Sea cucumbers symmetry (Echinodermata: Holothuroidea)

  title={Sea cucumbers symmetry (Echinodermata: Holothuroidea)},
  author={Alexey V. Smirnov},
  journal={Paleontological Journal},
  • A. Smirnov
  • Published 4 December 2014
  • Biology
  • Paleontological Journal
The types of symmetry that are characteristic for the class Holothuroidea and reflect different stages in the evolution of this group of echinoderms and the role of paedomorphosis in its origin are analyzed. A hypothesis is proposed to explain the distinctive structure of the water vessel (ambulacral) system of sea cucumbers and the origin of the class Holothuroidea. The development of holothurians was interrupted at the stage of five primary tentacles. It resulted in changing of the mode of… 

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Paedomorphosis and heterochrony in the origin and evolution of the class holothuroidea

The processes of paedomorphosis and heterochrony played an important role not only in the origin and formation of the class Holothuroidea, but also during its evolution of the order Synaptida.


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