''Astrothelium gyalostiolatum'' is a species of

corticolous This glossary of mycology is a list of definitions of terms and concepts relevant to mycology, the study of fungi. Terms in common with other fields, if repeated here, generally focus on their mycology-specific meaning. Related terms can be found ...

(bark-dwelling)

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

in the family

Trypetheliaceae The Trypetheliaceae are a family of mainly lichen-forming fungi in the order Trypetheliales. The family consists almost exclusively of corticolous (bark-dwelling), crustose lichens with an almost strictly tropical distribution. Taxonomy Trypethe ...

. Found in Brazil, it was described in 2022 by the Dutch lichenologist

André Aptroot André Aptroot ( Heemskerk, 1961) is a Dutch mycologist and lichenologist. His primary research focus is on biodiversity, particularly tropical lichens, encompassing systematics, floristic surveys, and taxonomic reviews. A prolific research ...

. It belongs to the genus ''

Astrothelium ''Astrothelium'' is a large genus of corticolous (bark-dwelling) lichens in the family Trypetheliaceae. The genus is characterized by a corticate thallus and diverse ascomata structures, which can be simple, aggregated, or forming . ''Astrotheli ...

'', sharing similarities with '' Astrothelium bicolor'' but uniquely characterized by the presence of

lichexanthone Lichexanthone is an organic compound in the structural class of chemicals known as xanthones. Lichexanthone was first isolated and identified by Japanese chemists from a species of foliose lichen, leafy lichen in the 1940s. The compound is known ...

exclusively around the

ostiole An ''ostiole'' is a small hole or opening through which algae or fungi release their mature spores. The word is a diminutive of wikt:ostium, "ostium", "opening". The term is also used in higher plants, for example to denote the opening of the ...

Description

The lichen has a dull, dirty ochraceous gray

thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...

, covering up to 15 cm in diameter. The thallus resembles

resin A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...

in texture and is bordered by a black

prothallus A prothallus, or prothallium, (from Latin ''pro'' = forwards and Greek ''θαλλος'' (''thallos'') = twig) is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young ...

line. It produces

ascomata An ascocarp, or ascoma (: ascomata), is the fruiting body (sporocarp (fungi), sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded ascus, asci, each of which typically contains four to ...

, which are immersed in groups within , and bears

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

ascospore In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...

s with three

septa SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...

(internal partitions). The unique chemical signature is the UV+ (yellow) reaction of its

s, indicating the presence of

Habitat and distribution

Exclusive to Brazil's

Mato Grosso Mato Grosso ( – ) is one of the states of Brazil, the List of Brazilian states by area, third largest by area, located in the Central-West Region, Brazil, Central-West region. The state has 1.66% of the Brazilian population and is responsible ...

region, ''A. gyalostiolatum'' grows on tree bark in primary

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

References

gyalostiolatum Lichen species Lichens described in 2022 Lichens of Brazil Taxa named by André Aptroot {{Dothideomycetes-stub