New late Paleocene (late middle Tiffanian) mammals from the Roche Percée local fauna, south-eastern Saskatchewan, Canada

Abstract

An exceptionally large and diverse assemblage of mammals from the early late Paleocene (about 58 million years ago) has been collected from the Ravenscrag Formation near Roche Percée, south-eastern Saskatchewan, Canada. Previous research of the Roche Percée local fauna has examined only a small portion of the mammals, with the vast majority of taxa remaining unstudied. Identification and descriptions of these latter taxa are provided here. With these new additions, the assemblage is now known to include 44 mammalian species. Notable among these findings is the substantial collection of the erinaceomorph lipotyphlan Litocherus lacunatus, the remarkable diversity of viverravid carnivorans, and the recovery of some of the first known elements of the upper dentition of the pantolestid Besseocetor pilodontus. A complete description of the mammalian fauna supports previous assignments of a late middle Tiffanian North American Land Mammal Age (Ti4 lineage zone) to the Roche Percée local fauna. Faunal comparisons further suggest a close similarity of the Roche Percée assemblage to the near contemporaneous Divide Quarry local fauna from the Bighorn Basin, northern Wyoming, but also reveal some similarities to slightly older middle Tiffanian local faunas (Ti3 lineage zone) at localities in the Paskapoo Formation of central Alberta. The specimens from the Roche Percée local fauna represent the largest and most taxonomically diverse assemblage of late middle Tiffanian mammals yet known, offering a unique perspective on mammalian evolution and diversity in North America during this time interval.

Keywords:

• Mammalia
• North America
• Saskatchewan
• Ravenscrag Formation
• Paleocene
• Tiffanian

Acknowledgements

Many thanks are owed to R. C. Fox and M. V. H. Wilson for their supervision and guidance during this research project. I am also grateful to C.S. Scott for sharing his insights on many of the mammals presented here. I thank R. A. Stockey, A. M. Murray, P. R. Willoughby, P. A. Holroyd and W. A. Clemens for their helpful comments on this work. K. C. Beard and T. Smith additionally provided useful reviews that greatly benefited the manuscript. Finally, for their arduous work in collecting and organizing the specimens that comprise the Roche Percée local fauna, I thank D. W. Krause, A. Voss and the countless UALVP assistants. This research was supported by Graduate Teaching Assistantships from the University of Alberta and an Alexander Graham Bell Canadian Graduate Scholarship from the Natural Science and Engineering Research Council of Canada (NSERC) to the author, and NSERC operating grants to R. C. Fox.

Supplemental data

Supplemental material for this article can be accessed at: https://doi.org/10.1080/14772019.2017.1296498