ABSTRACT
Ghost ranges occur where phylogenetic reconstructions predict fossil ranges beyond the known stratigraphic occurrence of the fossils. Cladistic methodology refers all closest relationships to sister groups and assumes they arose at the same time. Where the real relationship is ancestor-descendant, the ancestral taxon must have existed for some time before the descendant taxon evolved and cladistic analysis will produce an artificial ghost range. Alternatively, real ghost ranges are caused by gaps in the fossil record. First records of fossil species can only occur in the wrong order with respect to the true evolutionary order if the species coexisted. Estimates indicate that at least 95 per cent of Phanerozoic fossil species did not coexist at any time. This defines the minimum level of reliability of the stratigraphic sequence of fossils, a result which is independent of the completeness of the record. Discrepancies between stratigraphic occurrences of fossils and predictions of cladograms are a valid test of the cladograms, not of the incompleteness of the fossil record. If real ghost ranges were common, then first occurrences of fossils would frequently move back in time as new, earlier occurrences were detected. This provides a preliminary method for investigating the frequency of real ghost ranges in the fossil record.
