''Astrothelium globosum'' is a species of

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.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 ...

. This species is characterised by its immersed ascomata (fruiting bodies) and a thallus consisting of nearly spherical warts, along with distinctive 3-septate ascospores.

Taxonomy

''Astrothelium globosum'' was formally described as a new species in the journal '' The Lichenologist'' in 2016. The

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

specimen was collected in , Mata do Crasto, Brazil, on the bark of a tree, in March 2012.

Description

The thallus of ''Astrothelium globosum'' is , consisting of closely appressed, nearly spherical warts measuring 0.3–0.9 mm in diameter. These warts form a pale greyish-green cover over areas up to 3 cm in diameter and are approximately 0.9 mm thick. The thallus has a thick hyaline and does not induce

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

formation on the host bark. are pyriform, measuring 0.2–0.4 mm in diameter, and usually appear in groups of 2–5, immersed in the bark and visible from above by black ostioles between the thallus warts. The ascomata wall is and up to 50

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

thick. Ostioles are eccentric and brown. The is not inspersed, and are 8 per

ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

, 3-septate, long

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

, 35–40 by 11–13 μm, with diamond-shaped and surrounded by a gelatinous sheath. were not observed in this species. This species is distinguished by a unique thallus consisting of almost spherical warts, an unusual three-dimensional feature for a crustose lichen. It is most closely related to '' Astrothelium simplex'', which is differentiated by its longer ascospores.

Chemistry

The thallus surface of ''Astrothelium globosum'' is UV−, and the thallus medulla is K−. Thin-layer chromatography, a technique used to identify chemical substances, tests revealed no secondary substances.

Ecology and distribution

''Astrothelium globosum'' is found on the smooth bark of trees in lowland

Atlantic rainforest The Atlantic Forest ( pt, Mata Atlântica) is a South American forest that extends along the Atlantic coast of Brazil from Rio Grande do Norte state in the northeast to Rio Grande do Sul state in the south and inland as far as Paraguay and the ...

. At the time of its original publication, it was known to occur only in Brazil.

References

{{Taxonbar, from=Q95573599 Trypetheliaceae Lichen species Lichens described in 2016 Lichens of Brazil Taxa named by André Aptroot Taxa named by Marcela Cáceres