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The Danek Bonebed (Edmonton, Alberta, Canada) is a monodominant Edmontosaurus regalis assemblage of the upper Campanian (Upper Cretaceous) Horseshoe Canyon Formation. Bone histology of humeri and femora are used in this paper to test hypotheses about the growth dynamics and palaeobiology of Edmontosaurus. The high number of elements collected from the Danek Bonebed allow for an expansion of the multi-element histological record for hadrosaurs. Results indicate that Edmontosaurus had a growth trajectory similar to other large-bodied dinosaurs and reached the onset of somatic maturity at about 10-15 years of age; however, even the largest elements to preserve lines of arrested growth do not have external fundamental systems. This timing of the onset of somatic maturity agrees with the estimated body size of Edmontosaurus relative to other dinosaurs for which life-history data are available. Vascularity patterns support the hypothesis that edmontosaurs preserved at the Danek Bonebed were not subject to the same extreme seasonal environmental shifts as congenerics preserved at higher latitudes, further supporting overwintering behaviour in the latter. [ABSTRACT FROM AUTHOR]

Although considerable work has been conducted on the stratigraphy and dinosaur assemblages of the Horseshoe Canyon Formation of southern Alberta, equivalent strata and assemblages in central Alberta remain poorly understood. Data from the Danek Bonebed (Edmonton, Alberta) are beginning to fill this gap. The bonebed occurs 4 m above the #9 Big Island Coal Seam. This stratigraphic position lies just below the middle of the Horseshoe Canyon Formation in the Edmonton region, and also lies below a thick, stratigraphically significant non-coaly interval that is expressed throughout central and southern Alberta. The stratigraphic position of the Danek Bonebed equates best with the uppermost Horsethief Member of the Horseshoe Canyon Formation in the Drumheller region and the upper part of Unit 4 of the Wapiti Formation in the Grande Prairie region. In both Drumheller and Grande Prairie, the correlated position of the bonebed underlies a zone of marine transgression (Drumheller Marine Tongue), which, in turn, includes the Campanian-Maastrichtian boundary. In the context of Geologic Time Scale 2004, we infer a late Campanian age of 71.0-71.3 Ma for the bonebed. The Danek's dinosaurian assemblage is limited taxonomically, but compares well with the Edmontosaurus regalis - Pachyrhinosaurus canadensis fossil assemblage zone in the Drumheller region. We propose that a mega-herbivore faunal assemblage, characterized by Edmontosaurus and Pachyrhinosaurus, extended continuously across the climatically wet coastal plain of latest Campanian southern and central Alberta, and likely extended northwest into the North Slope of Alaska, where it persisted into the early Maastrichtian. [ABSTRACT FROM AUTHOR]

For fossil assemblages, quantitative size and shape studies are often complicated by diagenetic distortion. Different vertebrate elements, although subjected to similar burial stresses, exhibit deformations based upon their original shapes; this hypothesis is tested here by quantitatively comparing deformed humeri and femora from the Danek Bonebed (a monodominant Edmontosaurus regalis bonebed from the upper Campanian Horseshoe Canyon Formation in Edmonton, Alberta, Canada) with samples of undeformed humeri and femora from modern and fossil assemblages. Analyses suggest that at the Danek Bonebed a strong relationship exists between element length and circumference despite being distorted by crushing deformation. Major and minor axes of the midshaft cross section, however, were not uniformly distorted. Although their anatomical position did not change, the major axis became longer relative to the minor axis in distorted specimens. A regression based on the undeformed humeri was not able to accurately predict circumference in the Danek humeri. Further study might quantify the deformation of other bones in the Danek Bonebed and could be extended to other assemblages and genera. Caution should be taken when conducting studies in which diagenetic crushing may have altered morphological features of fossil vertebrate remains. [ABSTRACT FROM AUTHOR]