Tonian (1,000–720 Ma)

Diversification of acritarchs

The Tonian is the first period of the Neoproterozoic, occuring after the Stenian (Mesoproterozoic Era) and before the Cryogenian Period
  • Age
    1,000720 Ma
  • Subdivisions: no subdivisions
  • "Tonian" is Greek for stretch, referring to the continents during the Rodinian break-up
Above: acritarch

What happens during this time?
  • Geology
    • The supercontinent Rodinia begins to break up
  • Biology
    • Bitter Springs Formation (Australia) shows a diverse array of cells, called acritarchs
      • Acritarchs are small organic microfossils in marine sediments
      • Probably the reamins of different organisms (early metazoans, ancestral fungi and algae), some in their cyst stage
    • Cyanobacteria, green algae and fungi present in fossil record
      • Stromatolites begin to precipitously decline at about 1.0 Ga  (Bernard et al. 2013)
      • Filamentous algae fossils from this time show clean-cut circular holes in their cell walls similar to the feeding damage by Vampyrella-like amoebae.
AbovePalaeolyngbya, a cyanobacterium, from Bitter Springs (Schopf). Below: Vampyrella feeding on a filamentous green alga