''Astrothelium aeneum'' 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 ...

. It is widely distributed in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

regions. The lichen's

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 ...

is typically light olive-green to yellowish, often covered in orange

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

, and varies in texture from smooth to uneven. It fluoresces red under

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

light.

Taxonomy

The species was first described by Franz Gerhard Eschweiler in 1834, with the name ''Verrucaria aenea''. However, this name was not validly published, because it is a later

homonym In linguistics, homonyms are words which are either; '' homographs''—words that mean different things, but have the same spelling (regardless of pronunciation), or '' homophones''—words that mean different things, but have the same pronunciat ...

of a name already published by

Karl Friedrich Wilhelm Wallroth Karl Friedrich Wilhelm Wallroth (13 March 1792 in Breitenstein – 22 March 1857 in Nordhausen) was a German botanist. His name is abbreviated Wallr. as a taxon authority. He attended classes in medicine and botany at the University of Halle ...

in 1831 and thus unavailable for use according to the rules of botanical nomenclature. The first valid publication of a name for the species was by 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 part ...

, who named it ''Pseudopyrenula aenea'' in 1890.

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 ...

and

Robert Lücking Robert Lücking (born 1964) is a German lichenologist, known for his extensive research on foliicolous lichens (lichens that live on leaves) and his significant contributions to the taxonomy, ecology, and biodiversity of fungi and lichens. He e ...

transferred it 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 ...

'' in 2016 following a large-scale reorganisation of the Trypetheliaceae based on

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

Description

''Astrothelium aeneum'' has a (having a cortex-like structure)

, which typically appears as a light olive-green to yellowish colouration. Much of its surface is often covered with a distinctive orange pigment. The texture of the thallus ranges from smooth to uneven. The

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 ...

, or spore-producing structures, are of the type, characterised by their apical

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 (small openings). These ascomata are generally found either solitarily, irregularly merging with each other, or spreading diffusely in a pattern. Their size varies from 0.3 to 0.7 mm in diameter. They are , meaning they break through the thallus, and are covered by both the thallus and orange pigment, except for the darker area around the ostioles. The , the supportive tissue structure containing the asci, is clear. Each

ascus An ascus (; : asci) 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 gen ...

typically contains eight ascospores. These spores are (spindle-shaped), with a size range of 20–27

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 ...

in length and 7–10 μm in width. They are

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 ...

(translucent) and have 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). They do not react to

staining Staining is a technique used to enhance contrast in samples, generally at the Microscope, microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissue (biology), tissues), in cytology (microscopic ...

with

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

(IKI−). Chemically, both the thallus and ascomata of ''Astrothelium aeneum'' react to

light by fluorescing red (UV+ red) and produce a purple reaction when treated with potassium hydroxide (K+ purple). This is indicative of the presence of an

anthraquinone Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic hydrocarbon, aromatic organic compound with formula . Several isomers exist but these terms usually refer to 9,10-anthraquinone (IUPAC: 9,10-dioxoanthracene) wherein th ...

, a type of chemical compound.

Distribution

''Astrothelium aeneum'' is found in a wide range of

regions globally. Its presence has been recorded in various countries including the United States,

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

El Salvador El Salvador, officially the Republic of El Salvador, is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south by the Pacific Ocean. El Salvador's capital and largest city is S ...

, the

Revillagigedo Islands The Revillagigedo Islands (, ) or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem. They lie approximately from Socorro Island south and southwest of Cabo San Lucas, the sout ...

the Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an Archipelagic state, archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of ...

Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...

Jamaica Jamaica is an island country in the Caribbean Sea and the West Indies. At , it is the third-largest island—after Cuba and Hispaniola—of the Greater Antilles and the Caribbean. Jamaica lies about south of Cuba, west of Hispaniola (the is ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

Suriname Suriname, officially the Republic of Suriname, is a country in northern South America, also considered as part of the Caribbean and the West Indies. It is a developing country with a Human Development Index, high level of human development; i ...

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

, the

Galápagos Islands The Galápagos Islands () are an archipelago of volcanic islands in the Eastern Pacific, located around the equator, west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with a population of sli ...

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

, and

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

(specifically in

Sarawak Sarawak ( , ) is a States and federal territories of Malaysia, state of Malaysia. It is the largest among the 13 states, with an area almost equal to that of Peninsular Malaysia. Sarawak is located in East Malaysia in northwest Borneo, and is ...

and

Sabah Sabah () is a States and federal territories of Malaysia, state of Malaysia located in northern Borneo, in the region of East Malaysia. Sabah has land borders with the Malaysian state of Sarawak to the southwest and Indonesia's North Kalima ...

). Additionally, it is found in

Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

and Australia.

References

{{Taxonbar, from=Q80851951 aeneum Lichen species Lichens described in 1890 Lichens of Asia Lichens of Australia Lichens of the Caribbean Lichens of Central America Lichens of New Guinea Lichens of the Galápagos Islands Lichens of the United States Lichens of South America Taxa named by Edvard August Vainio