Why are arthropods segmented?

@article{Budd2001WhyAA,
  title={Why are arthropods segmented?},
  author={Graham E. Budd},
  journal={Evolution \& Development},
  year={2001},
  volume={3}
}
  • G. Budd
  • Published 1 September 2001
  • Biology
  • Evolution & Development
SUMMARY Segmentation as an attribute of organisms is being increasingly discussed in the recent literature because (1) new phylogenies suggest that organisms classically considered to be segmented may lie in separate clades; (2) the molecular basis of segmental development has been much studied; (3) various theories of bilaterian origins place weight on segmentation as a primitive character; (4) there has been recent stress on the importance of modularity as an evolutionary topic. However, the… 

Segmentation: mono- or polyphyletic?

  • E. Seaver
  • Biology
    The International journal of developmental biology
  • 2003
TLDR
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.

The Articulata hypothesis – or what is a segment?

TLDR
Based on numerous similarities not shared with other bilaterian taxa it is suggested that segmentation of annelids and arthropods is homologous and apomorphic for a monophyletic Articulata.

The Segmented Urbilateria: A Testable Scenario1

TLDR
This work proposes to test the hypothesis that the last common ancestor of bilaterian animals (Urbilateria) was segmented by comparing genes involved in mesodermal segmentation, and suggests several types of evolutionary mechanisms operating on a segmented ancestral body plan would explain the rapid emergence of body plans during the Cambrian.

Hunting for “factor X”: the genetic basis of segmental mismatch

  • G. Fusco
  • Biology
    Evolution & development
  • 2009
TLDR
There are some case studies which, better than others, illustrate the necessity and the potential of considering developmental causes for explaining the evolution of organisms’ body architecture.

Arthropod origins

TLDR
Results of molecular studies indicate a relationship to moulting worms, which means that if this is correct, the arthropod and moults worm lineages must have diverged when some “coelomate” features such as specific vascular and neural systems were still present.

Segmentation, metamerism and the Cambrian explosion.

  • J. Couso
  • Biology
    The International journal of developmental biology
  • 2009
TLDR
It is concluded that a metameric body plan is not only a likely ancestral character of bilaterian animals, but also a possible trigger for the Cambrian explosion in body morphology and complexity.

Evolution of developmental systems underlying segmented body plans of bilaterian animals: insights from studies of segmentation in a cricket

TLDR
Comparisons of regulatory networks of segmentation genes between Gryllus and Drosophila suggest that regulatory interactions between the genes vary among insects, despite conservation of the network component genes, whereas the segmented body plan itself has been conserved.

Ancestral Patterning of Tergite Formation in a Centipede Suggests Derived Mode of Trunk Segmentation in Trilobites

TLDR
The centipede Strigamia maritima is utilized to study the correspondence between the expression of engrailed during late embryonic to postembryonic stages, and the development of the dorsal exoskeletal plates, and it is suggested that this association represents a symplesiomorphy within Euarthropoda.

Segment formation in Annelids: patterns, processes and evolution.

  • G. Balavoine
  • Biology
    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.
...

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