Chytridiomycota are a division of zoosporic organisms in the kingdom Fungi , informally known as chytrids. Chytrids are saprobic , degrading refractory materials such as chitin and keratin , and sometimes act as parasites. Species of Chytridiomycota have traditionally been delineated and classified based on development, morphology, substrate, and method of zoospore discharge. In an older and more restricted sense not used here , the term "chytrids" referred just to those fungi in the class Chytridiomycetes. The chytrids have also been included among the Protoctista ,  but are now regularly classed as fungi.
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Systematics and Evolution pp Cite as. The Chytridiomycota comprises a monophyletic group of zoosporic fungi phylogenetically related to the true fungi, in contrast to pseudofungi Cavalier-Smith such as the Oomycota.
They have been classified in the kingdom Protista Whittaker and Protoctista Margulis et al. The Chytridiomycota are probably a very ancient group with extant forms possibly little changed from early times of eukaryotic evolution.
They may be the direct ancestoral group to higher fungi but the exact relationship remains uncertain. In this treatment there is a single class Chytridiomycetes and five orders Chytridiales, Spizellomycetales, Blastocladiales, Monoblepharidales, and Neocallimastigales. Collectively, the Chytridiomycota are often referred to as chytrids. Originally, this term was applicable just to the order Chytridiales, but it has been used for the entire group by so many authors in recent times that the broader meaning has become established.
Mycologia — CrossRef Google Scholar. Protoplasma 1—8 Google Scholar. Apperson CS, Federici BA, Stewart W, Tarver FR b Evidence for the copepods Acanthocyclops rohustus and Mesocyclops edax as competent intermediate hosts for Coelomomyces punctatus during an epizootic in a larval population of the mosquito Anopheles quadrimaculatus.
Barr DJS Phlyctochytrium arcticum n. Chytridiales ; morphology and physiology. Can J Bot — Google Scholar. Barr DJS Allochytridium expandens rediscovered: morphology, physiology and zoospore ultrastructure. Mycologia — Google Scholar. Jones and Bartlett, Boston, pp — Google Scholar.
Barr DJS Evolution and kingdoms of organisms from the perspective of a mycologist. Mycologia 1—11 CrossRef Google Scholar. Host-substrate range, and morphological variation of species of Rhizophydium.
Factors influencing parasitism of Rhizophydium sphaerocarpum on Spirogyra. Can J Bot 43 Google Scholar. Bartnicki-Garcia S Cell wall composition and other biochemical markers in fungal phylogeny.
In: Har-borne JB ed Phytochemical phylogeny. Academic Press, London, pp 81— Google Scholar. Bartnicki-Garcia S The cell wall in fungal evolution. Mycol Res Google Scholar. Protoplasma 23—37 CrossRef Google Scholar. Acta Geobot Hung 3: 79—99 Google Scholar.
Booth T Marine fungi from British Columbia: monocentric chytrids and chytridiaceous species from coastal and interior halmorphic soils. Syesis 2: Google Scholar. Booth T a Distribution of certain soil inhabiting chytrid and chytridiaceous species related to some physiological and chemical factors. Booth T b Ecotypic responses of chytrid and chytridiaceous species to various salinity and temperature combinations. Mol Biol Evol 9: — Google Scholar. Abh Berl Akad 21—83 Google Scholar. Arch Protistenkd — Google Scholar.
Fluctuations in the numbers of Asterionella formosa Hass. New Phytol — Google Scholar. Examples of the interaction between parasitism and other factors determining the growth of diatoms. The parasitism of diatoms with special reference to lakes in the English Lake District.
Cavalier-Smith T Eukaryote kingdoms: seven or nine? Cavalier-Smith T Eukaryotic cell division. Cook PW Host range studies of certain Phycomycetes parasitic on desmids. Academic Press, Orlando Google Scholar. Dogma IJ a Septochytrium willoughbyi ,a new poly-centric chytridiomycete with monocentric resting spore thalli.
Nova Hedwigia — Google Scholar. Dogman IJ b Developmental and taxonomic studies on rhizophlyctoid fungi, Chytridiales. Emerson R Current trends of experimental research on the aquatic Phycomycetes. Its organization and role in the ecosystem. Taxonomy, with an evaluation of genera and interrelationships in the family.
Am J Bot — Google Scholar. Palfrey contributions in botany, No 3. Phytoparasitica 3 CrossRef Google Scholar. Heath IB Nuclear division: a marker for protist phylogeny. Prog Protistol 1: — Google Scholar. Can J Bot Google Scholar. Mycotaxon — Google Scholar. Karling JS The life history of Anisolpidium ectocarpii gen.
Lloydia 29—71 Google Scholar. Karling JS Inoculation experiments with Synchytrium macrosporum. Sydowia Ann Mycol Google Scholar. Karling JS Synchytrium. Google Scholar. Entophlyctis , Diplophlyctis , Nephrochytrium and Google Scholar. Fusion in Rhizophlyctis. Karling JS Chytridiomycetarum Iconographia.
Koch WJ Studies of the motile cells of chytrids. Major types. Li J, Heath IB The phylogenetic relationship of the anaerobic chytridiomycetous gut fungi Neocallimasticaceae and the Chytridiomycota. Cladistic analysis of rRNA sequences. Cladistic analysis of structural data and description of Neocallimasticales ord. Arch Protistenkd 19—80 Google Scholar. Plant Cryptogamae — in Russian Google Scholar. Longcore JE a Morphology, occurrence, and zoospore ultrastructure of Podochytrium dentatum sp.
Longcore JE b Morphology and zoospore ultra-structure of Chytriomyces angularis sp. Longcore JE Morphology and zoospore ultrastructure of Lacustromyces hiemalis gen.
Longcore JE Morphology and zoospore ultrastructure of Entophlyctis luteolus sp. Chytridiales :implications for chytrid taxonomy. Mycologia CrossRef Google Scholar. Longcore JE Changes in chytridiomycete taxonomy since Lotsy JP Algen und Pilze. Jena, pp 1— Google Scholar. J Gen Microbiol — Google Scholar. Protoplasma 77—86 Google Scholar. Academic Press, London, pp — Google Scholar. Macfarlane I Lagena radicicola and Rhizophydium graminis ,two common and neglected fungi. Jones and Bartlett, Boston Google Scholar.
Martin WW The ultrastructure of Coelomomyces punctatus zoospores. McNitt R Zoosporogenesis in Phlyctochytrium irregulare.
24.2: Classifications of Fungi
The kingdom Fungi contains five major phyla that were established according to their mode of sexual reproduction or using molecular data. Not all mycologists agree with this scheme. Rapid advances in molecular biology and the sequencing of 18S rRNA a part of RNA continue to show new and different relationships between the various categories of fungi. The five true phyla of fungi are the Chytridiomycota Chytrids , the Zygomycota conjugated fungi , the Ascomycota sac fungi , the Basidiomycota club fungi and the recently described Phylum Glomeromycota. An older classification scheme grouped fungi that strictly use asexual reproduction into Deuteromycota, a group that is no longer in use. The only class in the Phylum Chytridiomycota is the Chytridiomycetes.
The Chytridiomycota, often called chytrids, are unique among all fungi in having motile stages in their life cycles; no other fungi have this trait. These motile stages take the form of zoospores, single cells with a single posterior at the rear flagellum. Obviously these sperm-like cells require water and it is thus not surprising that chytrids live in perminantly or temporarily aquatic habitats. Most chytrids are structually fairly simple. For example, the photo at left shows a species of the chytrid genus Rhizophidium growing on the surface of a grain of pine pollen. The organism is perfectly spherical and attached to the pollen grain by tiny invisible here threads extended into the interior of the pollen grain.