During the Cretaceous period, the Dallas-Fort Worth area was situated along a subtropical coastline, a paleogeographic peninsula similar to the Florida Everglades. A portion of this ecosystem is preserved at a diverse fossil locality called the Arlington Archosaur Site (AAS). A diverse fauna of dinosaurs, crocodiles, turtles, sharks, rays, lungfish, invertebrates, and plants have been recovered to date. The AAS is unique in producing numerous fossils from a relatively unexplored section of Cretaceous rock, and being within a densely populated urban setting. In time, this site will likely fall victim to further urban sprawl, so it is imperative that as much work is completed while time allows. Goals for the upcoming field season concern the continued excavation of two quarries: one contains the remains of a large crocodyliform and its young, and the other contains a potentially new species of dinosaur. Each species is very important to understanding the early evolutionary history of their respective groups. In addition, a series of bulk sediment samples will be taken from the AAS hillside to be screenwashed for tiny fossils, specifically to search for small reptiles, amphibians, and mammals. Demonstrated by the discovery of a new species of lungfish, the site holds the potential for producing important new species too small to be recovered through digging.
To date, the fossils represent an unusual mixture of primitive and advanced animals. This suggests that an important change was occurring in Texas at this time, when older species were being replaced by more advanced relatives. Therefore it is very important for paleontologists to understand what factors may have led to this unusual situation. Further analysis of the geological formation at the AAS will bring forth more data on the dynamics of Cretaceous coastal ecosystems in North America as well as address broader questions on the evolution of Cretaceous animal species.
Meet the Scientists
Derek J. Main
University of Texas, Arlington
Derek J. Main is currently studying for his PhD on the Arlington Archosaur Site (AAS) and Dinosaur Paleobiogeography at the University of Texas, Arlington, TX, with co-researcher Dr. Christopher Scotese. He is also a part time lecturer teaching courses on Earth Systems, Earth History & Dinosaurs and leads his students on excavations to the AAS. He received his M.Sc. degree at the same university in 2005 with a thesis on Woodbine Formation Stratigraphy, Paleoecology and Paleobiogeography. Derek has been involved in excavating at AAS since it was first discovered in 2003 and reported to Dr. Scotese. Derek has worked in several museums in Dallas, prior to entering academia and is a strong supporter of educational programs that bridge the divide between scientists and the public.
Dr. Christopher Scotese
University of Texas, Arlington
Dr. Christopher Scotese is geologist at the University of Texas at Arlington, having started there in 1990 and becoming a Full Professor in 2002. He received his PhD from the University of Chicago in 1985. His Research interests include plate tectonics, paleogeography, and paleoclimatology. He is creator of the Paleomap Project, which aims to map past configurations of the continents and ocean basins on Earth over the last billion years.
Dr. Chris Noto
University of Wisconsin-Parkside
Dr. Chris Noto attended the University of Chicago, where he worked with paleontologist Paul Sereno preparing fossil specimens of dinosaurs and giant crocodilians. Chris went on to earn a PhD in Ecology and Evolution at Stony Brook University, NY. Currently he is an Assistant Professor in the Biological Sciences Department at the University of Wisconsin-Parkside, where he teaches human anatomy and physiology. Chris has been working at the AAS since 2010. He has also done extensive field work in the Late Jurassic Morrison Formation of Wyoming and Utah. His research interests include paleoecology, functional morphology, taphonomy, and paleobiogeography. Chris is particularly interested in the evolution of the AAS ecosystem and how it compares to other Cretaceous terrestrial ecosystems.