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Loukozoa
Loukozoa (+ Ancyromonads) (From Greek ''loukos'': groove) is a proposed taxon used in some classifications of eukaryotes, consisting of the Metamonada and Malawimonadea. Ancyromonads are closely related to this group, as sister of the entire group, or as sister of the Metamonada. Amorphea may have emerged in this grouping, specifically as sister of the Malawimonads. Originally, Loukozoa included Anaeromonadea and Jakobea. In 2013, it consisted of three subphyla: Eolouka (Tsukubea and Jakobea), Metamonada and Neolouka (''Malawimonas''). Cavalier-Smith has recently removed Eolouka from Loukozoa, placing it instead in Discoba Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a formal taxon. It contains a variety of fre .... With the root of the Eukaryota likely close to or in Loukozoa or Discoba, these groupings are studied to giv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancyromonadida
Ancyromonadida or Planomonadida is a small group of biflagellated protists found in the soil and in aquatic habitats, where they feed on bacteria.Cavalier-Smith, T. (2013)Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa European journal of protistology, 49(2), 115-178. Includes freshwater or marine organisms, benthic, dorsoventrally compressed and with two unequal flagellae, each emerging from a separate pocket. The apical anterior flagellum can be very thin or end in the cell membrane, while the posterior flagellum is long and is inserted ventrally or laterally. The cell membrane is supported by a thin single layer teak and the mitochondrial crests are discoidal / flat. The group's placement is doubtful, as it seems to fall outside the five supergroups of eukaryotes. Cavalier-Smith considers that they constitute a basal group to Amoebozoa and Opisthokonta and places it together w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a 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 three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamonad
The metamonads are microscopic eukaryotic organisms, a large group of flagellate amitochondriate Loukozoa. Their composition is not entirely settled, but they include the retortamonads, diplomonads, and possibly the parabasalids and oxymonads as well. These four groups are all anaerobic (many being aerotolerant anerobes), occurring mostly as symbiotes or parasites of animals, as is the case with ''Giardia lamblia'' which causes diarrhea in mammals. Characteristics A number of parabasalids and oxymonads are found in termite guts, and play an important role in breaking down the cellulose found in wood. Some other metamonads are parasites. These flagellates are unusual in lacking mitochondria. Originally they were considered among the most primitive eukaryotes, diverging from the others before mitochondria appeared. However, they are now known to have lost mitochondria secondarily, and retain both organelles and nuclear genes derived from them. Mitochondrial relics include h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malawimonas
''Malawimonas'' is a Loukozoa genus, possible sister of the Podiata. History of the discovery of Malawimonads In 1993, Charles J O’ Kelly studied the jakobid groups flagellates and implications for the early diversification of eukaryotes and recognized that ''Jakoba, Reclimonas,'' and ''Histonia'' or often refer as “core jakobids” were morphologically somewhat similar. Interestingly, they included an unnamed and undescribed free-swimming, flagellate, and also groove- bearing cell. During the early study, these cells were thought to be a member from ''Jakoba'' due to the external morphology features that resembles ''Jakoba libera'' in terms of lack of cell covering, sessile trophic stages, swimming in a similar manner and sharing the tendency for the anterior flagellum to form a “crook. However, later discovery found that this species seems to not fit and can not be assigned to the genus ''Jakoba'', nor to any other genus of Jakobids, because of their discoidal mitochond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discoba
Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a formal taxon. It contains a variety of free-living and symbiotic forms, and also includes some important parasites of humans, including '' Giardia'' and ''Trichomonas''. Excavates were formerly considered to be included in the now obsolete Protista kingdom. They are classified based on their flagellar structures, and they are considered to be the most basal flagellate lineage. Phylogenomic analyses split the members of Excavata into three different and not all closely related groups: Discobids, Metamonads and Malawimonads. Except for Euglenozoa, they are all non-photosynthetic. Characteristics Most excavates are unicellular, heterotrophic flagellates. Only the Euglenozoa are photosynthetic. In some (particularly anaerobic intestinal parasites), the mitochondria have been gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excavata
Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a formal taxon. It contains a variety of free-living and symbiotic forms, and also includes some important parasites of humans, including ''Giardia'' and ''Trichomonas''. Excavates were formerly considered to be included in the now obsolete Protista kingdom. They are classified based on their flagellar structures, and they are considered to be the most basal flagellate lineage. Phylogenomic analyses split the members of Excavata into three different and not all closely related groups: Discobids, Metamonads and Malawimonads. Except for Euglenozoa, they are all non-photosynthetic. Characteristics Most excavates are unicellular, heterotrophic flagellates. Only the Euglenozoa are photosynthetic. In some (particularly anaerobic intestinal parasites), the mitochondria have been greatly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolouka
Malawimonadidae is a group of unicellular eukaryotes of outsize importance in understanding eukaryote phylogeny. Phylogeny Taxonomy * Phylum Neolouka Cavalier-Smith 2013 ** Class Malawimonadea Cavalier-Smith 2003 *** Order Malawimonadida Cavalier-Smith 2003 **** Family Malawimonadidae O’Kelly & Nerad 1999 ***** Genus '' Gefionella'' Heiss, Ekelund & Simpson 2018 ****** Species '' G. okellyi'' Heiss, Ekelund & Simpson 2018 ***** Genus ''Malawimonas ''Malawimonas'' is a Loukozoa genus, possible sister of the Podiata. History of the discovery of Malawimonads In 1993, Charles J O’ Kelly studied the jakobid groups flagellates and implications for the early diversification of eukaryotes and ...'' O’Kelly & Nerad 1999 ****** Species '' M. californiana'' ****** Species '' M. jakobiformis'' O’Kelly & Nerad 1999 References Excavata families {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malawimonadea
Malawimonadidae is a group of unicellular eukaryotes of outsize importance in understanding eukaryote phylogeny. Phylogeny Taxonomy * Phylum Neolouka Cavalier-Smith 2013 ** Class Malawimonadea Cavalier-Smith 2003 *** Order Malawimonadida Cavalier-Smith 2003 **** Family Malawimonadidae O’Kelly & Nerad 1999 ***** Genus '' Gefionella'' Heiss, Ekelund & Simpson 2018 ****** Species '' G. okellyi'' Heiss, Ekelund & Simpson 2018 ***** Genus ''Malawimonas ''Malawimonas'' is a Loukozoa genus, possible sister of the Podiata. History of the discovery of Malawimonads In 1993, Charles J O’ Kelly studied the jakobid groups flagellates and implications for the early diversification of eukaryotes and ...'' O’Kelly & Nerad 1999 ****** Species '' M. californiana'' ****** Species '' M. jakobiformis'' O’Kelly & Nerad 1999 References Excavata families {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Cavalier-Smith
Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford. His research has led to discovery of a number of unicellular organisms (protists) and advocated for a variety of major taxonomic groups, such as the Chromista, Chromalveolata, Opisthokonta, Rhizaria, and Excavata. He was known for his systems of classification of all organisms. Life and career Cavalier-Smith was born on 21 October 1942 in London. His parents were Mary Maude (née Bratt) and Alan Hailes Spencer Cavalier Smith. He was educated at Norwich School, Gonville and Caius College, Cambridge (MA) and King's College London (PhD). He was under the supervision of Sir John Randall for his PhD thesis between 1964 and 1967; his thesis was entitled "''Organelle Development in'' Chlamydomonas reinhardii". From 1967 to 1969, Cavalier-Smith was a guest investigato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varisulca
Varisulca was a proposed basal Podiate taxon. It encompassed several lineages of heterotrophic protists, most notably the ancyromonads (planomonads), collodictyonids (diphylleids), rigifilids (''Rigifila'', ''Micronuclearia'') and mantamonadids. Recent evidence suggests that the latter three are closely related to each other, forming a clade called CRuMs, but that this is unlikely to be specifically related to ancyromonads Cavalier-Smith had proposed the new subphylum Varisulca which consists of the classes Hilomonadea, Diphyllatea and Glissodiscea. The validity of this proposed taxonomy has yet to ruled upon by the Society of Protistologists. It is unlikely to be widely accepted, since Varisulca appears to be paraphyletic or polyphyletic (ancyromonads are not inferred to be the sister group to CRuMs). Glissodiscea and Multirhiza (a taxon encompassing Diphyllatea and Glissodiscea) also appear paraphyletic or polyphyletic, since ''Mantamonas'' belongs to CRuMs but ancyrom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaeromonadea
Anaeromonadea is a class of excavates, comprising the oxymonads and ''Trimastix ''Trimastix'' is a genus of excavates, the sole occupant of the order Trimastigida. ''Trimastix'' are bacterivorous, free living and anaerobic. When first observed in 1881 by William Kent, the morphology of Trimastix was not well describedKent, ...''. Another name used is "Preaxostyla". Phylogeny and Taxonomy Based on the work of Zhang et al. 2015. References External links Tree of Life: Preaxostyla Metamonads Excavata classes {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jakobid
Jakobids are an order of free-living, heterotrophic, flagellar eukaryotes in the supergroup Excavata. They are small (less than 15 μm), and can be found in aerobic and anaerobic environments. The order Jakobida, believed to be monophyletic, consists of only twenty species at present, and was classified as a group in 1993. There is ongoing research into the mitochondrial genomes of jakobids, which are unusually large and bacteria-like, evidence that jakobids may be important to the evolutionary history of eukaryotes. Molecular phylogenetic evidence suggests strongly that jakobids are most closely related to Heterolobosea (Percolozoa) and Euglenozoa. Structure and Biology Jakobids have two flagella, inserted in the anterior end of the cell, and, like other members of order Excavata, have a ventral feeding groove and associated cytoskeleton support. The posterior flagella has a dorsal vane and is aligned within the ventral groove, where it generates a current that the cell uses f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
