Lecanora subaureoides Aptroot & Bungartz, 2020

Bungartz, Frank, Elix, John A. & Printzen, Christian, 2020, Lecanoroid lichens in the Galapagos Islands: the genera Lecanora, Protoparmeliopsis, and Vainionora (Lecanoraceae, Lecanoromycetes), Phytotaxa 431 (1), pp. 1-85 : 69-71

Lecanora subaureoides Aptroot & Bungartz sp. nov. MycoBank no. 833378

Diagnosis. Similar to Lecanora subaurea with ±granular subsquamulose areoles with marginal soralia, but differs in being pale yellowish green and in containing usnic rather than rhizocarpic acid.

Type:— ECUADOR. GALÁPAGOS: Isabela, Volcán Alcedo, outer E-exposed slope just below the crater rim, 0˚25’17’’ S, 51˚5’8’’W, 1077 m alt., humid zone, basalt outcrops, SE-exposed slope with scattered shrubs of Tournefortia rufo-sericea , Opuntia insularis , Lantana peduncularis and occasional trees of Zanthoxylum fagara among basalt rubble, on lava rock, 08-Mar-2006, Aptroot, A. 65158 ( CDS 31741– holotype).

( Fig. 17F–G )

Thallus saxicolous, moderately thickened, areolate, areoles ±granular with subsquamulose margins; surface dull yellowish green, matt to ±shiny, epruinose, soralia marginal, extruding granular, almost subcoralloid, pale yellowish green soredia along the edges of individual areoles; prothallus absent or indistinct. Apothecia sparse, typically not much larger than the thalline areoles, circular to irregular, 0.1–0.7 mm in diam., adnate, barely emerging from the thallus surface and often indistinct among the subsquamulose areoles, with an indistinct lecanorine margin that becomes ±excluded with age or in part disintegrating into soredia; disc plane to ±convex, dull greenish or olivaceous, generally deeper in color than the surrounding thallus, ±shiny, epruinose; hymenium hyaline, not inspersed, but occasionally with sparse oil droplets; epihymenium with small orange brown granules, soluble in K, lacking distinct crystals, fuscous brown (elachista -brown: dissolving in K, HCl± dull greenish, N−); proper exciple thin, indistinct, with few small crystals; thalline exciple densely filled with small and medium-sized crystals that are insoluble in K; subhymenium and hypothecium hyaline; asci and ascospores not seen. Pycnidia not seen.

Chemistry: K± brownish, C−, KC± brownish, P−, UV−; only contains usnic acid [major]; [all specimens cited were analyzed with TLC].

Etymology: The epithet subaureoides refers to the superficial similarity of this new species with Lecanora subaurea .

Ecology and distribution: Known only from the Galapagos; occurs on exposed basalt lava in the humid and upper transition zone.

Notes:With its small bullate granules developing paler soredia along their margin, L.subaureoides is morphologically very similar to L. subaurea , a species with a temperate distribution. Lecanora epanora , another temperate species, is also similar but produces laminal rather than lateral soralia. Both L. subaurea and L. epanora are bright neon-yellow as they contain rhizocarpic acid and exhibit UV+ deep orange, but the thalli of L. subaureoides are much paler, yellowish green due to the usnic acid present. The thalli of L. subaureoides often lack apothecia and can then be confused with the superficially similar Bryonora granulata Fryday , a species first described from the Falkland Islands, here now also reported for the Galapagos [Volcán Cerro Azul, Spielmann, A.A. 10511 A ( CDS 51867); Bungartz, F. 10356 ( CDS 52330), 10386 ( CDS 52356)]. In addition to usnic acid, B. granulata also contains 2’- O -methylperlatolic acid (Galapagos specimens and the type material analyzed by J.A. Elix).

Additional specimens examined (paratypes). ECUADOR. GALÁPAGOS: Santiago, summit of Cerro Gavilan, inner N- and NE-exposed crater rim, 0˚12’20’’ S, 90˚47’3’’W, 840 m alt., humid zone, N- and NE-exposed, steep basalt cliffs of crater rim with ferns ( Pityrogramma calomelanos var. calomelanos , Polypodium tridens , Dryopteris palmata , Adiantum concinnum , Blechnum polypodioides ) growing in crevices, lava, on rock, 23-Mar-2006, Aptroot, A. 65751 ( CDS 32343). Isabela, Volcán Alcedo, on the crater rim near the hut, 0˚26’33’’ S, 91˚5’31’’W, 1100 m alt., humid zone, Pteridium arachnoideum and Stachytarpheta cayennensis , scattered low shrubs of Tournefortia rufo-sericea and outcrops of basalt tuff in between, lava, on rock, 07-Mar-2006, Aptroot, A. 65246 ( CDS 31832); in the crater near fumaroles, 0˚27’1’’ S, 91˚7’19’’W, 780 m alt., transition zone, mostly Bursera graveolens and dense scrub on uneven lava, lava, on rock, 07-Mar-2006, Aptroot, A. 64792 ( CDS 31367); close to Volcán Chico, along the trail, 0˚46’57.77’’ S, 91˚5’59.39’’W, 944 m alt., transition zone, dry and rocky area (young lava), with cacti and Macraea laricifolia , slope 40° NE, basalt lava, on rock, 14-Aug-2008, Herrera-Campos, M.A. GAL-408 ( CDS 43299); Truong, C. 1267 ( CDS 39578); Volcán Chico on the northern slope of Sierra Negra, 0˚46’43.27’’ S, 91˚6’0.2000’’W, 856 m alt., humid zone, bare lava flow, on somewhat weathered, slightly inclined N-exposed top of lava flow, 19-Apr-2009, Bungartz, F. 8730 ( CDS 44068).

Figures

FIGURE 17. Species in the L. varia-group. A–E. Lecanora pyrrhosporoides. A–B. Thallus variation on different substrates. A. Thick, granular leproid thallus with ±immersed to sessile apothecia, disc brown to darkened, coarsely pruinose, lecanorine margin either dissolved into blastidiate granules or excluded below; on decorticated branches of Prosopis (Aptroot, A. 64140, CDS 30703). B. Thallus of scattered clusters of coarse coralline blastidiate granules, with scarce apothecia; on smooth bark of Bursera (Bungartz, F. 5359, CDS 28443). C–D. Apothecial sections (in water, DIC). C. Exciple appearing biatorine, almost completely reduced to a layer of pale brown cells extending from the epihymenium to the outer exciple; lecanorine part not developed (Aptroot, A. 64140, CDS 30703). D. Exciple ±lecanorine, with a thin, inner, proper exciple, surrounded by a thick, disintegrating, outer, thalline part (Aptroot, A. 64140, CDS 30703). E. Filiform conidia (Aptroot, A. 64140, CDS 30703). F–G. Lecanora subaureoides (Aptroot,A. 65158, CDS 31741–holotype). F. Dispersed thallus squamules with marginal soredia extruding granular soredia, apothecia malformed, not clearly differentiated from thallus squamules. G. Section of poorly developed lecanorine apothecium lacking asci or ascospores. Scales: A, B & F = 5 mm; C, D & G = 100 µm; E = 20 µm.