title: Digital preparation of a probable neoceratopsian preserved within an egg, with comments on microstructural anatomy of ornithischian eggshells.
abstract: 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.
authors.affiliation: Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA. abalanoff@amnh.org
authors.forename: Amy M
authors.initials: AM
authors.lastname: Balanoff
authors.forename: Mark A
authors.initials: MA
authors.lastname: Norell
authors.forename: Gerald
authors.initials: G
authors.lastname: Grellet-Tinner
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Lewin
mesh_terms: D000818:Animals; D025061:Dinosaurs; D004528:Egg Shell / Q000648:ultrastructure*; D004531:Eggs / Q000032:analysis; D004625:Embryo, Nonmammalian / Q000033:anatomy & histology; D005260:Female; D005580:Fossils; D007091:Image Processing, Computer-Assisted; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny