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26-517: Entorrhizomycetidae Bauer & Oberwinkler 1997 Entorrhizomycetes is the sole class in the phylum Entorrhizomycota , within the Fungi subkingdom Dikarya along with Basidiomycota and Ascomycota . It contains three genera and is a small group of teliosporic root parasites that form galls on plants in the Juncaceae (rush) and Cyperaceae (sedge) families. Prior to 2015 this phylum

52-466: A convenient "artificial key" according to his Systema Sexuale , largely based on the arrangement of flowers. In botany, classes are now rarely discussed. Since the first publication of the APG system in 1998, which proposed a taxonomy of the flowering plants up to the level of orders, many sources have preferred to treat ranks higher than orders as informal clades . Where formal ranks have been assigned,

78-412: A general definition of a class is available, it has historically been conceived as embracing taxa that combine a distinct grade of organization—i.e. a 'level of complexity', measured in terms of how differentiated their organ systems are into distinct regions or sub-organs—with a distinct type of construction, which is to say a particular layout of organ systems. This said, the composition of each class

104-420: A sister group to Basidiomycota or a sister group to Dikarya as a whole. Entorrhizomycetes share many traits with basidiomycetes such as dikaryotic vegetative mycelium, fibrillate cell walls, hyphal septa with a tripartite profile, and similarities in the spindle pole body . Bauer et al. speculated that the teliospore tetrad in entorrhizomycetes might represent the ancestral state of dikaryan meiosporangia. This

130-516: Is based on the observation that the septa in the tetrads have pores, and that the tetrad compartments germinate into hyphae terminating in propagules. The basidial cells separated by pored septa in basidiomycete phragmobasidia represent meiospores that in turn release vegetative propagules (that are usually characterised as basidiospores ). It is possible that an ancestral structure similar to the teliospore tetrad evolved into phragmobasidia which in turn evolved into holobasidia on multiple occasions during

156-636: Is diagnosed by teliospores with longitudinally ridged or cerebriform ornamentation and infecting plants belonging to Cyperaceae , whilst Juncorrhiza is diagnosed by teliospores with verrucose-tuberculate ornamentation and infecting plants belonging to Juncaceae . Talbotiomyces is distinguished from species in Entorrhizales by hyphal septa with simple pores that lack caps or membranes (species in Entorrhizales have dolipores that lack caps or membranes) and infecting plants belonging to Caryophyllales . Molecular phylogeny place Entorrhizomycetes as either

182-518: Is estimated to approximately 42 Mya. Both Entorrhiza and Juncorrhiza underwent a major radiation during the Oligocene and Miocene epochs. Given that these divergence estimates are incongruent or only slightly congruent with the estimated stem ages of the host plant lineages, and incongruence in the co-phylogeny between Entorrhizales and host plants, host-shift speciation is more likely to have occurred than co-speciation during these divergences and

208-775: Is the last of the three geologic eras of the Proterozoic eon , spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era and succeeded by the Paleozoic era of the Phanerozoic eon, and is further subdivided into three periods , the Tonian , Cryogenian and Ediacaran . One of the most severe glaciation event known in

234-431: Is ultimately determined by the subjective judgment of taxonomists . In the first edition of his Systema Naturae (1735), Carl Linnaeus divided all three of his kingdoms of nature ( minerals , plants , and animals ) into classes. Only in the animal kingdom are Linnaeus's classes similar to the classes used today; his classes and orders of plants were never intended to represent natural groups, but rather to provide

260-721: The Mayanian (from 1000 to 850 Ma) followed by the Baikalian (from 850 to 650 Ma). The idea of the Neoproterozoic Era was introduced in the 1960s. Nineteenth-century paleontologists set the start of multicellular life at the first appearance of hard-shelled arthropods called trilobites and archeocyathid sponges at the beginning of the Cambrian Period. In the early 20th century, paleontologists started finding fossils of multicellular animals that predated

286-805: The Vendian , while Chinese geologists referred to it as the Sinian , and most Australians and North Americans used the name Ediacaran. However, in 2004, the International Union of Geological Sciences ratified the Ediacaran Period to be a geological age of the Neoproterozoic, ranging from 635 to 538.8 (at the time to 542) million years ago. The Ediacaran Period boundaries are the only Precambrian boundaries defined by biologic Global Boundary Stratotype Section and Points , rather than

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312-785: The Cambrian. A complex fauna was found in South West Africa in the 1920s but was inaccurately dated. Another fauna was found in South Australia in the 1940s, but it was not thoroughly examined until the late 1950s. Other possible early animal fossils were found in Russia, England, Canada, and elsewhere (see Ediacaran biota ). Some were determined to be pseudofossils , but others were revealed to be members of rather complex biotas that remain poorly understood. At least 25 regions worldwide have yielded metazoan fossils older than

338-402: The Neoproterozoic (early Tonian), but physical evidence for such animal life is lacking. Possible keratose sponge fossils have been reported in reefs dated to c. 890 million years before the present, but remain unconfirmed. The nomenclature for the terminal period of the Neoproterozoic Era has been unstable. Russian and Nordic geologists referred to the last period of the Neoproterozoic as

364-462: The classical Precambrian–Cambrian boundary (which is currently dated at 538.8  million years ago ). A few of the early animals appear possibly to be ancestors of modern animals. Most fall into ambiguous groups of frond-like organisms; discoids that might be holdfasts for stalked organisms ("medusoids"); mattress-like forms; small calcareous tubes; and armored animals of unknown provenance. These were most commonly known as Vendian biota until

390-632: The equator—a state known as the " Snowball Earth ". Neoproterozoic time is subdivided into the Tonian (1000–720 Ma), Cryogenian (720–635 Ma) and Ediacaran (635–538.8 Ma) periods. In the regional timescale of Russia, the Tonian and Cryogenian correspond to the Late Riphean ; the Ediacaran corresponds to the Early to middle Vendian. Russian geologists divide the Neoproterozoic of Siberia into

416-495: The fact that host plants don't show any aboveground symptoms of infection, and there might be species that don't cause galls on their hosts. Class (biology) The class as a distinct rank of biological classification having its own distinctive name – and not just called a top-level genus (genus summum) – was first introduced by French botanist Joseph Pitton de Tournefort in the classification of plants that appeared in his Eléments de botanique of 1694. Insofar as

442-854: The formal naming of the Period, and are currently known as Ediacaran Period biota. Most were soft bodied. The relationships, if any, to modern forms are obscure. Some paleontologists relate many or most of these forms to modern animals. Others acknowledge a few possible or even likely relationships but feel that most of the Ediacaran forms are representatives of unknown animal types. In addition to Ediacaran biota, two other types of biota were discovered in China. The Doushantuo Formation (of Ediacaran age) preserves fossils of microscopic marine organisms in great detail. The Huainan biota (of late Tonian age) consists of small worm-shaped organisms. Molecular phylogeny suggests that animals may have emerged even earlier in

468-494: The geologic record occurred during the Cryogenian period of the Neoproterozoic, when global ice sheets may have reached the equator and created a " Snowball Earth " lasting about 100 million years. The earliest fossils of complex life are found in the Tonian period in the form of Otavia , a primitive sponge , and the earliest fossil evidence of metazoan radiation are found in the Ediacaran period, which included

494-584: The late Mesoproterozoic, straddled the equator. During the Tonian, rifting commenced which broke Rodinia into a number of individual land masses. Possibly as a consequence of the low-latitude position of most continents, several large-scale glacial events occurred during the Neoproterozoic Era including the Sturtian and Marinoan glaciations of the Cryogenian Period. These glaciations are believed to have been so severe that there were ice sheets at

520-559: The namesaked Ediacaran biota as well as the oldest definitive cnidarians and bilaterians in the fossil record. According to Rino and co-workers, the sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust. At the onset of the Neoproterozoic the supercontinent Rodinia , which had assembled during

546-413: The radiation of Entorrhizales. Entorrhizomycetes have much lower number of species and more limited host range than their estimated age would indicate. One possible explanation is that many lineages have gone extinct along with their hosts during mass extinction events in the past. Another explanation is that much of the diversity in this phylum remains undiscovered. The latter explanation is supported by

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572-505: The ranks have been reduced to a very much lower level, e.g. class Equisitopsida for the land plants, with the major divisions within the class assigned to subclasses and superorders. The class was considered the highest level of the taxonomic hierarchy until George Cuvier 's embranchements , first called Phyla by Ernst Haeckel , were introduced in the early nineteenth century. Neoproterozoic Gradstein et al., 2012 Ediacaran Period, 630–541.0 Ma The Neoproterozoic Era

598-870: The roots of hosts. Galls are tubercular with a globoid, irregular or elongated shape and are composed of vascular bundles , parenchymatous cells and fungal mycelium . Younger segments of the galls are pale in color whilst older segments turn brown. Mycelium consists of dikaryotic and septate hyphae with fibrillate walls that lack clamp connections . Initially, the mycelium grows intercellularily before producing coiled intracellular hyphae terminating in globose cells that detach and develop into teliospores . Teliospores germinate into tetrads through internal septation, and each tetrad compartment produce hyphae that terminate in sigmoid propagules. Bauer et al. noted that young teliospores have two nuclei, older teliospores have only one nucleus, and each tetrad compartment has one nucelus each. This indicates that karyogamy and meiosis occurs in

624-434: The teliospore. It has been observed that teliospores are liberated when the host plant dies and the galls disintegrate, and that the number of galls is higher in waterlogged soils compared to well-drained soils. These observations might support the hypothesis that entorrhizomycetes disperse through soil moisture . Both Talbotiomyces and Juncorrhiza are segregate taxa from Entorrhiza sensu lato. Entorrhiza sensu stricto

650-549: The transition from water-dispersal to air-dispersal. If entorrhizomycetes are sister to Dikarya, it is also possible that the teliospore tetrad is homologous to the meiospore tetrads of early-diverging ascomycetes. The stem age of the Entorrhizomycota has been estimated to approximately 560 Mya during the late Neoproterozoic era. Divergence between Talbotiomycetales and Entorrhizales is estimated to approximately 50 Mya, and divergence between Entorrhiza and Juncorrhiza

676-439: Was placed under the subdivision Ustilaginomycotina . A 2015 study did a "comprehensive five-gene analyses" of Entorrhiza and concluded that the former class Entorrhizomycetes is possibly either a close sister group to the rest of Dikarya or Basidiomycota. Taxonomy based on the work of Wijayawardene et al. 2019. All members of Entorrhizomycetes are obligate parasites on the roots of plants. Sori are produced as galls on

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