The
thallus of
Astrothelium chulumanense is , with an uneven and somewhat shiny surface. are raised above the thallus and are hemispherical to wart-shaped. The ascomata are in the form of ; they are to hemispherical, and aggregated. The
asci are 8-spored, and the are ,
hyaline, and densely , with a gelatinous layer in younger stages and a distinct thickened median
septum. The thallus surface and pseudostromata surface both exhibit an orange-yellow
UV reaction. A trace of an unidentified substance was detected in the thallus by
thin-layer chromatography. Results of standard
chemical spot test are: K−, C−, KC−, in the thallus; UV+ (orange-yellow) in the surface of the thallus and the pseudostromata, and K+ (red) for the visible part of the perithecia.
Similar species Astrothelium chulumanense is
phylogenetically related and externally similar to
A. robustum. Both species have ascomata with fused ostioles, but ascospores in
A. robustum usually have between 5 and 7 septa (although sometimes as few as 3 or as many as 9).
A. chulumanense can be distinguished from other similar
Astrothelium species by its unique combination of characters, including pseudostromata not differing in colour from the thallus, the orange-yellow UV reaction, the absence of
lichexanthone, perithecia immersed for the most part in the thallus, apical and fused ostioles, clear hamathecium, 8-spored asci, and large, muriform ascospores with median septa. ==Habitat and distribution==