''Astrothelium disjunctum'' is a species of corticolous (bark-dwelling), crustose lichen in the family

Trypetheliaceae The Trypetheliaceae are a family of mainly lichen-forming fungi in the order Trypetheliales. Genera *'' Alloarthopyrenia'' – 1 sp. *''Aptrootia'' – 3 spp. *'' Architrypethelium'' – 8 spp. *''Astrothelium'' – ca. 275 spp. *'' Bathel ...

. Found in Brazil, it was formally described as a new species in 2016 by lichenologists

André Aptroot André Aptroot (Heemskerk, 1961) is a Dutch mycologist and lichenologist. In 1993 he did his PhD at the University of Utrecht under the supervision of Robbert Gradstein (nl). His dissertation was titled "Systematic studies on pyrenocarpous li ...

and Marcela Cáceres. The type specimen was collected by the authors in the Parque Natural Municipal de Porto Velho ( Porto Velho,

Rondônia Rondônia () is one of the 26 states of Brazil, located in the northern subdivision of the country (central-western part). To the west is a short border with the state of Acre, to the north is the state of Amazonas, in the east is Mato Grosso, ...

), in a low-altitude

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus that has a black prothallus line (about 0.3 mm wide) and covers areas of up to in diameter. The ascomata are roughly spherical (''globose'') and typically occur in groups of 5 to 25, usually immersed in the bark tissue as . The characteristic that largely distinguishes it from other members of '' Astrothelium'' are its smooth to coarsely uneven thallus. ''Astrothelium disjunctum'' is somewhat similar to '' A. bicolor'', but that species has smaller ascospores.

References

disjunctum Lichen species Lichens described in 2016 Taxa named by André Aptroot Taxa named by Marcela Cáceres Lichens of North Brazil {{Dothideomycetes-stub