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Paleoecological Utility of Feeding Traces at Egg Mountain, a Rich

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Paleoecological Utility of Feeding Traces at Egg Mountain, a Rich PALEOECOLOGICAL UTILITY OF FEEDING TRACES AT EGG MOUNTAIN, A RICH TERRESTRIAL VERTEBRATE LOCALITY OF THE UPPER CRETACEOUS TWO MEDICINE FORMATION, MONTANA, U.S.A. by William James Freimuth A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth Sciences MONTANA STATE UNIVERSITY Bozeman, Montana May 2020 ©COPYRIGHT by William James Freimuth 2020 All Rights Reserved ii ACKNOWLEDGEMENTS First, a huge thank you to my advisor Dr. David Varricchio, whose patience, guidance, and easygoing personality have shaped me from my first foray at Egg Mountain in 2015. Thank you doesn’t do it justice. Thanks to my committee members: Dr. Devon Orme, whose willingness to serve on my committee and put up with my incredibly infrequent communication should be commended, and Dr. Karen Chin, whose approach to paleobiology has been an inspiration to me for years. Thank you to Dr. John Scannella and Museum of the Rockies for collections access and facilitating loans; Amy Atwater who was always extremely helpful with access to collections and facilitating paperwork. The College of Letters and Science provided travel funding. Thanks to Dr. Dave Mogk, Elif Roehm, and ICAL for extra efforts and assistance with analyses. An immense thanks to Brenna and Austyn who helped with every minute and bizarre logistical issue I encounterd. Alex Brannick, Luke Weaver, and Dr. Greg Wilson for hospitality and access to Burke collections. Thank you to Egg Mountain volunteers and rubble-pickers for the hours of work and shared experiences. In no particular order: Giulio Panascí for helpful conversations and obscure Simpsons clips; Jack Wilson, Kevin Surya, and Jacob Gardner for conversations, living quarters, and cherished friendships; Jason Hogan for generosity with camera and tech equipment; Isaura Aguilar for putting up with the boys; utility man Eric Metz; Sara Oser of EMOT fame for access to field photos and notes. Importantly, Nate, Luke, and Keene for friendship. Thank you to Brenlee for welcome distractions and great friendship and love…and Bindi! Thank you to my mom, Karla, my dad, Bob, and my sister, Sara, for your unwavering support. I love you guys. iii TABLE OF CONTENTS 1. INTRODUCTION .........................................................................................................1 Literature Cited ..............................................................................................................4 2. MAMMAL-BEARING REGURGITALITES POTENTIALLY ATTRIBUTABLE TO TROODON FORMOSUS AT THE EGG MOUNTAIN LOCALITY, UPPER CRETACEOUS TWO MEDICINE FORMATION, MONTANA, U.S.A. ............................................................................................................................6 Contribution of Authors and Co-Authors ......................................................................6 Manuscript Information Page ........................................................................................7 Abstract ..........................................................................................................................9 Introduction ..................................................................................................................10 Geological Setting ........................................................................................................13 Two Medicine Formation and Willow Creek Anticline ..................................13 Egg Mountain locality......................................................................................14 Materials and Methods .................................................................................................17 Collection and field area ..................................................................................17 Taphonomic analysis .......................................................................................18 Body mass estimates ........................................................................................20 Pellet statistics and size comparisons ..............................................................20 Results ..........................................................................................................................21 MOR 10912 .....................................................................................................21 MOR 10913 .....................................................................................................26 MOR 11750 .....................................................................................................30 Discussion ....................................................................................................................38 Comparison to modern gastric pellets..............................................................44 Taphonomic patterns of predator groups .........................................................45 Assessment of predator ....................................................................................51 Ecological and evolutionary implications ........................................................61 Conclusions ..................................................................................................................65 Acknowledgements ......................................................................................................66 References ....................................................................................................................66 3. PALEOECOLOGICAL IMPLICATIONS OF INVERTEBRATE FECAL PELLETS (EDAPHICHNIUM) AT A RICH TERRESTRIAL VERTEBRATE LOCALITY, UPPER CRETACEOUS (CAMPANIAN) TWO MEDICINE FORMATION, MONTANA, U.S.A. ..........................................................................83 Contribution of Authors and Co-Authors ....................................................................83 Manuscript Information Page ......................................................................................84 iv TABLE OF CONTENTS CONTINUED Abstract ........................................................................................................................85 Introduction ..................................................................................................................86 Geological Setting ........................................................................................................92 Two Medicine Formation and Willow Creek Anticline ..................................92 Egg Mountain locality......................................................................................93 Sedimentary facies of study section .................................................................95 Paleoenvironments and depositional processes ...............................................98 Egg Mountain Oser Thesis (EMOT) quarry ..................................................100 Materials and Methods ...............................................................................................100 Field collection...............................................................................................100 Morphological analysis ..................................................................................101 Chemical analysis ..........................................................................................102 Repository and institutional abbreviations.....................................................102 Results ........................................................................................................................103 Descriptive overview .....................................................................................103 Type A ...........................................................................................................108 MOR 10878 EMOT-91A and 91B ....................................................110 MOR 10878 2012-49 .........................................................................112 MOR 10878 EMOT-115 ....................................................................113 MOR 10878 2013-57 .........................................................................115 Type B ............................................................................................................117 MOR 10878 2012-10 .........................................................................118 MOR 10878 B11.12-1 .......................................................................118 MOR 10878 2016-31 .........................................................................119 MOR 10878 2016-29 .........................................................................120 Type C ............................................................................................................123 MOR 10878 EMOT-43 ......................................................................123 MOR 10878 2015-40 .........................................................................123 Micromorphology ..........................................................................................126 XRD and pXRF analyses ...............................................................................129 Discussion ......................................................................................................131 Origin of pellets .................................................................................131 Assessment of trace-maker ................................................................134 Paleoenvironmental and paleoecological implications
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