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Sarcomonad
The sarcomonads () or class Sarcomonadea are a group of amoeboid biciliate protists in the phylum Cercozoa. They are characterized by a propensity to move through gliding on their posterior cilium or through filopodia, a lack of scales or external theca, a soft cell surface without obvious cortical filamentous or membranous skeleton, two cilia without scales or hairs, tubular mitochondrial cristae, near-spherical extrusomes, and a microbody (probably a peroxisome) attached to the nucleus. History In 1993 Cavalier-Smith described the sarcomonads as a subclass known as “Sarcomonadia”, an assemblage of unrelated cercozoans ( thaumatomonads, proteomyxids, cercomonads...) and excavates (jakobids), in the now defunct class “Heteromitea”, in the old phylum “Opalozoa”. This subclass was created to lump together protozoa that have an anisokont type of zoospore (i.e. two cilia of different lengths), are non-thecate and have isodiametric extrusomes. Sarcomonadia was composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Katabiidae
''Katabia'' is a genus of soil-dwelling heterotrophic flagellate cercozoans containing the single species ''Katabia gromovi'', and the only member of family Katabiidae. Morphology ''Katabia'' are drop-shaped unicellular flagellates with a broad anterior end and a tapering posterior end. They have two heterodynamic (with different movements) flagella. Inside their cells are a microbody, refractile granules shaped like mushrooms, kinetocysts and a well-developed cytoskeleton similar to the one found in '' Heteromita''. Their life cycle has two forms: a free-living trophozoite that feeds on bacteria through pseudopodia while swimming, and a cyst that is surrounded by a thick mucilage-like wall. Instead of gliding upon the substrate, like other cercozoans, they have secondarily lost the ability to glide with cilia, and only swim freely using their flagella. In particular, the species ''Katabia gromovi'' is a soil-dwelling flagellate with a prominent dorsal side and a flattened ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercomonas
Cercomonads are small flagellates, widespread in aqueous habitats and common in soils. Characteristics The cells are generally around 10 μm in length, without any shell or covering. They produce filose pseudopods to capture bacteria, but do not use them for locomotion, which usually takes place by gliding along surfaces. Most members have two flagella, one directed forward and one trailing under the cell, inserted at right angles near its anterior. The nucleus is connected to the flagellar bases and accompanied by a characteristic paranuclear body. Classification Genetic studies place the cercomonads among the Cercozoa, a diverse group of amoeboid and flagellate protozoans. They are divided into two families. * The Heteromitidae tend to be relatively rigid, and produce only temporary pseudopods. * The Cercomonadidae are more plastic, and when food supplies are plentiful may become amoeboid and even multinucleate. The classification of genera and species continues to u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opalozoa
Opalozoa is a subphylum of heterotrophic protists of the phylum Bigyra, and is the sister group to Sagenista. Opalozoans are non-photosynthetic heterokonts that are ancestrally phagotrophic but many times have evolved to be osmotrophic saprotrophs in the gut of vertebrate animals. Taxonomy History: phylum Opalozoa In 1993 the name “Opalozoa” referred to a group of protists that was very different from what it is now. It was a phylum composed of many unrelated zooflagellates, grouped together because of the common presence of tubular mitochondrial cristae and the lack of cortical alveoli or rigid tubular ciliary hairs ( retronemes). It also included the opalinids, proteomyxids and plasmodiophorids. Modern classification The modern taxonomy of Opalozoa, down to order level, is as follows: * Subphylum Opalozoa ** Infraphylum Bikosia *** Class Bikosea ****Subclass Bicosidia *****Superorder Cyathobodoniae ******Order Bicoecida ******Order Anoecida ******Order Pseud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercomonad
Cercomonads are small flagellates, widespread in aqueous habitats and common in soils. Characteristics The cells are generally around 10 μm in length, without any shell or covering. They produce filose pseudopods to capture bacteria, but do not use them for locomotion, which usually takes place by gliding along surfaces. Most members have two flagella, one directed forward and one trailing under the cell, inserted at right angles near its anterior. The nucleus is connected to the flagellar bases and accompanied by a characteristic paranuclear body. Classification Genetic studies place the cercomonads among the Cercozoa, a diverse group of amoeboid and flagellate protozoans. They are divided into two families. * The Heteromitidae tend to be relatively rigid, and produce only temporary pseudopods. * The Cercomonadidae are more plastic, and when food supplies are plentiful may become amoeboid and even multinucleate. The classification of genera and species continues to un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercomonadida
Cercomonads are small flagellates, widespread in aqueous habitats and common in soils. Characteristics The cells are generally around 10 μm in length, without any shell or covering. They produce filose pseudopods to capture bacteria, but do not use them for locomotion, which usually takes place by gliding along surfaces. Most members have two flagella, one directed forward and one trailing under the cell, inserted at right angles near its anterior. The nucleus is connected to the flagellar bases and accompanied by a characteristic paranuclear body. Classification Genetic studies place the cercomonads among the Cercozoa, a diverse group of amoeboid and flagellate protozoans. They are divided into two families. * The Heteromitidae tend to be relatively rigid, and produce only temporary pseudopods. * The Cercomonadidae are more plastic, and when food supplies are plentiful may become amoeboid and even multinucleate. The classification of genera and species continues to un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercozoa
Cercozoa is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major eukaryotic group to be recognized mainly through molecular phylogenies. They are the natural predators of many species of microbacteria and Archea. They are closely related to the phylum Retaria, comprising amoeboids that usually have complex shells, and together form a supergroup called Rhizaria. Characteristics The group includes most amoeboids and flagellates that feed by means of filose pseudopods. These may be restricted to part of the cell surface, but there is never a true cytostome or mouth as found in many other protozoa. They show a variety of forms and have proven difficult to define in terms of structural characteristics, although their unity is strongly supported by phylogenetic studies. Diversity Some cercozoans are grouped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thaumatomonadida
Thaumatomonadida is an order of flagellates. Taxonomy Order Thaumatomonadida Shirkina 1987 * Genus '' Cowlomonas'' Scoble & Cavalier-Smith 2014 * Genus '' Heterochromonas'' Lee & Patterson 2000 * Family Esquamulidae Shiratori, Yabuki & Ishida 2012 ** Genus '' Esquamula'' Shiratori, Yabuki & Ishida 2012 * Family Peregriniidae Cavalier-Smith 2011 ** Genus '' Gyromitus'' Skuja 1939 ** Genus '' Peregrinia'' Cavalier-Smith 2011 non Vorobyeva & Lebedev 1986 * Family Thaumatomonadidae Hollande 1952 (Thaumatomastigidae Vørs 1992; Thaumatomastigaceae Patterson & Zölffel 1991] ** Genus '' Allas (flagellate), Allas'' Sandon 1927 ** Genus '' Hyaloselene'' Skuja 1956 ** Genus ''Thaumatomastix'' Lauterborn 1899 'Chrysosphaerella'' Balonov 1980 non Lauterborn 1896; ; ''Spinifermonas">Chrysosphaerella.html" ;"title="'Chrysosphaerella">'Chrysosphaerella'' Balonov 1980 non Lauterborn 1896; ; ''Spinifermonas'' Nicholls 1984; ''Thaumatonema'' Lauterborn 1896] ** Genus ''Thaumatospina'' Scoble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proteomyxidea
Proteomyxidea is a class of Cercozoa. Although it is known to be paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ..., further research is needed before its classification can be improved. References External links Cercozoa classes {{Cercozoa-stub ... [...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] |
Protozoa
Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Historically, protozoans were regarded as "one-celled animals", because they often possess animal-like behaviours, such as motility and predation, and lack a cell wall, as found in plants and many algae. When first introduced by Georg Goldfuss (originally spelled Goldfuß) in 1818, the taxon Protozoa was erected as a class within the Animalia, with the word 'protozoa' meaning "first animals". In later classification schemes it was elevated to a variety of higher ranks, including phylum, subkingdom and kingdom, and sometimes included within Protoctista or Protista. The approach of classifying Protozoa within the context of Animalia was widespread in the 19th and early 20th century, but not universal. By the 1970s, it became usual to require th ... [...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] |
Extrusome
Extrusomes are membrane-bound structures in some eukaryotes which, under certain conditions, discharge their contents outside the cell. There are a variety of different types, probably not homologous, and serving various functions. Notable extrusomes include mucocysts, which discharge a mucous mass sometimes used in cyst formation, and trichocysts, which discharge a fibrous rod. The stinging nematocysts found in Cnidarian animals may be regarded as extrusomes as well. Extrusomes found in dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...s are important in the formation of red and black tides. References External links Image: extrusome (labeled EX) Organelles {{Protist structures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
