Page 20 - Introduction to Paleobiology and The Fossil Record

PALEONTOLOGY AS A SCIENCE 7

Box 1.1 Egg thief or good mother?

How dramatically some hypotheses can change! Back in the 1920s, when the fi rst American Museum
of Natural History (AMNH) expedition went to Mongolia, some of the most spectacular fi nds were
nests containing dinosaur eggs. The nests were scooped in the sand, and each contained 20 or 30
sausage-shaped eggs, arranged in rough circles, and pointing in to the middle. Around the nests were
skeletons of the plant-eating ceratopsian dinosaur Protoceratops (see p. 457) and a skinny, nearly

2-meter long, fl esh-eating dinosaur. This flesh eater had a long neck, a narrow skull and jaws with
no teeth, and strong arms with long bony fi ngers. Henry Fairfield Osborn (1857–1935), the famed

paleontologist and autocratic director of the AMNH, named this theropod Oviraptor, which means
“egg thief”. A diorama was constructed at the AMNH, and photographs and dioramas of the scene
were seen in books and magazines worldwide: Oviraptor was the mean egg thief who menaced
innocent little Protoceratops as she tried to protect her nests and babies.
Then, in 1993, the AMNH sent another expedition to Mongolia, and the whole story turned on
its head. More nests were found, and the researchers collected some eggs. Amazingly, they also found
a whole skeleton of an Oviraptor apparently sitting on top of a nest (Fig. 1.3). It was crouching
down, and had its arms extended in a broad circle, as if covering or protecting the whole nest. The
researchers X-rayed the eggs back in the lab, and found one contained an unhatched embryo. They
painstakingly dissected the eggshell and sediment away to expose the tiny incomplete bones inside
the egg – a Protoceratops baby? No! The embryo belonged to Oviraptor, and the adult over the
nest was either incubating the eggs or, more likely, protecting them from the sandstorm that buried
her and her nest.

Figure 1.3 Reconstructed skeleton of the oviraptorid Ingenia sitting over its nest, protecting its
eggs. This is a Bay State Fossils Replica.

As strong confirmation, an independent team of Canadian and Chinese scientists found another
Oviraptor on her nest just across the border in northern China.
Read more about these discoveries in Norell et al. (1994, 1995) and Dong and Currie (1996),
and at http://www.blackwellpublishing.com/paleobiology/.