Arthropod segments and segmentation – lessons from myriapods, and open questions

@article{Minelli2020ArthropodSA,
  title={Arthropod segments and segmentation – lessons from myriapods, and open questions},
  author={Alessandro Minelli},
  journal={Opuscula Zoologica},
  year={2020}
}
. The current understanding of the segmental organization of myriapods is dramatically different from the traditional views, due both to fresh research on a number of myriapod species and to progress in comparative developmental biology at large. In the late eighties, the emerging paradigm of ecdysozoan affinities of arthropods prompted a revisitation of the concept of the segment as an archetypical body unit. Fresh approaches to myriapod comparative morphology and pioneering studies on the… 

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References

SHOWING 1-10 OF 95 REFERENCES

Myriapod metamerism and arthropod segmentation

An improved model for arthropod segmentation is sketched, with some doubt about the homology between annelid and arthropody segmentation, and the final repetitive pattern is defined as metasegmental.

A three-phase model of arthropod segmentation

  • A. Minelli
  • Biology
    Development Genes and Evolution
  • 2001
Molecular and morphological evidence suggest that the segmental units of the arthropod body are specified, in early ontogeny, by three spatially and/or temporally distinct mechanisms and do not appear in a strict antero-posterior sequence.

Segmentation: mono- or polyphyletic?

  • E. Seaver
  • Biology
    The International journal of developmental biology
  • 2003
This review will discuss what the authors currently know about the segmentation process in each group and how the understanding of the development of segmented structures in distinct taxa have influenced the hypotheses explaining the presence of a segmented body plan in the metazoa.

Segmentation of the millipede trunk as suggested by a homeotic mutant with six extra pairs of gonopods

A very likely early determination of the sites of the future metamorphosis of walking legs into gonopod and a segmentation process according to the multiplicative model may provide a detailed explanation for the distribution of the extra gonopods in the homeotic specimen.

Exploring myriapod segmentation: the expression patterns of even-skipped, engrailed, and wingless in a centipede.

The adjacent expression of the engrailed and wingless stripes suggests that the regulatory relationship between the two genes may be conserved in the centipede, and thus this pathway may be a fundamental mechanism of segmental development in most arthropods.

Holomeric vs. meromeric segmentation: a tale of centipedes, leeches, and rhombomeres

The segmentation model proposed in this paper is mainly supported by evidence from comparative morphology, but it is compatible with known cellular and developmental mechanisms.

Trunk segment numbers and sequential segmentation in myriapods

  • G. Fusco
  • Biology
    Evolution & development
  • 2005
This work can at least outline the distinctive role in segmentation of a proliferative zone in the embryo, and suggests that these patterns result from multi‐layered developmental processes, where gene expression and epigenetic mechanisms interact in a nonstrictly hierarchical way.

Evolutionary conservation and divergence of the segmentation process in arthropods

  • W. Damen
  • Biology
    Developmental dynamics : an official publication of the American Association of Anatomists
  • 2007
This review focuses on the evolutionary conservation and divergence of the genetic mechanisms of segmentation within arthropod groups, and it has become clear that the activation of pair rule gene orthologs is a key step in the segmentation of all arthropods.

The geological record and phylogeny of the Myriapoda.

Expression of myriapod pair rule gene orthologs

Although the pair rule gene network is partially conserved among insects and myriapods, some aspects of PRG interaction are, as suggested by expression pattern analysis, convergent, even within the Myriapoda.
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