North America - WILSON MANTILLA LAB

Hell Creek, Montana

This area boasts ample outcrops of the Hell Creek and Fort Union fms (~68–65 Ma) and is famous for abundant dinosaur fossils and for studies of the K/Pg mass extinction and biotic recovery.

Introduced to this area in 1998 by Bill Clemens, Harley Garbani, and Jack Horner, Greg Wilson Mantilla has ever since done field work there with many colleagues, students, volunteers, and friends under the Hell Creek Project.

We collect vertebrate, invertebrate, and plant fossils, and geological data with permission from the Bureau of Land Management, Charles M. Russell Wildlife Refuge, State of Montana, and private land owners.

Fossils are later prepared and stored at the Burke Museum, but large collections also exist at the University of California Museum of Paleontology, Museum of the Rockies, and Denver Museum of Nature & Science.

This field work is central to the Wilson Mantilla Lab teaching, outreach, curatorial, and research objectives, particularly the K/Pg mass extinction & recovery and the radiation of placental mammals.

North & Central Montana

Historically important and extensive outcrops of the upper Campanian Judith River Formation (78–74 Ma) occur in north and central Montana.

In the Campanian, dinosaur diversity peaked, angiosperms taxonomically and ecologically diversified, and mammaliaform faunas transitioned from having more ancient taxa (eutriconodontans, dryolestoids) to being dominated by multituberculates and therians. These biotas also provide a “baseline” view prior to the K/Pg event.

In collaboration with Ray Rogers, Jack Horner, Mark Goodwin, and Holly Woodward, we have conducted field work in the area since 2019.

We sample from new and existing fossil sites and are assembling a well-constrained succession of mammaliaform communities to track diversity in relation to possible drivers (e.g., climate, vegetation).

Pawnee National Grasslands, Colorado

In 2006, we initiated a paleontological survey of Upper Cretaceous deposits in the Pawnee National Grassland (PNG) of northeastern Colorado. The project was spurred by a small but intriguing vertebrate microfossil assemblage collected by Ken Carpenter (1979).

We discovered 16 new vertebrate fossil localities and recovered more than 300 vertebrate micro- and macrofossils from the PNG. The vertebrate fauna includes >32 species of freshwater sharks and rays, fish, amphibians, turtles, lizards, crocodiles, dinosaurs, and mammals.

This work has implications for understanding the paleobiogeography and macroevolution of Late Cretaceous vertebrate faunas of the Western Interior of North America.

Baja California, México

During the Cretaceous, Baja California was contiguous with mainland México and possibly part of a terrestrial migration route between North and South America. The small fossil samples also suggest a fauna biogeographically distinctive from most in the Western Interior of North America.

Field work during the 1950s, 60s, and 70s led by Frank Kilmer, William J. Morris, Harley J. Garbani, and Jason A. Lillegraven in the Campanian “El Gallo” and “La Bocana Roja” fms focused on vertebrate macrofossils.

In 2004, 2005, 2007, 2009 and 2015, with colleagues from Universidad Nacional Autónoma de México (UNAM), we conducted field work to re-sample the vertebrate fauna, particularly the vertebrate microfossils.