Diagnosis: Cryptothecia with pustulate ascigerous areas, typically covered by coarse pruina and granular soredia, reacting P+ yellow, K+ yellow, containing confluentic, 2'-O-methylperlatolic, and 2'-O-methylmicrophyllinic acids.
Type: Ecuador. Galapagos Islands: Isla Pinzón, along the trail going up from Playa Escondida, SW-slope of the top, 0°36’36”S, 90°40’11”W, alt. 310 m, transition zone, dry transition zone with Prosopis juliflora, Opuntia galapageia ssp. macrocarpa, Croton scouleri, Cordia lutea, Scalesia baurii ssp. baurii, on Opuntia, 16-Feb-2006, Aptroot 64075 (CDS 30636-holotype).
Thallus corticolous, delimited by a white to brownish, compact prothallus of densely interwoven hyphae; thallus surface cottony, ecorticate, with a dull ±roughened surface, pale beige to yellowish or grayish white, typically abundantly covered with granular ‘soredia’ (pseudisidiate granules); medulla white, densely filled with minute colorless granules and sparse calcium oxalate crystals (insoluble in KOH, forming colorless, needle-shaped crystals in 25% H2SO4); ascigerous areas developing within yellowish pale, irregular to subglobose coarsely pruinose pustules, which at maturity break open and are generally densely covered in sorediate granules; asci bitunicate-fissitunicate, pyriform to broadly pyriform, with a short stalk, a thick wall (ca. 20 μm) and thick tholus with small ocular chamber, forming isolated to loosely grouped within the thalline pustule, very loosely entangled by few, IK+ violet-blue paraphysoids; one to several asci with age encapsulated by a brownish pigmentation, eventually becoming carbonized within “locules”, visible as black dots with erosion of the pustule surface, dots aggregated within the pustules, but not “lirellate”; ascospores hyaline, K+ pale olivaceous, ovoid, muriform, with curved septa, (13)14-17.5(19)×(6.5)7.5-9.5(10) μm, 8 per ascus; conidiomata not observed.
Spot tests and chemistry: P+ yellow, K+ yellow, C-, KC-; UV-; medulla ILugol’s+ deep blue; confluentic, 2'-O-methylperlatolic, and 2'-O-methylmicrophyllinic acids; occasionally possibly also with traces of gyrophoric acid (but all specimens C-).
Distribution and ecology: Currently known only from Galapagos and very likely endemic; a rare species, known only from the bark of the native tree Bursera graveolens and cactus pads (Opuntia galapageia ssp. macrocarpa); in sunny, wind- and rain-exposed habitats.
Notes: Cryptothecia galapagoana is a very rare species of which only three specimens have so far been collected. A minute piece of the species was first identified by R. Lücking as C. evergladensis Seavey based on similar ascospores and the P+ yellow reaction of the thallus fragment. Even when TLC did not confirm psoromic acid, it was assumed that the wrong material must have been accidentally analyzed. Repeating the TLC would have destroyed what was left of the specimen and only when a much larger specimen was subsequently discovered and analyzed was it possible to confirm that the material indeed lacked psoromic acid. This much larger specimen, selected here as the type, clearly shows that the species is not only chemically distinct, but that it also differs morphologically from C. evergladenis.
The thallus of C. galapagoana is quite unusual, because it is abundantly covered in sorediate granules that have a ±coarse pruinose appearance due to an abundance of colorless granules (?crystals) throughout the thallus. These granules not only appear on the thallus surface itself, but typically cover the ascigerous pustules.
Additional specimens examined: Ecuador: Galapagos: Isla Santa Cruz, on the North side of the island, along the dirt road to the ash quarry Mina Granillo Rojo, 0°36’ 56”S, 90°22’3”W, alt. 570m, lower transition zone, on bark of Bursera, 23-Feb-2006, Aptroot 64600 (CDS 31173); Isla Pinzón, along the trail going up from Playa Escondida, SW-slope of the top, 0°36’36”S, 90°40’11”W, alt. 310, transition zone, on Opuntia, 16-Feb-2006, Aptroot 64081 (CDS 30642).
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.