Figure 24.13 Diversification of Multicellular Organisms: The Cambrian “Explosion” Shortly after the end of Proterozoic glaciations (about 580 mya), several major radiations of multicellular organisms appear in the fossil record. (A) These microscopic fossils from the Doushantuo rock formation of China are the remains of tiny one-, two-, four-, and eight-celled stages of multicellular organisms. (B) Unusual soft-bodied marine invertebrates, unlike any animals alive at present, characterize the fossilized fauna preserved at Ediacara in southern Australia. (C) By the early Phanerozoic, fossilized faunas such as those preserved in Canada’s Burgess Shale include extinct representatives of some of the major animal groups alive today.