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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 ,
David B. Weishampel  and
Valerie B. Deleon
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, ;
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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
Information
Journal of Paleontology , Volume 85 , Issue 5 , September 2011 , pp. 916 - 924
Copyright
Copyright © The Paleontological Society 

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