Julia Heathcote, whose advisor is Josh Smith, Ph.D., Washington University assistant professor of earth and planetary sciences, examined data of more than 250 dinosaur genera, or classes, as well as various clades, or family tree branches, of dinosaur classes.
Heathcote found that existing data is between one-half and two-thirds complete, or of high quality, for dinosaur data. As template, she used two published whole dinosaur studies and compared them with smaller family trees within the context of the whole dinosaur data, commonly known as the Dinosauria. She also analyzed for congruence the correlation between the fossil record and family tree relationships. Heathcote found some of the clades both complete and congruent, while others are poor in both ways.
"The whole Dinosauria fossil record I would say is moderately good, which was a surprise, because I thought it would be much worse," Heathcote said. "It generally shows a low degree of completeness but a high degree of congruence with the existing phylogenies, or family trees, studied."
Her results are important for paleontologists who are especially focused on the evolution of dinosaurs. It is to the paleontologist what Beckett's Baseball Card Price guide is to the baseball card collector, and more - Heathcote's analysis provides information on the relationships between classes and groups, whereas the Beckett guide draws no lineages for players, for instance.
Heathcote said that there have been many attempts to analyze evolutionary patterns using the fossil record, but that the patterns can only be interpreted usefully in the context of stratigraphy -- essentially how old the fossils are. It's important to know th
Contact: Tony Fitzpatrick
Washington University in St. Louis