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Chytridiomycota are a division of zoosporic organisms in the
kingdom Kingdom commonly refers to: * A monarchy ruled by a king or queen * Kingdom (biology), a category in biological taxonomy Kingdom may also refer to: Arts and media Television * ''Kingdom'' (British TV series), a 2007 British television drama s ...
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 ...
, informally known as chytrids. The name is derived from the
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...
('), meaning "little pot", describing the structure containing unreleased zoöspores. Chytrids are one of the early diverging fungal lineages, and their membership in kingdom Fungi is demonstrated with
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 ...
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 ...
s, a posterior whiplash
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 ...
, absorptive nutrition, use of
glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one of ...
as an energy storage compound, and synthesis of
lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated − ...
by the -amino
adipic acid Adipic acid or hexanedioic acid is the organic compound with the formula (CH2)4(COOH)2. From an industrial perspective, it is the most important dicarboxylic acid: about 2.5 billion kilograms of this white crystalline powder are produced annuall ...
(AAA) pathway. Chytrids are
saprobic 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 ( ...
, degrading refractory materials such as
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 ...
and
keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up Scale (anatomy), scales, hair, Nail ...
, and sometimes act as
parasites 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 ha ...
. There has been a significant increase in the research of chytrids since the discovery of ''
Batrachochytrium dendrobatidis ''Batrachochytrium dendrobatidis'' ( ), also known as ''Bd'' or the amphibian chytrid fungus, is a fungus that causes the disease chytridiomycosis in amphibians. Since its discovery in 1998 by Lee Berger, the disease devastated amphibian popula ...
'', the causal agent of
chytridiomycosis Chytridiomycosis ( ) is an infectious disease in amphibians, caused by the chytrid fungi '' Batrachochytrium dendrobatidis'' and '' Batrachochytrium salamandrivorans''. Chytridiomycosis has been linked to dramatic population declines or extinc ...
.


Classification

Species of Chytridiomycota have traditionally been delineated and classified based on development, morphology, substrate, and method of zoöspore discharge. However, single spore isolates (or isogenic lines) display a great amount of variation in many of these features; thus, these features cannot be used to reliably classify or identify a species. Currently,
taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
in Chytridiomycota is based on molecular data, zoöspore ultrastructure and some aspects of thallus morphology and development. In an older and more restricted sense (not used here), the term "chytrids" referred just to those fungi in the
class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently ...
Chytridiomycetes. Here, the term "chytrid" refers to all members of Chytridiomycota. The chytrids have also been included among the
Protoctista A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exclu ...
, but are now regularly classed as fungi. In older classifications, chytrids, except the recently established
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
Spizellomycetales, were placed in the class
Phycomycetes Phycomycetes is an obsolete polyphyletic taxon for certain fungi with aseptate hyphae. It is used in the Engler system. Asexual reproduction takes place by zoospores(motile) or by Aplanospores(non-motile).These spores are endogenously produced in ...
under the subphylum Myxomycophyta of the kingdom Fungi. Previously, they were placed in the
Mastigomycotina Mastigomycotina is a former polyphyletic taxonomic grouping, a subdivision, of fungi, similar to Phycomycetes, and that included the zoosporic classes Chytridiomycetes, Hyphochytriomycetes, Plasmodiophoromycetes and Oomycetes. General feature ...
as the class Chytridiomycetes. The other classes of the Mastigomycotina, the Hyphochytriomycetes and oömycetes, were removed from the fungi to be classified as
heterokont Heterokonts are a group of protists (formally referred to as Heterokonta, Heterokontae or Heterokontophyta). The group is a major line of eukaryotes. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which a ...
pseudofungi Pseudofungi is a grouping of heterokonts, also known as the Heterokontimycotina. It consists of the Oomycota and Hyphochytridiomycetes. Although numerous biochemical, ultrastructural, and genetic traits clearly place them in the heterokonts, th ...
. The class Chytridiomycetes has over 750 chytrid species distributed among ten
orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
. Additional classes include the
Monoblepharidomycetes Members of the Monoblepharidomycetes have a filamentous thallus that is either extensive or simple and unbranched. They frequently have a holdfast at the base. In contrast to other taxa in their phylum, some reproduce using autospores, althou ...
, with two orders, and the Hyaloraphidiomycetes with a single order.
Molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
, and other techniques such as ultrastructure analysis, has greatly increased the understanding of chytrid phylogeny, and led to the formation of several new zoösporic fungal phyla: * The order
Blastocladiales Blastocladiomycota is one of the currently recognized phyla within the kingdom Fungi.Hibbett DS et al. 2007. A higher-level phylogenetic classification of the fungi. Mycological Research 111:509–47. Blastocladiomycota was originally the order ...
, originally within the Chytridiomycota, are now classified as a separate phylum, the
Blastocladiomycota Blastocladiomycota is one of the currently recognized phyla within the kingdom Fungi.Hibbett DS et al. 2007. A higher-level phylogenetic classification of the fungi. Mycological Research 111:509–47. Blastocladiomycota was originally the order ...
. * The
Neocallimastigales Neocallimastigomycota is a phylum containing anaerobic fungi, which are symbionts found in the digestive tracts of larger herbivores. Anaerobic fungi were originally placed within phylum Chytridiomycota, within Order Neocallimastigales but later ...
, originally an order of
anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: * Anaerobic adhesive, a bonding a ...
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 ...
of the class Chytridiomycetes, found in the digestive tracts of herbivores, was later raised to a separate phylum, the Neocallimastigomycota. * The Olpidiaceae, including the
type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...
'' Olpidium'', formerly classified in the order
Chytridiales Fungi of the order Chytridiales, like other members of its division, may either have a monocentric thallus or a polycentric rhizomycelium. When the ribosomal genes of members classified in this order were first examined using molecular techniq ...
, were raised to a separate phylum, the Olpidiomycota.


Life cycle and body plan

Chytridiomycota are unusual among the Fungi in that they reproduce with zoöspores. For most members of Chytridiomycota, sexual reproduction is not known. Asexual reproduction occurs through the release of zoöspores (presumably) derived through
mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...
. Where it has been described, sexual reproduction of chytrids occurs via a variety of methods. It is generally accepted that the resulting zygote forms a resting spore, which functions as a means of surviving adverse conditions. In some members, sexual reproduction is achieved through the fusion of isogametes (gametes of the same size and shape). This group includes the notable plant pathogens ''
Synchytrium ''Synchytrium'' is a large genus of plant pathogens within the phylum Chytridiomycota. Species are commonly known as false rust or wart disease. Approximately 200 species are described,Karling, J.S. 1964. ''Synchytrium''.Academic Press: New York. ...
''. Some algal parasites practice oögamy: A motile male gamete attaches itself to a nonmotile structure containing the female gamete. In another group, two thalli produce tubes that fuse and allow the gametes to meet and fuse. In the last group, rhizoids of compatible strains meet and fuse. Both nuclei migrate out of the zoösporangium and into the conjoined rhizoids where they fuse. The resulting zygote germinates into a resting spore. Sexual reproduction is common and well known among members of the Monoblepharidomycetes. Typically, these chytrids practice a version of oögamy: The male is motile and the female is stationary. This is the first occurrence of oögamy in kingdom Fungi. Briefly, the monoblephs form oögonia, which give rise to eggs, and antheridia, which give rise to male gametes. Once fertilized, the zygote either becomes an encysted or motile oöspore, which ultimately becomes a resting spore that will later germinate and give rise to new zoösporangia. File:06 12 life cycle, asexual, Batrachochytrium dendrobatidis, Chytridiomycota (M. Piepenbring).png, alt=A diagram displaying the life cycle of Batrachochytrium dendrobatidis. Starting at the top and moving clockwise: A zoöspore seeks out an amphibian and encysts on the skin. It grows and develops rhizoids to anchor it and absorb nutrients. The thallus divides numerous times to form a colony of zoösoporia, which develop discharge tubes when mature. When ready, the discharge tubes open and the zoöspores are released.,
Life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring * Life-cycle hypothesis ...
of ''Batrachochytrium dendrobatidis'' File:06 11 ciclo de vida, Synchytrium endobioticum en papa, Chytridiomycota (M. Piepenbring).png, alt=Diagram of the asexual and sexual parts of the Synchytrium endobioticum life cycle., Life cycle of ''
Synchytrium endobioticum ''Synchytrium endobioticum'' is a chytrid fungus that causes the potato wart disease, or black scab. It also infects some other plants of the genus ''Solanum'', though potato is the only cultivated host. Systematics Traditionally, ''Synchytr ...
'' in potato File:Synchytridium endobioticum.jpg, ''
Synchytrium endobioticum ''Synchytrium endobioticum'' is a chytrid fungus that causes the potato wart disease, or black scab. It also infects some other plants of the genus ''Solanum'', though potato is the only cultivated host. Systematics Traditionally, ''Synchytr ...
'' on potatoes.
Upon release from the germinated resting spore, zoöspores seek out a suitable substrate for growth using
chemotaxis Chemotaxis (from '' chemo-'' + '' taxis'') is the movement of an organism or entity in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemica ...
or
phototaxis Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from a stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive ...
. Some species encyst and germinate directly upon the substrate; others encyst and germinate a short distance away. Once germinated, enzymes released from the zoöspore begin to break down the substrate and utilize it produce a new
thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms ...
. Thalli are coenocytic and usually form no true
mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...
(having
rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be uni ...
s instead). Chytrids have several different growth patterns. Some are holocarpic, which means they only produce a zoösporangium and zoöspores. Others are eucarpic, meaning they produce other structures, such as
rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be uni ...
s, in addition to the zoösporangium and zoöspores. Some chytrids are monocentric, meaning a single zoöspore gives rise to a single zoösporangium. Others are polycentric, meaning one zoöspore gives rise to many zooöporangium connected by a rhizomycelium. Rhizoids do not have nuclei while a rhizomycelium can. File:06 10 types of thalli, Chytridiomycota (M. Piepenbring).png, alt=Line drawing diagram of the five major classifications of chytrid thalli displayed in two columns. At the top of the left column is a diagram of a eucarpic, monocentric chytrid thallus before and after zoöspore discharge. Below that is a diagram of an epibotic chytrid followed by a diagram of an endobiotic chytrid. At the top of the right column is a diagram of a holocarpic chytrid thallus. Below that is a diagram of a eucarpic polycentric chytrid thallus., Types of chytrid thalli File:8-30-11 Crowned Duckweed Chytrid (2).jpg, alt=A zoösporangium of Phylctochytrium sp. on a duckweed frond. The zoösporangium is empty and the spines that had crowned it are folded back. Suspended above the empty zoösporangium is a mass of zoöspores., Zoöspore discharge from ''Phylctochytrium'' sp. File:CSIRO ScienceImage 1392 Scanning Electron Micrograph of Chytrid Fungus.jpg, alt=Scanning elecron image of a sporangium of Batrachochytrium dendrobatidis. The sproangium is sphereical with four discharge papillae spaced equidistant around the circumference of the sphere.,
Sporangium A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cy ...
and zoöspores of the chytrid fungus ''B. dendrobatidis'', under a scanning electron microscope File:Chytrid under the microscope.webm, alt=A video of zoöspores being released from a chytrid thallus., Chytrid
sporangium A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cy ...
and zoöspores under the microscope
Growth continues until a new batch of zoöspores are ready for release. Chytrids have a diverse set of release mechanisms that can be grouped into the broad categories of operculate or inoperculate. Operculate discharge involves the complete or incomplete detachment of a lid-like structure, called an operculum, allowing the zoöspores out of the sporangium. Inoperculate chytrids release their zoöspores through pores, slits, or papillae.


Habitats

Chytrids are aquatic fungi, though those that thrive in the capillary network around soil particles are typically considered terrestrial. The zoöspore is primarily a means of thoroughly exploring a small volume of water for a suitable substrate rather than a means of long-range dispersal. Chytrids have been isolated from a variety of aquatic habitats, including peats, bogs, rivers, ponds, springs, and ditches, and terrestrial habitats, such as acidic soils, alkaline soils, temperate forest soils, rainforest soils, Arctic and Antarctic soils. This has led to the belief that many chytrid species are ubiquitous and cosmopolitan. However, recent taxonomic work has demonstrated that this ubiquitous and cosmopolitan morphospecies hide cryptic diversity at the genetic and ultrastructural levels. It was first thought aquatic chytrids (and other zoösporic fungi) were primarily active in fall, winter, and spring. However, recent molecular inventories of lakes during the summer indicate that chytrids are an active, diverse part of the eukaryotic microbial community. One of the least expected terrestrial environments the chytrid thrive in are periglacial soils. The population of the Chytridiomycota species are able to be supported even though there is a lack of plant life in these frozen regions due to the large amounts of water in periglacial soil and pollen blowing up from below the timberline.


Ecological functions


''Batrachochytrium dendrobatidis''

The chytrid ''
Batrachochytrium dendrobatidis ''Batrachochytrium dendrobatidis'' ( ), also known as ''Bd'' or the amphibian chytrid fungus, is a fungus that causes the disease chytridiomycosis in amphibians. Since its discovery in 1998 by Lee Berger, the disease devastated amphibian popula ...
'' is responsible for
chytridiomycosis Chytridiomycosis ( ) is an infectious disease in amphibians, caused by the chytrid fungi '' Batrachochytrium dendrobatidis'' and '' Batrachochytrium salamandrivorans''. Chytridiomycosis has been linked to dramatic population declines or extinc ...
, a disease of amphibians. Discovered in 1998 in
Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
and
Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...
this disease is known to kill
amphibian Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbo ...
s in large numbers, and has been suggested as a principal cause for the worldwide amphibian decline. Outbreaks of the fungus were found responsible for killing much of the
Kihansi Spray Toad The Kihansi spray toad (''Nectophrynoides asperginis'') is a small toad endemic to Tanzania.Channing and Howell. (2006). ''Amphibians of East Africa.'' Pp. 106-107. The species is live-bearing and insectivorous. The Kihansi spray toad is curre ...
population in its native habitat of
Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...
, as well as the extinction of the golden toad in 1989. Chytridiomycosis has also been implicated in the presumed extinction of the Southern Gastric Brooding Frog, last seen in the wild in 1981, and the Northern Gastric Brooding Frog, last recorded in the wild in March 1985. The process leading to frog mortality is thought to be the loss of essential ions through pores made in the epidermal cells by the chytrid during its replication. Recent research has revealed that elevating salt levels slightly may be able to cure chytridiomycosis in some Australian frog species, although further experimentation is needed.


Other parasites

Chytrids mainly infect algae and other
eukaryotic Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the ...
and
prokaryotic A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Connec ...
microbes. The infection can be so severe as to control primary production within the lake. It has been suggested that parasitic chytrids have a large effect on lake and pond food webs. Chytrids may also infect plant species; in particular, ''
Synchytrium endobioticum ''Synchytrium endobioticum'' is a chytrid fungus that causes the potato wart disease, or black scab. It also infects some other plants of the genus ''Solanum'', though potato is the only cultivated host. Systematics Traditionally, ''Synchytr ...
'' is an important
potato The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae. Wild potato species can be found from the southern Unit ...
pathogen.


Saprobes

Arguably, the most important ecological function chytrids perform is decomposition. These ubiquitous and cosmopolitan organisms are responsible for decomposition of refractory materials, such as
pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
,
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...
,
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 ...
, and
keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up Scale (anatomy), scales, hair, Nail ...
. There are also chytrids that live and grow on pollen by attaching threadlike structures, called rhizoids, onto the pollen grains. This mostly occurs during asexual reproduction because the zoöspores that become attached to the pollen continuously reproduce and form new chytrids that will attach to other pollen grains for nutrients. This colonization of pollen happens during the spring time when bodies of water accumulate pollen falling from trees and plants. File:Dead Bd-infected Atelopus limosus at Sierra Llorona (posed to show ventral lesions and chytridiomycosis signs).jpg, Dead frog with chytridiomycosis (''B. dendrobatidis'') signs


Fossil record

The earliest
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 preserved ...
s of chytrids are from the Scottish
Rhynie chert The Rhynie chert is a Lower Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness (a Lagerstätte). It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is locate ...
, a
Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
-age
lagerstätte A Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These f ...
with anatomical preservation of
plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
s and fungi. Among the microfossils are chytrids preserved as
parasite 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 ...
s on
rhyniophyte The rhyniophytes are a group of extinct early vascular plants that are considered to be similar to the genus '' Rhynia'', found in the Early Devonian (around ). Sources vary in the name and rank used for this group, some treating it as the class ...
s. These fossils closely resemble the modern genus ''
Allomyces ''Allomyces'' is a genus of fungi in the family Blastocladiaceae. It was circumscribed by British mycologist Edwin John Butler in 1911. Species in the genus have a polycentric thallus and reproduce sexually or asexually by zoospores that have a ...
''. Holocarpic chytrid remains were found in cherts from Combres in central France that date back to the late Visean. These remains were found along with eucarpic remains and are ambiguous in nature although they are thought to be of chytrids. Other chytrid-like fossils were found in cherts from the upper Pennsylvanian in the Saint-Etienne Basin in
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, dating between 300~350  ma.


In fictional media

The novel '' Tom Clancy's Splinter Cell: Fallout'' (2007) features a species of chytrid that feeds on petroleum and oil-based products. In the story the species is modified using
nuclear radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...
, to increase the rate at which it feeds on oil. It is then used by
Islamic extremist Islamic extremism, Islamist extremism, or radical Islam, is used in reference to extremist beliefs and behaviors which are associated with the Islamic religion. These are controversial terms with varying definitions, ranging from academic und ...
s in an attempt to destroy the world's oil supplies, thereby taking away the technological advantage of the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. The
webcomic Webcomics (also known as online comics or Internet comics) are comics published on a website or mobile app. While many are published exclusively on the web, others are also published in magazines, newspapers, or comic books. Webcomics can be c ...
'' Black Mudpuppy'' by Ethan Kocak features an arc with an evil, anthropomorphic chytrid developed as a Nazi experiment to infect Xolotl, a giant, talking black
axolotl The axolotl (; from nci, āxōlōtl ), ''Ambystoma mexicanum'', is a paedomorphic salamander closely related to the tiger salamander. Axolotls are unusual among amphibians in that they reach adulthood without undergoing metamorphosis. I ...
.


References


External links

* * — Includes links on how to isolate and culture chytrids. * * * *
Chytrid fungus 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. Chytrid ...
and how it impacts amphibians kept as domestic pets in the Aquarium Wiki Encyclopaedia. * {{Authority control Aquatic fungi Fungus phyla Fungi by classification