Evolutionary Scenario of the Early History of the Animal Kingdom: Evidence from Precambrian (Ediacaran) Weng’an and Early Cambrian Maotianshan Biotas, China

摘要: Late Proterozoic (Ediacaran) Weng’an (580 mya) and Early Cambrian Maotianshan (c. 530 faunas of South China, illustrated here, document diverse body plans at phylum subphylum level confirm that bilaterians evolved well before the “Cambrian explosion”. The (from Guizhou), oldest record metazoans, consist mainly embryos with possible affinities to living sponges, cnidarians, bilaterians, but adult specimens (though microscopic) same groups. Shale Yunnan), remarkably species (over 100 species), have great diversity metazoan plans, many comparable those Because they occur or near evolutionary roots animal groups, intermediate forms are present. Evolution metazoans was surprisingly rapid. Worm-like ancestral euarthropods elucidate origins arthropods. vertebrates, representing “missing” history between an amphioxus-like ancestor craniate provide improved understanding early evolution vertebrates.