''Absconditella'' is a

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 ...

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 ...

-forming

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

in the family Stictidaceae. These lichens are characterised by their inconspicuous growth and small, cup-shaped fruiting bodies (

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 ...

) that are often hidden within a jelly-like mass containing

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

. The genus name, meaning "hidden", reflects their elusive nature. ''Absconditella'' species are typically found on short-lived surfaces such as decaying wood,

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

es, and unstable soil. Genetic studies have revealed that the genus is more complex than previously thought, with some species being moved to a new genus, '' Absconditonia'', and others potentially representing groups of closely related species. Despite their small size and easily overlooked nature,

environmental DNA Environmental DNA or eDNA is DNA that is collected from a variety of environmental samples such as soil, seawater, snow or air, rather than directly sampled from an individual organism. As various organisms interact with the environment, DNA ...

studies suggest that ''Absconditella'' lichens may be more widespread than collections indicate.

Taxonomy

The genus was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

in 1965 by Czech lichenologist

Antonín Vězda Antonín (Toni) Vězda (25 November 1920 – 10 November 2008) was a Czech lichenologist. After completing a university education that was postponed by World War II, Vězda taught botany at the Czech University of Life Sciences Prague, Czech U ...

, with '' Absconditella sphagnorum'' assigned as the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

. ''Absconditella'' is characterised by gyalectoid

with a

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...

that is not

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the human ...

, without a dark

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

thalli 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 ...

containing

green alga The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ( ...

e as

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

s. The genus name means "hidden", a reference to the scant structure of the thallus and its small apothecia.

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 ...

studies have shown that ''Absconditella'' is

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

within Stictidaceae. The genus ''Geisleria'' has been found to be nested within ''Absconditella'', leading to the transfer of ''Geisleria sychnogonioides'' to ''Absconditella''. Additionally, a new genus, '' Absconditonia'', has been

to accommodate some species previously placed in ''Absconditella''. The conservation of the name ''Absconditella'' against ''Geisleria'' has been proposed to maintain nomenclatural stability.

Characteristics

''Absconditella'' species typically have minute, (deeply cup-shaped)

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 ...

(fruiting bodies) that are often sunken into a gel-like thallus. The can be either composed of parallel hyphae or cellular.

Paraphyses Paraphyses are erect sterile filament-like support structures occurring among the reproductive apparatuses of fungi, ferns, bryophytes and some thallophytes. The singular form of the word is paraphysis. In certain fungi, they are part of the f ...

are simple and indistinctly

septate In biology, a septum (Latin for ''something that encloses''; 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 * Interatrial se ...

, occasionally branched only in the upper part. vary in shape and septation among species.

Habitat and distribution

Species of ''Absconditella'' are often found on ephemeral substrates such as decaying wood,

bryophyte Bryophytes () are a group of embryophyte, land plants (embryophytes), sometimes treated as a taxonomic Division (taxonomy), division referred to as Bryophyta ''Sensu#Common qualifiers, sensu lato'', that contains three groups of non-vascular pla ...

s, and unstable soil.

Environmental DNA Environmental DNA or eDNA is DNA that is collected from a variety of environmental samples such as soil, seawater, snow or air, rather than directly sampled from an individual organism. As various organisms interact with the environment, DNA ...

studies suggest that both ''Absconditella'' and ''Absconditonia'' may be more widespread than previously thought based on collected specimens alone.

Species

Species Fungorum ''Index Fungorum'' is an international project to index all formal names (Binomial nomenclature, scientific names) in the fungus Kingdom (biology), kingdom. As of 2015, the project is based at the Royal Botanic Gardens, Kew, one of three partn ...

(in the

Catalogue of Life The Catalogue of Life (CoL) is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxono ...

) accepts 13 species of ''Absconditella'', although more species than this have been proposed for inclusion. * '' Absconditella amabilis'' – Canada * '' Absconditella annexa'' * '' Absconditella antarctica'' – Antarctica * '' Absconditella baegasanensis'' * '' Absconditella celata'' – Lappland * '' Absconditella delutula'' * '' Absconditella duplicella'' * '' Absconditella fossarum'' * '' Absconditella lignicola'' * '' Absconditella pauxilla'' * '' Absconditella rosea'' – South America * '' Absconditella sphagnorum'' * '' Absconditella sychnogonioides'' * '' Absconditella termitariicola'' – Brazil * '' Absconditella trivialis'' * '' Absconditella viridithallina'' – South America Research suggests that ''A. sphagnorum'' may represent a complex of multiple species.

References

{{Taxonbar, from=Q4669681 Lichen genera Ostropales Ostropales genera Taxa described in 1965 Taxa named by Antonín Vězda