A Pair of Shelled Eggs Inside A Female Dinosaur
Tamaki Sato,1*
Yen-nien Cheng,2
Xiao-chun Wu,1*
Darla K. Zelenitsky,3
Yu-fu Hsiao4
An oviraptosaurian specimen (Dinosauria, Theropoda) from an Upper Cretaceous formation in China retains a pair of shelled eggs in the pelvis, providing direct evidence that oviraptorosaurian dinosaurs laid paired elongatoolithid eggs. The presence of the paired eggs suggests that theropod dinosaurs had two functional oviducts (like crocodiles) but that each oviduct produced only one egg at a time and that an entire egg clutch was laid through multiple ovipositions (like birds). The orientations of the eggs inside the skeleton and in clutches indicate that the mother came to the center of the nest to lay eggs.
1 Canadian Museum of Nature (CMN), Post Office Box 3443, STN D, Ottawa, Ontario K1P 6P4, Canada.
2 National Museum of Natural Science, 1 Kuan Chien Road, Taichung, Taiwan (ROC).
3 The University of Calgary, Department of Geology and Geophysics, 2500 University Drive North-west, Calgary, AB T2N 1N4, Canada.
4 Paleowonders Fossil and Mineral Museum, 442 Section 2, Wen-Hwa Road, Banchiao, Taipei, Taiwan (ROC).
* To whom correspondence should be addressed. E-mail: tsato{at}mus-nature.ca (T.S.); xcwu{at}mus-nature.ca (X.-c.W.)
