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Xenacoelomorpha

Xenacoelomorpha ( Africâner )

fornecido por wikipedia AF
Klades
  • Nemertodermatida
  • Acoela
  • Xenoturbella

Die Xenacoelomorpha is 'n filum van tweesydig simmetriese wurmagtige diere (Bilateria) wat geen regte maagdermstelsel, anus, nephridia of bloedsomloop het nie. Hulle is die eenvoudigste Bilateria en word op grond van DNS-navorsing as 'n sustergroep van die Nephrozoa beskou, wat die Proto- en Deuterostomia bevat. Hulle taksonomiese posisie is nogtans nie heeltemal duidelik nie.[1]

Bilateria Nephrozoa

Protostomia



Deuterostomia




Xenacoelomorpha



Die filum bestaan uit drie groepe (klasse):

  1. Nemertodermatida
  2. Acoela
  3. Xenoturbella

Die oudste Bilateria het dalk soos die Acoela gelyk: 'n tweesydig simmetriese liggaam met drie lae selle, net een opening in die epidermis wat tot 'n liggaamsholte toegang gee. Hierdie organismes was waarskynlik benties.

Verwysings

  1. Xenacoelomorpha is the sister group to Nephrozoa Johanna Taylor Cannon et al Nature Letter doi:10.1058/nature16520
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Xenacoelomorpha: Brief Summary ( Africâner )

fornecido por wikipedia AF

Die filum bestaan uit drie groepe (klasse):

Nemertodermatida Acoela Xenoturbella

Die oudste Bilateria het dalk soos die Acoela gelyk: 'n tweesydig simmetriese liggaam met drie lae selle, net een opening in die epidermis wat tot 'n liggaamsholte toegang gee. Hierdie organismes was waarskynlik benties.

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wikipedia AF

Xenacoelomorpha ( Alemão )

fornecido por wikipedia DE
Wissenschaftlicher Name Xenacoelomorpha Philippe et al., 2011

Die Xenacoelomorpha sind ein erst 2009 beschriebener Stamm wurmartiger Tiere. Er besteht aus zwei Unterstämmen, den Acoelomorpha mit etwa 370 Arten und den nur aus sechs Arten bestehenden Xenoturbellida. Beide Unterstämme hatten ursprünglich selber den Rang von Stämmen.

Merkmale

Die Arten der Xenacoelomorpha werden häufig nur wenige Millimeter groß, die bislang größte bekannte Art Xenoturbella monstrosa kann jedoch eine Länge von bis zu 20 Zentimetern erreichen.[1] Sie besitzen keinen durchgängigen Darm, keinen After (der Mund dient auch als Ausscheidungsorgan), keine Kiemenbögen und kein Coelom (Körperhöhle). Sie leben im Meer, zwischen den Partikeln des Sediments, planktonisch, auf der Oberfläche von Algen oder Korallen oder im Darm von Seegurken, ernähren sich dort meist von organischen Partikeln und entwickeln sich direkt ohne Larvenstadium.

Systematik

Die Acoelomorpha wurden ursprünglich zur Klasse der Strudelwürmer (Turbellaria) und damit zum Stamm der Plattwürmer (Plathelminthes) gezählt, später an die Basis der Bilateria gestellt[2]. Auch die Xenoturbellida wurden nach ihrer Entdeckung und Erstbeschreibung den Strudelwürmern zugeordnet.[3] 2003 wurden sie, nach langer Unsicherheit und verschiedenen Hypothesen, zunächst in die Neumünder gestellt.[4]

Untersuchungen der microRNA, von Aminosäuren der komplett sequenzierten mitochondrialen DNA einiger Arten, sowie von mehreren hundert Genen zeigten eine Verwandtschaft dieser Tiere miteinander und mit den Deuterostomia. So wurde das Gen RSB66 nachgewiesen, das bisher nur bei Deuterostomiern gefunden werden konnte. Auch die microRNA der Xenacoelomorpha ist bisher nur von Stachelhäutern und Eichelwürmern, zwei Taxa der Deuterostomia, bekannt. Nach einer 2011 formulierten Hypothese, die auf dem Vergleich verschiedener homologer DNA-Sequenzen beruht (Phylogenomik), ergab sich eine Position der Gruppe innerhalb der Deuterostomia.[5] Die Xenacoelomorpha haben, dieser Hypothese zufolge, im Laufe der Evolution ihren Bauplan vereinfacht und viele der für Deuterostomier charakteristischen Merkmale verloren, so dass mit Ausnahme einiger Merkmale der Feinstruktur der Epidermis[6] keinerlei morphologische Merkmale für diese Platzierung existieren. Die Studie wurde allerdings aus methodischen Gründen kritisiert.[7] Spätere Analysen ergaben eine abweichende Position[8][9] Demnach ist die Gruppe wahrscheinlicher die Schwestergruppe der übrigen Bilateria zusammengenommen, das heisst der gemeinsamen Gruppe aus Protostomia und Deuterostomia, als Taxon Nephrozoa genannt. Diese Platzierung ist aber noch mit Unsicherheiten behaftet[10] und kann sich durch neuere Erkenntnisse erneut verschieben.

Die systematische Position der Xenacoelomorpha, dieser Hypothese zufolge, zeigt das folgende Kladogramm:

Bilateria

Xenacoelomorpha


Nephrozoa

Deuterostomia


Protostomia




Vorlage:Klade/Wartung/Style

Literatur

  • Hiroaki Nakano, Kennet Lundin, Sarah J. Bourlat, Maximilian J. Telford, Peter Funch, Jens R. Nyengaard, Matthias Obst, Michael C. Thorndyke: Xenoturbella bocki exhibits direct development with similarities to Acoelomorpha. In: Nature Communications. Article number: 1537, Februar 2013, doi:10.1038/ncomms2556
  • Seth Tyler, Stephen Schilling: Phylum Xenacoelomorpha. (PDF; 33 kB). In: Zootaxa. 3148, Magnolia Press, 2011.

Einzelnachweise

  1. Greg W. Rouse, Nerida G. Wilson, Jose I. Carvajal, Robert C. Vrijenhoek: New deep-sea species of Xenoturbella and the position of Xenacoelomorpha. In: Nature. 530, 4. Februar 2016, S. 94–97 doi:10.1038/nature16545
  2. A. Mwinyi, X. Bailly, S. J. Bourlat, U. Jondelius, D. T. J. Littlewood, L. Podsiadlowski: The phylogenetic position of Acoela as revealed by the complete mitochondrial genome of Symsagittifera roscoffensis. In: BMC Evolutionary Biology. 10, 2010, S. 309. doi:10.1186/1471-2148-10-309
  3. E. Westblad: Xenoturbella bocki n.g., n.sp., a peculiar, primitive turbellarian type. In: Arkiv för Zoologi. Vol. 1, 1949, S. 3–29.
  4. S. J. Bourlat, C. Nielsen, A. E. Lockyer, D. Timothy, J. Littlewood, M. J. Telford: Xenoturbella is a deuterostome that eats molluscs. In: Nature. Vol. 424, 2003, S. 925–928, (nature.com)
  5. Hervé Philippe, Henner Brinkmann, Richard R. Copley, Leonid L. Moroz, Hiroaki Nakano, Albert J. Poustka, Andreas Wallberg, Kevin J. Peterson, Maximilian J. Telford: Acoelomorph flatworms are deuterostomes related to Xenoturbella. In: Nature. 470, 10. Februar 2011, S. 255–258, doi:10.1038/nature09676
  6. K. J. Pedersen, L. R. Pedersen: Ultrastructural observations on the epidermis of Xenoturbella bocki Westblad, 1949, with a discussion of epidermal cytoplasmic filament systems of Invertebrates. In: Acta Zoologica. 69, 1988, S. 231–246. doi:10.1111/j.1463-6395.1988.tb00920.x
  7. Amy Maxmen: A can of worms. In: Nature. 470, 2011, S. 161–162. (PDF)
  8. J. T. Cannon, B. Cossermelli, J. Smith III, F. Ronquist, U. Jondelius, A. Hejnol: Xenacoelomorpha is the sister group to Nephrozoa. In: Nature. 530, 2016, S. 89–93. doi:10.1038/nature16520
  9. G. W. Rouse, N. G. Wilson, J. I. Carvajal, R. C. Vrijenhoek: New deep-sea species of Xenoturbella and the position of Xenacoelomorpha. In: Nature. 530, 2016, S. 94–97. doi:10.1038/nature16545
  10. Iñaki Ruiz-Trillo, Jordi Paps: Acoelomorpha: earliest branching bilaterians or deuterostomes? In: Organisms Diversity & Evolution. 16 (2), 2016, S. 391–399. doi:10.1007/s13127-015-0239-1
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Xenacoelomorpha: Brief Summary ( Alemão )

fornecido por wikipedia DE

Die Xenacoelomorpha sind ein erst 2009 beschriebener Stamm wurmartiger Tiere. Er besteht aus zwei Unterstämmen, den Acoelomorpha mit etwa 370 Arten und den nur aus sechs Arten bestehenden Xenoturbellida. Beide Unterstämme hatten ursprünglich selber den Rang von Stämmen.

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wikipedia DE

Xenacoelomorpha ( Interlingua (Associação Internacional de Línguas Auxiliares) )

fornecido por wikipedia emerging languages

Xenacoelomorpha es un taxon.

Classification

Es un phylo del superphylo Deuterostomia, regno Animalia.

Cladogram

Deuterostomia

Xenacoelomorpha


Ambulacraria

Hemichordata



Echinodermata





Chordata



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Xenacoelomorpha ( Macedônio )

fornecido por wikipedia emerging languages

Xenacoelomorphaколено на мали и многу едноставни двострани животни, во кое спаѓаат потколената Xenoturbellida и Acoelomorpha. Првичната причина за заедничко групирање на овие две групи биле морфолошките синапоморфии,[1] кои подоцна биле потврдени со филогеномски анализи на молекуларни податоци.[2][3] Xenacoelomorpha еволуирале како сестрински клад на Nephrozoa.

Филогенетика

Кладот Xenacoelomorpha, во кој се групирани Acoelomorpha и родот Xenoturbella, бил откриен со помош на молекуларни истражувања.[2] Првично се сметало дека кладот припаѓа на второусните (деутеростоми),[3] но поновите анализи на транскриптомот заклучиле дека тој е всушност сестринска група на кладот Nephrozoa, кој ги опфаќа второусните заедно со првоусните (протостоми). Од овие причини Xenacoelomorpha се смета за најбазалниот клад на двостраните животни.[4][5]

Карактеристики

Кај сите припадници на Xenacoelomorpha недостасува типичен стоматогастричен систем, односно, тие немаат вистински гастроинтестинален систем. Кај Acoela, устата се отвора директно во голем ендодермален синцитиум, додека кај Nemertodermatida и Xenoturbellida постои вреќесто „црево“ кое е обложено со слој на клетки без трепки.[6]

Нервниот систем е базиепидермален, односно, се наоѓа веднаш под епидермисот. Кај Xenoturbellida тој се состои од едноставна нервна мрежа, без каква било посебна концентрација на неврони, додека кај Acoelomorpha тој се состои од серија на лонгитудинални (надолжни) снопови кои се обединуваат во предниот регионот со прстенеста комисура, која има варијабилна комплексност.[7]

Сетилните органи ги вклучуваат статоцистот и, кај некои групи, две едноклеточни оцели.[6][7]

Епидермисот на сите припадници на Xenacoelomorpha поседува трепки (цилии). Трепките се изградени од збир на девет пара на периферни микротубули и еден или два централни микротубули (9+1 и 9+2, соодветно). Паровите 4-7 завршуваат пред врвот, градејќи структура која се нарекува „полица“.[8]

Поврзано

Наводи

  1. Lundin, K. The epidermal ciliary rootlets of Xenoturbella bocki (Xenoturbellida) revisited: new support for a possible kinship with the Acoelomorpha (Platyhelminthes). „Zoologica Scripta“ том 27 (3): 263–270. doi:10.1111/j.1463-6409.1998.tb00440.x.
  2. 2,0 2,1 Hejnol, A.; Obst, M.; Stamatakis, A.; Ott, M.; Rouse, G. W.; Edgecombe, G. D.. Assessing the root of bilaterian animals with scalable phylogenomic methods. „Proceedings of the Royal Society B: Biological Sciences“ том 276 (1677): 4261–4270. doi:10.1098/rspb.2009.0896. PMID 19759036.
  3. 3,0 3,1 Philippe, H.; Brinkmann, H.; Copley, R. R.; Moroz, L. L.; Nakano, H.; Poustka, A. J.; Wallberg, A.; Peterson, K. J.; и др. (10 февруари 2011 г). Acoelomorph flatworms are deuterostomes related to Xenoturbella. „Nature“ том 470 (7333): 255–258. doi:10.1038/nature09676. PMID 21307940. Bibcode: 2011Natur.470..255P.
  4. Perseke, M.; Hankeln, T.; Weich, B.; Fritzsch, G.; Stadler, P.F.; Israelsson, O.; Bernhard, D.; Schlegel, M. (август 2007 г). The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis. „Theory Biosci“ том 126 (1): 35–42. doi:10.1007/s12064-007-0007-7. PMID 18087755. http://www.bioinf.uni-leipzig.de/Publications/PREPRINTS/07-009.pdf.
  5. Cannon, J.T.; Vellutini, B.C.; Smith, J.; Ronquist, F.; Jondelius, U.; Hejnol, A. (4 февруари 2016 г). Xenacoelomorpha is the sister group to Nephrozoa. „Nature“ том 530 (7588): 89–93. doi:10.1038/nature16520. PMID 26842059. Bibcode: 2016Natur.530...89C. http://urn.kb.se/resolve?urn=urn:nbn:se:nrm:diva-1844.
  6. 6,0 6,1 Achatz, Johannes G.; Chiodin, Marta; Salvenmoser, Willi; Tyler, Seth; Martinez, Pedro (јуни 2013 г). The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis). „Organisms Diversity & Evolution“ том 13 (2): 267–286. doi:10.1007/s13127-012-0112-4. ISSN 1439-6092. PMID 24098090.
  7. 7,0 7,1 Perea-Atienza, E.; Gavilan, B.; Chiodin, M.; Abril, J. F.; Hoff, K. J.; Poustka, A. J.; Martinez, P.. The nervous system of Xenacoelomorpha: a genomic perspective. „Journal of Experimental Biology“ том 218 (4): 618–628. doi:10.1242/jeb.110379. ISSN 0022-0949. PMID 25696825.
  8. Franzen, Ake; Afzelius, Bjorn A. (јануари 1987 г). The ciliated epidermis of Xenoturbella bocki (Platyhelminthes, Xenoturbellida) with some phylogenetic considerations. „Zoologica Scripta“ том 16 (1): 9–17. doi:10.1111/j.1463-6409.1987.tb00046.x. ISSN 0300-3256.
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Xenacoelomorpha ( Bósnia )

fornecido por wikipedia emerging languages

Xenacoelomorpha je novoimenovano koljeno morskih životinja koje obuhvata crve Acoelomorpha i Xenoturbellida[2], a za koje se zna da imaju zajednčkog pretka od kojih su evoluirale Deuterostomia. To je mala grupa gotovo isključivo morskih crvolikih i dorzoventralno spljoštenih crva, identifikovana filogenomskom analizom, jer je prethodno smatrano da spadaju u Plathelmintes (trakavice).[3] Prema većini studija, smatraju se vrlo primitivnom grupom i postavljaju ih kao bazna grupa Bilateralia; iako ih druge studije povezuju sa složenim skupinama poput hordata.[4]

Opis

Ovo je koljeno jednostavnih organizama, kojima nedostaje tipski probavni sistem, odnosno nemaju ispravo crievo, nego crevnu vrećicu bez anusa. Imaju jednostavan, difuzni i subepidermni nervni sistem; nedostaju im mozag, ali imaju senzor statocist a ponekad i dvije fotosenzitivne ocele.[5] Oni su Acoelomata i Bilateralia, imaju specifičnu trepljastu epidermu koja ih razlikuje od ostalih bilateralnih životinja; usta se postavljaju ventralno. Nedostaje im organiziraan cirkulacijski, mokraćni i reprodukcijski sistem. Mišići su kružni i uzdužni. Nemaju lerveni stadij.[6]

Taksonomija

Koljeno Xenacoelomorpha

Također pogledajte

Reference

  1. ^ Acoelomorph flatworms are deuterostomes related to Xenoturbella
  2. ^ WoRMS Xenacoelomorpha
  3. ^ Hervé Philippe et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470, 255–258 (10 Feb 2011) doi:10.1038/nature09676
  4. ^ Xenacoelomorpha – a new phylum in the animal kingdom © 2003-2015, Max-Planck-Gesellschaft, München
  5. ^ Achatz, Johannes G.; Chiodin, Marta; Salvenmoser, Willi; Tyler, Seth; Martinez, Pedro (June 2013). "The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis)". Organisms Diversity & Evolution. 13 (2): 267–286. doi:10.1007/s13127-012-0112-4. ISSN 1439-6092.
  6. ^ Sinauer Associates 2016, Introduction to the Bilateria and the Phylum Xenacoelomorpha. Chapter 9.

Vanjski linmkovi

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Xenacoelomorpha ( North Frisian )

fornecido por wikipedia emerging languages
Amrum.pngTekst üüb Öömrang

Xenacoelomorpha san en stam faan diarten, di iarst 2009 beskrewen wurden as. Di stam faadet tau onerstamer tuup, diar tuföören aanj stamer wiar: Acoelomorpha mä amanbi 370 slacher an Xenoturbellida mä sääks slacher.

Iindialang

  • Onerstam: Acoelomorpha
    Klas: Acoela
    Familin: Actinoposthiidae - Anaperidae - Antigonariidae - Antroposthiidae - Childiidae - Convolutidae - Dakuidae - Diopisthoporidae - Hallangiidae - Haploposthiidae - Hofsteniidae - Isodiametridae - Mecynostomidae - Nadinidae - Otocelididae - Paratomellidae - Polycanthiidae - Proporidae - Sagittiferidae - Solenofilomorphidae - Taurididae
    Klas: Nemertodermatida
    Famile: Ascopariidae
    Famile: Nemertodermatidae
  • Onerstam: Xenoturbellida
    Klas: -
    Famile: Xenoturbellidae

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Wikipedia authors and editors
original
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wikipedia emerging languages

Xenacoelomorpha: Brief Summary ( Bósnia )

fornecido por wikipedia emerging languages

Xenacoelomorpha je novoimenovano koljeno morskih životinja koje obuhvata crve Acoelomorpha i Xenoturbellida, a za koje se zna da imaju zajednčkog pretka od kojih su evoluirale Deuterostomia. To je mala grupa gotovo isključivo morskih crvolikih i dorzoventralno spljoštenih crva, identifikovana filogenomskom analizom, jer je prethodno smatrano da spadaju u Plathelmintes (trakavice). Prema većini studija, smatraju se vrlo primitivnom grupom i postavljaju ih kao bazna grupa Bilateralia; iako ih druge studije povezuju sa složenim skupinama poput hordata.

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Autori i urednici Wikipedije
original
visite a fonte
site do parceiro
wikipedia emerging languages

Xenacoelomorpha: Brief Summary ( Macedônio )

fornecido por wikipedia emerging languages

Xenacoelomorpha — колено на мали и многу едноставни двострани животни, во кое спаѓаат потколената Xenoturbellida и Acoelomorpha. Првичната причина за заедничко групирање на овие две групи биле морфолошките синапоморфии, кои подоцна биле потврдени со филогеномски анализи на молекуларни податоци. Xenacoelomorpha еволуирале како сестрински клад на Nephrozoa.

licença
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Direitos autorais
Автори и уредници на Википедија
original
visite a fonte
site do parceiro
wikipedia emerging languages

Xenacoelomorpha: Brief Summary ( North Frisian )

fornecido por wikipedia emerging languages

Xenacoelomorpha san en stam faan diarten, di iarst 2009 beskrewen wurden as. Di stam faadet tau onerstamer tuup, diar tuföören aanj stamer wiar: Acoelomorpha mä amanbi 370 slacher an Xenoturbellida mä sääks slacher.

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original
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wikipedia emerging languages

ज़ीनासीलोमोर्फ़ा ( Hindi )

fornecido por wikipedia emerging languages

ज़ीनासीलोमोर्फ़ा (Xenacoelomorpha) बहुत सूक्ष्म और सरल प्राणियों का एक क्लेड है, जो बाइलेटेरिया (द्विभागीय सममिति रखने वाले) समूह का एक उपसमूह है। बाइलेटेरिया में नेफ़्रोज़ोआ और ज़ीनासीलोमोर्फ़ा दो क्लेड आते हैं।[1][2]

इन्हें भी देखें

सन्दर्भ

  1. Philippe, H.; Brinkmann, H.; Copley, R. R.; Moroz, L. L.; Nakano, H.; Poustka, A. J.; Wallberg, A.; Peterson, K. J.; Telford, M. J. (10 February 2011). "Acoelomorph flatworms are deuterostomes related to Xenoturbella". Nature. 470 (7333): 255–258. PMID 21307940. डीओआइ:10.1038/nature09676. बिबकोड:2011Natur.470..255P.
  2. Hejnol, A., Obst, M., Stamatakis, A., Ott, M., Rouse, G. W., Edgecombe, G. D., et al. (2009). Assessing the root of bilaterian animals with scalable phylogenomic methods. Proceedings of the Royal Society, Series B, 276, 4261–4270.
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विकिपीडिया के लेखक और संपादक
original
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wikipedia emerging languages

ज़ीनासीलोमोर्फ़ा: Brief Summary ( Hindi )

fornecido por wikipedia emerging languages

ज़ीनासीलोमोर्फ़ा (Xenacoelomorpha) बहुत सूक्ष्म और सरल प्राणियों का एक क्लेड है, जो बाइलेटेरिया (द्विभागीय सममिति रखने वाले) समूह का एक उपसमूह है। बाइलेटेरिया में नेफ़्रोज़ोआ और ज़ीनासीलोमोर्फ़ा दो क्लेड आते हैं।

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wikipedia emerging languages

Xenacoelomorpha ( Inglês )

fornecido por wikipedia EN

Xenacoelomorpha[2] /ˌzɛnəˌsɛlˈmɔːrfə/ is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2016 and suggested based on morphological synapomorphies (physical appearances shared by the animals in the clade),[3] which was then confirmed by phylogenomic analyses of molecular data (similarities in the DNA of the animals within the clade).[2][4]

Phylogenetics

The clade (groupings of organisms based on their most recent shared/common ancestors) Xenacoelomorpha groups the Acoelomorpha and the genus Xenoturbella, due to molecular studies.[4] Initially this phylum was considered to be a member of the deuterostomes,[2] (meaning during development, as an embryo, the anus develops first and then the mouth), but because of recent transcriptome analysis, it was concluded that phylum Xenacoelomorpha is the sister group (two closest relatives in a phylogenetic tree) to the Nephrozoa, which includes both the protostomes (where in development of the embryo, the mouth forms first, then the anus) and the deuterostomes, therefore phylum Xenacoelomorpha is the basalmost bilaterian clade.[5][6] This would mean they are neither a deuterostome nor protostome.

However, some studies point out that their basal placement may be caused by high mutation rates leading to long branch attraction (LBA). These analyses suggest that the xenacoelomorphs are instead the sister group of Ambulacraria forming the clade Xenambulacraria and that despite their simple body plans, they actually derive from a more complex ancestor.[7][8] Having a larger number of species within this group would allow for better conclusions and analysis to be made within the phylum and in groups closely related to the phylum.

Characteristics

All species within phylum xenacoelomorphs are bilateral, meaning they have a mirror image on their right and left axis, like humans. While they are triploblasts (meaning they have the three germ layers: ectoderm, endoderm, and mesoderm) they do not have a true body cavity (they lack a coelom) because they have an acoelomate body plan. While animals that are diploblastic (only have two germ layers: ectoderm and endoderm) also lack a coelom, they do not have an acoelomate body plan because they lack the mesoderm germ layer. In acoels, the mouth opens directly into a large endodermal syncytium, while in nemertodermatids and xenoturbellids there is a sack-like gut lined by unciliated cells.[9]

The nervous system is basiepidermal, i.e., located right under the epidermis, and a brain is absent. In xenoturbellids it is constituted by a simple nerve net without any special concentration of neurons, while in acoelomorphs it is arranged in a series of longitudinal bundles united in the anterior region by a ring comissure of variable complexity.[10]

The sensory organs include a statocyst (for balance) and some groups have two unicellular ocelli (simple eyes).[9][10]

The epidermis of all species within the phylum is ciliated. The cilia are composed of a set of 9 pairs of peripheral microtubules and one or two central microtubules (patterns 9+1 and 9+2, respectively). The pairs 4–7 terminate before the tip, creating a structure called a "shelf".[11]

This phylum consists of species that are free-living, parasitic, and symbiotic. They are small flat like worms found in marine and sometimes brackish water environments, on the sediments. They can be found at depths of almost 4 km and near hydrothermal vents. The phylum is hermaphrodite (male and female sex organs) and reproduces sexually with direct development, meaning they skip the vulnerable larval stage.

See also

References

  1. ^ Tyler, S.; Schilling, S.; Hooge, M.; Bush, L.F. (2006–2016). "Xenacoelomorpha". Turbellarian taxonomic database. Version 1.7. Retrieved 3 February 2016.
  2. ^ a b c Philippe, H.; Brinkmann, H.; Copley, R. R.; Moroz, L. L.; Nakano, H.; Poustka, A. J.; Wallberg, A.; Peterson, K. J.; Telford, M. J. (10 February 2011). "Acoelomorph flatworms are deuterostomes related to Xenoturbella". Nature. 470 (7333): 255–258. Bibcode:2011Natur.470..255P. doi:10.1038/nature09676. PMC 4025995. PMID 21307940.
  3. ^ Lundin, K (1998). "The epidermal ciliary rootlets of Xenoturbella bocki (Xenoturbellida) revisited: new support for a possible kinship with the Acoelomorpha (Platyhelminthes)". Zoologica Scripta. 27 (3): 263–270. doi:10.1111/j.1463-6409.1998.tb00440.x. S2CID 85324766.
  4. ^ a b Hejnol, A.; Obst, M.; Stamatakis, A.; Ott, M.; Rouse, G. W.; Edgecombe, G. D.; et al. (2009). "Assessing the root of bilaterian animals with scalable phylogenomic methods". Proceedings of the Royal Society B: Biological Sciences. 276 (1677): 4261–4270. doi:10.1098/rspb.2009.0896. PMC 2817096. PMID 19759036.
  5. ^ Perseke, M.; Hankeln, T.; Weich, B.; Fritzsch, G.; Stadler, P.F.; Israelsson, O.; Bernhard, D.; Schlegel, M. (August 2007). "The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis" (PDF). Theory Biosci. 126 (1): 35–42. CiteSeerX 10.1.1.177.8060. doi:10.1007/s12064-007-0007-7. PMID 18087755. S2CID 17065867.
  6. ^ Cannon, J.T.; Vellutini, B.C.; Smith, J.; Ronquist, F.; Jondelius, U.; Hejnol, A. (4 February 2016). "Xenacoelomorpha is the sister group to Nephrozoa". Nature. 530 (7588): 89–93. Bibcode:2016Natur.530...89C. doi:10.1038/nature16520. PMID 26842059. S2CID 205247296.
  7. ^ Philippe, Hervé; Poustka, Albert J.; Chiodin, Marta; Hoff, Katharina J.; Dessimoz, Christophe; Tomiczek, Bartlomiej; Schiffer, Philipp H.; Müller, Steven; Domman, Daryl; Horn, Matthias; Kuhl, Heiner; Timmermann, Bernd; Satoh, Noriyuki; Hikosaka-Katayama, Tomoe; Nakano, Hiroaki; Rowe, Matthew L.; Elphick, Maurice R.; Thomas-Chollier, Morgane; Hankeln, Thomas; Mertes, Florian; Wallberg, Andreas; Rast, Jonathan P.; Copley, Richard R.; Martinez, Pedro; Telford, Maximilian J. (2019). "Mitigating Anticipated Effects of Systematic Errors Supports Sister-Group Relationship between Xenacoelomorpha and Ambulacraria". Current Biology. 29 (11): 1818–1826.e6. doi:10.1016/j.cub.2019.04.009. hdl:21.11116/0000-0004-DC4B-1. ISSN 0960-9822. PMID 31104936. S2CID 155104811.
  8. ^ Kapli, Paschalia; Telford, Maximilian J. (11 December 2020). "Topology-dependent asymmetry in systematic errors affects phylogenetic placement of Ctenophora and Xenacoelomorpha". Science Advances. 6 (10): eabc5162. doi:10.1126/sciadv.abc5162. PMC 7732190. PMID 33310849.
  9. ^ a b Achatz, Johannes G.; Chiodin, Marta; Salvenmoser, Willi; Tyler, Seth; Martinez, Pedro (June 2013). "The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis)". Organisms Diversity & Evolution. 13 (2): 267–286. doi:10.1007/s13127-012-0112-4. ISSN 1439-6092. PMC 3789126. PMID 24098090.
  10. ^ a b Perea-Atienza, E.; Gavilan, B.; Chiodin, M.; Abril, J. F.; Hoff, K. J.; Poustka, A. J.; Martinez, P. (2015). "The nervous system of Xenacoelomorpha: a genomic perspective". Journal of Experimental Biology. 218 (4): 618–628. doi:10.1242/jeb.110379. ISSN 0022-0949. PMID 25696825.
  11. ^ Franzen, Ake; Afzelius, Bjorn A. (January 1987). "The ciliated epidermis of Xenoturbella bocki (Platyhelminthes, Xenoturbellida) with some phylogenetic considerations". Zoologica Scripta. 16 (1): 9–17. doi:10.1111/j.1463-6409.1987.tb00046.x. ISSN 0300-3256. S2CID 85675105.
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Xenacoelomorpha: Brief Summary ( Inglês )

fornecido por wikipedia EN

Xenacoelomorpha /ˌzɛnəˌsɛloʊˈmɔːrfə/ is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2016 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).

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Wikipedia authors and editors
original
visite a fonte
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wikipedia EN

Xenacoelomorpha ( Espanhol; Castelhano )

fornecido por wikipedia ES

Los xenacelomorfos (Xenacoelomorpha) son un pequeño grupo de gusanos casi exclusivamente marinos vermiformes y aplanados dorsoventralmente, identificados como nuevo filo a través del análisis filogenómico, ya que antes eran considerados platelmintos.[1]

La mayoría de estudios los consideran un grupo muy primitivo y situado como el grupo basal de los bilaterales;[2]​ aunque otros estudios los relacionan con los ambulacrarios.[3]​ El clado de ambulacrarios y xenacelomorfos se denomina Xenambulacraria y se ha sugerido que representa el clado basal de Bilateria[4]​ con los cordados evolucionando en una posición cercana a los protóstomos y que Deuterostomia no es compatible.[5]​ Siendo que la mayoría de los estudios han encontrado que Deuterostomia es monofilético.

Características

Son simples, carecen de un sistema estomatogástrico típico, es decir no poseen un verdadero intestino, sino un saco intestinal sin ano. Tienen un sistema nervioso simple, difuso y subepidérmico; carecen de cerebro, pero tienen un estatocisto sensorial y a veces dos ocelos.[6]

Son acelomados y bilaterales, tienen una epidermis ciliada específica que los diferencia de los demás animales bilaterales; la boca se sitúa ventralmente; carecen de sistema circulatorio, urinario y reproductivo organizado. Los músculos son circulares y longitudinales. No poseen formas larvales.[7]

Filogenia

Cladograma basado en análisis genéticos:[8]

Bilateria

XenacoelomorphaSterreria rubra2.png


Nephrozoa Protostomia

SpiraliaGrapevinesnail 01.jpg



Ecdysozoa European wasp white bg02.jpg



Deuterostomia

AmbulacrariaAquilonastra coronata.jpg



Chordata Jackal Cape cross 2009 white background.JPG





Taxonomía

Filo Xenacoelomorpha

Referencias

  1. Hervé Philippe et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470, 255–258 (10 Feb 2011) doi:10.1038/nature09676
  2. Canon, J.T.; Vellutini, B.C.; Smith, J.; Ronquist, F.; Jondelius, U.; Hejnol, A. (4 de febrero de 2016). «Xenacoelomorpha is the sister group to Nephrozoa». Nature 530 (7588): 89-93. PMID 26842059. doi:10.1038/nature16520.
  3. Xenacoelomorpha – a new phylum in the animal kingdom © 2003-2015, Max-Planck-Gesellschaft, München
  4. Philippe, Hervé; Poustka, Albert J.; Chiodin, Marta; Hoff, Katharina J.; Dessimoz, Christophe; Tomiczek, Bartlomiej; Schiffer, Philipp H.; Müller, Steven; Domman, Daryl; Horn, Matthias; Kuhl, Heiner; Timmermann, Bernd; Satoh, Noriyuki; Hikosaka-Katayama, Tomoe; Nakano, Hiroaki; Rowe, Matthew L.; Elphick, Maurice R.; Thomas-Chollier, Morgane; Hankeln, Thomas; Mertes, Florian; Wallberg, Andreas; Rast, Jonathan P.; Copley, Richard R.; Martinez, Pedro; Telford, Maximilian J. (2019). «Mitigating Anticipated Effects of Systematic Errors Supports Sister-Group Relationship between Xenacoelomorpha and Ambulacraria». Current Biology 29 (11): 1818-1826.e6. ISSN 0960-9822. PMID 31104936. doi:10.1016/j.cub.2019.04.009. Parámetro desconocido |hdl= ignorado (ayuda)
  5. Marlétaz, Ferdinand; Peijnenburg, Katja T. C. A.; Goto, Taichiro; Satoh, Noriyuki; Rokhsar, Daniel S. (2019). «A new spiralian phylogeny places the enigmatic arrow worms among gnathiferans». Current Biology 29 (2): 312-318.e3. doi:10.1016/j.cub.2018.11.042.
  6. Achatz, Johannes G.; Chiodin, Marta; Salvenmoser, Willi; Tyler, Seth; Martinez, Pedro (June 2013). "The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis)". Organisms Diversity & Evolution. 13 (2): 267–286. doi:10.1007/s13127-012-0112-4. ISSN 1439-6092.
  7. Sinauer Associates 2016, Introduction to the Bilateria and the Phylum Xenacoelomorpha. Chapter 9.
  8. Johanna Taylor Cannon et al. 2016, Xenacoelomorpha is the sister group to Nephrozoa. Nature volume 530, pages 89–93 (04 February 2016) doi:10.1038/nature16520

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original
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Xenacoelomorpha: Brief Summary ( Espanhol; Castelhano )

fornecido por wikipedia ES

Los xenacelomorfos (Xenacoelomorpha) son un pequeño grupo de gusanos casi exclusivamente marinos vermiformes y aplanados dorsoventralmente, identificados como nuevo filo a través del análisis filogenómico, ya que antes eran considerados platelmintos.​

La mayoría de estudios los consideran un grupo muy primitivo y situado como el grupo basal de los bilaterales;​ aunque otros estudios los relacionan con los ambulacrarios.​ El clado de ambulacrarios y xenacelomorfos se denomina Xenambulacraria y se ha sugerido que representa el clado basal de Bilateria​ con los cordados evolucionando en una posición cercana a los protóstomos y que Deuterostomia no es compatible.​ Siendo que la mayoría de los estudios han encontrado que Deuterostomia es monofilético.

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Autores y editores de Wikipedia
original
visite a fonte
site do parceiro
wikipedia ES

Siuglejad ( Estônio )

fornecido por wikipedia ET

Siuglejad (Xenacoelomorpha) on väikeste väga lihtsate ussitaoliste loomade klaad ja hõimkond kahekülgsete rühmast.

Hõimkonda kuulub kaks alamhõimkonda: umbeliselaadsed (Acoelomorpha) (umbes 370 liiki) ja ksenoturbelliidid (Xenoturbellida) (6 liiki). Varem vaadeldi neid eraldi hõimkondadena.

Taksonoomia

Hõimkonna autorid on Philippe et al. (2011). Klaadina avastasid selle Andreas Hejnol et al. (2009). Sünapomorfiate põhjal oletas umbeliselaadsete ja ksenoturbelliidide sugulust Kennet Lundin (1998).

Klassifikatsioon

Siuglejatel on kaks alamhõimkonda ning umbes 400 liiki, 115 perekonda ja 19 sugukonda.

Süstemaatika

Umbeliselaadsed arvati algul ripsusside klassi, seega lameusside hõimkonda, hiljem kahekülgsete baasi.[1]. Ka ksenoturbelliidid arvati pärast avastamist ja esmakirjeldamist lameusside hulka.[2] Aastal 2003 arvati nad pärast pikaajalist ebakindlust ja mitmesuguseid hüpoteese kõigepealt teissuuste hulka[3].

Mikro-RNA, mõnede liikide täielikult sekveneeritud mitokondriaalse DNA ning sadade geenide uurimine näitas nende loomade omavahelist sugulust ja sugulust teissuustega. Näiteks tõestati geen RSB66, mida seni oli leitud ainult teissuustelt. Ka siuglejate mikro-DNA on seni tuntud ainult kahelt teissuuste taksonilt okasnahksetelt ja neelhingsetelt. Aastal 2011 püstitatud hüpoteesi järgi, mis põhines mitmesuguste homoloogsete DNA järjestuste võrdlusel (fülogenoomika), paikneb rühm teissuuste seas[4]. Selle hüpoteesi järgi on siuglejate ehitusplaan evolutsiooni käigus lihtsustunud ning nad on kaotanud paljud teissuustele iseloomulikud tunnused, nii et peale mõnede tunnuste epidermise peenstruktuuris[5] ei ole morfoloogilisi tunnuseid nende paigutamiseks teissuuste hulka. Selle uurimuse metoodikat aga kritiseeriti.[6] Hilisemad transkriptoomiuurimused andsid tulemused teistsuguse paigutuse[7]: siuglejad on tõenäosemalt ülejäänud kahekülgsete (Nephrozoa; teissuused ja esmassuused kokku) sõsarrühm, kõige basaalsem kahekülgsete klaad. Selles paigutuses on siiski veel üht-teist ebakindlat[8] ning uuemad uurimused võivad seda veel muuta.

On välja pakutud klaad Xenambulacraria, mis ühendab siuglejad ja ambulakraarid.

Tunnused

Paljud siuglejad kasvavad ainult mõne millimeetri pikkuseks; seni suurim teadaolev liik Xenoturbella monstrosa kasvab kuni 20 cm pikkuseks.[9]

Neil ei ole läbivat soolt, pärakut (suu on ka erituselund). Umbelistel avaneb suu otse suurde süntsüütiumi, mis pärineb endodermist; teistel siuglejatel on kotitaoline sool, mida vooderdavad ripsmeteta rakud[10].

Neil ei ole lõpusekaari ega tsöloomi.

Nad elavad meres (ainult kaks teadaolevat umbeliste liiki elab magevees) setete osakeste vahel (bentos), planktonina, vetikate või korallide pinnal või meripurade sooles.

Nad toituvad enamasti orgaanilistest osakestest.

Nad arenevad otse ilma vastsestaadiumita.

Närvisüsteem on basiepidermaalne (paikneb kohe epidermise all), aju puudub. Ksenoturbelliididel on see lihtne närvivõrk, neuronite spetsialiseerunud kontsentratsioon puudub. Umbeliselaadsetel koosneb see pikikimpudest, mida eesosas ühendab varieeruva keerukusega rõngjas nide.[11]

Meeleelundite seas on statotsüstid ja mõnedel rühmadel kaks lihtsaimat üherakulist lihtsilma (otselli).[12]

Kõigi siuglejate epidermise rakkudel on ripsmed. Need koosnevad 9 paarist perifeersetest mikrotuubulitest ja 1 või 2 paarist tsentraalsetest mikrotuubulitest. Paarid 4 kuni 7 on lühemad ja moodustavad "riiuli"[13]

Viited

  1. Adina Mwinyi, X. Bailly, S. J. Bourlat, U. Jondelius, D. T. J. Littlewood, L. Podsiadlowski. The phylogenetic position of Acoela as revealed by the complete mitochondrial genome of Symsagittifera roscoffensis. – BMC Evolutionary Biology, 2010, 10, lk 309. Veebis.
  2. E. Westblad. Xenoturbella bocki n.g., n.sp., a peculiar, primitive turbellarian type.Arkiv för Zoologi, kd 1, 1949, lk 3–29.
  3. Sarah J. Bourlat, C. Nielsen, A. E. Lockyer, D. Timothy, J. Littlewood, M. J. Telford. Xenoturbella is a deuterostome that eats molluscs.Nature 2003, kd 424, lk 925–928. Resümee.
  4. Philippe et al. 2011.
  5. Knud Jørgen Pedersen, L. R. Pedersen. Ultrastructural observations on the epidermis of Xenoturbella bocki Westblad, 1949, with a discussion of epidermal cytoplasmic filament systems of Invertebrates. – Acta Zoologica, 1988, 69, lk 231–246. doi:10.1111/j.1463-6395.1988.tb00920.x
  6. Amy Maxmen. A can of worms.Nature, 2011, 470, lk 161–162. Veebis.
  7. Cannon et al. 2016, Rouse et al. 2016.
  8. Iñaki Ruiz-Trillo, Jordi Paps. Acoelomorpha: earliest branching bilaterians or deuterostomes? – Organisms Diversity & Evolution, 2016, 16 (2), lk 391–399. Veebis.
  9. Rouse et al. 2016.
  10. Achatz et al. 2013.
  11. Perea-Atienza et al. 2015.
  12. Achatz et al. 2013, Perea-Atienza et al. 2015.
  13. Åke Franzén, Björn A. Afzelius. The ciliated epidermis of Xenoturbella bocki (Platyhelminthes, Xenoturbellida) with some phylogenetic considerations. – Zoologica Scripta, 1987, 16 (1), lk 9–17.

Kirjandus

  • Kennet Lundin. The epidermal ciliary rootlets of Xenoturbella bocki (Xenoturbellida) revisited: new support for a possible kinship with the Acoelomorpha (Platyhelminthes)". – Zoologica Scripta, 27 (3), lk 263–270.Resümee.
  • Andreas Hejnol, M. Obst, A. Stamatakis, M. Ott, G. W. Rouse, G. D. Edgecombe et al. Assessing the root of bilaterian animals with scalable phylogenomic methods. – Proceedings of the Royal Society B: Biological Sciences, 2009, 276 (1677), lk 4261–4270. Veebis.
  • Hervé Philippe, Henner Brinkmann, Richard R. Copley, Leonid L. Moroz, Hiroaki Nakano, Albert J. Poustka, Andreas Wallberg, Kevin J. Peterson, Maximilian J. Telford. Acoelomorph flatworms are deuterostomes related to Xenoturbella.Nature, 10. veebruar 2011, lk 255–258, Resümee.
  • Johannes G. Achatz, Marta Chiodin, Willi Salvenmoser, Seth Tyler, Pedro Martinez. The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis). – Organisms Diversity & Evolution, 2013, 13 (2), lk 267–286. Veebis.
  • Elena Perea-Atienza, Brenda Gavilán, Marta Chiodin, Josep F. Abril, Katharina J. Hoff, Albert J. Poustka, Pedro Martinez. The nervous system of Xenacoelomorpha: a genomic perspective. – Journal of Experimental Biology, 2015, 218 (4), lk 618–628. Veebis
  • Johanna Taylor Cannon, Bruno Cossermelli Vellutini, Julian Smith, Fredrik Ronquist, Ulf Jondelius, Andreas Hejnol. Xenacoelomorpha is the sister group to Nephrozoa. – Nature, 4. veebruar 2016, 530, lk 83–93. Resümee.
  • Greg W. Rouse, Nerida G. Wilson, Jose I. Carvajal, Robert C. Vrijenhoek. New deep-sea species of Xenoturbella and the position of Xenacoelomorpha. – Nature, 4. veebruar 2016, 530, lk 94–97. Resümee.

Välislingid

Vaata ka

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Vikipeedia autorid ja toimetajad
original
visite a fonte
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wikipedia ET

Siuglejad: Brief Summary ( Estônio )

fornecido por wikipedia ET
 src= Neochildia fusca  src= Proporus

Siuglejad (Xenacoelomorpha) on väikeste väga lihtsate ussitaoliste loomade klaad ja hõimkond kahekülgsete rühmast.

Hõimkonda kuulub kaks alamhõimkonda: umbeliselaadsed (Acoelomorpha) (umbes 370 liiki) ja ksenoturbelliidid (Xenoturbellida) (6 liiki). Varem vaadeldi neid eraldi hõimkondadena.

licença
cc-by-sa-3.0
Direitos autorais
Vikipeedia autorid ja toimetajad
original
visite a fonte
site do parceiro
wikipedia ET

Xenacoelomorpha ( Francês )

fornecido por wikipedia FR

Les Xenacoelomorpha ou Xénacélomorphes sont un embranchement dont la monophylie a été découverte très récemment. Ils réunissent les Xenoturbellida et les Acoelomorpha, qui eux-mêmes regroupent les Acoela et les Nemertodermatida, deux groupes autrefois considérés comme des Turbellariés au sein des Plathelminthes.

Phylogénie et taxinomie

La place exacte du groupe dans l'arbre phylogénétique du vivant n'est pas encore déterminée : à la base des Ambulacraires au sein des Deutérostomiens (là où se trouvaient les Xénoturbellidés) ou alors à la base de tous les Bilatériens, avant la séparation entre Protostomiens et Deutérostomiens. De nombreuses espèces ont souvent été assimilées aux plathelminthes du fait de l'absence de cavité interne (coelome)[1].

En 2016, un article de Rouse, Wilson, Carvajal et Vrijenhoek publie dans la revue Nature[2] les résultats d'une vaste étude phylogénétique sur de nouveaux spécimens de Xenoturbellida : elle aboutit à classer les xénoturbellides parmi les acoelomorphes (Xenacoelomorpha), groupe sœur des bilatériens (Nephrozoa et Protostomia).

Liste des sous-embranchements et ordres

Selon World Register of Marine Species (20 décembre 2017)[3] :

Notes et références

  1. Bruno Corbara, « La ronde solaire des vers de Roscoff », sur Regards, Société Française d’Écologie, 19 décembre 2018.
  2. (en) Rouse, Wilson, Carvajal & Vrijenhoek, « New deep-sea species of Xenoturbella and the position of Xenacoelomorpha », Nature, vol. 530,‎ 2016, p. 94–97 (DOI , lire en ligne).
  3. World Register of Marine Species, consulté le 20 décembre 2017
licença
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original
visite a fonte
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wikipedia FR

Xenacoelomorpha: Brief Summary ( Francês )

fornecido por wikipedia FR

Les Xenacoelomorpha ou Xénacélomorphes sont un embranchement dont la monophylie a été découverte très récemment. Ils réunissent les Xenoturbellida et les Acoelomorpha, qui eux-mêmes regroupent les Acoela et les Nemertodermatida, deux groupes autrefois considérés comme des Turbellariés au sein des Plathelminthes.

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Auteurs et éditeurs de Wikipedia
original
visite a fonte
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wikipedia FR

Xenacoelomorpha ( Croato )

fornecido por wikipedia hr Croatian

Xenacoelomorpha, novo koljeno među morskim životinjama koje obuhvaća crve Acoelomorpha i Xenoturbellida[2], i za koje znanstvenici kažu da imaju zajednčkog pretka od kojih su se razvile drugousti (Deuterostomia).

Ovo novo koljeno opisala je tek 2011 godine skupina znanstvenika[3], za koju kažu da je mnogo bliža čovjeku, nego što je prije to smatrano, i danas se zajedno sa koljenima chordata, Echinodermata i Hemichordata svrstava kao četvrto koljeno drugousti (Deuterostomia)[4].

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Izvori

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Xenacoelomorpha ( Indonésio )

fornecido por wikipedia ID

Xenacoelomorpha adalah sebuah filum hewan yang kecil dan sederhana yang terdiri dari xenoturbellida dan acoelomorpha. Pengelompokan ini didukung oleh data molekuler.[1]

Filogeni

Klad Xenacoelomorpha terdiri dari Acoelomorpha dan genus Xenoturbella dan diungkapkan oleh studi molekuler. Awalnya klad ini dianggap sebagai anggota deuterostomia, lebih tepatnya takson saudara dari Ambulacraria, tetapi yang analisa transkriptomika terbaru menyimpulkan bahwa Xenacoelomorpha adalah kelompok saudara dari Nephrozoa, yang meliputi protostomia dan deuterostomia.[1][2]

Karakteristik

Semua xenacoelomorphs tidak mempunyai sistem stomatogastrik, yaitu, mereka tidak punya usus sejati. Di acoela, mulut terbuka langsung ke mesoderm atau menuju sinsitium yang besar, sementara di nemertodermatida dan xenoturbellida ada usus berbentuk kantong yang dilapisi oleh sel-sel tak bersilia.[3]

Sistem saraf mereka adalah basiepidermal, yaitu terletak tepat di bawah epidermis dan tidak memiliki otak. Di xenoturbellida terdiri dari jaring saraf sederhana tanpa ada konsentrasi neuron, sedangkan di acoelomorpha hal ini diatur dalam serangkaian bundel longitudinal disatukan di wilayah anterior.[4]

Organ sensorik mencakup statosista dan, dalam beberapa kelompok, dua oseli uniseluler.[3][4] Semua Xenacoelomorpha memiliki epidermis yang bersilia.

Referensi

  1. ^ a b Philippe, H.; Brinkmann, H.; Copley, R. R.; Moroz, L. L.; Nakano, H.; Poustka, A. J.; Wallberg, A.; Peterson, K. J.; Telford, M. J. (10 February 2011). "Acoelomorph flatworms are deuterostomes related to Xenoturbella". Nature. 470 (7333): 255–258. Bibcode:2011Natur.470..255P. doi:10.1038/nature09676. PMID 21307940.
  2. ^ Perseke, M.; Hankeln, T.; Weich, B.; Fritzsch, G.; Stadler, P.F.; Israelsson, O.; Bernhard, D.; Schlegel, M. (August 2007). "The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis" (PDF). Theory Biosci. 126 (1): 35–42. doi:10.1007/s12064-007-0007-7. PMID 18087755.
  3. ^ a b Achatz, Johannes G.; Chiodin, Marta; Salvenmoser, Willi; Tyler, Seth; Martinez, Pedro (June 2013). "The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis)". Organisms Diversity & Evolution. 13 (2): 267–286. doi:10.1007/s13127-012-0112-4. ISSN 1439-6092.
  4. ^ a b Perea-Atienza, E.; Gavilan, B.; Chiodin, M.; Abril, J. F.; Hoff, K. J.; Poustka, A. J.; Martinez, P. (2015). "The nervous system of Xenacoelomorpha: a genomic perspective". Journal of Experimental Biology. 218 (4): 618–628. doi:10.1242/jeb.110379. ISSN 0022-0949.
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Xenacoelomorpha: Brief Summary ( Indonésio )

fornecido por wikipedia ID

Xenacoelomorpha adalah sebuah filum hewan yang kecil dan sederhana yang terdiri dari xenoturbellida dan acoelomorpha. Pengelompokan ini didukung oleh data molekuler.

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Xenacoelomorpha ( Italiano )

fornecido por wikipedia IT
 src=

Xenacoelomorpha è un phylum basale bilaterale di animali piccoli e molto semplici, che raggruppa gli xenoturbellidi con gli acoelomorfi. È stato suggerito da sinapomorfie morfologiche e confermato da analisi filogenomiche di dati molecolari. Gli xenacoelomorfi emersero con il Nephrozoa come clade sorella.

Filogenetica

Il clade Xenacoelomorpha, che raggruppa Acoelomorpha e il genere Xenoturbella, è stato rivelato da studi molecolari. Inizialmente era considerato un membro dei deuterostomi, ma una più recente analisi del trascrittoma ha concluso che è il gruppo gemello del Nephrozoa, che comprende i protostomi e i deuterostomi, essendo quindi il clade basale più bilaterale.

Caratteristiche

Tutti gli xenacoelomorfi mancano di un tipico sistema stomatogastrico, cioè non hanno un vero intestino. Negli acelomorfi, la bocca si apre direttamente in un grande sincizio endodermico, mentre nei nemertodermatidi e negli xenoturbellidi vi è un budello simile a un sacco rivestito da cellule non ciliate. Il sistema nervoso è basiepidermico, cioè localizzato proprio sotto l'epidermide, e un cervello è assente. Negli xenoturbellidi è costituito da una semplice rete nervosa senza alcuna concentrazione speciale di neuroni, mentre negli acoelomorfi è disposto in una serie di fasci longitudinali uniti nella regione anteriore da una comissura ad anello di complessità variabile. Gli organi sensoriali comprendono una statocista e, in alcuni gruppi, due ocelli unicellulari. L'epidermide di tutti gli xenacoelomorpani è ciliata. Le ciglia sono composte da un insieme di 9 coppie di microtubuli periferici e uno o due microtubuli centrali (modelli 9 + 1 e 9 + 2, rispettivamente). Le coppie 4-7 terminano prima della punta, creando una struttura chiamata "scaffale"

Bibliografia

  • (EN) Tyler, S.; Schilling, S.; Hooge, M.; Bush, L.F. (2006–2016) "Xenacoelomorpha". Turbellarian taxonomic database. Version 1.7. Retrieved 2016-02-03.
  • (EN) Philippe, H.; Brinkmann, H.; Copley, R. R.; Moroz, L. L.; Nakano, H.; Poustka, A. J.; Wallberg, A.; Peterson, K. J.; Telford, M. J. (10 February 2011). "Acoelomorph flatworms are deuterostomes related to Xenoturbella". Nature. 470 (7333): 255–258. Bibcode:2011Natur.470..255P. doi:10.1038/nature09676. PMC 4025995 .
  • (EN) Lundin, K (1998). "The epidermal ciliary rootlets of Xenoturbella bocki (Xenoturbellida) revisited: new support for a possible kinship with the Acoelomorpha (Platyhelminthes)". Zoologica Scripta. 27: 263–270. doi:10.1111/j.1463-6409.1998.tb00440.x.
  • (EN) Hejnol, A.; Obst, M.; Stamatakis, A.; Ott, M.; Rouse, G. W.; Edgecombe, G. D.; et al. (2009). "Assessing the root of bilaterian animals with scalable phylogenomic methods". Proceedings of the Royal Society B: Biological Sciences. 276: 4261–4270. doi:10.1098/rspb.2009.0896. PMC 2817096 .
  • (EN) Perseke, M.; Hankeln, T.; Weich, B.; Fritzsch, G.; Stadler, P.F.; Israelsson, O.; Bernhard, D.; Schlegel, M. (August 2007). "The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis" (PDF). Theory Biosci. 126 (1): 35–42. doi:10.1007/s12064-007-0007-7.
 title=
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original
visite a fonte
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wikipedia IT

Xenacoelomorpha: Brief Summary ( Italiano )

fornecido por wikipedia IT
 src=

Xenacoelomorpha è un phylum basale bilaterale di animali piccoli e molto semplici, che raggruppa gli xenoturbellidi con gli acoelomorfi. È stato suggerito da sinapomorfie morfologiche e confermato da analisi filogenomiche di dati molecolari. Gli xenacoelomorfi emersero con il Nephrozoa come clade sorella.

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original
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wikipedia IT

Xenacoelomorpha ( Neerlandês; Flamengo )

fornecido por wikipedia NL

Xenacoelomorpha[1] is een stam van kleine en zeer eenvoudige diertjes, die de Xenoturbellida en Acoelomorpha groepeert. Het zijn eenvoudige in het water levende organismen, die geen coeloom (embryonale secundaire lichaamsholte) hebben. De stam is gebaseerd op morfologische synapomorfieën[2] en later nog eens bevestigd door fylogenetische analyses van moleculaire gegevens.[1][3] Xenacoelomorpha zijn een zustergroep van de Nephrozoa aangezien ze de Bilateria in twee groepen verdelen.

Kenmerken

Zenuwstelsel

De Xenacoelomorpha bezitten een eenvoudig zenuwstelsel. In sommige gevallen worden de zenuwen samengeperst tot zenuwbundels op verschillende plaatsen in het lichaam. Bovendien hebben Xenacoelomorpha een epidermaal zenuwstelsel, dat wil zeggen dat de zenuwen dicht tegen de huid gelegen zijn.[4] Ze bezitten nooit hersenen.

Spijsvertering

Sommige Xenacoelomorphen (de Xenoturbellida en Nemertodermatida) missen een typisch stomatogastrisch systeem, met andere woorden ze hebben geen echte darm. Acoela daarentegen hebben wel darmen.

Evenwicht

Het evenwichtsorgaan statocyst is aanwezig in alle Xenacoelomorpha, hetzij met verschillende ultrastructuren.[5]

Grootte

Xenacoelomorpha hebben een grootte van 100 µm - 4 cm.

Voorkomen

Buiten een paar uitzonderingen, leven alle Xenacoelomorpha in zoutwater, zoals in zeeën en oceanen.

Taxonomie

Men was voor een lange tijd niet zeker van de plaats van Xenacoelomorpha in het dierenrijk. Sommige wetenschappers formuleerde dat deze een zustergroep was van alle overblijvende Bilateria (ook wel Nephrozoa)[6][7], terwijl anderen zeiden dat het een groep was in de Deuterostomata.[8] Nu is het dus met zekerheid een zustergroep van de Nephrozoa.

Bronnen

  • Wanniger, A. (2015) Evolutionary Developmental Biology of Invertebrates 1, 251 pagina's
Bronnen, noten en/of referenties
  1. a b (10 February 2011). Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470 (7333): 255–258 . PMID: 21307940. PMC: 4025995. DOI: 10.1038/nature09676.
  2. (1998). The epidermal ciliary rootlets of Xenoturbella bocki (Xenoturbellida) revisited: new support for a possible kinship with the Acoelomorpha (Platyhelminthes). Zoologica Scripta 27: 263–270 . DOI: 10.1111/j.1463-6409.1998.tb00440.x.
  3. (2009). Assessing the root of bilaterian animals with scalable phylogenomic methods. Proceedings of the Royal Society B: Biological Sciences 276: 4261–4270 . PMID: 19759036. PMC: 2817096. DOI: 10.1098/rspb.2009.0896.
  4. Achatz en Martinez 2012; Hejnol 2015
  5. Ferrero 1973; Ehlers 1991
  6. Hejnol, A. et al. . Proc. R. Soc. B 276, 4261–4270 (2009)
  7. Srivastava, M., Mazza-Curll, K. L., van Wolfswinkel, J. C. & Reddien, P. W. . Curr. Biol. 24, 1107–1113 (2014)
  8. Philippe, H. et al. . Nature 470, 255–258 (2011)
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Xenacoelomorpha ( Romanian; Moldavian; Moldovan )

fornecido por wikipedia RO

Xenacoelomorpha este o încrengătură de animale nevertebrate cu aspect viermifor. Anterior, xenacelomorfele erau apropiate, din punct de vedere taxonomic, de viermii plați. Însă, analiza moleculară a genelor a demonstrat că grupul face parte din deuterostomate [1][2]. Xenacelomorfele se caracterizează prin ultrastructura ciliată a epiteliului și sistemul nervos difuz [3].

Note

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Xenacoelomorpha: Brief Summary ( Romanian; Moldavian; Moldovan )

fornecido por wikipedia RO

Xenacoelomorpha este o încrengătură de animale nevertebrate cu aspect viermifor. Anterior, xenacelomorfele erau apropiate, din punct de vedere taxonomic, de viermii plați. Însă, analiza moleculară a genelor a demonstrat că grupul face parte din deuterostomate . Xenacelomorfele se caracterizează prin ultrastructura ciliată a epiteliului și sistemul nervos difuz .

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Xenacoelomorpha ( Russo )

fornecido por wikipedia русскую Википедию
Царство: Животные
Подцарство: Эуметазои
Тип: Xenacoelomorpha
Международное научное название

Xenacoelomorpha Philippe et al., 2011

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Систематика
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ITIS 914162NCBI 1312402

Xenacoelomorpha (лат.)тип двусторонне-симметричных животных[1][2].

Описание

Червеобразные животные, обитатели морей. Бентосные, планктонные, а также на поверхности водорослей или кораллов, или в кишечнике морских огурцов. Длина тела от нескольких миллиметров до 10 см и более. Нервная система базиэпидермальная, мозг отсутствует. У ксенотурбеллид это простая нервная сеть, специализированная концентрация нейронов отсутствует. Органы чувств включают статоцисты и, у некоторых групп, простейшие оцеллии[3][4]. В ранге типа впервые выделены в 2011 году на основании молекулярно-генетических данных и морфологических синапоморфий (Philippe et al., 2011)[5]. Включённых в их состав Xenoturbella в 2006 году предлагалось выделить в свой отдельный тип Xenoturbellida, сестринский к кладе Ambulacraria (включающей два типа: иглокожие + полухордовые)[6][7]. Однако более современные исследования с помощью транскриптомного анализа показали (Canon et al., 2016), что клада Xenacoelomorpha, включающая Acoelomorpha и Xenoturbella, рассматривается в качестве сестринской группы к Nephrozoa, включающей в том числе примитивных Bilateraria, лежащих в основании филогенетического древа двусторонне-симметричных животных[8].

Bilateria

Xenacoelomorpha


Nephrozoa

Первичноротые (Protostomia)



Вторичноротые (Deuterostomia)




Классификация

Включает два подтипа и около 400 видов, 115 родов и 19 семейств[2].

Примечания

  1. Род Xenacoelomorpha (англ.) в Мировом реестре морских видов (World Register of Marine Species). (Проверено 22 сентября 2016).
  2. 1 2 Seth Tyler & Schilling: Phylum Xenacoelomorpha (PDF; 33 kB), Zootaxa 3148 © 2011 Magnolia Press.
  3. Achatz Johannes G., Chiodin Marta, Salvenmoser Willi, Tyler Seth, Martinez Pedro. (June 2013). “The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis)”. Organisms Diversity & Evolution. 13 (2): 267—286. DOI:10.1007/s13127-012-0112-4. ISSN 1439-6092.
  4. Perea-Atienza E., Gavilan B., Chiodin M., Abril J. F., Hoff K. J., Poustka A. J., Martinez P. (2015). “The nervous system of Xenacoelomorpha: a genomic perspective”. Journal of Experimental Biology. 218 (4): 618—628. DOI:10.1242/jeb.110379. ISSN 0022-0949.
  5. Philippe H., Brinkmann H., Copley R. R., Moroz L. L., Nakano H., Poustka A. J., Wallberg A., Peterson K. J., Telford M. J. (10 February 2011). “Acoelomorph flatworms are deuterostomes related to Xenoturbella”. Nature. 470 (7333): 255—258. Bibcode:2011Natur.470..255P. DOI:10.1038/nature09676. PMID 21307940.
  6. Bourlat Sarah J.; Juliusdottir Thorhildur; Lowe Christopher J.; Freeman Robert; Aronowicz Jochanan; Kirschner Mark; Lander Eric S.; Thorndyke Michael; Nakano Hiroaki; Kohn Andrea B.; Heyland Andreas; Moroz Leonid L.; Copley Richard R.; Telford Maximilian J. (2006). “Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida” (PDF). Nature. 444 (7115): 85—88. DOI:10.1038/nature05241. ISSN 0028-0836.
  7. Telford, M.J. (2008). Xenoturbellida: the fourth deuterostome phylum and the diet of worms. Genesis, 46: 580—586.
  8. Canon J.T., Vellutini B.C., Smith J., Ronquist F., Jondelius U., Hejnol A. (4 February 2016). “Xenacoelomorpha is the sister group to Nephrozoa”. Nature. 530 (7588): 89—93. DOI:10.1038/nature16520. PMID 26842059.
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Xenacoelomorpha: Brief Summary ( Russo )

fornecido por wikipedia русскую Википедию

Xenacoelomorpha (лат.) — тип двусторонне-симметричных животных.

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異無腔動物 ( Chinês )

fornecido por wikipedia 中文维基百科
亞門

異無腔動物Xenacoelomorpha)是包括異渦蟲無腔動物的簡單生物。這種分類的依據是分子生物學資訊與衍徴[1]

系統發生學

異無腔動物演化枝包含無腔動物與異渦蟲,在演化樹上的具體位置有多種説法[2]。起先被認爲是后口動物步帶動物旁係群,但最近的轉錄組分析表明異無腔動物在系統發生樹上位於兩側對稱動物的基部,實為腎管動物的旁係群,而腎管動物則包含所有原口動物與后口動物[1][3]

參考資料

  1. ^ 1.0 1.1 Philippe, H.; Brinkmann, H.; Copley, R. R.; Moroz, L. L.; Nakano, H.; Poustka, A. J.; Wallberg, A.; Peterson, K. J.; Telford, M. J. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature. 10 February 2011, 470 (7333): 255–258. Bibcode:2011Natur.470..255P. PMID 21307940. doi:10.1038/nature09676.
  2. ^ Cannon, J. T.; Vellutini, B. C.; Smith, J.; Ronquist, F.; Jondelius, U.; Hejnol, A. Xenacoelomorpha is the sister group to Nephrozoa. Nature: 89–93. [2016-11-29]. doi:10.1038/nature16520.
  3. ^ Perseke, M.; Hankeln, T.; Weich, B.; Fritzsch, G.; Stadler, P.F.; Israelsson, O.; Bernhard, D.; Schlegel, M. The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis (PDF). Theory Biosci. August 2007, 126 (1): 35–42. PMID 18087755. doi:10.1007/s12064-007-0007-7.
小作品圖示这是一篇关于生物小作品。你可以通过编辑或修订扩充其内容。
后鞭毛生物:动物现存分类表
侧生动物 中生动物 真后生动物
肾管动物英语Nephrozoa
未命名基群
合皮动物英语Syndermata
地位未定
吮食动物英语Rouphozoa
(?)为地位未定
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異無腔動物: Brief Summary ( Chinês )

fornecido por wikipedia 中文维基百科

異無腔動物(Xenacoelomorpha)是包括異渦蟲無腔動物的簡單生物。這種分類的依據是分子生物學資訊與衍徴

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original
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wikipedia 中文维基百科