Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dinosaur fossil record compiled, analyzed

10.02.2004


500 or more dinosaurs possible yet to be discovered


Julia Heathcote, graduate student in earth and planetary sciences in Arts & Sciences, holds a dinosaur model in a McDonnell building laboratory. Heathcote has done an inventory of the complete dinosaur fossil record to determine the quality and congruence of the record. She calls the record, known as the Dinosauria, "moderately good," and says her results indicate that there might be 500 or more dinosaurs yet to be discovered.
David Kilper/WUSTL Photo



A graduate student in earth and planetary sciences in Arts & Sciences at Washington University in St. Louis has combed the dinosaur fossil record from T. Rex to songbirds and has compiled the first quantitative analysis of the quality and congruence of that record.

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 the quality of the fossil record to better assess whether an apparently large number of genera at any one time - say, the late Jurassic period - is due to genuine species diversity or just exceptionally good preservation. Congruence matters, too, to provide information on the adequacy of data and confidence to construct evolutionary relationships.

Heathcote presented her results at the annual meeting of the Geological Society of America, held Nov. 2-5, 2003, in Seattle.

Heathcote used three different calculations to achieve her results: the Stratigraphic Consistency Index, the Relative Completeness Index and the Gap Excess Ratio. The first is a measure of how well the relationships that have been proposed for dinosaurs fit in with the stratigraphic data, which contributes to a timeline for evolution. The Relative Completeness Index measures the percentage of how much missing data there might be to how much researchers actually have. And the Gap Excess Ratio measures how much missing data there actually is to the minimum missing data possible if the genera were arranged in the family tree in order of age.

Heathcote said that the known number of dinosaurs now stands at slightly more than 250. But because her results give a maximum possible completeness value, there might be 500 or more yet to be discovered, and she hopes that with each discovery, the researchers will enter their data into her program so that all paleontologists can benefit by seeing how the new discovery relates to previous ones.

She called the work "a new tool that draws together all of the data of the past 150 years, all plotted out accurately for the first time. You can see how far back these dinosaurs go, see their relationships with each other."

Tony Fitzpatrick | WUSTL

More articles from Earth Sciences:

nachricht Artificial Glaciers in Response to Climate Change?
10.08.2018 | Universität Heidelberg

nachricht Planet at risk of heading towards irreversible “Hothouse Earth” state
07.08.2018 | Potsdam-Institut für Klimafolgenforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

Im Focus: A molecular switch may serve as new target point for cancer and diabetes therapies

If certain signaling cascades are misregulated, diseases like cancer, obesity and diabetes may occur. A mechanism recently discovered by scientists at the Leibniz- Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin and at the University of Geneva has a crucial influence on such signaling cascades and may be an important key for the future development of therapies against these diseases. The results of the study have just been published in the prestigious scientific journal 'Molecular Cell'.

Cell growth and cell differentiation as well as the release and efficacy of hormones such as insulin depend on the presence of lipids. Lipids are small...

Im Focus: Touring IPP’s fusion devices per virtual-reality viewer

ASDEX Upgrade and Wendelstein 7-X – as if you were there / 360° view of fusion research

You seem to be standing in the plasma vessel looking around: Where otherwise plasmas with temperatures of several million degrees are being investigated, with...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Ph.D. student develops spinning heat shield for future spacecraft

10.08.2018 | Physics and Astronomy

Investigating global air pollution

10.08.2018 | Life Sciences

The “TRiC” to folding actin

10.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>