Late Maastrichtian paleoenvironments and dinosaur biogeography in the western interior of North America

Physical evidence of predatory behavior in Tyrannosaurus rex

“…This is unambiguous evidence that T. rex was an active predator, fulfilling the criteria that Farlow and Holtz (3) advanced. As T. rex comprises between 1% and 16% of the Upper Cretaceous dinosaurian fauna in Western North America (41)(42)(43)(44)(45), its status as a predator or obligate scavenger is nontrivial and could have significant implications for paleoecological reconstructions of that time period. The present contribution provides unique information demonstrating the ecological role for T. rex as that of an active predator.…”

The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia

“…As noted, biases in this study reflecting taxonomically or occurrence-wise inaccurate faunal lists relied on herein may also be present (e.g., Lehman, 1997;Lloyd et al, 2011). However, given the extensive literature review undertaken for the review of Appalachian faunas and for their comparison with Laramidian faunas and the large amount of data compiled, any such discrepancies seem not to be a large bias in the analyses undertaken.…”

“…The creation of the seaway caused the formation of a long, slender landmass known as Laramidia to the west and the wider, more rectangular Appalachia to the east (e.g., Schwimmer, 2002;Sampson et al, 2010), having appreciable consequences in the evolution of North American dinosaurs. The former of these two landmasses apparently experienced a heightened level of non-avian dinosaur diversification during the Campanian , when a high level of local dinosaur endemism partnered with regional differences in non-avian dinosaur faunas may have occurred there (Lehman, 1997;Sampson et al, 2010;Loewen et al, 2013). The cause for this rapid diversification of non-avian dinosaurs and other vertebrates on Laramidia has been hypothesized as a consequence of climate variability leading to floral variability, of orogenesis or orogenic activity, and of transgressions and regressions of the Western Interior Seaway (Horner et al, 1992;Lehman, 1997;Sampson et al, 2010;Loewen et al, 2013).…”

“…Analysis of dinosaur faunal provincialism on Appalachia. Because it has been noted that Laramidia may have had multiple different dinosaur faunal provinces during the Campanian (e.g., Lehman, 1997;Sampson et al, 2010a;, dinosaur provincialism on Appalachia was also investigated for during the Coniacian, Santonian, and Campanian Stages of the Late Cretaceous. This was done by first rarefying the assemblages, which represent the most wellknown (in terms of number of specimens) faunas of units from the aforementioned Stages of the Late Cretaceous and then by employing the Simpson similarity index and Jaccard coefficient to compare faunal similarities at the genus and family levels for each.…”

“…Biases. As previous studies have noted, biases in the collection of fossils, use of previously published literature, taphonomic biases among and within sedimentary units, and temporal differences among sedimentary units studied and within their faunas all play a role in skewing paleobiogeographic analyses (e.g., Nicholls and Russell, 1990;Lehman, 1997;Gates et al, 2010). Because of these factors, the specific paleoenvironments, taphonomy, and age of sediments compared herein were extensively reviewed and compared in the Results section.…”