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Paracercomonadida
The paracercomonads are a group of cercozoan protists. Taxonomically, they comprise the family Paracercomonadidae, order Paracercomonadida and subclass Paracercomonada. Due to their morphological similarities to the cercomonads, members of this family were grouped with ''Cercomonas'' and similar taxa from the beginning. However, their similarities are due to convergent evolution. Classification There are currently 5 genera of paracercomonads: *'' Brevimastigomonas'' *'' Metabolomonas'' *'' Nucleocercomonas'' *''Paracercomonas ''Paracercomonas'' is a genus of rhizaria. It includes the species ''Paracercomonas marina''. Species * '' P. ambulans'' Howe & Cavalier-Smith 2009 * '' P. astra'' Howe & Cavalier-Smith 2009 * '' P. baikali'' Howe et al. 2011 * '' P. bassi'' B ...'' *'' Phytocercomonas'' References {{Cercozoa-stub Cercozoa families ... [...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] |
Cercomonadidae
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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracercomonas
''Paracercomonas'' is a genus of rhizaria. It includes the species ''Paracercomonas marina''. Species * '' P. ambulans'' Howe & Cavalier-Smith 2009 * '' P. astra'' Howe & Cavalier-Smith 2009 * '' P. baikali'' Howe et al. 2011 * '' P. bassi'' Brabender et al. 2012 * '' P. compacta'' Bass & Cavalier-Smith 2009 * '' P. crassicauda'' (Dujardin 1841) Bass & Cavalier-Smith 2009 * '' P. ekelundi'' Cavalier-Smith & Bass 2006 * '' P. elongata'' Howe & Cavalier-Smith 2009 * '' P. filosa'' Bass & Cavalier-Smith 2009 * '' P. kruegeri'' Brabender et al. 2012 * '' P. marina'' Cavalier-Smith & Bass 2006 * '' P. metabolica'' (Mylnikov 1992) Cavalier-Smith & Bass 2006 * '' P. minima'' (Mylnikov 1985) Bass & Cavalier-Smith 2009 * '' P. oxoniensis'' Howe & Cavalier-Smith 2009 * '' P. paralaciniaegerens'' Bass & Cavalier-Smith 2009 * '' P. pleomorpha'' Bass & Cavalier-Smith 2009 * '' P. proboscata'' Brabender et al. 2012 * '' P. producta'' Howe & Cavalier-Smith 2009 * '' P. saepenatans'' Vickerman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercozoan
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 by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protists
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 exclusion of other eukaryotes means that protists do not form a natural group, or clade. Therefore, some protists may be more closely related to animals, plants, or fungi than they are to other protists. However, like the groups ''algae'', ''invertebrates'', and ''protozoans'', the biological category ''protist'' is used for convenience. Others classify any unicellular eukaryotic microorganism as a protist. The study of protists is termed protistology. History The classification of a third kingdom separate from animals and plants was first proposed by John Hogg in 1860 as the kingdom Protoctista; in 1866 Ernst Haeckel also proposed a third kingdom Protista as "the kingdom of primitive forms". Originally these also included prokaryotes, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
