Cryptothecia galapagoana
Cryptothecia galapagoana is a rare species of corticolous crustose lichen in the family Arthoniaceae. Found on the Galápagos Islands, it was described as a new species in 2013.
Taxonomy
Cryptothecia galapagoana was formally described as a new species in 2013 by the lichenologists Frank Bungartz and John Elix. It belongs to the genus Cryptothecia, a group of crustose lichens characterized by asci that develop within areas rather than in distinct fruiting bodies. The genus is closely related to Herpothallon, but is generally distinguished by the presence of ascigerous areas and the absence of .The species was initially misidentified as Cryptothecia evergladensis based on similar ascospores and chemical reactions, but further analysis revealed distinct chemical and morphological differences. C. galapagoana is named after its type locality, the Galápagos Islands, where it appears to be endemic.
Description
Cryptothecia galapagoana forms a crust-like growth on bark. The thallus is bordered by a white to brownish, compact margin of densely interwoven fungal filaments. The surface has a cottony texture, lacks a, and has a dull, roughened appearance. Its colour ranges from pale beige to yellowish or greyish white.A distinctive feature of this species is the abundant coverage of granular "soredia". The medulla is white and densely filled with minute colourless and sparse calcium oxalate crystals.
The reproductive structures develop within yellowish pale, irregular to almost spherical, coarsely frosted, which break open as they mature. These pustules are typically densely covered with sorediate granules. The asci are -, pear-shaped to broadly pear-shaped, with a short stalk and thick wall, and contain a thick upper portion with a small.
The asci form isolated to loosely grouped within the thalline pustule, loosely entangled by a few filaments that stain violet-blue with iodine. As they age, one to several asci become encapsulated by a brownish pigmentation that eventually becomes, forming visible "" or black dots when the pustule surface erodes. These dots are aggregated within the pustules but do not form .
The are colourless, are K+, ovoid, with curved septa, and measure 14–17.5 by 7.5–9.5 μm. Each ascus contains eight spores.
In chemical spot tests, the thallus is P+, K+, C−, and KC−. It does not fluoresce under ultraviolet light. The medulla reacts deep blue with Lugol's iodine solution. Chemical analysis reveals the presence of confluentic acid, 2'-O-methylperlatolic acid, and 2'-O-methylmicrophyllinic acids, occasionally with traces of gyrophoric acid.