Encyclopedia > Vendian faunas

  Article Content

Vendian faunas

The Vendian Faunas -- Vendazoa are ancient lifeforms found in rocks a bit older than the Cambrian faunas that represent the oldest fossils of classical paleontology. The original descriptions came from the Ediacaran faunas of South Australia. It later turned out that similar faunus had been described previously from Namibia, but their great age had not been appreciated. Subsequent discoveries have found similar fossils in Brazil, Antarctica, Newfoundland, The Canadian Maritimes, North Carolina, England, Canada's Northwest Territories, The Western US, Scandanavia, The White Sea region of Russia, and Poland, and other places.

The Vendian 'animals' (assuming that they were animals) are probably too large and complex to be single celled. They universally lack mouths, any organs, or appendages. Symmetries may be two, three, four, or even five fold. No tracks are found that appear to be associated with the creatures. Some appear to be or have holdfasts. They include frond like forms, disks with various ornamentations, what appear to be air matress like forms, and other unlikely shapes. They were originally thought to be simple precursors of more modern forms, and a few elements of the fauna still look like possible precursors of such later forms as arthropods and mollusks. But most appear to belong to some evolutionary sidetrack. It has been proposed that they consitute an ancient phylum the vendazoa that largely died out just before the beginning of the Cambrian.

Other than a few dubious fossils from the Upper Cambrian of Ireland, there is no known overlap between the vendazoa and modern lifeforms.

Well known Vendian forms include Arkarua, Ausia[?], Charnia[?], Cyclomedusa, Dickinsonia, Ediacaria[?], Marywadea, Pteridinium. The full list runs to 50 or more taxa. Some of those named are rare but interesting for one reason or another. Others are widely distributed.

All Wikipedia text is available under the terms of the GNU Free Documentation License

  Search Encyclopedia

Search over one million articles, find something about almost anything!
  Featured Article
Sanskrit language

... all distinct) zero, guna[?], and vrdhii[?] grades. If V is the vowel of the zero grade, the guna grade vowel is traditionally thought of a V + a, and the vrdhii ...

This page was created in 39.7 ms