Dinosaurs in Their Time

Field Guide to the Oviraptorosaur

OviraptorosaurEvolutionary Relationships

This oviraptorosaur differs significantly from all of its nearest relatives. Its distinctive features indicate that it represents a previously unknown species of dinosaur. One goal of Carnegie Museum of Natural History's scientific study of the oviraptorosaur is to name this new species.

Most known oviraptorosaurs belong to the group Oviraptoridae [OH-vih-RAP-tor-ih-day], which includes the infamous "egg-thief" Oviraptor. However, Carnegie Museum of Natural History paleontologists think that our new dinosaur belongs to a bizarre, poorly understood group of oviraptorosaurs called the Caenagnathidae [SEE-nuh-NAYTH-ih-day]. This idea rests on skeletal features shared by our oviraptorosaur and other caenagnathids, such as lower jawbones that are fused together, a hipbone whose forward portion is longer than its rearward portion, and a middle foot bone whose upper end is "pinched" between the upper ends of the other two foot bones. The Carnegie Museum of Natural History oviraptorosaur is by far the most complete caenagnathid in the world, and its study will reveal the anatomy and behavior of these mysterious dinosaurs for the first time.

Dinosaur, Bird, or Both?

With its toothless jaws, relatively short tail, long spindly legs, and three-toed feet, our new oviraptorosaur looks more like a bird than a typical dinosaur.

For more than a century, the idea that birds arose from dinosaurs was hotly debated among scientists. Then, beginning in 1996, a number of spectacular discoveries from approximately 120-million-year-old lakebeds in northeastern China effectively confirmed the dinosaur origin of birds. These discoveries, indisputable dinosaurs preserved with impressions of feathers attached to their bodies, have convinced all but the most stubborn skeptics.

So dinosaurs are not extinct; they live on! The national symbol of the United States, the bald eagle, is a highly modified dinosaur. The ostriches that strut the savannas of Africa are dinosaurs. The tuxedoed penguins that frolic among Antarctic ice sheets are dinosaurs. Dinosaurs fly south for the winter. And distant cousins of Tyrannosaurus rex appear on dinner tables across America every Thanksgiving!

The Egg Thieves: A Case of Mistaken Identity

ProtoThe first known oviraptorosaur skeleton, discovered in Mongolia in 1923, was found atop a clutch of dinosaur eggs thought to belong to the early horned dinosaur Protoceratops. Paleontologists therefore concluded that this theropod had died in the act of raiding a Protoceratops nest. This led to its being named Oviraptor philoceratops—literally, “egg thief who prefers horned dinosaurs.” It is from this dinosaur that the entire oviraptorosaur group takes its name.

In the 1990s, further expeditions to Mongolia turned up many more dinosaur fossils. However, paleontologists were shocked by what they found: a supposed “Protoceratops” egg with a baby oviraptorosaur inside! So the eggs that paleontologists originally thought belonged to horned dinosaurs actually belonged to oviraptorosaurs.

At the same time, a spectacular oviraptorosaur skeleton was discovered with its arms outstretched around a nest. The 22 eggs in this nest were the same kind as those that contained the baby oviraptorosaur...they were oviraptorosaur eggs! Since it’s not very likely that a parent would raid the nest of its own species, that adult appears to have died guarding its nest.

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