Taphonomy on Rusinga Island, Kenya a Dissertation
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TAPHONOMY ON RUSINGA ISLAND, KENYA A DISSERTATION SUBMITTED TO THE FACULTY OF THE UNIVERSITY OF MINNESOTA BY KIRSTEN ELISE HOLT JENKINS IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY KIERAN McNULTY MARTHA TAPPEN AUGUST 2018 © Kirsten Jenkins, 2018 ACKNOWLEDGEMENTS It took several villages to raise this dissertation. In addition to the people and institutions below, I am grateful for the support of the National Museums of Kenya, the local communities on Rusinga Island, my committee in its multiple iterations—Kieran McNulty, Martha Tappen, Mike Wilson, and Ray Rogers- but also David Fox, Gil Tostevin, and Gilliane Monnier. The comradery from my communities of friends and mentors at the University of Minnesota’s Department of Anthropology and in Nairobi helped me through every step of this research. Kieran and Martha both took a very active role in my training, for which I am very grateful. Thank you for your years of advice, editing, teaching, listening, support, and friendship. My family—my husband Austin Jenkins, my parents Tim and Leeann Holt, my in-laws John and Vicki Jenkins, and my daughter Leona -- has made this research possible with their love and support (both finical and moral). Thank you i for supporting my Kenya habit and helping my helping my dreams become reality. Acknowledgements for chapter 2 This work has been a multidisciplinary effort and portions of the synthesis presented here are the work of team members: This work was predicated on efforts lead by Kieran McNulty, Holly Dunswoth and Will Harcourt-Smith. Thomas Lehmann, Kieran McNulty, and Jack Conrad lead efforts on faunal IDs. Sheila Nightengale, Thomas Lehmann, and Sulemon Okayo assisted in leading excavations. Holly Dunsworth, Catya Maysef, Shelia Nightengale, and Lauren Michel all assisted in profile drawing. Geologists Dan Peppe, David Fox, Steven Driese and Lauren Michel all contributed their geologic interpretations and descriptions. Eddie Kadieda, Edwin Wandango, Elly Owino, Kennedy Oteino, Kellen Odira, Semekia Ponue, Victor Lare, Evans Siro, Martin Onoto, Moses Onwento, Fred Onyango, Charles Okongo, Dick Misasa, Kenneth Kaunda, Kennedy MIsiami, Edwin Siembo, Adam Cossette, Jack Conrad, Derek Nelson all diligently excavated the site. Blasto Oyango, Samuel Odhiambo, Joshua Siembo, and Ezra Kadieda provided support in the field. The total station was lent to the team for use by Christian Tryon. Students and team members conducted surface collections. Fieldwork and Museum research was conducted with support of the Emma Mbua, Fredrick Manthi, Kenya National Museum, and NACOSTI (exploration permits issued to Kieran McNulty, Holly Dunsworth and Will Hartcourt-Smith; and a research permit issued to myself ii (NCST/5/002/R/605) with affiliation to the Department of Earth Sciences at the National Museum of Kenya. Fieldwork was funded by NSF grants to Kieran McNulty, Holly Dunsworth, and Will Hartcourt-Smith. Funding from the Leakey Foundation and University of Minnesota Doctoral Dissertation Fellowship and Department of Anthropology Block Grants supported taphonomic data collection in the museum. Samantha Porter stitched excavation photos using photogrammetry and assisted in producing figures. Field images were taken from a pooled collection of the team’s photographs. Austin Jenkins assisted in creating the site map and collating total station data. Peter Andrews shared a copy of his 1972 report, which was critical to this research. This work was aided by many helpful conversations with Martha Tappen, Kieran McNulty, Dan Peppe, Sheila Nightengale, Lauren Michel, Jack Conrad, and Austin Jenkins. Kirsten is grateful for the support of her team, her advisors, the National Museum of Kenya, the Kaswanga community, anthropology community at the University of Minnesota, and her family. Acknowledgements for chapter 4 This research was made possible by funding from the National Science Foundation, Leakey Foundation, and the University of Minnesota. Research on fossil specimens was conducted at the National Museums of Kenya under permits issued to K. Jenkins. I would like to thank the following persons for their helpful comments, ideas, and support during this research: Dr. Emma Mbua, Dr. Fredrick Manthi, and the curational staff at the National Museums of Kenya for iii their support of this research and making specimens available. Scott McGraw, Susanne Shultz, Bill Sanders, and John Mitani for making the Taï and Ngogo actualistic collections available for study and for helpful conversations about the predatory habits of raptors. Actualistic collections for the Ngogo nests collections were housed at the University of Michigan’s Natural History Museum and are now in the University of Michigan’s Department of Anthropology Collections. Actualistic collections for Taï nest sites were made available at the University of Ohio and are now housed in the S. Shultz Lab at the University of Manchester. Lars Werdlin, Matthew Borths, Thomas Lehman, Gerald Mayr, Kieran McNulty, Holly Dunsworth, Rutger Jansma for their expertise and helpful conservations about the carnivore, hyenadont, avian, and primate fossil records. Martha Tappen, Kay Behresmeyer, Linda Chisholm, and Aaron Armstrong all generously shared their own taphonomic comparative collections and expertise with the author and these conversations helped improve this paper and research design. The author is grateful to Austin Jenkins for assistance with figures. Lastly, the author would like to thank the numerous researchers and field assistances who have collected the many fossil primates from Rusinga Island through the decades. Acknowledgements for chapter 6 Fieldwork was conducted under permits issued by the Kenya National Government and the Kenya National Museum. Funding was provided by National Science Foundation (BCS-1013199 and BCS-1013108), the Leakey Foundation, iv the National Geographic Society's Committee for Research and Exploration (8762-10), a graduate research grant from the Geological Society of America, the University of Minnesota, Baylor University, New York University, and the University of Queensland. This work would not have been possible if not for the support of the Kenya National Museum, Dr. Emma Mbua, Dr. Fredrick Manthi, Dr. Purity Kiura, and the always helpful museum staff in the Paleontology, Archaeology, Preparation Departments. The British Institute in East Africa, the Rusinga Island Lodge, Stephen Longoria, Matthew Macharwas, Julian Ogondo, Samuel Odhiambo, Lucyline Mbogori, Joshua Siembo, Adam Cosset, Jared Olelo, Breanne Clifton, and Myra Laird all provided exceptional support in the field. This work has benefited from helpful conversations with Martha Tappen, Gil Tostevin, Emily Beverly, Austin Jenkins, Reed Coil, Samantha Porter, Linda Chisholm, Phil Slater, Aaron Armstrong, Haley O'Brien, Katherine Hayes, and John Speth and from suggestions of four anonymous reviewers, an associate editor, and Sarah Elton. Samantha Porter and Austin Jenkins assisted with editing figures and Cornel Faith provided the artistic reconstruction of Rusingoryx. Lastly, we thank the Wakondo community on Rusinga Island and the excellent and skilled excavators for their support, hard work, and enthusiasm for this project: David Ochieng Miriga, Joseph Ochieng Oyugi, Robert Onkondoyo, Isayah Onyango, Samwel Odoyo, and William Ondongo Oyoro. v DEDICATIONS To the communities and children on Rusinga Island who have been so generous, curious, and supportive of this research. To my dear friend Joshua Seimbo – you are a true steward of Rusinga’s prehistory. To my daughter: Watching the world become new again through your eyes inspires me to keep exploring this big, ancient, and amazing planet. To my husband: In the depths of my uncertainty, Austin Jenkins says to me, “I think our daughter will be very proud of you- I am”. Thank you for your unwavering support and love. vi ABSTRACT Understanding taphonomy and site formation processes for fossil human and primate sites is central to testing hypotheses about paleoenvironments and the natural selection of various traits and behaviors in our lineage. Strong inferences about paleoenvironmental and behavioral reconstructions, however, rest on demonstrated associations between both fossil and sedimentary environmental proxies and taphonomic actualistic data. On Rusinga Island, Kenya, Miocene and Pleistocene fossils have been collected and studied for a century, yielding a rich assemblage of early Miocene stem hominoids and catarrhines—Ekembo, Dendropithecus, Limnopithecus, Rangwapithecus, and Nyanzapithecus. Numerous mammalian, avian, reptilian, invertebrate, and plant fossils are preserved alongside these primates. Pleistocene fossils on Rusinga are often in association with Middle Stone Age tools made my early Modern Humans. Despite the long history of collection, little consensus has been reached about the paleoenvironmental contexts in Miocene Rusinga, in part due to faunal mixing and lack of broad taphonomic studies. Furthermore, behavioral reconstructions of have been limited by not engaging with taphonomic surface modification data. Pleistocene deposits are generally understudied compared to the Miocene fossils and behavioral reconstructions have been similarly limited. vii This dissertation examines taphonomic site formation processes of both time periods using archaeological style excavations, systematic surface collections and taphonomic data collection. Bonebed excavations and taphonomic data at Miocene R5-Kaswanga inform paleoenvironmental