Taxonomy
The genus was circumscription (taxonomy), circumscribed in 1991 by the Dutch lichenologist André Aptroot, with ''Architrypethelium seminudum, A. seminudum'' assigned as the type species. It is a segregate of genus ''Trypethelium''.Description
''Architrypethelium'' is marked by a thallus with a protective outer layer known as the . This genus has ascomata (fruiting bodies responsible for spore production) that can be found either singularly or clustered together. The ostioles are positioned either at the apex (top) or eccentrically (off-centre). Their walls consist of intertwined hyphal 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) 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, a xanthone compound, is rare in ''Architrypethelium''. ''Architrypethelium'' bears a resemblance to species in the genus ''Astrothelium'', as well as those previously classified under ''Laurera'', ''Cryptothelium'', and ''Trypethelium''. However, it distinguishes itself anatomically with its particularly large, 3-septate ascospores, which mature from hyaline (clear) to dark brown, lacking the diamond-shaped typical of mature ''Astrothelium'' species. Phylogenetically, ''Architrypethelium'' is closely related to ''Astrothelium''. The genus ''Pyrenula'', 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 ''Pyrenula laii, P. laii'' and ''Pyrenula montocensis, P. montocensis'' have ascospores with angular lumina, thick septa, and lateral walls. Notably, 3-septate ascospores in ''Pyrenula'' are typically shorter than 90 micrometre, μm, 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