Newcomers
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![]() In new mouths, the original mouth (blastopore) becomes the anus (anus), the mouth opening is newly formed. |
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Scientific name | ||||||||||||
Deuterostomia | ||||||||||||
Grobben , 1908 |
The new mouths ( new mouth animals, deuterostomia) represent an overstem of the bilateral animals ( bilateria ), of which the back string animals ( chordates , chordata - including humans) and the echinoderms (echinodermata) are the main taxa . One of the two common characteristic features of the deuterostomia is the further development of the original mouth in the embryonic development . Here, in the course of gastrulation, the original mouth becomes the anus and the mouth arises again (deuterostomy). The second characteristic is the dorsal (back) position of the central nervous system (CNS). In the other two-sided animals, the protostomia, however , the original mouth becomes the mouth and the anus breaks through secondarily; the CNS lies ventrally (on the abdomen).
term
The nineteenth century saw the beginning of developmental biology . Early stages of embryonic development were closely observed and described under the microscope. The achievements of the German-Baltic naturalist Karl Ernst von Baer and the German zoologist Ernst Haeckel proved to be particularly groundbreaking and influential . The scientists recognized that the digestive tract is established in two different ways among the three-seeded animals: on the one hand the original mouth becomes the later mouth, the future intestinal tract grows through the embryo and the anus finally breaks through; at other times the original mouth becomes the later anus, the future intestinal tract grows through the embryo and the mouth finally breaks through.
This developmental difference was first interpreted in terms of evolutionary biology by the British biologist Thomas Henry Huxley in 1875 and published twice. Huxley saw in the constitution of the digestive tract a trait that had been developed by very distant ancestors and has since been inherited more and more through diversifying progeny. As a result, all three-seeded animals living today either descended from an ancestor whose embryonic primal mouth became the later mouth - primal mouths; or else they came from an ancestor whose embryonic original mouth became the later anus - new mouths. Huxley called the first group of animals the Archaeostomata and the second group of animals the Deuterostomata .
Both terms were introduced to a wider public in his textbook by the Irish anatomist Alexander MacAlister as early as the next year . However, the knowledge of the Archaeostomata and Deuterostomata remained limited to the English-speaking specialist audience. The words could not establish themselves in the German-speaking area. That is why the Austrian zoologist Berthold Hatschek coined the new word Zygoneura twelve years later for the group of animals that Huxley had previously referred to as the archaeostomata. On the other hand, Hatschek did not offer a synonym for Huxley's deuterostomata.
This technical language gap was only closed in 1908 by the Austrian zoologist Karl Grobben . For his treatise The Systematic Division of the Animal Kingdom , Grobben initially adopted the term Zygoneura from Berthold Hatschek, but added his own synonym Protostomia to it in the course of the text . And he contrasted the protostomia with that group of tricotyledonous animals whose original mouth becomes the later anus. Grobben called this group Deuterostomia .
Thirty-three years after Huxley's Deuterostomata , Karl Grobben had coined an almost identical word for the same concept. During the twentieth century Grobben's pair of terms prevailed in developmental and evolutionary biology. Berthold Hatschek's Zygoneura fell into oblivion as well as Thomas Henry Huxley's Archaeostomata and just like his deuterostomata . The biological terminology today normally only uses the terms protostomia and deuterostomia .
“New age” as an ordering characteristic
After the new age (deuterostomy) was discovered, it served to bring together the very different animal groups of the chordates (chordata), gill animals ( hemichordata ) and echinoderms (echinodermata) to form a common community of descent. The community of descent was given the name “new mouths” ( new mouths , second mouths) or Deuterostomia (from ancient Greek δεύτερο- deutero “second” and στόμα stoma “mouth”).
However, there are other animals that also show deuterostomous embryonic development. New age can be observed in arrow worms ( Chaetognatha ), as well as in some wreath antennae ( Lophophorata ) and some string worms ( Nematomorpha ) and arthropods ( Arthropoda ). For decades it was controversial whether the animals should belong to the deuterostomia. With the help of molecular biological relationship research ( phylogenomics ), great clarity has been achieved on this question. According to this, chordates, gill animals and echinoderms actually form a community of descent. The remaining animal groups mentioned do not belong to it. Instead, their deuterostomies each evolved convergently independently of one another .
Systematics
The new mouth animals (Deuterostomia) represent a large group within the system of animals . Its sister taxon are the primordial mouth animals (Protostomia). With them they form the community of descent of the kidney animals ( Nephrozoa ). The kidney animals are combined with the Xenacoelomorpha to the bilateral animals (Bilateria).
External systematics of Deuterostomia (Neumünder)
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Several animal groups are in turn assigned to the new mouths. Five of them still exist, so they're recent . Taxonomically , each is considered a stem or sub-stem . Because of certain similarities, the five groups can be assigned to a pair of even broader ancestral communities. Based on phylogenomic and comparative developmental findings, the two strains of Ambulacraria are compared to the three strains of the back-stringed animals.
Large groups of recent Deuterostomia (Neumünder)
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The system of recent newcomers, however, only gives a sketchy idea of the diversity of the animal group. Because it does not take into account that other Neumünder branches had evolved in past periods of the earth's history. Those branches are only known from fossils today. They can still be built into the existing system. However, the positions of the extinct Vetulicolia and Vetulocystida remain uncertain. Currently they are placed on the same level as the groups of echinoderms and back-string animals as a separate branch of Neumünder.
Systematics of recent and fossil deuterostomia (Neumünder) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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a : The group of mirror-symmetrical echinoderms. Echinodermata bilateralia belonged to the Paraphylum of the Homalozoa . |
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In the illustrated system specific group names are different reasons no longer uses: Acrania (Paraphylum from Leptocardia, Myllokunmingiida, Pikaiidae and Conodontophora) ambulacrals ( synonym to ambulacraria) Anencephala (synonym to Leptocardia) Branchiotremata (synonym to Hemichrodata) Cephalochordata ( synonymous with Acrania) Cirrostomi (synonymous with Leptocardia) Chordonia (synonymous with Chordata) Coelomorpha (synonymous with ambulacraria) craniota (synonymous with Craniata) Deuterostomata (synonymous with Deuterostomia) Encephalota (synonymous with Craniata) Enterocoelomata (Synonyms to Deuterostomia) Euchordata (synonym to Notochordata) Myomerozoa (synonym to Notochordata) Notochordata (Paraphylum from Acrania and Craniata) Notoneuralia (synonym to Deuterostomia) Pachycardia (synonym to Craniata) Pharyngobranchia (synonym to Leptocardia), Proto Chordata ( Paraphylum from Acrania and Tunicata), Urochordata (synonym for Tunicata), Vertebrata (synonym for Cristozoa o that of Craniata), Xenambulacraria (Paraphylum from Xenacoelomorpha and Ambulacraria), Yunnanozoa (controversial synonym for Myllokunmingiida). |
evolution
The new mouth animals are assigned to the group of kidney animals (Nephrozoa) within the bilateral animals (Bilateria). Their sister group consists of the primordial mouth animals (Protostomia). The last common ancestors of new mouth animals and primitive mouth animals therefore consisted of mirror-symmetrical kidney animals. The body of these animals had a main direction of movement ("front"). Correspondingly, more nerve cells and sensory cells were created at the front end of the body ( cephalization ). The body organs, which also included nephridia , developed from three cotyledons .
Phylogenomic studies with a molecular clock suggest that these kidney animals must have lived in the Upper Proterozoic . More precisely, they should have existed during the geological period called Cryogenium in the middle of the Sturtic Ice Age about 680 million years ago, before the lines of the new mouth animals and the primitive mouth animals finally separated. Already about 30 million years later, the new mouths split into the two groups still occurring today, the ambulacraria and the back animals (chordata). The split occurred in the warm period between the Sturtic Ice Age and the Marino Ice Age . The Cryogenium was followed by the Ediacarium . During this period there were further splits. Echinodermata (Echinodermata) and gillfish (Hemichordata) as well as lancetfish (Leptocardia), cristozoa and tunicates (Tunicata) thrived in their own lines before the Cambrian began. The soft-skinned animals were probably only a few millimeters tall. The search for their fossils has so far been unsuccessful. It was not until the fossil deposits of the Lower Cambrian that organisms were extracted that most certainly belonged to the new mouth animals. These animals, too, were hardly longer than a few centimeters. Only representatives of the new mouth branch of the Vetulicolia achieved greater body lengths, whereby the species Vetulicola longbaoshanensis represented the utmost possible with just under a decimeter.
Oldest fossil genera of Deuterostomia a, b, c
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Ambulacraria • Echinodermata • Echinodermata bilateralia | |
Ambulacraria • Echinodermata • Echinodermata asymmetrica | |
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Ambulacraria • Echinodermata • Echinodermata radiata |
Ambulacraria • Hemichordata • Enteropneusta | |
Ambulacraria • Hemichordata • Pterobranchia | |
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Chordata • Leptocardia |
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Chordata • Olfactores • Cristozoa |
Chordata • Olfactores • Tunicata | |
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Vetulicolia |
Vetulocystida | |
a : Many of the fossils come from two Cambrian fossil sites. The Maotianshan slates from southern China are 520 to 525 million years old. The Burgess Shales from western Canada are approximately 508 million years old. b : Because of its uncertain taxonomic classification, the genus Yunnanozoon (= Cathayamyrus = Zhongxiniscus , = Haikouella ) is not considered here. Perhaps it was an ancestor of the string animals (chordata). c : Because of their uncertain taxonomic classification, the Cambroernida group with its genera Herpetogaster and Phlogites is not considered here. Maybe it was ambulacraria. d : There are no fossils of lancetfish (Leptocardia). Although four fossil genera had already been assigned to the class, all four could not keep this assignment for different reasons. e : The genus Skeemella may also belong to the Vetulicolia. |
Body shapes and types of movement
The millimeter-sized representatives of the genus Saccorhytus could represent the oldest fossilized new mouth animals. The bag-like organisms were taxonomically placed in the vicinity of the Vetulicolia and Vetulocystida and found in the 535 million year old Kuanchuanpu schist in southern China. Presumably the tiny animals showed a very simplified blueprint. In contrast to Saccorhytus , the last common ancestors of all new mouths were probably worm-shaped. It has not been clarified whether the animals were stuck on the sea floor (or the like) ( benthic-sessile movement type ), crawled over the sea floor or bored through it ( benthic-vagile movement type or subbenthic-vagile movement type ) or even moved freely swimming ( pelagic -vagile movement type ), although the latter is currently considered rather unlikely.
The majority of the Ambulacraria retained the benthic way of life. The first echinoderms (Echinodermata) were built bilaterally symmetrically and moved crawling or jumping over the sea floor. But even in the Lower Cambrian, many lost their mirror symmetry in favor of asymmetrical or radially symmetrical bodies. The exchange of bilateral symmetry with radial symmetry went hand in hand with the exchange of the benthic-vagile movement type with the benthic-sessile movement type. Permanently stuck animals no longer need a body structure that is designed for one main direction of movement. All recent forms are derived from such sessile and pentaradial echinoderms; they may have emerged from the fossil genus Camptostroma . Only the larvae retained a bilaterally symmetrical structure. Besides the still sessile sea lilies, the other echinoderms groups later returned to the benthic-vagile movement type. This applies to the closely related hairy stars as well as to the entirety of the Eleutherozoa, i.e. sea cucumbers (Holothuroidea), sea urchins (Echinoidea), starfish (Asteroidea) and brittle stars (Ophiuroidea). Almost half of all today's sea urchin species (“ irregularia ”) show signs of a secondary bilateral symmetrical body shape, which was fully developed again in the sea rollers.
The other ambulacraria, the hemichordata, also settled on benthic types of movement. Acorn worms (Enteropneusta) burrow through the upper seabed, wing gills (Pterobranchia) stay in fixed tubes most of the time, which they sometimes leave by crawling. Animals from the wing-gill family of the Cephalodiscidae move around on the sea floor without ever building living tubes.
The back string animals (Chordata) on the other hand went over to a free-swimming way of life. They developed elongated and laterally flattened bodies that were stabilized with a chorda dorsalis . Today's lancet fish (Leptocardia) rarely move in open water. Instead, they bury their tail end first in coarse sand or lie flat on their side on a firmer seabed. The first olfactores probably also led a pelagic life. The early Cristozoa did not deviate from this, as can be seen from the fossils of the Myllokunmingiida, Pikaiidae and Conodontophora. The other olfactores, the tunicata, switched to the benthic-sessile movement type as early as the Lower Cambrian, but retained pelagic larval stages. The adult animals lost their bilaterally symmetrical physique. Later, the tuniculate groups of the Salps ( Thaliacea ) and the Appendicularia ( Copelata ) returned to the open water for adult life. In addition, the appendicularia remained in their bilaterally symmetrical larval shape for adulthood.
The body shapes of the extinct Vetulocystida and Vetulicolia can only be traced using fossils from the Cambrian. Vetulocystida were built bilaterally symmetrically. Their bodies were divided into two parts with flattened, wide fore bodies and tails, which were centered at the back of the fore bodies and were about a third of their width. Most of the time, Vetulocystida presumably rested in one place on the sea floor. They found support by burying their tails underground so that only the front part of the body peeked out. Occasionally they changed their location by creating propulsion with the help of their tails, which they swung sideways to and fro.
The physique of the Vetulicolia was in a way similar to that of the Vetulocystida. They too had bilaterally symmetrical shapes with broad front bodies and tails. However, the front bodies were not flattened, but flattened on the sides. Furthermore, the tails do not start in the middle, but near the upper rear ends of the body ( dorsal-posterior ). Vetulicolia probably spent most of the time on the seabed and could simply swim away in case of danger. Two species differed from this way of life. Banffia went on to a digging existence. In contrast, Vetulicola developed into pure swimmers with a very streamlined physique.
Web links
Individual evidence
- ^ Hynek Burda: General Zoology. Verlag Eugen Ulmer, Stuttgart, 2005, ISBN 3-8001-2838-1 , p. 55.
- ^ Thomas Henry Huxley: On the classification of the animal kingdom . In: The Journal of the Linnean Society. Zoology . Volume 12, 1875, doi : 10.1111 / j.1096-3642.1875.tb02582.x , pp. 200, 207.
- ↑ Karl Ernst von Baer: About the history of the development of animals • First part . Publishing house Gebrüder Bornträger, Königsberg, 1828.
- ↑ Ernst Haeckel: The biology of the lime sponges . Georg Reimer Verlag, Berlin, 1872, pp. 328–339 ( digitized version ).
- ^ Thomas Henry Huxley: On the classification of the animal kingdom . In: The Journal of the Linnean Society. Zoology . Volume 12, 1875, doi : 10.1111 / j.1096-3642.1875.tb02582.x , pp. 199-226.
- ^ Thomas Henry Huxley: On the classification of the animal kingdom . In: The American Naturalist . Volume 09, 1875, doi : 10.1086 / 271442 , pp. 65-70.
- ^ Thomas Henry Huxley: On the classification of the animal kingdom . In: The Journal of the Linnean Society. Zoology . Volume 12, 1875, doi : 10.1111 / j.1096-3642.1875.tb02582.x , p. 207.
- ^ Thomas Henry Huxley: On the classification of the animal kingdom . In: The American Naturalist . Volume 09, 1875, doi : 10.1086 / 271442 , p. 67.
- ↑ Alexander MacAlister: An Introduction to Animal Morphology and Systematic Zoology • Part I . Publishers Longmans, Green and Co., London, 1876. p. 48 ( digitized ).
- ↑ Berthold Hatschek: Textbook of Zoology • First delivery . Gustav Fischer Verlag, Jena, 1888, p. 41.
- ↑ Karl Grobben: The systematic division of the animal kingdom . In: Negotiations of the Zoological-Botanical Society in Vienna . Volume 58, 1908, pp. 496-497 ( digitized version ).
- ^ Johanna Taylor Cannon, Bruno Cossermelli Vellutini, Julian Smith, Fredrik Ronquist, Ulf Jondelius, Andreas Hejnol: Xenacoelomorpha is the sister group to Nephrozoa . In: Nature . Volume 530, 2016, doi : 10.1038 / nature16520 , pp. 89-93.
- ^ Alfred Goldschmid: Deuterostomia . In: Wilfried Westheide, Gunde Rieger (ed.): Special Zoology • Part 1 . Springer-Verlag, Berlin / Heidelberg, 2013, ISBN 978-3-642-34695-8 , p. 716.
- ↑ a b c d Jian Han, Simon Conway Morris, Qiang Ou, Degan Shu, Hai Huang: Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China) . In: Nature . Volume 542, 2017, doi : 10.1038 / nature21072 , p. 230.
- ↑ Systematics according to (1a) Diego C. García-Bellido, Michael SY Lee, Gregory D. Edgecombe, James B. Jago, James G. Gehling, John R. Paterson: A new vetulicolian from Australia and its bearing on the chordate affinities of to enigmatic Cambrian group . In: BMC Evolutionary Biology . Volume 14, 2014, doi : 10.1186 / s12862-014-0214-z , p. 8, updated with (1b) Jian Han, Simon Conway Morris, Qiang Ou, Degan Shu, Hai Huang: Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China) . In: Nature . Volume 542, 2017, doi : 10.1038 / nature21072 , p. 230. (2) Philip CJ Donoghue, Joseph N. Keating: Early vertebrate evolution . In: Palaeontology . Volume 57, 2014, doi : 10.1111 / pala.12125 , p. 880. Systematics of Echinodermata simplified according to (3) Andrew B. Smith, Samuel Zamora: Cambrian spiral-plated echinoderms from Gondwana reveal the earliest pentaradial body plan . In: Proceedings of the Royal Society B . Volume 280, 2013, doi : 10.1098 / rspb.2013.1197 , p. 5. Systematics of the Hemichordata according to (4) Johanna T. Cannon, Kevin M. Kocot, Damien S. Waits, David A. Weese, Billie J. Swalla, Scott R. Santos, Kenneth M. Halanych: Phylogenomic Resolution of the Hemichordate and Echinoderm Clade . In: Current Biology . Volume 24, 2014, doi : 10.1016 / j.cub.2014.10.016 , p. 2829. Systematics of Vetulicolia according to (5) Richard J. Aldridge, Hou Xian-Guang, David J. Siveter, Derek J. Siveter and Sarah E. Gabbot: The Systematics and Phylogenetic Relationships of Vetulicolians . In: Palaeontology . Volume 50, 2007, doi : 10.1111 / j.1475-4983.2006.00606.x , pp. 133, 147.
- ↑ a b Georges Ubaghs: Early Paleozoic Echinoderms . In: Annual Review of Earth and Planetary Sciences . Volume 3, 1975, doi : 10.1146 / annurev.ea.03.050175.000455 , p. 95.
- ↑ Georges Ubaghs: Early Paleozoic Echinoderms . In: Annual Review of Earth and Planetary Sciences . Volume 3, 1975, doi : 10.1146 / annurev.ea.03.050175.000455 , p. 96.
- ↑ a b c d e f Andrew B. Smith, Samuel Zamora: Cambrian spiral-plated echinoderms from Gondwana reveal the earliest pentaradial body plan . In: Proceedings of the Royal Society B . Volume 280, 2013, doi : 10.1098 / rspb.2013.1197 , p. 5.
- ↑ Andrew B. Smith, Samuel Zamora: Cambrian spiral-plated echinoderms from Gondwana reveal the earliest pentaradial body plan . In: Proceedings of the Royal Society B . Volume 280, 2013, doi : 10.1098 / rspb.2013.1197 , p. 1.
- ↑ Compare (1) Georges Ubaghs: General Characters of Echinodermata . In: Raymond C. Moore (ed.): Treatise of Invertebrate Paleontology - Part S • Echinodermata 1 . University of Kansas and Geological Society of America, Lawrence (Kansas), 1989, ISBN 0-8137-3020-1 , p. 54. with (2) Arno Hermann Müller: Textbook of Palaeozoology - Volume II, Part 3 . Gustav Fischer Verlag, Jena, 1989, ISBN 3-334-00165-2 , p. 314.
- ^ Greg W. Rouse, Lars S. Jermiin, Nerida G. Wilson, Igor Eeckhaut, Deborah Lanterbecq, Tatsuo Oji, Craig M. Young, Teena Browning, Paula Cisternas, Lauren E. Helgen, Michelle Stuckey, Charles G. Messing: Fixed , free, and fixed: The fickle phylogeny of extant Crinoidea (Echinodermata) and their Permian – Triassic origin . In: Molecular Phylogenetics and Evolution . Volume 66, 2013, doi : 10.1016 / j.ympev.2012.09.018 , pp. 161, 171, 178.
- ↑ Maximilian J. Telford, Christopher J. Lowe, Christopher B. Cameron, Olga Ortega-Martinez, Jochanan Aronowicz, Paola Oliveri, Richard R. Copley: Phylogenomic analysis of echinoderm class relationships supports Asterozoa . In: Proceedings of the Royal Society B . Volume 281, 2014, doi : 10.1098 / rspb.2014.0479 , p. 6.
- ↑ Jun-Yuan Chen: Early crest animals and the insight they provide into the evolutionary origin of craniates . In: Genesis . Volume 46, 2008, doi : 10.1002 / dvg.20445 , p. 623.
- ^ A b Simon Conway Morris, Jean-Bernard Caron: Pikaia gracilens Walcott, a stem-group chordate from the Middle Cambrian of British Columbia . In: Biological Reviews . Volume 87, 2012, doi : 10.1111 / j.1469-185X.2012.00220.x , p. 480.
- ↑ Philip CJ Donoghue, Joseph N. Keating: Early vertebrate evolution . In: Palaeontology . Volume 57, 2014, doi : 10.1111 / pala.12125 , p. 883.
- ↑ Michael J. Benton: Paleontology of the vertebrates . Publishing house Dr. Friedrich Pfeil, Munich 2007, ISBN 978-3-89937-072-0 , p. 53.
- ^ Johanna Taylor Cannon, Bruno Cossermelli Vellutini, Julian Smith, Fredrik Ronquist, Ulf Jondelius, Andreas Hejnol: Xenacoelomorpha is the sister group to Nephrozoa . In: Nature . Volume 530, 2016, doi : 10.1038 / nature16520 , p. 89.
- ^ Andrew B. Smith: Cambrian problematica and the diversification of deuterostomes . In: BMC Biology . Volume 10, 2012, doi : 10.1186 / 1741-7007-10-79 , Article No. 79, p. 3.
- ↑ Volker Storch, Ulrich Welsch: Systematic Zoology . Spektrum Akademischer Verlag, Heidelberg / Berlin, 2004, ISBN 3-8274-1112-2 , pp. 80, 82.
- ↑ Martin Dohrmann, Gert Wörheide: Dating early animal evolution using phylogenomic data . In: Scientific Reports . Volume 7, 2017, doi : 10.1038 / s41598-017-03791-w , p. 4.
- ↑ Rachel Wood, Andrey Yu Ivantsov, Andrey Yu Zhuravlev: First macrobiota biomineralization was environmentally triggered . In: Proceedings of the Royal Society B . Volume 284, 2017, doi : 10.1098 / rspb.2017.0059 , p. 1.
- ↑ a b c Jian Han, Simon Conway Morris, Qiang Ou, Degan Shu, Hai Huang: Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China) . In: Nature . Volume 542, 2017, doi : 10.1038 / nature21072 , p. 231.
- ↑ John A. Cunningham, Alexander G. Liu, Stefan Bengtson and Philip CJ Donoghue: The origin of animals: Can molecular clocks and the fossil record be reconciled? In: Bioessays . Volume 39, 2016, doi : 10.1002 / bies.201600120 , pp. 1–12.
- ↑ Michael J. Benton: Paleontology of the vertebrates . Publishing house Dr. Friedrich Pfeil, Munich 2007, ISBN 978-3-89937-072-0 , pp. 19, 21.
- ↑ Samuel Zamora, Imran A. Rahman, Andrew B. Smith: Plated Cambrian Bilaterians Reveal the Earliest Stages of Echinoderm Evolution . In: PLoS ONE . Volume 7, 2012, doi : 10.1371 / journal.pone.0038296 , e38296, p. 2.
- ↑ JinShu Li, JianNi Liu, Qiang Ou: New observations on Vetulicola longbaoshanensis from the Lower Cambrian Guanshan Biota (Series 2, Stage 4), South China . In: Science China Earth Sciences . Volume 60, 2017, doi : 10.1007 / s11430-017-9088-y , p. 1798.
- ↑ Samuel Zamora, Imran A. Rahman, Andrew B. Smith: Plated Cambrian Bilaterians Reveal the Earliest Stages of Echinoderm Evolution . In: PLoS ONE . Volume 7, 2012, doi : 10.1371 / journal.pone.0038296 , e38296, p. 4.
- ↑ Domínguez Alonso: Sistemática, anatomía, estructura y función de Ctenocystoidea (Echinodermata, Carpoidea) del Paleozoico Inferior . Universidad Complutense de Madrid, Madrid 1999, pp. 207-215 ( PDF file ).
- ^ A b Samuel Zamora, Imran A. Rahman, Andrew B. Smith: Plated Cambrian Bilaterians Reveal the Earliest Stages of Echinoderm Evolution . In: PLoS ONE . Volume 7, 2012, doi : 10.1371 / journal.pone.0038296 , e38296, p. 10.
- ^ Jean-Bernard Caron, Simon Conway Morris, Christopher B. Cameron: Tubicolous enteropneusts from the Cambrian period . In: Nature . Volume 495, 2013, doi : 10.1038 / nature12017 , p. 503.
- ↑ Shixue Hu, Bernd-D. Erdtmann, Michael Steiner, Yuandong Zhang, Fangchen Zhao, Zhiliang Zhang, Jian Han: Malongitubus: a possible pterobranch hemichordate from the early Cambrian of South China . In: Journal of Paleontology . Volume 92, 2017, doi : 10.1017 / jpa.2017.134 , p. 26.
- ↑ Degan Shu: A paleontological perspective of vertebrate origin . In: Chinese Science Bulletin . Volume 48, 2003, doi : 10.1007 / BF03187041 , p. 725.
- ↑ Hou Xian-gang, Richard J. Aldridge, David J. Siveter, Derek J. Siveter, and Feng Xiang-hong: New evidence on the anatomy and phylogeny of the earliest vertebrates . I. Proceedings of the Royal Society B: Biological Sciences . Volume 269, 2002, doi : 10.1098 / rspb.2002.2104 , p. 1865.
- ^ Simon Conway Morris, Jean-Bernard Caron: A Primitive Fish from the Cambrian of North America . In: Nature . Volume 512, 2014, doi : 10.1038 / nature13414 , p. 419.
- ↑ Degan Shu: A paleontological perspective of vertebrate origin . In: Chinese Science Bulletin . Volume 48, 2003, doi : 10.1007 / BF03187041 , p. 727.
- ↑ Vladimir V. Missarzhevsky: Conodont-shaped organisms from the Precambrian-Cambrian boundary strata of the Siberian Platform and Kazakhstan. In: IT Zhuravleva (Ed.): Palaeontological and Biostratigraphic Problems in the Lower Cambrian of Siberia and the Far East . Nauka, Novosibirsk 1973, p. 53.
- ↑ a b Jun-Yuan Chen, Di-Ying Huang, Qing-Qing Peng, Hui-Mei Chi, Xiu-Qiang Wang, Man Feng: The first tunicate from the Early Cambrian of South China . In: Proceedings of the National Academy of Sciences . Volume 100, 2003, doi : 10.1073 / pnas.1431177100 , p. 8314.
- ↑ Systematics according to (1a) Diego C. García-Bellido, Michael SY Lee, Gregory D. Edgecombe, James B. Jago, James G. Gehling, John R. Paterson: A new vetulicolian from Australia and its bearing on the chordate affinities of to enigmatic Cambrian group . In: BMC Evolutionary Biology . Volume 14, 2014, doi : 10.1186 / s12862-014-0214-z , p. 2.
- ↑ D.-G. Shu, S. Conway Morris, J. Han, Z.-F. Zhang, J.-N. Liu: Ancestral echinoderms from the Chengjiang deposits of China . In: Nature . Volume 430, 2004, doi : 10.1038 / nature02648 , p. 422.
- ↑ Simon Conway Morris, Susan L. Halgedahl, Paul Selden, and Richard D. Jarrard: Rare primitive deuterostomes from the Cambrian (Series 3) of Utah . In: Journal of Paleontology . Volume 89, 2015, doi : 10.1017 / jpa.2015.40 , p. 634.
- ↑ Jun-Yuan Chen: Early crest animals and the insight they provide into the evolutionary origin of craniates. In: Genesis . Volume 46, 2008, doi : 10.1002 / dvg.20445 , p. 625.
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- ^ Derek EG Briggs, Bruce S. Lieberman, Susan L. Halgedahl, Richard D. Jarrard: A new metazoan from the Middle Cambrian of Utah and the nature of the Vetulicolia . In: Palaeontology . Volume 48, 2005, doi : 10.1111 / j.1475-4983.2005.00489.x , p. 681.
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- ^ Alfred Goldschmid: Deuterostomia . In: Wilfried Westheide, Gunde Rieger (Ed.): Special Zoology Part 1: Protozoa and Invertebrates . Springer-Verlag, Berlin / Heidelberg 2013, ISBN 978-3-642-34695-8 , p. 717.
- ↑ Samuel Zamora, Imran A. Rahman, Andrew B. Smith: Plated Cambrian Bilaterians Reveal the Earliest Stages of Echinoderm Evolution . In: PLoS ONE . Volume 7, 2012, doi : 10.1371 / journal.pone.0038296 , e38296, p. 1.
- ↑ Junfeng Guo, Yong Li, Huiping Han, Qiang Ou, Jianren Zhou, Yajuan Zheng: New Macroscopic Problematic Fossil from the Early Cambrian Yanjiahe Biota, Yichang, Hubei, China . In: Acta Geologica Sinica . Volume 86, 2012, doi : 10.1111 / j.1755-6724.2012.00706.x , p. 795.
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- ↑ Arno Hermann Müller: Textbook of Paleozoology - Volume II, Part 3 . Gustav Fischer Verlag, Jena, 1989, ISBN 3-334-00165-2 , pp. 296, 299.
- ^ Richard PS Jefferies, Nigel A. Brown and Paul EJ Daley: The Early Phylogeny of Chordates and Echinoderms and the Origin of Chordate Left-Right Asymmetry and Bilateral Symmetry . In: Acta Zoologica . Volume 77, 1996, doi : 10.1111 / j.1463-6395.1996.tb01256.x , p. 106, Fig. A.
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- ^ Andrew B. Smith: Deuterostomes in a twist: the origins of a radical new body plan . In: Evolution & Development . Volume 10, 2008, doi : 10.1111 / j.1525-142X.2008.00260.x , p. 493.
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- ↑ Arno Hermann Müller: Textbook of Paleozoology - Volume II, Part 3 . Gustav Fischer Verlag, Jena, 1989, ISBN 3-334-00165-2 , p. 314.
- ^ Alfred Goldschmid: Deuterostomia . In: Wilfried Westheide, Gunde Rieger (Ed.): Special Zoology Part 1: Protozoa and Invertebrates . Springer-Verlag, Berlin / Heidelberg 2013, ISBN 978-3-642-34695-8 , p. 745.
- ↑ Volker Storch, Ulrich Welsch: Systematic Zoology . Spektrum Akademischer Verlag, Heidelberg / Berlin, 2004, ISBN 3-8274-1112-2 , p. 452.
- ^ Greg W. Rouse, Lars S. Jermiin, Nerida G. Wilson, Igor Eeckhaut, Deborah Lanterbecq, Tatsuo Oji, Craig M. Young, Teena Browning, Paula Cisternas, Lauren E. Helgen, Michelle Stuckey, Charles G. Messing: Fixed , free, and fixed: The fickle phylogeny of extant Crinoidea (Echinodermata) and their Permian – Triassic origin . In: Molecular Phylogenetics and Evolution . Volume 66, 2013, doi : 10.1016 / j.ympev.2012.09.018 , p. 170.
- ^ Alfred Goldschmid: Deuterostomia . In: Wilfried Westheide, Gunde Rieger (Ed.): Special Zoology Part 1: Protozoa and Invertebrates . Springer-Verlag, Berlin / Heidelberg 2013, ISBN 978-3-642-34695-8 , p. 729.
- ↑ Volker Storch, Ulrich Welsch: Systematic Zoology . Spektrum Akademischer Verlag, Heidelberg / Berlin, 2004, ISBN 3-8274-1112-2 , p. 445.
- ↑ Volker Storch, Ulrich Welsch: Systematic Zoology . Spektrum Akademischer Verlag, Heidelberg / Berlin, 2004, ISBN 3-8274-1112-2 , pp. 442-443.
- ↑ Volker Storch, Ulrich Welsch: Systematic Zoology . Spektrum Akademischer Verlag, Heidelberg / Berlin, 2004, ISBN 3-8274-1112-2 , p. 489.
- ↑ Volker Storch, Ulrich Welsch: Systematic Zoology . Spektrum Akademischer Verlag, Heidelberg / Berlin, 2004, ISBN 3-8274-1112-2 , p. 507.
- ^ Alfred Goldschmid: Deuterostomia . In: Wilfried Westheide, Gunde Rieger (Ed.): Special Zoology Part 1: Protozoa and Invertebrates . Springer-Verlag, Berlin / Heidelberg 2013, ISBN 978-3-642-34695-8 , p. 780.
- ↑ Volker Storch, Ulrich Welsch: Systematic Zoology . Spektrum Akademischer Verlag, Heidelberg / Berlin, 2004, ISBN 3-8274-1112-2 , p. 493.
- ^ Alfred Goldschmid: Deuterostomia . In: Wilfried Westheide, Gunde Rieger (ed.): Special Zoology • Part 1 . Springer-Verlag, Berlin / Heidelberg, 2013, ISBN 978-3-642-34695-8 , p. 781.
- ^ Alfred Goldschmid: Deuterostomia . In: Wilfried Westheide, Gunde Rieger (Ed.): Special Zoology Part 1: Protozoa and Invertebrates . Springer-Verlag, Berlin / Heidelberg 2013, ISBN 978-3-642-34695-8 , p. 786.
- ↑ D.-G. Shu, S. Conway Morris, J. Han, Z.-F. Zhang, J.-N. Liu: Ancestral echinoderms from the Chengjiang deposits of China . In: Nature . Volume 430, 2004, doi : 10.1038 / nature02648 , pp. 422-423.
- ↑ D.-G. Shu, S. Conway Morris, J. Han, Z.-F. Zhang, J.-N. Liu: Ancestral echinoderms from the Chengjiang deposits of China . In: Nature . Volume 430, 2004, doi : 10.1038 / nature02648 , p. 423.
- ↑ D.-G. Shu, S. Conway Morris, J. Han, Z.-F. Zhang, J.-N. Liu: Ancestral echinoderms from the Chengjiang deposits of China . In: Nature . Volume 430, 2004, doi : 10.1038 / nature02648 , p. 426.
- ↑ Qiang Ou, Simon Conway Morris, Jian Han, Zhifei Zhang, Jianni Liu, Ailin Chen, Xingliang Zhang, Degan Shu: Evidence for gill slits and a pharynx in Cambrian vetulicolians: implications for the early evolution of deuterostomes . In: BMC Biology . Volume 10, 2012, doi : 10.1186 / 1741-7007-10-81 , Article No. 81, p. 2.
- ↑ Qiang Ou, Simon Conway Morris, Jian Han, Zhifei Zhang, Jianni Liu, Ailin Chen, Xingliang Zhang, Degan Shu: Evidence for gill slits and a pharynx in Cambrian vetulicolians: implications for the early evolution of deuterostomes . In: BMC Biology . Volume 10, 2012, doi : 10.1186 / 1741-7007-10-81 , Article No. 81, pp. 5, 10.
- ↑ Qiang Ou, Simon Conway Morris, Jian Han, Zhifei Zhang, Jianni Liu, Ailin Chen, Xingliang Zhang, Degan Shu: Evidence for gill slits and a pharynx in Cambrian vetulicolians: implications for the early evolution of deuterostomes . In: BMC Biology . Volume 10, 2012, doi : 10.1186 / 1741-7007-10-81 , Article No. 81, p. 10.
- ↑ JinShu Li, JianNi Liu, Qiang Ou: New observations on Vetulicola longbaoshanensis from the Lower Cambrian Guanshan Biota (Series 2, Stage 4), South China . In: Science China Earth Sciences . Volume 60, 2017, doi : 10.1007 / s11430-017-9088-y , pp. 1795, 1799.
- ↑ Systematics according to (1a) Diego C. García-Bellido, Michael SY Lee, Gregory D. Edgecombe, James B. Jago, James G. Gehling, John R. Paterson: A new vetulicolian from Australia and its bearing on the chordate affinities of to enigmatic Cambrian group . In: BMC Evolutionary Biology . Volume 14, 2014, doi : 10.1186 / s12862-014-0214-z , p. 3.
- ^ A b Simon Conway Morris, Susan L. Halgedahl, Paul Selden, and Richard D. Jarrard: Rare primitive deuterostomes from the Cambrian (Series 3) of Utah . In: Journal of Paleontology . Volume 89, 2015, doi : 10.1017 / jpa.2015.40 , p. 635.
- ↑ JinShu Li, JianNi Liu, Qiang Ou: New observations on Vetulicola longbaoshanensis from the Lower Cambrian Guanshan Biota (Series 2, Stage 4), South China . In: Science China Earth Sciences . Volume 60, 2017, doi : 10.1007 / s11430-017-9088-y , p. 1801.
- ↑ Qiang Ou, Simon Conway Morris, Jian Han, Zhifei Zhang, Jianni Liu, Ailin Chen, Xingliang Zhang, Degan Shu: Evidence for gill slits and a pharynx in Cambrian vetulicolians: implications for the early evolution of deuterostomes . In: BMC Biology . Volume 10, 2012, doi : 10.1186 / 1741-7007-10-81 , Article No. 81, pp. 7-8.