''Xenus lithophylli'' is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of lichenized

ascomycete Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The d ...

fungus A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

discovered in 1992, composing the entire

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

''Xenus''. It is found parasiting the calcified algae ''

Lithophyllum ''Lithophyllum'' is a genus of thalloid red algae belonging to the family Corallinaceae. Fossil record This genus is known in the fossil record from the Silurian to the Quaternary (from about 418.7 to 0.0 million years ago). Fossils of spe ...

'', and lives attached to

corals Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secre ...

Belize Belize (; bzj, Bileez) is a Caribbean and Central American country on the northeastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a wa ...

, in the Caribbean. This species is currently under

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...

in the order

Pyrenulales The ''Pyrenulales'' are an order of ascomycetous fungi within the class Eurotiomycetes and within the subphylum Pezizomycotina. Taxonomy As of 2022 the order contains one family, 14 genera and around 296 species. *Order Pyrenulales **Family Pyr ...

References

{{Taxonbar, from=Q21400219 Lichen species Pyrenulales Lichens described in 1992