While Love et al. (2009) argues for the presence of sponges in rocks below the Marinoan cap carbonate at ~635 Ma (millions of years ago),[REF] Antcliffe (2013) estimates the age of the biomarker-bearing rock to be between 645 Ma and ~580 Ma [REF].
The presence of sponges before ~540 Ma has profound implications for the evolution of multicellular life and the coupling of the biosphere to Neoproterozoic climate.