The paleoenvironment of<i>Tyrannosaurus rex</i>from southwestern Saskatchewan, Canada

McIver, E. E.

doi:10.1139/e01-073

Cited by 23 publications

(31 citation statements)

References 28 publications

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“…This hypothesis largely depends on the ability of using lithology to distinguish between channel and floodplain palaeoenvironments. Nine lithofacies are generally recognized in the study area [18,22,23,25,27,28]. As summarized in table 1, channel lithofacies are generally composed of sandstone, and floodplain lithofacies are generally composed of mudstone.…”

Section: Discussionmentioning

confidence: 99%

Spatial niche partitioning in dinosaurs from the latest cretaceous (Maastrichtian) of North America

Lyson

Longrich

2010

Proc. R. Soc. B.

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We examine patterns of occurrence of associated dinosaur specimens (n ¼ 343) from the North American Upper Cretaceous Hell Creek Formation and equivalent beds, by comparing their relative abundance in sandstone and mudstone. Ceratopsians preferentially occur in mudstone, whereas hadrosaurs and the small ornithopod Thescelosaurus show a strong association with sandstone. By contrast, the giant carnivore Tyrannosaurus rex shows no preferred association with either lithology. These lithologies are used as an indicator of environment of deposition, with sandstone generally representing river environments, and finer grained sediments typically representing floodplain environments. Given these patterns of occurrence, we argue that spatial niche partitioning helped reduce competition for resources between the herbivorous dinosaurs. Within coastal lowlands ceratopsians preferred habitats farther away from rivers, whereas hadrosaurs and Thescelosaurus preferred habitats in close proximity to rivers, and T. rex, the ecosystem's sole large carnivore, inhabited both palaeoenvironments. Spatial partitioning of the environment helps explain how several species of large herbivorous dinosaurs coexisted. This study emphasizes that different lithologies can preserve dramatically dissimilar vertebrate assemblages, even when deposited in close proximity and within a narrow window of time. The lithology in which fossils are preserved should be recorded as these data can provide unique insights into the palaeoecology of the animals they preserve.

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Section: Discussionmentioning

confidence: 99%

Spatial niche partitioning in dinosaurs from the latest cretaceous (Maastrichtian) of North America

Lyson

Longrich

2010

Proc. R. Soc. B.

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“…Here, birds are known from three formations: the Hell Creek Formation of Montana, North Dakota, and South Dakota, the Lance Formation of Wyoming, and the Frenchman Formation of Saskatchewan (SI Appendix). These rocks were deposited during the final 1.5 million years of the Cretaceous, but most of the fossils described here can be correlated to magnetochron c29r (24,25), placing them within 300,000 y of the K-Pg boundary (26).…”

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confidence: 99%

Mass extinction of birds at the Cretaceous–Paleogene (K–Pg) boundary

Longrich

Tokaryk

Field

2011

Proc. Natl. Acad. Sci. U.S.A.

194

174

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The effect of the Cretaceous-Paleogene (K-Pg) (formerly Cretaceous–Tertiary, K–T) mass extinction on avian evolution is debated, primarily because of the poor fossil record of Late Cretaceous birds. In particular, it remains unclear whether archaic birds became extinct gradually over the course of the Cretaceous or whether they remained diverse up to the end of the Cretaceous and perished in the K–Pg mass extinction. Here, we describe a diverse avifauna from the latest Maastrichtian of western North America, which provides definitive evidence for the persistence of a range of archaic birds to within 300,000 y of the K–Pg boundary. A total of 17 species are identified, including 7 species of archaic bird, representing Enantiornithes, Ichthyornithes, Hesperornithes, and an Apsaravis -like bird. None of these groups are known to survive into the Paleogene, and their persistence into the latest Maastrichtian therefore provides strong evidence for a mass extinction of archaic birds coinciding with the Chicxulub asteroid impact. Most of the birds described here represent advanced ornithurines, showing that a major radiation of Ornithurae preceded the end of the Cretaceous, but none can be definitively referred to the Neornithes. This avifauna is the most diverse known from the Late Cretaceous, and although size disparity is lower than in modern birds, the assemblage includes both smaller forms and some of the largest volant birds known from the Mesozoic, emphasizing the degree to which avian diversification had proceeded by the end of the age of dinosaurs.

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“…The Frenchman Formation is the uppermost of five Maastrichtian age rock units in southern Saskatchewan (Fig. 2); in ascending order, the others are the Bearpaw, Eastend, Whitemud, and Battle formations (Fraser et al 1935;Furnival 1946;Johnston 1980b;Russell 1974;McIver 2002). The type area for the Frenchman Formation is along the north side of the Frenchman River, from west of Ravenscrag to east of Saskatchewan Highway 37 (Hendry 1990).…”

Section: Regional Geologymentioning

confidence: 98%

“…In the Ravenscrag-Eastend-Shaunavon area, the Frenchman Formation ranges in thickness from 8-68 meters and thickens to the east. The formation consists of two distinct, but informally recognized facies: a sand-dominated facies and a clay-dominated facies (Furnival 1946;Kupsch 1956;Russell 1974;McIver 2002;Bamforth et al 2014). The sand-dominated facies consists largely of medium-to fine-grained quartz and lithic sandstones that are cross-bedded, poorly cemented with locally bearing indurated masses, and are intercalated with clay and silt lenses.…”

Section: Regional Geologymentioning

confidence: 99%

“…The Frenchman and Ravenscrag formations of southern Saskatchewan, Canada, record an apparently continuous vertical sequence of nonmarine clastic sediments of latest Maastrichtian to late Paleocene, respectively (Dawson 1875;Davis 1918;McLearn 1929;Williams and Dyer 1930;Fraser et al 1935;Furnival 1946;Kupsch 1956;Russell 1974;Krause 1977;Johnston 1980a;Lerbekmo 1985;Fox 1989;McIver and Basinger 1993;Lerbekmo et al 1996;Tokaryk 1997;McIver 2002;Fox et al 2007;Braman and Sweet 2012;Bamforth et al 2014). These Creek and in the vicinity of Wood Mountain, Saskatchewan (Dawson 1875).…”

Section: Introductionmentioning

confidence: 97%

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Geological setting of vertebrate microfossil localities across the Cretaceous–Paleogene boundary in southwestern Saskatchewan, Canada

et al. 2015

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The Frenchman and Ravenscrag formations of southwestern Saskatchewan, Canada, record an apparently continuous sequence of nonmarine clastic sediments across the Cretaceous–Paleogene (K–Pg) boundary. Extensive exposures of these fossil-rich sediments occur in the Frenchman River Valley, near the towns of Ravenscrag, Eastend, and Shaunavon, and have been a focus of study since the 1970s. Despite this long history of investigation, a comprehensive account of the geographic and stratigraphic positions of many of the significant fossil localities has yet to be published. Given this state of affairs, the goals of this paper are to (i) document the geographic locations, stratigraphic positions, and lithologies of 11 key vertebrate microfossil localities, including several new localities that have been recently discovered, and (ii) provide an update on the status of these fossil localities, the majority of which have not been sampled in the last 20 years. Four fossil localities are known from the lower Paleocene Ravenscrag Formation, all of which are Puercan in age: Rav W-1 (Pu2), French Fry (Pu1), Croc Pot (?Pu2), and Pine Cree (?Pu2). With the exception of Rav W-1, which has since been lost as a consequence of quarry reclamation, all of the Ravenscrag Formation localities remain accessible and continue to be productive. Seven vertebrate microfossil localities from the upper Maastrichtian Frenchman Formation are reported here, all of which are Lancian in age: Long Fall, Fr-1, By Gar Gap, Hairpin, Wounded Knee, Wounded C, and Gryde. With the exception of Long Fall and Wounded Knee, which have been lost through reclamation or construction, all of the Frenchman Formation localities are accessible and remain productive.

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The paleoenvironment ofTyrannosaurus rexfrom southwestern Saskatchewan, Canada

Cited by 23 publications

References 28 publications

Spatial niche partitioning in dinosaurs from the latest cretaceous (Maastrichtian) of North America

Spatial niche partitioning in dinosaurs from the latest cretaceous (Maastrichtian) of North America

Mass extinction of birds at the Cretaceous–Paleogene (K–Pg) boundary

Geological setting of vertebrate microfossil localities across the Cretaceous–Paleogene boundary in southwestern Saskatchewan, Canada

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