''Lichenostigma'' 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 ...

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 Phaeococcomycetaceae. It includes several species which are lichenicolous (i.e.

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

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 ...

s).A synopsis of Lichenostigma subgen. Lichenogramma (Arthoniales) with a key to the species, Vicent Calatayud1, Pere Navarro-Rosinés, Josef Hafellner, Mycological Research, Volume 106, Issue 10, October 2002, Pages 1230–1242

/ref> The genus was circumscription (taxonomy), circumscribed in 1983 by the Austrian mycologist

Josef Hafellner Josef Hafellner (1951– ) is an Austrian mycologist and lichenologist. He was awarded the Acharius Medal in 2016 for his lifetime contributions to lichenology. Before his retirement, he was a professor at the Karl-Franzens-Universität in Graz ...

, with '' Lichenostigma maureri'' 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 ...

Fossil history

The

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

history of ''Lichenostigma'' provides insights into its ancient origins and long-standing ecological relationships. Discoveries from European

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

amber have identified two fossil specimens of ''Lichenostigma'' associated with the

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

genus ''

Ochrolechia ''Ochrolechia'' is the sole genus in the fungus, fungal family Ochrolechiaceae. It comprises about 40 species of crustose lichens. These lichens typically form uneven, often thick, crust-like growths on various surfaces and are characterised by t ...

''. These fossils date back approximately 34 million years, to the uppermost

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. The presence of ''Lichenostigma'' in these amber inclusions confirms that both the genus and its specialised

association with ''Ochrolechia'' were already well-established during this period. The fossilised ''Lichenostigma'' specimens have

conidiomata Conidiomata (singular: Conidioma) are blister-like fruiting structures produced by a specific type of fungus called a coelomycete. They are formed as a means of dispersing asexual spores call conidia, which they accomplish by creating the blister- ...

and

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 ...

(specialised structures to produce asexual and sexual

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s, respectively) that are morphologically similar to those of modern species, demonstrating the evolutionary continuity of these lichenicolous fungi. This discovery not only pushes back the minimum age of the genus ''Lichenostigma'' but also provides calibration points for

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

studies. The identification of ''Lichenostigma'' in amber fossils marks a significant advancement in

paleomycology Paleomycology is the study of fossil fungi. Paleomycology is considered a subdiscipline of paleobotany, centered on mushrooms, fungal spores, and hyphae preserved in sediment layers and rock. Fungi have been found in the palaeoecological record as ...

, particularly regarding the fossil record of lichenicolous fungi. Prior to these findings, evidence of ancient lichen-associated microfungi was limited to more general and likely

saprotrophic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ...

associations. The ''Lichenostigma'' fossils, however, represent the first concrete evidence of mycoparasitic relationships in the fossil record, highlighting the ecological importance of these interactions.

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 ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

*'' Lichenostigma spermatomanis'' *'' Lichenostigma subradians'' *'' Lichenostigma supertegentis'' – Scandinavia *'' Lichenostigma svandae'' *'' Lichenostigma triseptatum'' *'' Lichenostigma verrucosum'' – Iran

References

{{Taxonbar, from=Q93756 Arthoniomycetes Ascomycota genera Lichenicolous fungi Taxa named by Josef Hafellner Taxa described in 1983