''Architrypethelium'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

-forming

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

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 ...

Taxonomy

The genus was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

in 1991 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 ...

, with '' A. seminudum'' assigned as the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. It is a segregate of genus '' Trypethelium''.

Description

''Architrypethelium'' is marked by a

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 ...

with a protective outer layer known as the . This genus has

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 ...

(fruiting bodies responsible for spore production) that can be found either singularly or clustered together. 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 ...

s are positioned either at the apex (top) or eccentrically (off-centre). Their walls consist of intertwined

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

l threads, known as ', and have a (blackened) appearance. The , a tissue layer inside the ascomata containing filamentous structures, is either transparent or with oil droplets. These filaments are slender and form an interwoven network known as anastomosing . in ''Architrypethelium'' are typically (having a two-part

septum In biology, a septum (Latin language, Latin for ''something that encloses''; septa) is a wall, dividing a Body cavity, cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Hum ...

) and euseptate (only one wall layer is visible), predominantly brown in colour, large in size, and generally have three to five septa. These spores often have longitudinal folds in their walls and are occasionally colourless. , asexual reproductive structures, are not known to occur in this genus. In terms of chemical composition, 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 ...

, a

xanthone Xanthone is an organic compound with the molecular formula C13H8O2. It is a white solid. In 1939, xanthone was introduced as an insecticide and it currently finds uses as ovicide for codling moth eggs and as a larvicide. Xanthone is also use ...

compound, is rare in ''Architrypethelium''. ''Architrypethelium'' bears a resemblance to species in 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 ...

'', as well as those previously classified under ''

Laurera ''Laurera'' is a genus of fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. The ...

'', '' Cryptothelium'', and '' Trypethelium''. However, it distinguishes itself anatomically with its particularly large, 3-septate ascospores, which mature from

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 ...

(clear) to dark brown, lacking the diamond-shaped typical of mature ''Astrothelium'' species. Phylogenetically, ''Architrypethelium'' is closely related to ''Astrothelium''. The genus ''

Pyrenula ''Pyrenula'' is a genus of lichen-forming fungi in the family Pyrenulaceae. The genus has a widespread distribution, especially in tropical regions, and contains about 200 species. Taxonomy The genus was circumscribed in 1814 by Erik Acharius ...

'', which includes species with large, 3-septate ascospores, may sometimes be confused with ''Architrypethelium''. They can be differentiated by their hamathecium structure and the shape of their ascospores. For example, '' Pyrenula subpraelucida'' has ascospores with small terminal lumina against the , whereas '' P. laii'' and '' P. montocensis'' have ascospores with angular lumina, thick septa, and lateral walls. Notably, 3-septate ascospores in ''Pyrenula'' are typically shorter than 90

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

, whereas in ''Architrypethelium'', they usually exceed 90 μm in length, reaching up to 160 μm.

Species

*'' Architrypethelium barrerae'' – Mexico *'' Architrypethelium columbianum'' *'' Architrypethelium grande'' *'' Architrypethelium hyalinum'' – Costa Rica *'' Architrypethelium lauropaluanum'' *'' Architrypethelium murisporum'' – Thailand *'' Architrypethelium nitens'' *'' Architrypethelium penuriixanthum'' – Bolivia *'' Architrypethelium seminudum'' *'' Architrypethelium submuriforme'' – Brazil *'' Architrypethelium uberinum''

References

{{Taxonbar, from=Q4787230 Trypetheliaceae Lichen genera Dothideomycetes genera Taxa described in 1991 Taxa named by André Aptroot