Sipunculans and segmentation

@article{Wanninger2009SipunculansAS,
  title={Sipunculans and segmentation},
  author={Andreas Wanninger and Alen Kristof and Nora Brinkmann},
  journal={Communicative \& Integrative Biology},
  year={2009},
  volume={2},
  pages={56 - 59}
}
Comparative molecular, developmental, and morphogenetic analyses show that the three major segmented animal groups – Lophotrochozoa, Ecdysozoa, and Vertebrata - use a wide range of ontogenetic pathways to establish metameric body organization. Even in the life history of a single specimen, different mechanisms may act on the level of gene expression, cell proliferation, tissue differentiation, and organ system formation in individual segments. Accordingly, in some polychaete annelids the first… Expand
Segment formation in Annelids: patterns, processes and evolution.
  • G. Balavoine
  • Biology, Medicine
  • The International journal of developmental biology
  • 2014
TLDR
The various patterns of evolution of the metameric body plan in annelids are summarized, showing the remarkable evolvability of this trait, similar to what is also found in arthropods. Expand
Neural development in Onychophora (velvet worms) suggests a step-wise evolution of segmentation in the nervous system of Panarthropoda.
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Evidence is presented that the onychophoran "ventral organs," previously interpreted as segmental anlagen of the nervous system, do not contribute to nerve cord formation and therefore cannot be regarded as vestiges of segmental ganglia, and the hypothesis that the ancestral panarthropod had only a partially segmented nervous system is supported. Expand
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