Evolutionary biologists have long been concerned by the incompleteness of the fossil record. Although our knowledge of the diversity of life in 'deep time' has improved, many lineages of extant animals and plants still have only sparse fossil documentation. Even groups with 'hard parts' that render them suitable for fossilization often only have a limited record. Thus, although the fossil record is viewed as critical to the reconstruction of the evolutionary history of life, many biologists question its utility. Fortunately, discoveries of occurrences of exceptionally preserved fossils, known...