''Cruentotrema'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 ...

. It has seven species.

Taxonomy

The genus was

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

in 2012 by Rivas Plata, Papong, H. Thorsten Lumbsch, and

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 Univ ...

, with '' Cruentotrema cruentatum'' assigned as 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 ...

. This enigmatic lichen had previously been described three times under different names: as ''Stictis cruentata'' , as ''Arthothelium puniceum'' , and as ''Thelotrema rhododiscum'' .

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 ...

revealed its true affinities in the subfamily ''Fissurinoideae'' of the family Graphidaceae. The genus name combines the species epithet of the type species with the suffix ''-trema''. Three species were included in the original circumscription of the genus.

Description

Characteristics of the genus include rounded, erumpent

ascomata An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

, a carbonised (blackened) excipulum, the absence of a

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

, and

inamyloid In mycology a tissue or feature is said to be amyloid if it has a positive amyloid reaction when subjected to a crude chemical test using iodine as an ingredient of either Melzer's reagent or Lugol's solution, producing a blue to blue-black stain ...

asci and hamathecium. The

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 of ''Cruentotrema'' lichens number eight per

ascus 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 ...

, and are colourless and

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 thick

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five coun ...

and diamond-shaped chambers (''lumina'') of the ''

Trypethelium ''Trypethelium'' is a genus of lichenized fungi in the family Trypetheliaceae. The widespread genus contains about 50 species that are predominantly found in tropical areas. ''Trypethelium'' was circumscribed by German botanist Kurt Polycarp Joa ...

''-type.

Species

*'' Cruentotrema amazonum'' *'' Cruentotrema cruentatum'' *'' Cruentotrema kurandense'' *'' Cruentotrema lirelliforme'' *'' Cruentotrema puniceum'' *'' Cruentotrema siamense'' *'' Cruentotrema thailandicum''

References

{{Taxonbar, from=Q22105344 Graphidaceae Ostropales genera Lichen genera Taxa described in 2012 Taxa named by Robert Lücking Taxa named by Helge Thorsten Lumbsch