Show simple item record

dc.contributor.authorJackson, Frankie D.
dc.contributor.authorSchaff, Rebecca J.
dc.contributor.authorVarricchio, David J.
dc.contributor.authorSchmitt, James G.
dc.identifier.citationJackson, Frankie D., Rebecca J. Schaff, David J. Varricchio, and James G. Scmitt. "A theropod nesting trace with eggs from the upper cretaceous (Campanian) Two Medicine Formation of Montana." Palaios 38, no. 5 (May 2015): 362-372. DOI:
dc.description.abstractA nesting trace preserved in alluvial floodplain deposits in the Upper Cretaceous Two Medicine Formation at the Willow Creek anticline in north-central Montana contains four crushed theropod eggs referable to the oospecies Continuoolithus canadensis. These eggs immediately overlie the lower surface of a 35-cm-long × 7-cm-thick, dark-green mudstone lens, surrounded by reddish-purple mudstone. The long axes of three eggs are parallel to one another and to the lower boundary of the lens, whereas the fourth egg lies at a 30° angle to the others. A thin, 1-cm-thick organic horizon overlies the eggs, suggesting they were buried with some vegetation. Geometric modeling of the slightly asymmetrical C. canadensis eggs yields a volume and mass of approximately 194 cm3 and 205 g for each egg. This method provides a more accurate estimation for the surface area than allometric equations that are based on modern bird eggs because of the elongate shape of many non-avian theropod eggs. Pore density and water vapor conductance (GH2O) calculated from one egg in the trace and five additional C. canadensis eggs from the Willow Creek anticline vary across three regions. High, moderate, and very low GH2O characterize the equatorial zone, blunt, and tapering poles, respectively. The average GH2O for all eggs exceeds that of an avian egg of similar mass by 3.9×, thus supporting sedimentologic evidence of substrate burial during incubation.en_US
dc.description.sponsorshipNational Science Foundation grant #0847777 (EAR)en_US
dc.titleA theropod nesting trace with eggs from the upper cretaceous (Campanian) Two Medicine Formation of Montanaen_US
mus.identifier.categoryLife Sciences & Earth Sciencesen_US
mus.relation.departmentEarth Sciences.en_US
mus.relation.universityMontana State University - Bozemanen_US
mus.contributor.orcidVarricchio, David J.|0000-0002-0594-0929en_US

Files in this item


This item appears in the following Collection(s)

Show simple item record

MSU uses DSpace software, copyright © 2002-2017  Duraspace. For library collections that are not accessible, we are committed to providing reasonable accommodations and timely access to users with disabilities. For assistance, please submit an accessibility request for library material.