My research is based on direct observation and examination of skeletal specimens for comparative morphological descriptions and phylogenetic analyses. In order to add new data to those in existing museum collections, I have an active collaborative field program in the Triassic and Eocene. My fieldwork mainly is in the American West and Southwest, but I also am involved in Permian-Triassic fieldwork in Tanzania. You can see some of my field projects below.
I became interested in the Triassic of Wyoming really early in my research. Most of my fieldwork is in the Chugwater Group in Natrona and Fremont counties. The phytosaurs Parasuchus bransoni and Angistorhinus grandis are from the Popo Agie Formation of the Chugwater Group.
Wyoming, Chugwater Group, Triassic
Petrified Forest National Park is one of the best places in the world for Late Triassic paleontology. My work at PEFO resulted in the collection of three phytosaur specimens that were part of my MS thesis (the referred specimens of Pravusuchus hortus and the holotype of Protome batalaria), and I continue to have many projects there.
Petrified Forest National Park
Chinle Formation, Upper Triassic
Wyoming, Great Divide
and Washakie Basins, Eocene
The southwest portion of Wyoming has been important for understanding the early evolution of primates and the associated fauna for over a century. There are hundreds of specimens of turtles, squamates, and crocodylian fossils from that critical period of climate change in the Paleogene, and understanding if and how the evolution of those ectothermic taxa responded to those climatic changes can shed light on diversity changes across the continent as well as the possible effects of future climate change on the current fauna.
The Devil's Graveyard Formation is famous for the fossil collections made by Jack Wilson, The University of Texas at Austin, and Margaret and James Stevens. Those local faunas were based on the mammal fossils they collected, but more recent fieldwork headed up by Dr. Chris Kirk, The University of Texas at Austin, resulted in our collection of hundreds of turtle, squamate, and crocodylian fossils from that critical period of climate change near the Eocene-Oligocene boundary.
West Texas, Devil's Graveyard Formation, Middle Eocene
Ghost Ranch, New Mexico
Chinle Formation, Upper Triassic
I've been involved with the collaborative fieldwork at Ghost Ranch since 2006. Our localities produce important specimens of phytosaurs, aetosaurs, and amphibians, together with an interesting mix of dinosauromorph taxa, that have allowed interpretations of biogeography, diversification, and faunal change near the end of the Triassic.
Ruhuhu and Usili Formations, Manda Beds; Permian and Triassic
Our team examines the Permian-Triassic mass extinction and the subsequent recovery in the Ruhuhu Basin in southwestern Tanzania. We relocated fossil sites that were collected in the 1930s and 1960s by British and German paleontologists. We've collected taxa such as Asilisaurus kongwe, Parringtonia, many rhynchosaurs, cynodonts, and amphibians. In the field we often see yellow baboons, Nile monitors, agamid lizards, and many amazing local birds.
Dockum Group, Upper Triassic
I've done fieldwork in multiple counties in the Panhandle of Texas to address the diversity of archosauriforms in the Late Triassic. Some of this was in conjunction with Texas Tech University. All of the exposed Triassic rocks in Texas are part of the Dockum Group, and this sequence produced many famous localities and holotypes of important specimens. Those include the Post Quarry, exposures in Palo Duro Canyon, Rotten Hill, and the Otis Chalk localities that were collected by the WPA in the 1930s and 1940s.