In mycology, a dark taxon (pl.: dark taxa; or dark fungus [1] ) is a taxon that does not appear to produce any observable morphological structure and that appears impossible to cultivate in laboratory conditions. Dark taxa are chiefly detected by DNA sequencing, and in particular environmental metabarcoding. [2]
Dark taxa make up a paraphyletic group, with dark taxa appearing in every major fungal lineage. [2] Dark taxa appear to make up a significant portion of extant fungal taxa. According to Wang et al. (2016) "the majority of the extant fungal diversity produces no distinguishing morphological structures that are visible or describable", [3] and according to Martin Ryberg dark fungi "could well prove to be the dominant life style in the fungal kingdom". [1]
The naming of dark taxa is not supported by the ICN [4] as a type specimen requires direct observation.
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 Cristidiscoidea can provide crucial information on the divergent lifestyles of these groups and the evolution of opisthokonts and slime mold multicellularity. The holomycota tree is following Tedersoo et al.
The Hypocreales are an order of fungi within the class Sordariomycetes. In 2008, it was estimated that it contained some 237 genera, and 2647 species in seven families. Since then, a considerable number of further taxa have been identified, including an additional family, the Stachybotryaceae. Wijayawardene et al. in 2020 added more families and genera to the order. According to the Catalog of Life, As of April 2021 the Hypocreales contains 6 families, 137 genera, and 1411 species. Hyde et al. (2020a) listed 14 families under Hypocreales, while, Wijayawardene et al. (2022) accepted 15 families in the order, where Cylindriaceae was additionally added. Earlier, Hyde et al. (2020a) had placed Cylindriaceae in class Xylariomycetidae. Samarakoon et al. (2022) agreed. Hence, Cylindriaceae should have been excluded from Hypocreales and placed in Xylariomycetidae. Xiao et al. (2022) recently introduced a new family Polycephalomycetaceae to Hypocreales.
Hypocreomycetidae is a subclass of sac fungi.
Pleosporaceae is a family of sac fungi. They are pathogenic to humans or saprobic on woody and dead herbaceous stems or leaves.
The Dactylosporaceae or Sclerococcaceae are a family of lichen-forming fungi in the class Eurotiomycetes. It is the only family of the order Sclerococcales and subclass Sclerococcomycetidae.
MortierellalesCaval.-Sm., 1998 is a monotypic fungal order, within the phylum of Zygomycota and the monotypic, division of Mortierellomycota. It contains only 1 known family, MortierellaceaeLuerss., Handb. Syst. Bot. 1: 63. 1877, and 6 genera and around 129 species.
Dimargaritales is a monotypic order of fungi in the monotypic Dimargaritomycetes class within the subdivision of Kickxellomycotina.
The Filozoa are a monophyletic grouping within the Opisthokonta. They include animals and their nearest unicellular relatives.
Holomycota or Nucletmycea are a basal Opisthokont clade as sister of the Holozoa. It consists of the Cristidiscoidea and the kingdom Fungi. The position of nucleariids, unicellular free-living phagotrophic amoebae, as the earliest lineage of Holomycota suggests that animals and fungi independently acquired complex multicellularity from a common unicellular ancestor and that the osmotrophic lifestyle was originated later in the divergence of this eukaryotic lineage. Opisthosporidians is a recently proposed taxonomic group that includes aphelids, Microsporidia and Cryptomycota, three groups of endoparasites.
Biological dark matter is an informal term for unclassified or poorly understood genetic material. This genetic material may refer to genetic material produced by unclassified microorganisms. By extension, biological dark matter may also refer to the un-isolated microorganisms whose existence can only be inferred from the genetic material that they produce. Some of the genetic material may not fall under the three existing domains of life: Bacteria, Archaea and Eukaryota; thus, it has been suggested that a possible fourth domain of life may yet be discovered, although other explanations are also probable. Alternatively, the genetic material may refer to non-coding DNA and non-coding RNA produced by known organisms.
Aphelida is a phylum of Fungi that appears to be the sister to true fungi.
Opisthosporidia is a superphylum of intracellular parasites with amoeboid vegetative stage, defined as a common group of eukaryotic groups Microsporidia, Cryptomycota and Aphelidea. They have been considered to represent a monophyletic lineage with shared ecological and structural features, being a sister clade of the Fungi. Together with the Fungi they represent a sister clade of the Cristidiscoidea, together forming the Holomycota.
Cladochytriales is an order of chytrid fungi. It is the only order in the monotypic class Cladochytriomycetes. The order was described in 2009 to accommodate a monophyletic clade containing many genera of chytrid fungi often observed growing over decaying plant tissue and other cellulosic substrates from aquatic habitats and humid soils.
Saccharomyceta is a clade of fungi containing Pezizomycotina and Saccharomycotina, or all Ascomycete fungi except Taphrinomycotina according to the 2007 fungal phylogeny "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research" and Tedersoo et al. 2018.
Schizosaccharomyceta is a clade of fungi within Taphrinomycotina containing all members of the clade except Neolectomycetes and Taphrinomycetes according to the 2007 fungal phylogeny "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research" and Tedersoo et al. 2018. Its members are single-celled and yeast-like and include Pneumocystis and Schizosaccharomycetes and Archaeorhizomycetes
Calcarisporiellaceae is a family of fungi within the subkingdom Mucoromycota. It is the only family in the order Calcarisporiellales, class Calcarisporiellomycetes, subphylum Calcarisporiellomycotina and phylum Calcarisporiellomycota. It contains two known genera, Calcarisporiella and Echinochlamydosporium. The two genera each have one species.
Savoryellomycetidae is a subclass of sac fungi within the class of Sordariomycetes. It contains 4 known orders of Conioscyphales, Fuscosporellales, Pleurotheciales and Savoryellales.
Conioscyphales is an order of freshwater and terrestrial fungi within the division Ascomycota. It is in the subclass Savoryellomycetidae and the class Sordariomycetes and the subdivision of Pezizomycotina.
Pararamichloridium is a genus of fungi in the monotypic family Pararamichloridiaceae and within the monotypic order of Pararamichloridiales and also in the subclass Hypocreomycetidae. They are saprobic on wood in terrestrial and freshwater habitats.
The Torpedosporales are an order of marine based fungi in the class Sordariomycetes, subclass Hypocreomycetidae. Most are found on wood substrates in the water.