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Xenambulacraria
Xenambulacraria is a proposed clade of animals with bilateral symmetry as an embryo, consisting of the Xenacoelomorpha (i.e., ''Xenoturbella'' and acoelomorphs) and the Ambulacraria (i.e., echinoderms and hemichordates). If confirmed, the clade would either be the sister group to the chordates (if deuterostomes are monophyletic) or the sister group to all the other bilaterians, grouped together in Centroneuralia (with deuterostomes being paraphyletic). Although the validity of the clade relies mostly on phylogenomics, molecular genetics studies have proposed pigment cell clusters expressing polyketide synthase (PKS) and sulfotransferase as a synapomorphy of Xenambulacraria. Phylogeny Xenambulacraria has usually been recovered as a clade inside of either of two distinct phylogenies. Basal Xenambulacraria The following phylogeny assumes a paraphyletic Deuterostomia, with Xenambulacraria at the base of Bilateria. Xenambulacraria inside Deuterostomia The following ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bilateria
Bilateria () is a large clade of animals characterised by bilateral symmetry during embryonic development. This means their body plans are laid around a longitudinal axis with a front (or "head") and a rear (or "tail") end, as well as a left–right–symmetrical belly ( ventral) and back ( dorsal) surface. Nearly all bilaterians maintain a bilaterally symmetrical body as adults; the most notable exception is the echinoderms, which have pentaradial symmetry as adults, but bilateral symmetry as embryos. With few exceptions, bilaterian embryos are triploblastic, having three germ layers: endoderm, mesoderm and ectoderm, and have complete digestive tracts with a separate mouth and anus. Some bilaterians lack body cavities, while others have a primary body cavity derived from the blastocoel, or a secondary cavity, the coelom. Cephalization is a characteristic feature among most bilaterians, where the sense organs and central nerve ganglia become concentrated at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenacoelomorpha
Xenacoelomorpha () is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2011 and suggested based on morphological synapomorphies (physical appearances shared by the animals in the clade), which was then confirmed by phylogenomic analyses of molecular data (similarities in the DNA of the animals within the clade). Phylogenetics Prior to molecular studies, xenacoelomorphs were considered to be flatworms based on their superficial similarities. Like flatworms, they do not have a coelom and are dorsoventrally flattened. With the advent of phylogenetics, '' Xenoturbella'' and Acoelomorpha were found to be sister groups and only distantly related to flatworms. Initially this phylum was considered to be a member of the deuterostomes, but because of recent transcriptome analyses, it was concluded that phylum Xenacoelomorpha is the sister group to the Nephrozoa, which includes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centroneuralia
Centroneuralia is a proposed clade of animals with bilateral symmetry as an embryo, consisting of the Chordata and Protostomia, united by the presence of a central nervous system. An alternative to the traditional protostome-deuterostome dichotomy, it has found weak support in several studies. Under this hypothesis, Centroneuralia would be sister to Xenambulacraria (Xenacoelomorpha + Ambulacraria) at the base of Bilateria Bilateria () is a large clade of animals characterised by bilateral symmetry during embryonic development. This means their body plans are laid around a longitudinal axis with a front (or "head") and a rear (or "tail") end, as well as a left� .... Centroneuralia, as a proposed clade, originates in phylogenomics. More precisely, recent studies correlate support for Deuterostomia with simpler, site-homogeneous models, while more sophisticated and site-heterogeneous models recover Centroneuralia more often. Phylogeny References {{Taxonbar, from= ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deuterostome
Deuterostomes (from Greek: ) are bilaterian animals of the superphylum Deuterostomia (), typically characterized by their anus forming before the mouth during embryonic development. Deuterostomia comprises three phyla: Chordata, Echinodermata, Hemichordata, and the extinct clade Cambroernida. In deuterostomes, the developing embryo's first opening (the blastopore) becomes the anus and cloaca, while the mouth is formed at a different site later on. This was initially the group's distinguishing characteristic, but deuterostomy has since been discovered among protostomes as well. The deuterostomes are also known as enterocoelomates, because their coelom develops through pouching of the gut, enterocoely. Deuterostomia's sister clade is Protostomia, animals that develop mouth first and whose digestive tract development is more varied. Protostomia includes the ecdysozoans and spiralians, as well as the extinct '' Kimberella''. Together with the Xenacoelomorpha, these constit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoelomorph
Acoelomorpha is a subphylum of very simple and small soft-bodied animals with planula-like features which live in marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, such as algae and corals.Cannon, L. R. G. (1986) ''Turbellaria of the World. A guide to families and genera''. Brisbane, Queensland Museum, 136 p. With the exception of two acoel freshwater species, all known acoelomorphs are marine. Systematics Etymology The term "acoelomorph" derives from the Ancient Greek words (), the ''alpha privative'', expressing negation or absence, (), meaning "cavity", and (), meaning "form". This refers to the fact that acoelomorphs have a structure lacking a fluid-filled body cavity. Classification The subphylum Acoelomorpha is divided into two classes. There are at least 408 described species, with a majority of these falling within the Crucimusculata infraorder in Acoela. * Acoela comprise small fla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambulacraria
Ambulacraria , or Coelomopora , is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member of this group is called an ambulacrarian. Phylogenetic analysis suggests the echinoderms and hemichordates separated around 533 million years ago. The Ambulacraria are part of the deuterostomes, a clade that also includes the many Chordata, and the few extinct species belonging to the Vetulicolia. Phylogeny The two living clades with representative organisms are: * Echinodermata (sea stars, sea urchins, brittle stars, sea cucumbers, feather stars, sea lilies, etc.) * Hemichordata ( acorn worms (Enteropnuesta) and Pterobranchia (including Graptolithina)) (These together sometimes are called the ''lower deuterostomes''.) Whether the Xenacoelomorpha clade is the sister group to the Ambulacraria remains a contentious issue, with some authors arguing that the former should be placed more basally among metazoans, and other authors asserting that the best choice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoelomorpha
Acoelomorpha is a subphylum of very simple and small soft-bodied organism, soft-bodied animals with planula-like features which live in marine (ocean), marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, such as algae and corals.Cannon, L. R. G. (1986) ''Turbellaria of the World. A guide to families and genera''. Brisbane, Queensland Museum, 136 p. With the exception of two acoel freshwater species, all known acoelomorphs are marine. Systematics Etymology The term "acoelomorph" derives from the Ancient Greek words (), the ''alpha privative'', expressing negation or absence, (), meaning "cavity", and (), meaning "form". This refers to the fact that acoelomorphs have a structure lacking a fluid-filled body cavity. Classification The subphylum Acoelomorpha is divided into two classes. There are at least 408 described species, with a majority of these falling within the Crucimusculata infraorder in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deuterostomia
Deuterostomes (from Ancient Greek, Greek: ) are bilaterian animals of the superphylum Deuterostomia (), typically characterized by their anus forming before the mouth during embryogenesis, embryonic development. Deuterostomia comprises three Phylum, phyla: chordate, Chordata, Echinodermata, hemichordate, Hemichordata, and the extinct clade Cambroernida. In deuterostomes, the developing embryo's first opening (the blastopore) becomes the anus and cloaca, while the mouth is formed at a different site later on. This was initially the group's distinguishing characteristic, but deuterostomy has since been discovered among protostomes as well. The deuterostomes are also known as enterocoelomates, because their coelom develops through pouching of the gut, enterocoely. Deuterostomia's sister clade is Protostomia, animals that develop mouth first and whose digestive tract development is more varied. Protostomia includes the ecdysozoans and spiralians, as well as the extinct ''Kimberella'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel Phenotypic trait, character or character state that has evolution, evolved from its ancestral form (or Plesiomorphy and symplesiomorphy, plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxon, taxa and is therefore Hypothesis#Scientific hypothesis, hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies Homology (biology), homology. Examples of apomorphy are the presence of Terrestrial locomotion#Posture, erect gait, fur, Evolution of mammalian auditory ossicles, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a Terrestrial locomotion#Posture, sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfotransferase
In biochemistry, sulfotransferases (SULTs) are transferase enzymes that catalyze the transfer of a sulfo group () from a donor molecule to an acceptor alcohol () or amine (). The most common sulfo group donor is 3'-phosphoadenosine-5'-phosphosulfate (PAPS). In the case of alcohol as acceptor, the product is a sulfate (): :\ce \ + \ \ce \quad \xrightarrowtext\quad \ce \ + \ \ce whereas an amine leads to a sulfamate (): :\ce \ + \ \ce \quad \xrightarrowtext\quad \ce \ + \ \ce Both reactive groups for a sulfonation via sulfotransferases may be part of a protein, lipid, carbohydrate or steroid. Examples The following are examples of sulfotransferases: * carbohydrate sulfotransferase: CHST1, CHST2, CHST3, CHST4, CHST5, CHST6, CHST7, CHST8, CHST9, CHST10, CHST11, CHST12, CHST13, CHST14 * galactose-3-O-sulfotransferase: GAL3ST1, GAL3ST2, GAL3ST3, GAL3ST4 * heparan sulfate 2-O-sulfotransferase: HS2ST1 * heparan sulfate 3-O-sulfotransferase: HS3ST1, HS3S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
