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The first hatchling dinosaur reported from the eastern United States: Propanoplosaurus marylandicus (Dinosauria: Ankylosauria) from the Early Cretaceous of Maryland, U.S.A.

Published online by Cambridge University Press:  14 July 2015

Ray Stanford
Affiliation:
1Mesozoic Track Project, P.O. Box 845, College Park, MD 20741, USA,
David B. Weishampel
Affiliation:
2Center for Functional Anatomy and Evolution, Johns Hopkins University, Baltimore, MD 21205, USA, ;
Valerie B. Deleon
Affiliation:
2Center for Functional Anatomy and Evolution, Johns Hopkins University, Baltimore, MD 21205, USA, ;

Abstract

Abundant and diverse dinosaur footprints have been discovered recently on bedding surfaces of the Lower Cretaceous Patuxent Formation of Maryland and Virginia. Found along with those ichnofossils is a fossil preserved partially as natural casts and partially as natural molds of a baby nodosaurid ankylosaur so small as to justify interpreting it as a hatchling. Despite the rather unusual type of preservation, the find is properly termed a body fossil and not an ichnite, per se, because it records not the action of an organism, but the body form and bone structure (including partial articulation) of a dinosaur. We here name it Propanoplosaurus marylandicus and provide a description of its diagnostic characteristics. Although actual skeletal remains referable to P. marylandicus have not been found in the Patuxent Formation, other nodosaurids recognized from skeletal remains are known from both the Lower and Upper Cretaceous strata of the Western Interior of North America and Europe. P. marylandicus represents the only diagnostic nodosaurid from the Early Cretaceous of the eastern U.S.A., provides information on growth patterns among nodosaurids, and is the first direct evidence of a dinosaur hatchling and, deductively, nesting, on the entire eastern seaboard.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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References

Brown, B. 1908. The Ankylosauridae, a new family of armored dinosaurs from the Upper Cretaceous. Bulletin of the American Museum of Natural History, 24: 187201.Google Scholar
Carpenter, K. 1984. Skeletal reconstruction and life restoration of Sauropelta (Ankylosauria: Nodosauridae) from the Cretaceous of North America. Canadian Journal of Earth Sciences, 21: 14911498.CrossRefGoogle Scholar
Carpenter, K. 1990. Ankylosaur systematics: example using Panoplosaurus and Edmontonia (Ankylosauria: Nodosauridae), p. 281298. In Carpenter, K. and Currie, P. J. (eds.), Dinosaur Systematics: Approaches and Perspectives. Cambridge University Press, Cambridge.CrossRefGoogle Scholar
Carpenter, K. and Kirkland, J. I. 1998. Review of Lower and middle Cretaceous ankylosaurs from North America, p. 249270. In Lucas, S. G., Kirkland, J. I., and Estep, J. W. (eds.), Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin 14.Google Scholar
Coombs, W. P. 1972. The bony eyelid of Euoplocephalus (Reptilia, Ornithischia). Journal of Paleontology, 46: 637650.Google Scholar
Coombs, W. P. 1978. The families of the ornithischian dinosaur Order Ankylosauria. Palaeontology, 21: 143170.Google Scholar
Coombs, W. P. and Maryańska, T. 1990. Ankylosauria, p. 456483. In Weishampel, D. B., Dodson, P., and Osmólska, H. (eds.), The Dinosauria. University of California Press, Berkeley.Google Scholar
Doyle, J. A. 1992. Reversed palynological correlation of the Lower Potomac Group (U.S.A.) and the Cocobeach sequence of Gabon (Barremian–Aptian). Cretaceous Research, 13: 337349.CrossRefGoogle Scholar
Dryden, I. and Mardia, K. 1998. Statistical Shape Analysis. John Wiley and Sons, Hoboken, N.J.Google Scholar
Garcia, R. A. 2007. An “egg-tooth”-like structure in titanosaurian sauropod embryos. Journal of Vertebrate Paleontology, 27: 247252.Google Scholar
Glaser, J. D. 1969. Petrology and origin of Potomac and Magothy (Cretaceous) sediments, middle Atlantic Coastal Plain. Maryland Geological Survey Report of Investigation, 11: 1101.Google Scholar
Heinrich, R. E., Ruff, C. B., and Weishampel, D. B. 1993. Femoral ontogeny and locomotor biomechanics of Dryosaurus lettowvorbecki (Dinosauria, Iguanodontia). Zoological Journal of the Linnean Society, 108: 179196.Google Scholar
Jacobs, L. L., Winkler, D. A., Murry, P. A., and Maurice, J. M. 1994. A nodosaurid scuteling from the Texas shore of the Western Interior Seaway, p. 337346. In Carpenter, K., Hirsch, K. F., and Horner, J. R. (eds.), Dinosaur Eggs and Babies. Cambridge University Press, Cambridge.Google Scholar
Lambe, L. M. 1919. Description of a new genus and species (Panoplosaurus mirus) of armored dinosaur from the Belly River Beds of Alberta. Transactions of the Royal Society of Canada (Series 3), 13: 3950.Google Scholar
Lee, Y-N. 1996. A new nodosaurid ankylosaur (Dinosauria: Ornithischia) from the Paw Paw Formation (late Albian) of Texas. Journal of Vertebrate Paleontology, 16: 232345.Google Scholar
Marsh, O. C. 1888. Notice of a new genus of Sauropoda and other new dinosaurs from the Potomac Formation. American Journal of Science (Series 3), 35: 8994.Google Scholar
Marsh, O. C. 1890. Additional characters of the Ceratopsidae, with notice of new Cretaceous dinosaurs. American Journal of Science (Series 3), 39: 418426.Google Scholar
Nopcsa, F. 1915. Die Dinosaurier der siebenbürgischen Landesteile Ungarns. Mitteilung des Jahrbuches der königliche Ungarische Geologische Reichsanstalt, 23: 126.Google Scholar
O'Higgins, P. and Jones, N. 1998. Facial growth in Cercocebus torqatus: an applicationof three-dimensional geometric morphometric techniques to the study of morphological variation. Journal of Anatomy, 193: 251272.Google Scholar
Osborn, H. F. 1923. Two Lower Cretaceous dinosaurs of Mongolia. American Museum Novitates, 95: 110.Google Scholar
Owen, R. 1842. Report on British fossil reptiles. Part. II. Report of the British Association for the Advancement of Science, 1841: 60204.Google Scholar
Russell, L. S. 1940. Edmontonia rugosidens (Gilmore), an armored dinosaur from the Belly River series of Alberta. University of Toronto Studies (Geology Series), 43: 328.Google Scholar
Seeley, H. G. 1887. On the classification of the fossil animals commonly called Dinosauria. Proceedings of the Royal Society of London, 43: 165171.Google Scholar
Sereno, P. C. 1997. The origin and evolution of dinosaurs. Annual Review of Earth and Planetary Science, 25: 435489.Google Scholar
Stanford, R., Weems, R. E., and Lockley, M. G. 2004. A new dinosaur ichnotaxon from the Lower Cretaceous Pautuxent Formation of Maryland and Virginia. Ichnos, 11: 251259.CrossRefGoogle Scholar
Stanford, R., Lockley, M., and Weems, R. 2007. Diverse dinosaur-dominated ichnofaunas from the Potomac Group (Lower Cretaceous), Maryland. Ichnos, 14: 155173.Google Scholar
Vickaryous, M. K., Russell, A. P., and Currie, P. J. 2001. Cranial ornamentation of ankylosaurs (Dinosauria: Thyreophora): reappraisal of developmental hypotheses, p. 318340. In Carpenter, K. and Kirkland, J. I. (eds.), The Armored Dinosaurs. Indiana University Press, Bloomington.Google Scholar
Vickaryous, M. K., Maryańska, T., and Weishampel, D. B. 2004. Ankylosauria, p. 363392. In Weishampel, D. B., Dodson, P., and Osmólska, H. (eds.), The Dinosauria, 2nd edition. University of California Press, Berkeley.Google Scholar
Weishampel, D. B. 2006. Another look at the dinosaurs of the East Coast of North America, p. 129168. In Coletivo Arqueológico-Paleontológico Salense (eds.), Actas de las III Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno. Salas de los Infantes, Burgos, Spain.Google Scholar
Weishampel, D. B., Barrett, P. M., Coria, R. E., le Loeuff, J., Gomani, E. S., Zhao, Z., Xu, X., Sahni, A., and Noto, C. 2004. Dinosaur distribution, p. 517606. In Weishampel, D. B., Dodson, P., and Osmólska, H. (eds.), The Dinosauria, 2nd edition. University of California Press, Berkeley.Google Scholar
Weishampel, D. B. and Young, L. 1996. Dinosaurs of the East Coast. Johns Hopkins University Press, Baltimore, 275 p.Google Scholar
Xu, X., Wang, X.-L., and You, H. L. 2001. A juvenile ankylosaur from China. Naturwissenschaften, 88: 297300.Google Scholar
Zarra, L. 1989. Sequence stratigraphy and foraminiferal biostratigraphy for selected wells in the Albemarle Embayment, North Carolina. North Carolina Geological Survey Open File Report 89-5: 148.Google Scholar