Lecanora pyrrhosporoides Bungartz, Elix & Printzen, 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 : 65-66

Lecanora pyrrhosporoides Bungartz, Elix & Printzen sp. nov. MycoBank no. 833377

Diagnosis. Superficially similar to Pyrrhospora quernea (Dicks.) Körb. , but generally with broader ascospores [8.0–)10.3–11.4(–12.5) × (3.5–)4.4–7.8(–9.5) µm], the epihymenium lacking granular anthraquinones, and the thalli characterized by a different cohort of xanthones.

Type:— ECUADOR. GALÁPAGOS: Pinzón, along the trail going up from Playa Escondida, 0˚36’0’’ S, 90˚39’46’’W, 150 m alt., dry zone, open woodland with Prosopis juliflora , Alternanthera filifolia , Maytenus octogona , and Croton scouleri , on twigs, 16-Feb-2006, Aptroot, A. 64140 ( CDS 30703– holotype).

( Fig. 17A–E )

Thallus corticolous or lignicolous, leproid (see Bungartz et al. 2013), almost entirely composed of coarse, granular soredia, which develop on the surface of a thin ± contiguous, whitish to almost transparent, film-like prothallus, delimited along the margin by a conspicuous, black prothalline line; granules pseudocorticate, yellowish green to pale greenish beige, surface sometimes discolored, tinged bluish black by an aeruginose pigment, K+ blackish green (30–)44–65(–100) µm in diam., irregularly ±aggregating, individual granules either scattered, in isolated clusters (ca. 300–500 µm in diam.), or in well developed thalli packed into a thick, secondarily rimose-areolate crust. Apothecia absent or sparse, rarely numerous, if present typically ±aggregated in small groups and often, ±deformed by mutual pressure, 0.2–0.6(–0.8) µm in diam, adnate to sessile, biatorine, proper margin thin, soon excluded, but frequently surrounded by a secondary, false thalline margin formed from a few to many thalline granules, disc plane to ±convex, pale brown to beige, increasingly discolored with age, olivaceous to blackened, covered by a coarse, hyaline pruina; hymenium hyaline, not inspersed; epihymenium with small orange brown granules, soluble in K (but unlike the anthraquinone granules of P. quernea not turning purple!), lacking distinct crystals, fuscous brown (elachista -brown: dissolving in K, HCl± dull greenish, N−), occasionally in parts or entirely discolored by a diffuse aeruginose pigment (cinereorufa -green: intensifying in K, HCl+ bluish green, N+ reddish violet); proper exciple distinct, hyaline within, outer part concolorous with the epihymenium and covered with small orange brown granules soluble in K, granules at the base of the exciple often very abundant, often ±radiating from the lower inner to the lower outer part of the exciple; thalline exciple absent; subhymenium and hypothecium hyaline; asci Lecanora - type, ascospores 8/ascus, colorless, simple, broadly ellipsoid, (8.0−)10.3−11.4(−12.5) × (3.5−)4.4−7.8(−9.5) µm (n = 30). Pycnidia immersed, ostiole brown, wall hyaline; conidia filiform, 25−32 × ca. 1−1.2 µm (n = 15).

Chemistry: Thallus cortex P+ yellow, rarely P–, K+ yellow, rarely K–, KC+ orange, C+ orange, UV+ deep red; with ±atranorin [major], thiophanic acid [major], arthothelin [major], ±3- O -methylthiophanic acid [minor], ±4-chloronorlichexanthone [minor, trace or absent], ±5-chloronorlichexanthone [minor, trace or absent], ±4,5- dichloronorlichexanthone [trace], ±lichexanthone [trace]; [specimens analyzed by TLC: Aptroot, A. 63062 ( CDS 29790 ), 64117 ( CDS 30678 ), 64140 ( CDS 30703 – holotype), 65589 ( CDS 32178 ); Bungartz, F. 4359 ( CDS 28443 ), 4375 ( CDS 28459 ), 7354 ( CDS 37841 ), 8225 ( CDS 40871 )] .

Etymology: The specific epithet refers to the superficial similarity of the species to Pyrrhospora quernea .

Ecology and Distribution: Known only from the Galapagos; common on bark or wood in exposed, sunny habitats of the coastal and dry zone, rarely also in the transition zone, one specimen collected on a fence post in the humid zone .

Notes: Specimens of L. pyrrhosporoides with granular, slightly darker soredia and a distinct black hypothallus were previously identified as Pyrrhospora quernea (Dicks.) Körb. in the key to the leprose and leproid lichens of the Galapagos ( Bungartz et al. 2013). The chemistry and thalli of the two species are very similar, but several specimens have now been found fertile and reports of Pyrrhospora from the archipelago are therefore erroneous. Apothecial characters suggest that L. pyrrhosporoides belongs to the L. varia -group as it lacks the K+ violet epihymenial anthraquinone granules typical for Pyrrhospora .

Additional specimens examined (paratypes). ECUADOR. GALÁPAGOS: Española, trail from Bahía Manzanillo on the N-coast of the island to the highest point, 1˚22’18.69’’ S, 89˚42’7.40’’W, 125 m alt., dry zone, Cordia lutea shrubland with some Prosopis juliflora shrubs at bottom of basalt outcrop, on wood of Cordia lutea , 11-Nov-2010, Bungartz, F. 9124 ( CDS 45942); 1˚21’40.60’’ S, 89˚41’56.60’’W, 48 m alt., dry zone, open scrub of Cordia lutea and Prosopis juliflora with grasses and few trees of Bursera graveolens over weathered lava boulders, on wood of Cordia lutea , 11-Nov-2010, Bungartz, F. 9091 ( CDS 45909); along S-coast of the island; SE of Punta Suárez, 30 m inland from coast, 1˚22’59.77’’ S, 89˚43’17.10’’W, 109 m alt., dry zone, Cordia lutea shrubland with Prosopis juliflora and opening, twigs of shrub; sunny, on bark, 10-Nov-2010, Yánez-Ayabaca, A. 1602 ( CDS 45490). Pinzón, along the trail going up from Playa Escondida, 0˚36’10’’ S, 90˚40’1’’W, 254 m alt., dry zone, dry zone vegetation with Prosopis juliflora , Alternanthera filifolia , Maytenus octogona , and Croton scouleri , on wood, 16-Feb-2006, Aptroot, A. 64117 ( CDS 30678). Santa Cruz, Puerto Ayora, near Charles Darwin Research Station ( CDRS), 0˚44’32’’ S, 90˚18’10’’W, 5 m alt., coastal zone, shrub, on bark, 24-May-2005, Aptroot, A. 63062 ( CDS 29790); E-side of island, trail from parking lot to El Garrapatero beach, N-side of trail, 0˚41’26.69’’ S, 90˚13’19.10’’W, 6 m alt., dry zone, open deciduous forest of Bursera graveolens , Cordia lutea , Opuntia echios with Castela galapageia and Alternanthera echinocephala and others in the understory, Bursera graveolens , on bark, 16-Jun-2010, Jonitz, H. 48 B ( CDS 55774). Santiago, Guayabillos nuevo abierto, 0˚14’0’’ S, 90˚43’52’’W, 625 m alt., transition zone, open woodland of Psidium galapageium , Zanthoxylum fagara , Bursera graveolens , Trema micrantha and shrubs of Clerodendrum molle in between, on wood, 25-Mar-2006, Aptroot, A. 65589 ( CDS 32178). Isabela, Volcán Alcedo, along the trail going up the E-slope, at the NW-side of the trail, 0˚24’5’’ S, 91˚2’36’’W, 420 m alt., dry zone, open Bursera graveolens stand with an occasional Pisonia floribunda and Zanthoxylum fagara and shrubs of Macraea laricifolia and Waltheria ovata , trunk of Bursera graveolens (ca. 25 cm in diam.), SE-exposed, on bark, 09-Mar-2006, Bungartz, F. 4359 ( CDS 28443), 4375 ( CDS 28459); Volcán Darwin, southwestern foothills, above Tagus Cove, 0˚14’50’’ S, 91˚21’29.89’’W, 67 m alt., dry zone, open Bursera graveolens forest with Waltheria ovata and Macraea laricifolia , few Acacia rorudiana and Cordia lutea , along small lava flow, on N-exposed trunk of Bursera graveolens , 11-Nov-2007, Bungartz, F. 7354 ( CDS 37841); Volcán Sierra Negra, along dirt road from Puerto Villamil to the crater, 0˚51’40.27’’ S, 91˚1’41.89’’W, 307 m alt., humid zone, agricultural area, alley and fence posts of Cedrela odorata along the road, on SW-exposed side of fence post, 15-Aug-2008, Bungartz, F. 8225 ( CDS 40871).

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.