Research Training Program

Matthew Oreska
College of William and Mary
Williamsburg, Virginia

Matt Carrano, Ph.D.
Supervising Scientist
Department of Paleobiology

"To see an entire ecosystem spanning millions of years of geologic time condensed into a collection of fragments under a microscope is truly amazing."

Uncovering the Secrets of an Early Cretaceous Ecosystem

While the discovery of a single skeleton can be important, collections of thousands of small vertebrate fossils (microvertebrates) can provide significantly more information about a past environment or ecosystem. Such microvertebrate collections have been found in the Early Cretaceous Cloverly Formation (approximately 121-98.9 million years ago). Despite yielding Deinonychus, the bird-like animal that first cast doubt on our concept of sluggish dinosaurs, little is known about the Cloverly Formation's ancient environment or about life in the Early Cretaceous. Such gaps in our knowledge of the past prevent paleontologists from observing long term trends in the progression of life, information that is relevant to our study of modern biology. This study seeks to fill gaps in our knowledge about this critical time interval by analyzing the microvertebrate fossils from several Cloverly sites. The kinds of environments and ecosystems that existed at this time can be determined by identifying and counting the animals recovered. Using this information and knowledge about the animals' ecologies, it is possible to reconstruct how the paleoenvironment appeared. It was unknown whether the Cloverly recorded one type of environment or several, but the samples indicate at least two environments, freshwater and terrestrial, that were broadly similar to those of other Early Cretaceous formations. From these results it is possible to see how the different ecosystems were related to one another. In addition, many new types of fossils are present, greatly increasing the known diversity of the Early Cretaceous.

This research was supported by a grant from the NMNH Office of the Director.

Letter of gratitude