Holomycota or Nucletmycea are a basal Opisthokont clade as sister of the

Holozoa Holozoa is a group of organisms that includes animals and their closest single-celled relatives, but excludes fungi. ''Holozoa'' is also an old name for the tunicate genus ''Distaplia''.'' Because Holozoa is a clade including all organisms mor ...

. It consists of the

Cristidiscoidea Cristidiscoidea or Nucleariae is a proposed basal holomycota clade in which Fonticula and Nucleariida emerged, as sister of the fungi. Since it is close to the divergence between the main lineages of fungi and animals, the study of Cristidiscoi ...

and the kingdom

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

. The position of

nucleariids Nucleariida is a group of amoebae with filose pseudopods, known mostly from soils and freshwater. They are distinguished from the superficially similar vampyrellids mainly by having mitochondria with discoid cristae, in the absence of superf ...

, unicellular free-living phagotrophic amoebae, as the earliest lineage of Holomycota suggests that animals and

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

independently acquired complex multicellularity from a common unicellular ancestor and that the osmotrophic lifestyle (one of the fungal hallmarks) was originated later in the divergence of this eukaryotic lineage. Opisthosporidians is a recently proposed taxonomic group that includes aphelids,

Microsporidia Microsporidia are a group of spore-forming unicellular parasites. These spores contain an extrusion apparatus that has a coiled polar tube ending in an anchoring disc at the apical part of the spore. They were once considered protozoans or pr ...

and Cryptomycota, three groups of

endoparasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

. ''

Rozella ''Rozella'' is a fungal genus of obligate endoparasites of a variety of hosts, including Oomycota, Chytridiomycota, and Blastocladiomycota. ''Rozella'' was circumscribed by French mycologist Marie Maxime Cornu in 1872. Considered one of the ear ...

'' ( Cryptomycota) is the earliest diverging fungal genus in which

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

has been observed at least in some stages of their life cycle, although the chitinous

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mec ...

(another fungal hallmark) and osmotrophy originated in a common ancestor of Blastocladiomycota and

Chytridiomycota Chytridiomycota are a division of zoosporic organisms in the kingdom Fungi, informally known as chytrids. The name is derived from the Ancient Greek ('), meaning "little pot", describing the structure containing unreleased zoöspores. Chytri ...

, which still contain some ancestral characteristics such as the

flagellum A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

in zoosporic stage. The groups of

with the characteristic

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

l growth, Zoopagomycota,

Mucoromycotina Mucoromycotina is a subphylum of uncertain placement in Fungi. It was considered part of the phylum Zygomycota, but recent phylogenetic studies have shown that it was polyphyletic and thus split into several groups, it is now thought to be a para ...

and

Dikarya Dikarya is a subkingdom of Fungi that includes the divisions Ascomycota and Basidiomycota, both of which in general produce dikaryons, may be filamentous or unicellular, but are always without flagella. The Dikarya are most of the so-called " ...

, originated from a common ancestor ~700 Mya. Zoopagomycota are mostly pathogens of animals or other

, Mucoromycotina is a more diverse group including parasites, saprotrophs or ectomycorrhizal.

is the group embracing

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 defi ...

and

Basidiomycota Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Bas ...

, which comprise ~98% of the described fungal species. Because of this rich diversity,

includes highly morphologically distinct groups, from

e or unicellular

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constit ...

s (such as the model organism ''

Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have b ...

'') to the complex multicellular

popularly known as mushrooms. Contrary to animals and land plants with complex multicellularity, the inferred phylogenetic relationships indicate that

acquired and lost multicellularity multiple times along

and

evolution.

Phylogeny

The

phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

depicts the fungi and their close relationship to other organisms, based on the work of Philippe Silar and "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research". The holomycota tree is following Tedersoo et al.

References

{{Taxonbar, from=Q2943473 Opisthokont unranked clades