How to make a protostome

  title={How to make a protostome},
  author={Claus Nielsen},
  journal={Invertebrate Systematics},
  pages={25 - 40}
  • C. Nielsen
  • Published 19 June 2012
  • Biology
  • Invertebrate Systematics
Abstract. The origin and radiation of the major metazoan groups can be elucidated by phylogenomic studies, but morphological evolution must be inferred from embryology and morphology of living organisms. According to the trochaea theory, protostomes are derived from a holoplanktonic gastraea with a circumblastoporal ring of downstream-collecting compound cilia (archaeotroch) and a nervous system comprising an apical ganglion and a circumblastoporal nerve ring. The pelago-benthic life cycle… 

Evolution of deuterostomy – and origin of the chordates

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  • Biology
    Biological reviews of the Cambridge Philosophical Society
  • 2017
The conclusion must be that the chordate mouth (and that of the deuterostomes in general) is homologous to the protostomian mouth and that the latest common ancestor of protostomes and deuterstomes developed through amphistomy, as suggested by the trochaea theory.

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  • A. Zhuravlev
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    Biology Bulletin Reviews
  • 2015
In the aggregate, modern data from molecular biology, palaeontology, and comparative embryology/morphology, having been revitalized by the introduction of new microscopy techniques, imply that the hypothesized planktotrophic gastrae-like common ancestor is the least likely of the diverse suggestions on the origins of the Metazoa.

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  • C. Nielsen
  • Biology
    Journal of Experimental Biology
  • 2015
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All the available information is strongly in favor of multiple evolution of non-planktotrophic development, and only the terminal addition theory is in accordance with the Darwinian theory by explaining the evolution through continuous series of adaptational changes.

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Trochophora larvae: cell-lineages, ciliary bands, and body regions. 1. Annelida and Mollusca.

  • C. Nielsen
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2004
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Homology of ciliary bands in Spiralian Trochophores.

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Trochophora larvae: cell-lineages, ciliary bands and body regions. 2. Other groups and general discussion.

  • C. Nielsen
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2005
The embryology of sipunculans, entoprocts, nemertines, platyhelminths, rotifers, ectoproCTs, phoronids, brachiopods, echinoderms and enteropneusts is reviewed with special emphasis on cell-lineage and differentiation of ectodermal structures.

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