''Paratricharia'' is a single-species fungal

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

in the family

Gomphillaceae The Gomphillaceae are a family of lichen-forming fungi in the order Graphidales. Species in this family are found mostly in tropical regions. The family underwent a major molecular phylogenetics-led reorganisation in 2023, in which 17 genera were ...

. It is

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 "unisp ...

, containing the single species ''Paratricharia paradoxa'', a

foliicolous Foliicolous refers to the growth habit of certain lichens, algae, fungi, liverworts, and other bryophytes that prefer to grow on the leaves of vascular plants. ''Foliicolous'' simply means 'growing upon leaves' whilst epiphyllous derives from the ...

(leaf-dwelling)

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

. A two-gene

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

study published in 2024 showed that the genus sits in the ''Aulaxina''

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

and forms a strongly supported

sister lineage In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to ''

Caleniopsis ''Caleniopsis'' is a genus of fungi in the family Gomphillaceae The Gomphillaceae are a family of lichen-forming fungi in the order Graphidales. Species in this family are found mostly in tropical regions. The family underwent a major molecul ...

'', well away from ''

Tricharia ''Tricharia'' is a genus of lichens in the family Gomphillaceae. It has an estimated 30 species. Taxonomy Recent molecular studies have shown that the long, carbon-black bristles (sterile ) that once united many species under ''Tricharia'' evol ...

'' and the other "black-setae" genera ''

Microxyphiomyces ''Microxyphiomyces'' is a genus of lichen-forming fungi in the family Gomphillaceae. The genus was originally proposed in 1961 by Augusto Chaves Batista and colleagues, but was later merged into the genus ''Tricharia'' for much of the twentieth ...

'' and ''

Santricharia ''Santricharia'' is a fungal genus in the family Gomphillaceae. It is a monospecific genus, comprising the single species ''Santricharia farinosa'', a leaf-dwelling lichen. Taxonomy ''Santricharia'' was circumscribed by Amanda Xavier-Leite, M ...

''.

Taxonomy

Costa Rican material bearing robust, sterile black bristles (setae) was first described in 1991 as ''Tricharia paradoxa''. Subsequent work recognised that its

apothecia An ascocarp, or ascoma (: ascomata), 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. As ...

—tiny, disc-shaped spore-producing structures with a margin—and a unique sterile column () in the centre of each did not match ''

'', prompting

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 ...

to erect the new genus ''Paratricharia'' in 1997. Until recently the genus had not been sequenced, and its placement relied on

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

. Newly generated

mitochondria A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...

l (mtSSU) and nuclear ribosomal (nuLSU) DNA sequences resolved ''Paratricharia'' as sister to ''Caleniopsis''; together these genera form the earliest branch within a wider ''Aulaxina''

that also contains ''

Aulaxina ''Aulaxina'' is a genus of lichen-forming fungi in the family Gomphillaceae. Species , Species Fungorum (in the Catalogue of Life The Catalogue of Life (CoL) is an online database that provides an index of known species of animals, plants, ...

'' and '' Aulaxinella''. The study rejected any close relationship with ''Tricharia'' despite the shared presence of long black , confirming that these bristles have evolved several times independently inside

Description

The

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 ...

(lichen body) forms a thin, pale green film on living leaves in humid tropical forests. From it arise two conspicuous features. First are the carbon-black, hair-like setae—sterile, thick-walled bristles up to several millimetres long that give the colony a spiky appearance. Second are the minute blackish brown apothecia. Each apothecium has a heavily carbonised, slightly raised rim (a margin) and encloses a central sterile column (columella), an uncommon feature within the family. The combination of setae and carbonised apothecia is diagnostic among foliicolous lichens.

Distribution and ecology

All confirmed collections come from lowland rainforests of Costa Rica, where the lichen grows on the upper surfaces of evergreen leaves. Like many foliicolous species it is thought to rely on frequent rainfall and high humidity for growth and spore dispersal.

References

{{Taxonbar , from1=Q7136197 , from2=Q17387008 , from3=Q59563263 Gomphillaceae Lichen genera Graphidales genera Taxa named by Robert Lücking Taxa described in 1997