Diagnosis: Similar to Cryptothecia assimilis and C. lichexanthonica but with confluentic acid in addition to lichexanthone; ascospores much larger than those of C. lichexanthonica and only slightly larger than those of C. assimilis; of the 8 ascospores several often abortive.
Type: Ecuador. Galapagos Islands: Isla Floreana, Ladera N del Cerro Ventanas, 1°16’12”S, 90°25’49”W, alt. 400 m, zona húmeda, sobre corteza de tallo de Bursera graveolens, 27-Mar-2006, Simbaña 556 (CDS 32392-holotype).
Thallus corticolous or lignicolous, delimited by a distinct byssoid prothallus of white to brownish, radiating hyphae; thallus surface smooth, shiny, ecorticate, yellowish white, with storage intensifying lemon yellow, occasionally with sparse granular ‘soredia’ (pseudisidiate granules); medulla white, densely filled with minute colorless crystals (soluble in KOH, not forming colorless, needle-shaped crystals in 25% H2SO4); ascigerous areas developing within roundish, broad, lemon yellow, pruinose, irregular pustules with a ±roughened surface which at maturity breaks open; asci bitunicate-fissitunicate, broadly pyriform to globose, with a short stalk, a thick wall (ca. 21µm) and thick tholus with small ocular chamber; forming isolated within thalline pustules, entangled by strongly ramified and anatomizing, KI+ violet-blue paraphysoids; one to few asci with age encapsulated by a brownish pigmentation, eventually becoming carbonized forming “locules” that are irregularly arranged or develop into striae, when eroded at their surface these ascigerous pustules thus appearing similar to ramified, carbonized lirellae; ascospores hyaline, K+ pale olivaceous, ovoid, muriform, with curved septa, (50-)60-85(-95)×(22-)32-40(-48) μm, typically 8 per ascus, but frequently 1-2(-3) spores aborted, these asci thus remaining (5-)6-7-spored; conidiomata not observed.
Spot tests and chemistry: P-, K-, C-, KC-; UV+ bright orange; medulla ILugol’s+ deep blue; confluentic acid, lichexanthone.
Distribution and ecology: Currently known only from the Galapagos and possibly endemic; common throughout the dry zone and lower transition zone, currently known only from bark of native and endemic tree species, most commonly Bursera graveolens and Erythrina velutina, in sunny, wind- and rain-exposed habitats.
Notes: Two other Cryptothecia species with a UV+ bright yellow to orange fluorescence are currently known - Cryptothecia assimilis Makhija & Patw. described from India, and C. lichexanthonica E.L. Lima, Aptroot & M Cácares described from Brazil. For C. assimilis Makhija & Patwardhan (1994 p. 63) mention a lichen substance that, when analyzed with TLC, gives a “UV + bright yellow fluorescence; unknown yellow spot at atranorin (UV + orange pink fluo.)”. Lima et al. (2013) state that both C. lichexanthonica and C. assimilis contain lichexanthone, a substance also present in C. darwiniana.
The three species are very similar: according to Lima et al. (2013) C. lichexanthonica has asci that are globose and not pedicellate, and its ascigerous areas are generally much smaller than those of C. assimilis. The ascospores of C. lichexanthonica (55-75 ´ 22-28 µm) are also smaller than those of C. assimilis (66-83 ´ 25-33 µm). Both species generally have 8 spores per ascus. The Galapagos specimens of C. darwiniana have distinctly pedicellate asci, their ascigerous areas vary considerably in size, but are generally larger than those of both of the other species, and, when very well developed, form distinct pustules. With ascospores 60-85 × 32-40 μm, C. darwiniana has the largest ascospores of the three, though only slightly broader than those of C. assimilis. Cryptothecia darwiniana is the only species to contain confluentic acid in addition to lichexanthone.
During our studies, the identity of C. darwiniana remained unresolved for a considerable time. Weber (1986) first reported Chiodecton effusum Fée for the Galapagos, a species cited as Syncesia effusa (Fée) Tehler by Elix & McCarthy (1998). The thalli are indeed superficially similar to those of Syncesia effusa, especially when the surface of the ascigerous pustules becomes abraded. Ascospores of Syncesia, however, are slender, fusiform, 3-septate, whereas those of Cryptothecia are broad, oblong to ovoid and muriform.
The record by Weber (1986) of Chiodecton effusum is even more confusing and a revision of the COLO specimens confirmed that this material was not Cryptothecia darwiniana. Instead most specimens of Ch. effusum in COLO are misidentifications of Sclerophyton murex Egea & Torrente ex Sparrius, and one specimen is Syncesia graphica (Fries) Tehler.
Reports of Syncesia effusa from Galapagos are thus erroneous, no material of that species was found in COLO and it has not been collected during our recent inventory.
Selected specimens examined: Ecuador: Galapagos: Isla Española, trail from Bahía Manzanillo on the N-coast of the island to the highest point, 1°21’41”S, 89°41’57”W, alt. 48m, dry zone, on bark, 11-Nov-2010, Bungartz 9086 (CDS 45904); Bungartz 9125 (CDS 45943). Isla Floreana, along trail going to Post Office Bay off the dirt road between highlands and Puerto Velasco Ibarra, at Laguna Seca, 1°15’31”S, 90°26’27”W, alt. 206m, dry zone, on bark, 14-Jan-2011, Bungartz 9530 (CDS 46813); inside the crater of Cerro Laguna at E-side of island, on W-exposed slope, 1°16’12”S, 90°23’17”W, alt. 245m, transition zone, on bark, 20-Jan-2011, Bungartz 9941 (CDS 47310). Isla Pinta, along the trail up to the summit from the S-coast, 0°34’3”N, 90°44’56”W, alt. 233m, transition zone, on bark, 28-Feb-2007, Bungartz 5973 (CDS 33651). Isla Pinzón, along the trail going up from Playa Escondida, 0°36’10”S, 90°40’1”W, alt. 254m, dry zone, on bark, 16-Feb-2006, Bungartz 3639 (CDS 27457), Aptroot 64116 (CDS 30677). Isla San Cristóbal, northwestern foothills of Media Luna, inland from the NW-coast, 0°43’41”S, 89°18’44”W, alt. 75m, dry zone, on bark, 22-Apr-2007, Bungartz 6177 (CDS 34389). Isla Santa Cruz, above Mina Granillo Rojo, on the N-side of the island, 0°37’4”S, 90°21’57”W, alt. 600m, transition zone, 07-Aug-2008, Clerc 08-27 (CDS 39881); along the road from Bellavista to El Garrapatero, ca. 4 km W from the campsite of the National Park, 0°40’38”S, 90°14’54”W, alt. 159m, dry zone, on bark, 14-Feb-2006, Bungartz 3569 (CDS 27368); along the road from Bellavista to El Garrapatero, ca. 4 km W from the campsite of the National Park, 0°40’38”S, 90°14’54”W, alt. 159m, dry zone, on bark, 14-Feb-2006, Aptroot 63979 (CDS 30539). Isla Santiago, ca. 5 km inland from the E-coast, ± at the same latitude as Bahía Sullivan, 0°16’52”S, 90°37’17”W, alt. 175m, dry zone, on bark, 16-Jul-2006, Bungartz 5033 (CDS 29246, ), ca. 7 km inland from the E-coast, ± at the same latitude as Bahía Sullivan, 0°17’4”S, 90°38’21”W, alt. 190m, dry zone, on bark, 17-Jul-2006, Bungartz 5088 (CDS 29301); en el parte sureste de la isla, 0°17’5”S, 90°38’35”W, alt. 160m, zona seca, sobre corteza, 20-Jul-2006, Nugra 114 (CDS 32768). Isla Isabela, Volcán Alcedo, along the trail going up the E-slope, basalt rubble field to the SE-side of the trail and the barranco, 0°24’6”S, 91°2’53”W, alt. 530m, dry zone, on bark, 10-Mar-2006, Aptroot 64914 (CDS 31493); alt. 434m, on bark, 09-Mar-2006, Aptroot 64981 (CDS 31561); plain at the base of the outer E-exposed slope, along the trail going up to the rim, 0°24’47”S, 91°4’12”W, alt. 768m, transition zone, on bark, 08-Mar-2006, Aptroot 65184 (CDS 31768); Volcán Sierra Negra, area around the Muro de las Lagrimas, ca. 5 km W of Puerto Villamil, 0°57’54”S, 91°0’49”W, alt. 81m, dry zone, on bark, 17-Aug-2008, Bungartz 8399 (CDS 41045); Cerro Orchilla, ca. 4 km W of Puerto Villamil, 0°57’47”S, 91°0’27”W, alt. 56m, dry zone, on bark, 17-Aug-2008, Bungartz 8473 (CDS 41119).
from: Bungartz, F., Dútan, V. & Elix, J.A. (2013) The lichen genera Cryptothecia, Herpothallon and Helminthocarpon (Arthoniales) in the Galapagos Islands, Ecuador. The Lichenologist45(6): 1–24.