Cratiria sorediata is a species of corticolous (bark-dwelling), crustose lichen in the family Caliciaceae. It was first described as a new species in 2009. The type specimen was collected from Aldabra in the Seychelles.
Cratiria sorediata was described as a new species by the lichenologists André Aptroot and Mark Seaward in 2009. The type specimen was collected in 1973 from Cinque Cases, Aldabra, where it was found growing on dead Pemphis. The species is notable for being the first in the genus Cratiria to have both soredia and the lichen product norstictic acid.
Cratiria sorediata has a slightly shiny, thallus that is smooth and pale ochraceous grey, covering an area of up to in diameter. Soredia are formed in roundish, shallow , later covering much of the thallus, and are ochraceous yellow in colour.
Apothecia (fruiting bodies) of Cratiria sorediata are , round to wavy in outline, saucer-shaped, and measure 0.3âÂÂ0.5 mm in diameter. The of the apothecia is black, shiny, and flat, without . The margin of the apothecium is prominent, raised above the disc; it is black and shiny, measuring about 0.1 mm wide. The is about 75 üm wide, black on the outside, dark brown to pale brown inside, and with crystals and about 10 üm wide. The is dark brown, measuring about 20âÂÂ30 üm high. The hymenium is not and measures about 70âÂÂ90 üm high, with an consisting of brown caps of paraphyses without crystals, about 4 üm high, and Kâ in reaction. The are , have a single septum, brownish-black, measuring 13âÂÂ15 by 7âÂÂ8 üm, and are not ornamented.
The species contains norstictic acid. This results in the thallus and soredia turning K+ (red) in chemical spot tests.
Cratiria sorediata is known to occur only at the type locality in Aldabra, Seychelles. It grows on the bark of coastal trees and shrubs.