Fossils, phylogeny, and discovery: a cladistic study of the history of tree topologies and ghost lineage durations

The history of discoveries of new species of euornithopod dinosaurs, merychippine horses, and hominid primates is analyzed using cladistic analyses. Using decade-by-decade additions of newly discovered species, these analyses were used to evaluate changes in tree topology and completeness of the fossil record of each clade. Most discoveries have been assimilated by and thus have strengthened prior phylogenetic patterns. Discoveries have also overthrown prior tree topologies. In addition, new species have either widened or closed previously-recognized stratigraphic gaps implied by phylogeny, or in some cases even revealed new gaps. In this way, discoveries can increase the patchiness of the fossil record. Such gaps may disclose aspects of yet undiscovered, but deducible diversity from the Earth's past biotas.