Mesozoa

The division of living beings into systematics is a continuous subject of research. Different systematic classifications exist side by side and one after the other. The taxon treated here has become obsolete due to new research or is not part of the group systematics presented in the German-language Wikipedia.

As Mesozoa ( Gr . Between animals , means animals ) were formerly multicellular animals referred to, which, however, the main features of the other animal in the cell structure of multicellular organisms do not share (Metazoa). They were grouped together for the reason that they are not a natural group, a so-called monophyletic taxon . Today it is known, however, that this group of animals are secondary simplified tissue animals from the Bilateria .

All known mesozoa are worm-shaped and no larger than 2 mm. They consist of a generative core zone that is surrounded by a single-layer somatic shell. Further characteristics are a change in sexually and asexually reproducing generations ( metagenesis ) and an exclusively endosymbiotic or endoparastic life in marine invertebrates .

The two groups of animals combined earlier are:

• Rhombozoa : endosymbionts in cephalopods
  • Dicyemidae (approx. 75 species)
  • Heterocyemidae (2 species)
• Orthonectida : endoparasites (approx. 30 species)

literature

• Wilfried Westheide & Reinhard Rieger (eds., 2007): Special Zoology - Part 1: Protozoa and invertebrates (2nd edition). Elsevier, Spektrum Akademischer Verlag, Munich. ISBN 3-8274-1575-6