Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the 'Albertosaurus sarcophagus' bonebed

Title
Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the 'Albertosaurus sarcophagus' bonebed
Publication Date
2010
Author(s)
Larson, Derek W
Brinkman, Donald B
Bell, Phil
( author )
OrcID: https://orcid.org/0000-0001-5890-8183
Email: pbell23@une.edu.au
UNE Id une-id:pbell23
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
NRC Research Press
Place of publication
Canada
DOI
10.1139/E10-005
UNE publication id
une:15071
Abstract
The faunal assemblage from the early Maastrichtian portion of the Horseshoe Canyon Formation is described on the basis of four new vertebrate microfossil localities and remains from the Albertosaurus bonebed. All of the localities sampled were deposited during a cool, dry climate at a palaeolatitude of ~58°N. Thus, these assemblages provide insight into a northern cool-climate assemblage in the early Maastrichtian of western North America. This fauna is characterized by the presence of taxa with more northern affinities, such as Holostean A, champsosaurs, Troodon, and toothed birds. Warm-climate taxa, such as crocodylians, large and diverse turtles, and albanerpetontids are notable in their absence. The 'Albertosaurus' bonebed locality at the top of unit 4 of the Horseshoe Canyon Formation was deposited during the initial stages of a trend to a warmer and wetter climate that is represented in unit 5. The bonebed shares many taxa with the underlying vertebrate microfossil localities. However, a notable difference is the presence of Atrociraptor marshalli from the 'Albertosaurus' bonebed but not the other localities in the upper Horseshoe Canyon Formation. The presence of Atrociraptor may be attributable to this change in climate rather than local ecological conditions. Also, the assemblages are different in the paucity of fish remains in the bonebed, and the relative rarity of shed hadrosaur teeth. The low abundance of aquatic taxa and rarity of shed teeth of hadrosaurs indicate that the locality is largely autochthonous, with little material being transported into the site.
Link
Citation
Canadian Journal of Earth Sciences, 47(9), p. 1159-1181
ISSN
1480-3313
0008-4077
Start page
1159
End page
1181

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