title: Minute theropod eggs and embryo from the Lower Cretaceous of Thailand and the dinosaur-bird transition.
abstract: We report on very small fossil eggs from the Lower Cretaceous of Thailand, one of them containing a theropod embryo, which display a remarkable mosaic of characters. While the surficial ornamentation is typical of non-avian saurischian dinosaurs, the three-layered prismatic structure of the eggshell is currently known only in extant and fossil eggs associated with birds. These eggs, about the size of a goldfinch's, mirror at the reproductive level the retention of small body size that was paramount in the transition from non-avian theropods to birds. The egg-layer may have been a small feathered theropod similar to those recently found in China.
authors.affiliation: CNRS (UMR 5125, Paléoenvironnements et Paléobiosphère), 16 cour du Liégat, 75013 Paris, France. eric.buffetaut@wanadoo.fr
authors.forename: Eric
authors.initials: E
authors.lastname: Buffetaut
authors.forename: Gerald
authors.initials: G
authors.lastname: Grellet-Tinner
authors.forename: Varavudh
authors.initials: V
authors.lastname: Suteethorn
authors.forename: Gilles
authors.initials: G
authors.lastname: Cuny
authors.forename: Haiyan
authors.initials: H
authors.lastname: Tong
authors.forename: Adrijan
authors.initials: A
authors.lastname: Kosir
authors.forename: Lionel
authors.initials: L
authors.lastname: Cavin
authors.forename: Suwanna
authors.initials: S
authors.lastname: Chitsing
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Griffiths
authors.forename: Jérôme
authors.initials: J
authors.lastname: Tabouelle
authors.forename: Jean
authors.initials: J
authors.lastname: Le Loeuff
mesh_terms: D000818:Animals; D001717:Birds / Q000033:anatomy & histology* / Q000196:embryology; D002681:China; D025061:Dinosaurs / Q000033:anatomy & histology* / Q000196:embryology; D004625:Embryo, Nonmammalian; D005260:Female; D005580:Fossils; D008855:Microscopy, Electron, Scanning; D010063:Ovum / Q000648:ultrastructure; D010163:Paleontology; D013785:Thailand