''Schistophoron aurantiacum'' is a species of corticolous (bark-dwelling)

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

. Found in Costa Rica, it was formally described as a new species in 2007 by lichenologists

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 ...

and

Harrie Sipman Henricus (Harrie) Johannes Maria Sipman (born 1945) is a Dutch lichenologist. He specialises in tropical and subtropical lichens, and has authored or co-authored more than 250 scientific publications. He was the curator of the lichen herbarium ...

. 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 by the second author from Carara National Park (

Puntarenas Province Puntarenas () is a province of Costa Rica. It is located in the western part of the country, covering most of Costa Rica's Pacific Ocean coast, and it is the largest province in Costa Rica. Clockwise from the northwest it borders on the provinces ...

), where it was found along a stream in a partly disturbed primary forest dominated by an understory of the shrub ''

Erythrochiton gymnanthus ''Erythrochiton gymnanthus'' is an endangered tree or shrub from the family Rutaceae. It is endemic to Costa Rica. The genus Erythrochiton consists of only twelve species and it native to the Neotropical region. Description ''Erythrochiton gymnan ...

''. The lichen has an orange-tinged, white

thallus Thallus (plural: 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. Many of these organisms wer ...

with an orange-brown

prothallus A prothallus, or prothallium, (from Latin ''pro'' = forwards and Greek ''θαλλος'' (''thallos'') = twig) is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young ...

. Its ascomata are in the form of short with carbonised walls. Its

ascospore 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 ...

s are

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 ...

with a single

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

, and measure 10–12 by 5–7

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 ...

. ''Schistophoron aurantiacum'' contains lichexanthone, a lichen product that causes the thallus to fluoresce yellow when lit with a long-wavelength

UV light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...

. The orange colouring of the thallus results from an anthraquinone compound that has a K+ (deep violet red) chemical spot test. This species is the only one in genus ''

Schistophoron ''Schistophoron'' is a genus of lichenized fungi 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. ...

'' with either lichexanthone or an anthraquinone.

References

Graphidaceae Lichen species Lichens described in 2007 Taxa named by André Aptroot Taxa named by Harrie Sipman Lichens of Central America {{Ostropales-stub