''Diorygma antillarum'' is a species of corticolous (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

Graphidaceae The Graphidaceae are a family of lichens in the order Ostropales. Distribution and ecology The vast majority of Graphidaceae species are restricted to the tropics. Most Graphidaceae species are epiphytic (i.e. they grow only on plants). Gener ...

. It is common and widespread in the

Neotropical realm The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

, primarily found on trees in the shady understory and in slightly illuminated habitats of lowland to montane rainforests. It produces

norstictic acid Norstictic acid is a depsidone produced as a secondary metabolites in lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.

and

salazinic acid Salazinic acid is a depsidone with a lactone ring. It is found in some lichens, and is especially prevalent in ''Parmotrema'' and ''Bulbothrix'', where its presence or absence is often used to help classify species in those genera. History I ...

Taxonomy

The lichen was first formally described as a new species in 1915 by the Finnish lichenologist

Edvard August Vainio Edvard August Vainio (born Edvard Lang; 5 August 185314 May 1929) was a Finnish lichenology, lichenologist. His early works on the lichens of Lapland (Finland), Lapland, his three-volume monograph on the lichen genus ''Cladonia'', and, in parti ...

, who initially classified it in the genus ''

Chiodecton ''Chiodecton'' is a genus of lichens in the family Roccellaceae. The genus was circumscribed by lichenologist Erik Acharius in 1814, with '' Chiodecton sphaerale'' assigned as the type species. Species , Species Fungorum accepts 22 species in '' ...

''. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

was collected in 1803 by the American botanist Stephen Elliott from the Laudat Mountain in the

Lesser Antilles The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc betwe ...

(now

Dominica Dominica ( or ; Kalinago: ; french: Dominique; Dominican Creole French: ), officially the Commonwealth of Dominica, is an island country in the Caribbean. The capital, Roseau, is located on the western side of the island. It is geographically ...

) at an elevation of .

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 ...

Robert Lücking Robert Lücking (born 1964) is a German lichenologist. He is a leading expert on foliicolous lichens–lichens that live on leaves. Life and career Born in Ulm in 1964, Lücking earned both his master's (1990) and PhD degree (1994) at the Univer ...

, and

Göran Thor Göran or Jöran (both pronounced ) is the Swedish form of George, not to be confused with the Slavic Goran. Notable people with the name include: * Göran Andersson, Swedish sport sailor *Göran Bror Benny Andersson Swedish musician, composer ...

proposed a transfer to '' Herpothallon'' when they resurrected that genus in 2009. The genus ''Herpothallon'' typically includes

crustose Crustose is a habit of some types of algae and lichens in which the organism grows tightly appressed to a substrate, forming a biological layer. ''Crustose'' adheres very closely to the substrates at all points. ''Crustose'' is found on rocks and ...

- species with a thallus and

isidia An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting o ...

-like structures. These structures, while superficially resembling true isidia, lack and thus referred to as isidia-like. ''Herpothallon'' species are mostly sterile, with mature

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

known from only a few taxa.

Molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

data has shown that ''H. antillarum'' does not align closely with the

type species In 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 species that contains the biological type specimen ...

of ''Herpothallon'' ('' H. rubrocinctum'') in the family

Arthoniaceae The Arthoniaceae are a family of lichenized, lichenicolous and saprobic fungi in the order Arthoniales. The Arthoniaceae is the largest family of Arthoniales, with around 800 species. Most species in Arthoniaceae belong in '' Arthonia'' which is ...

. Instead, ''H. antillarum'' is closely related to species within the genus ''Diorygma'' (

). The presence of a , fragile in ''H. antillarum'', a feature common in ''Diorygma'' species, along with its production of salazinic and

s, supports this reclassification. These chemical compounds are not typical for ''Herpothallon'' but are found in ''Diorygma''. Further phylogenetic analyses confirmed that ''H. antillarum'' belongs to the Graphidaceae, specifically within the subfamily Graphidoideae. For these reasons, Matthew Nelsen, Lücking, and Eimy Rivas Plata transferred the taxon to ''Diorygma'' in 2012.

References

{{Taxonbar, from=Q21268810 antillarum Lichen species Lichens described in 1915 Lichens of Central America Lichens of North America Lichens of South America Lichens of the Caribbean Taxa named by Edvard August Vainio