Complex organisms from the Udokan Complex of Eastern Siberia with implications for its age
Abstract The age of the Udokan Complex, which is currently considered a parastratotype for the Early Proterozoic, should be reconsidered based on the recovery of complex fossils referred to Udokania problematica Leytes. The morphology of U. problematica is described and illustrated in detail and it is proposed that the skeletal complexity is comparable to that of some Early Paleozoic organisms. It is possible that the metasediments of the Udokan complex are of Late Proterozoic or Early Paleozoic age and that their present spatial position in the Kodar-Udokan zone is a consequence of regional overthrusting.