@article{abfe0aa0bd8b4d209bea9e81dc159f7f,
title = "Microstructural description of the maniraptoran egg Protoceratopsidovum",
abstract = "Since their discovery in the 1920s, some asymmetric, elongated dinosaur eggs from the Upper Cretaceous of Mongolia have been interpreted as ceratopsian eggs. However, recent views support a maniraptoran affinity mainly based on macroscopic features. Technical advancements in palaeontology provide a novel approach to diagnose maniraptoran eggs, and the discovery of soft ceratopsian eggs makes the debate a timely issue worth revisiting. Here, we analysed Protoceratopsidovum eggshell from southern Mongolia with electron backscatter diffraction and the results were compared with East Asian and North American maniraptoran and ornithischian eggs. The microstructure and crystallography of Protoceratopsidovum confirms the maniraptoran hypothesis, given that it shows diagnostic features of the clade absent from ornithischian (e.g. hadrosaur) eggs. Additional characters, such as egg shape, ornamentation, egg pairing and clutch structure also support a maniraptoran affinity. Protoceratopsidovum has both elongatoolithid (oviraptorosaur egg) and prismatoolithid (troodontid egg) features, and it may bridge the morphological gap between the two established oofamilies. Considering the similarity between Protoceratopsidovum and potential dromaeosaur eggs, at least some Protoceratopsidovum may be deinonychosaur eggs. Fossil localities that yield both deinonychosaurs and Protoceratopsidovum may yield conclusive evidence for the true affinity of this ootaxon. Future discovery of the egg-laying taxon of Protoceratopsidovum will not only improve our understanding of maniraptoran reproductive biology but also make Protoceratopsidovum a reliable indicator of the palaeobiogeography of that maniraptoran clade.",
keywords = "electron backscatter diffraction, Late Cretaceous, microstructure, Mongolia, Ornithischia, Theropoda",
author = "Seung Choi and Barta, {Daniel E.} and Miguel Moreno-Azanza and Kim, {Noe Heon} and Shaw, {Colin A.} and Varricchio, {David J.}",
note = "Funding Information: We sincerely thank Konstantin Mikhailov (Borissiak Institute of Paleontology) for loans of PIN specimens and all his contributions to knowledge of that made our study possible. We thank Adam Halamski and Cyprian Kulicki (Institute of Paleobiology, Polish Academy of Sciences) for collections access and assistance with photomicrographs, Mark Norell (American Museum of Natural History) for permission to sample eggshell, Giulio Panasc{\'i} (Montana State University) for photography (Fig. 2 ), Gregory Funston (University of Edinburgh) for helpful discussion on the fauna of the Nemegt Basin, and anonymous reviewers and Sally Thomas and the editor Daniel Field, who greatly improved the manuscript. This research was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (grant number: 2020R1A6A3A03038316) to SC; NSF grant 0847777 (EAR) to DJV also supported this research. DEB is funded by the Oklahoma State University Center for Health Sciences. MM‐A is funded by Funda{\c c}{\~a}o para a Ci{\'e}ncia e a Tecnolog{\'i}a (SFRH/BPD/113130/2015, PTDC/CTA‐PAL/31656/2017 and UID/GEO/04035/2019), the Ministerio de Econom{\'i}a y Competitividad (CGL2013‐47521‐P and CGL2017‐85038‐P, MINECO/ERDF, EU), and the Government of Arag{\'o}n ({\textquoteleft}DGA{\textquoteright} and {\textquoteleft}Grupos de Referencia{\textquoteright} E18_17R). Protoceratopsidovum Oviraptor philoceratops Funding Information: We sincerely thank Konstantin Mikhailov (Borissiak Institute of Paleontology) for loans of PIN specimens and all his contributions to knowledge of Protoceratopsidovum that made our study possible. We thank Adam Halamski and Cyprian Kulicki (Institute of Paleobiology, Polish Academy of Sciences) for collections access and assistance with photomicrographs, Mark Norell (American Museum of Natural History) for permission to sample Oviraptor philoceratops eggshell, Giulio Panasc{\'i} (Montana State University) for photography (Fig. 2), Gregory Funston (University of Edinburgh) for helpful discussion on the fauna of the Nemegt Basin, and anonymous reviewers and Sally Thomas and the editor Daniel Field, who greatly improved the manuscript. This research was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (grant number: 2020R1A6A3A03038316) to SC; NSF grant 0847777 (EAR) to DJV also supported this research. DEB is funded by the Oklahoma State University Center for Health Sciences. MM-A is funded by Funda{\c c}{\~a}o para a Ci{\'e}ncia e a Tecnolog{\'i}a (SFRH/BPD/113130/2015, PTDC/CTA-PAL/31656/2017 and UID/GEO/04035/2019), the Ministerio de Econom{\'i}a y Competitividad (CGL2013-47521-P and CGL2017-85038-P, MINECO/ERDF, EU), and the Government of Arag{\'o}n ({\textquoteleft}DGA{\textquoteright} and {\textquoteleft}Grupos de Referencia{\textquoteright} E18_17R). SC and DJV designed the research. DJV and CAS provided fossil specimens, specimen preparation facilities and guided specimen preparation. SC, DEB, MM-A and N-HK acquired the data. SC, DEB and MM-A drafted the manuscript and constructed the figures and tables. All authors reviewed and revised the draft and confirmed the final version. Publisher Copyright: {\textcopyright} 2022 The Palaeontological Association.",
year = "2022",
month = mar,
day = "1",
doi = "10.1002/spp2.1430",
language = "English",
volume = "8",
journal = "Papers in Palaeontology",
issn = "2056-2802",
publisher = "John Wiley and Sons Ltd",
number = "2",
}