WAGGONER, B.M.: The Ediacara biota in space and time

The enigmatic “Ediacara organisms”, which preceded and overlapped with the Cambrian radiation of metazoans, include many forms whose systematic positions remain contentious after over fifty years of study. It might seem that nothing particularly useful can be learned from a biota full of oddballs. However, preliminary biogeographic analyses can be carried out without having to guess at the systematic position of the organisms. Combining these results with data on paleotectonics, paleoenvironmental parameters, and the ages of various assemblages sheds light on the origins, ecology, and even the systematic positions of the Ediacara organisms. Paleotectonic position was the first-order determinant of similarity among biotas, but paleoenvironmental factors also played a role in constraining the ranges of various Ediacaran taxa.