, cells usually 2–4 μm wide, angular to round; algal layer uneven, interrupted by hyphal bundles 10–60 μm wide, forming algal palisades, 150–200 μm thick, algal cells 8–12 μm wide; medulla obscure, white to brownish, 200–300 μm thick of conglutinated anticlinal hyphae mostly 1–2 μm wide, continuous with stipe; apothecia 1–10 per squamule, disc reddish-brown, epruinose, 0.1– 0.4 mm wide, with or without a distinct parathecial ring, same color as the thallus or reddish brown, darker than disc; parathecium 10–100 μm wide at surface of disc, intergrading with cortex. Layer between parathecium and hymenium I+ blue, up to two thirds of distance to disc (referred to as an abscission layer in Castello & Nimis 1994); epihymenium ca. 20–25 μm, yellowish-brown, with thin hyaline gelatinous upper layer; hymenium 200–250 μm tall, hyaline I+ blue turning red, paraphyses thin, 1–1.5(–2.0) μm wide, apices not expanded, some branching; a sci 100–150 × 15–30 μm, hundreds of ascospores, ellipsoid, 2.5–3.0 × 1.5–2.0 μm; subhymenium 20–30 μm tall, I+ blue; hypothecium 20–30 μm tall, I–; pycnidia not observed, but apothecial initials abundant.

Chemistry: rhizocarpic acid by tlc.

Distribution and Habitat: The new species is known only from the upper surface of low siliceous rocks (quartz sandstone), close to penguin rookeries on the north shore of Saunders Island, north of West Falkland. Etymology: The species is named after the brave fishermen of St. Malo, who were the first to inhabit the Falkland Islands.

Additional specimens of A. malouina studied . FALKLAND ISLANDS: Saunders Island, north shore between Rookery Cottage and rockhopper penguin rookery, –51.305938°, –60.112033°, 64 m, saxicolous on boulders, 5 November 2015, A. M. Fryday 11338 ( MSC) ; ibid. –51.307733°, –60.118877°, 64 m, saxicolous on boulders, 5 November 2015, A. M. Fryday 11346 ( MSC) ; ibid, east of The Neck , –51.30, –60.22, 50 m, rocks and stones on hillside above rockhopper penguin and black-browed albatross colony, 23 January 2000, R. I. Lewis Smith 11058 ( AAS) .

Additional selected specimens of A.gwynnii studied (apart from those used in DNA studies–see Table 1): ANTARCTICA, Dronning Maud Land, Vestfjella, Fossilryggen , 1979, Haugerud & Winsnes (BG) ; ibid., Vestfjella , 1985, K. M. Bratlien (BG) ; Ellsworth Land, Scotia Sector, Novocin Peak N, Hauberg Mountains , 1109 m, January 2000, P. Wickens 155 ( AAS) ; MacRobinson Coast, Mawson , Feb. 1954, A. M. Gwynn s.n. (Holotype, FH) . Victoria Land, Ross Sector, North end of Kay Island, Wood Bay , 130 m, dry sandy terraces, R. I. Lewis Smith 10235 ( AAS) ; Ross Dependency, Darwin Glacier, Diamond Hill , surroundings of the field camp, site 57, 495 m, on sandy soil over granite, 26.1.2009, R. Türk 4463 (Herb. Türk) .

Figures

FIGURE 2: Habitat of Acarospora malouina:A: penguin rookery on north shore of Saunders Island.The rocks are dominated by crustose Teloschistaceae (e.g., Austroplaca hookeri (C.W. Dodge) Søchting, Frödén & Arup) but Acarospora malouina also occurs on the low rocks and boulders. B: rock with A. malouina (arrow). C: A. malouina (scale bar = 1 cm).

FIGURE 3: Acarospora malouina (Fryday 11352—holotype); the surrounding black apothecia belong to Lecanora capistrata (Darb.) Zahlbr. (scale bar = 1.5 cm).