Field Guide
Ancient Environments

oviraptorosaur in environmentOur oviraptorosaur skeletons were discovered in northwestern South Dakota in rocks belonging to the famed Hell Creek Formation. Other notable dinosaur discoveries from this area include the duckbilled herbivore Edmontosaurus, the three-horned Triceratops, the thick-skulled Pachycephalosaurus, and the terrifying Tyrannosaurus rex. These animals lived between 68 and 65 million years ago at the end of the Mesozoic Era. At this time in Earth history, this area of South Dakota was a warm, humid coastal plain drained by meandering rivers that flowed into an ancient inland sea.

The World of the Carnegie Museum of Natural History Oviraptorosaur
The new oviraptorosaur wound its way through a balmy maze of forest unlike any that exists on Earth today. Stands of palm trees, other flowering plants, cycads, and unusual conifers thrived beneath a canopy of broad-leafed deciduous and evergreen trees. The oviraptorosaur shared this green world with a broad diversity of other animals, including snails, clams, fishes, amphibians, turtles, lizards, snakes, crocodile-like champsosaurs, true crocodilians, pterosaurs, primitive birds, small mammals, and other dinosaurs. Carnegie Museum of Natural History's Vertebrate Paleontology collection contains fossils of many of these animals.  Click the thumbnails to learn more about some of these creatures:

turtle shell

“Baena hatcheri” (BAY-nuh HATCH-er-eye)
(probably Eubaena cephalica or Stygiochelys estesi)
“John Bell Hatcher’s turtle”

This turtle shell is the holotype, or original specimen, of the species “Baena hatcheri,” named by Oliver Hay in 1901. Hay named this specimen after celebrated Carnegie Museum of Natural History paleontologist John Bell Hatcher, who had discovered it earlier that year.


Didelphodon vorax (die-DELF-o-don VORE-ax)
“Voracious opossum tooth”

This animal was a carnivore and an extinct relative of modern marsupials. Reaching the size range of the modern Virginia opossum, Didelphodon is much larger than many other tiny mammals that co-existed with dinosaurs at the end of the Cretaceous in North America.

sclerotic ring

Eusuchian crocodyliform (you-SUE-key-en crock-oh-DIE-lih-form)

This very incomplete skeleton (including a possible skull fragment, several vertebrae, and two dermal scutes) belongs to a small relative of living crocodylians. More specifically, we know it pertains to the group Eusuchia, because its tail vertebrae are deeply concave in front and convex behind.

unionid bivalve

Unionid bivalve
(YOON–yun–id BI-valve)

The Hell Creek environment contained many rivers and lakes, which were home to a variety of freshwater bivalves. The most common of these are mussels belonging to the group Unionidae. These animals used a pointed muscular foot to burrow and move around.

Plant Life of the Hell Creek Formation
The Carnegie Museum of Natural History oviraptorosaur inhabited a humid, forested plain that was populated by a rich diversity of plants and animals. This environment is preserved in a rock unit that is known today as the Hell Creek Formation. Flowering plants, which had evolved earlier in the Cretaceous Period, were diverse and abundant in this ecosystem.

Plants represented in our exhibit include Ginkgo adiantoides (similar to the modern ginkgo tree), Sabalites (a fan palm), Platanus raynoldsii (a relative of modern sycamore trees), and Palaeoaster inquirenda (a relative of modern poppies).

Appearance & Behavior Evolutionary History Geography & Distribution Research at CMNH
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