The Arthoniales is the second largest order of mainly
crustose
Crustose is a Habit (biology), habit of some types of algae and lichens in which the organism grows tightly appressed to a substrate, forming a biological layer. ''Crustose'' adheres very closely to the Substrate (biology), substrates at all poin ...
lichens
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 ...
, but
fruticose
A fruticose lichen is a form of lichen fungi that is characterized by a coral-like shrubby or bushy lichen growth forms, growth structure. It is formed from a symbiotic relationship of a photobiont such as green algae or less commonly cyanobacteri ...
lichens are present as well. The order contains around 1500 species,
while the largest order with lichenized fungi, the
Lecanorales, contains more than 14000 species.
Classification
The Arthoniales is one of two
orders
Order, ORDER or Orders may refer to:
* A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* H ...
of the class
Arthoniomycetes
Arthoniomycetes are a class of ascomycete fungi. It includes two orders: Arthoniales and Lichenostigmatales. Most of the taxa in these orders are tropical and subtropical lichens.
Systematics
Phylogenetic analysis supports the monophyly of thi ...
within the
phylum
In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is below Kingdom (biology), kingdom and above Class (biology), class. Traditionally, in botany the term division (taxonomy), division has been used instead ...
Ascomycota
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 def ...
.
The order includes seven families (
Andreiomycetaceae,
Arthoniaceae
The Arthoniaceae are a family (biology), family of lichenized, Lichenicolous fungus, lichenicolous and saprobic fungi in the order Arthoniales. The Arthoniaceae is the largest family of Arthoniales, with around 800 species. Most species in Arthon ...
,
Chrysotrichaceae,
Lecanographaceae,
Opegraphaceae,
Roccellaceae
The Roccellaceae are a family (biology), family of mostly lichen-forming fungi in the order Arthoniales, established by the French botanist François Fulgis Chevallier in 1826. Species in the family exhibit various lichen growth forms, growth ...
and
Roccellographaceae).
Lecanographaceae, Roccellographaceae, Opegraphaceae and Roccellaceae are well-supported families within Arthoniales, and they were circumscribed in 2011.
Andreiomycetaceae was described as a new family by Hodkinson and Lendemer in 2013.
The Arthoniales is the sister group to
Dothideomycetes
Dothideomycetes is the largest and most diverse class of ascomycete fungi. It comprises 11 orders 90 families, 1,300 genera and over 19,000 known species.
Wijayawardene et al. in 2020 added more orders to the class.
Traditionally, most of it ...
.
Distribution and habitats
The Arthoniales is distributed in most habitats worldwide, as it ranges at latitudes from arctic to tropical regions.
They grow on different types of substrates like bark, wood, rocks, bryophytes and living leaves. The order has adapted to live in both humid forests and dry habitats like savannas and steppes, as well as varying altitudes from sea level to alpine regions. The highest species diversity are known from subtropical coastal areas with a Mediterranean or dry climate. The species diversity of the Arthoniales is expected to be higher than currently reported from several areas worldwide like the tropical rain forests.
Ecology
The majority of species in Arthoniales have a
lichenized lifestyle, but
lichenicolous and
saprophytic
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 ...
species are presented as well. The original state in the Arthoniales is believed to be the lichenized state, and the non-lichenized and parasitic states have evolved independently several times. The lichenized fungi live in symbiosis with a
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. that in most cases is a species of
Trentepohliaceae
Trentepohliaceae are a family (biology), family of green algae, and the only family in the order Trentepohliales. It is a member of the Ulvophyceaen green algae. The family is characterized by traits like net-like chloroplasts without pyrenoids, ...
, but photobionts from
Chlorococcaleae are known from
Chrysotrichaceae and a few species in ''
Arthonia''.
Characters
It is difficult to mention typical morphological characters like fruit body, exiple, hypothecium,
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 ...
, chemistry, ascospore color and ascospore septation that can be used as uniting traits for delimiting families and genera in the Arthoniales. The reason is that the Arthoniales is an old order and taxa have evolved in parallel for a long time, which gives a high level of homoplasy.
Ascomatal anatomy
The ascomata are usually apothecial and it produces bitunicate asci. The bitunicate asci are thick-walled, with an outer and inner layer. The outer and inner layer of the ascus wall are called exotunica and endotunica, and they separate during ascospore release.
The asci usually contains eight ascospores, while the shape and separation of the ascospores are more variating.
Thallus
The majority of the species in Arthoniales are crustose lichens, with a thallus growing tight to the surface. Fruticose lichens have a bushy thallus and are known in Roccellaceae, where it has evolved and been lost multiple times.
The thalli among crustose lichens can either grow within the substrate, called or it can grow at the surface of the substrate, called epiphloedal.
Genera ''incertae sedis''
The following
genera
Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...
have been tentatively classified in the Arthoniales but have not been placed with any certainty into a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
.
*''
Angiactis'' – 3 spp.
*''
Arthophacopsis'' – 1 sp.
*''
Bactrospora'' – 35 spp.
*''
Bryostigma'' – 3 spp.
*''
Catarraphia'' – 1 sp.
*''
Felipes'' – 1 sp.
*''
Glyphopsis'' – 1 sp.
*''
Gossypiothallon'' – 1 sp.
*''
Helminthocarpon'' – 3 spp.
*''
Hormosphaeria'' – 1 sp.
*''
Minksia'' – 2 spp.
*''
Nipholepis'' – 1 sp.
*''
Paradoxomyces'' – 1 sp.
*''
Perigrapha'' – 5 spp.
*''
Phacothecium'' – 1 sp.
*''
Phoebus
Apollo is one of the Olympian deities in ancient Greek and Roman religion and Greek and Roman mythology. Apollo has been recognized as a god of archery, music and dance, truth and prophecy, healing and diseases, the Sun and light, poetry, ...
'' – 1 sp.
*''
Sporostigma'' – 1 sp.
*''
Synarthonia'' – 5 spp.
*''
Synarthothelium'' – 2 spp.
*''
Tarbertia'' – 1 sp.
*''
Trichophyma'' – 2 spp.
*''
Tylophorella'' – 1 sp.
*''
Wegea'' – 1 sp.
References
{{Taxonbar, from=Q148747
Arthoniomycetes
Lichen orders
Ascomycota orders
Taxa named by David Leslie Hawksworth
Taxa described in 1986