Paleobiogeography: The relevance of fossils to biogeography

Paleobiogeography has advanced as a discipline owing to the increasing utilization of a phylogenetic approach to the study of biogeographic patterns. Coupled with this, there has been an increasing interdigitation of paleontology with molecular systematics because of the development of techniques to analyze ancient DNA and because of the use of sophisticated methods to utilize molecules to date evolutionary divergence events. One pervasive pattern emerging from several paleontological and molecular analyses of paleobiogeographic patterns is the recognition that repeated episodes of range expansion or geo-dispersal occur congruently in several different lineages, just as congruent patterns of vicariance also occur in independent lineages. The development of new analytical methods based on a modified version of Brooks Parsimony Analysis makes it possible to analyze both geo-dispersal and vicariance in a phylogenetic context, suggesting that biogeography as a discipline should focus on the analysis of a variety of congruent phenomena, not just vicariance. The important role that extinction plays in influencing apparent biogeographic patterns among modem and fossil groups suggests that this is another area ripe for new methodological developments.