, Volume 95, Issue 6, pp 493–500 | Cite as

Digital preparation of a probable neoceratopsian preserved within an egg, with comments on microstructural anatomy of ornithischian eggshells

  • Amy M. BalanoffEmail author
  • Mark A. Norell
  • Gerald Grellet-Tinner
  • Matthew R. Lewin
Original Paper


We describe the first known embryo of a neoceratopsian dinosaur, perhaps the most ubiquitous Laurasian group of Cretaceous dinosaurs, which is preserved completely enclosed within an egg. This specimen was collected from Late Cretaceous beds of southern Mongolia, which commonly preserve fossils of the neoceratopsian, Yamaceratops dorngobiensis. The small egg was scanned using high-resolution X-ray computed tomography and digitally prepared from the matrix. The preserved and imaged elements support a diagnosis of the embryo to Neoceratopsia and allow preliminary observations of ontogenetic transformations within this group. The addition of an embryo also adds another important data point to the already impressive postnatal ontogenetic series that are available for this clade.


Ornithischia Computed tomography Eggshell microstructure Embryo 



GGT would like to acknowledge E. Duke at the Analytical Facilities of Engineering and Mining Experiment Station of SDSMT for the use of the SEM. MRL would like to thank E. Kernberg, UCSF, for preliminary radiological analyses of the specimen. Mick Ellison provided much help in the preparation of figures. Jessie Maisano assisted in the preparation of the web-based imagery accompanying this paper. Thanks to Gabe Bever, Peter Makovicky, and three anonymous reviewers for their useful comments. CT scanning was performed by the HRCT Facility at The University of Texas at Austin. Support for this project came from the American Museum of Natural History, Division of Paleontology and DEES, Columbia University.

Supplementary material (3 mb)
S1 Spinning animation of the three-dimensional reconstruction of the skeletal elements contained within the egg. The matrix and eggshell have been rendered transparent (MOV 3.1 MB).


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Amy M. Balanoff
    • 1
    Email author
  • Mark A. Norell
    • 1
  • Gerald Grellet-Tinner
    • 2
  • Matthew R. Lewin
    • 3
  1. 1.Division of PaleontologyAmerican Museum of Natural HistoryNew YorkUSA
  2. 2.Department of Geology and Geological EngineeringSouth Dakota School of MinesRapid CityUSA
  3. 3.Department of Emergency MedicineUniversity of California, San Francisco School of MedicineSan FranciscoUSA

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