Vendobionta

Vendobionts or Vendozoans (Vendobionta) are a proposed very high-level, extinct clade of benthic organisms that is made up of the majority of the organisms that were part of the Ediacaran biota. It is a hypothetical group. It would be the oldest of the animals that populated the Earth about 580 million years ago, in the Ediacaran period (formerly Vendian). They became extinct shortly after the so-called Cambrian explosion, with the introduction of fauna forming groups more recognizably related to modern animals, however sponges may be descended from this clade. It is likely that the whole Ediacaran biota is not a monophyletic clade and not every genus placed in its subtaxa is an animal.

This biological group is not widely recognized; credibility is limited by the expansive speculation needed to establish phylogenetic relationships between such ancient extinct groups. The hypothesis was formulated by the German geologist Adolf Seilacher, who even doubts its relationship with the animal kingdom, or its multicellular nature — the group might have originated independently, and could be large unicellular forms. It has also been proposed that they could have been cnidarians, or articulates; perhaps a fungus, colonial protist, alga, or lichen; or a group divergent from all current animals. The only current consensus is that they could not have been photosynthetic. In any case, like the acritarchs, they are considered evolutionary enigmas, and possibly an independent and extinct kingdom.