La Brea and Beyond: the Paleontology of Asphalt-Preserved Biotas
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La Brea and Beyond: The Paleontology of Asphalt-Preserved Biotas Edited by John M. Harris Natural History Museum of Los Angeles County Science Series 42 September 15, 2015 Cover Illustration: Pit 91 in 1915 An asphaltic bone mass in Pit 91 was discovered and exposed by the Los Angeles County Museum of History, Science and Art in the summer of 1915. The Los Angeles County Museum of Natural History resumed excavation at this site in 1969. Retrieval of the “microfossils” from the asphaltic matrix has yielded a wealth of insect, mollusk, and plant remains, more than doubling the number of species recovered by earlier excavations. Today, the current excavation site is 900 square feet in extent, yielding fossils that range in age from about 15,000 to about 42,000 radiocarbon years. Natural History Museum of Los Angeles County Archives, RLB 347. LA BREA AND BEYOND: THE PALEONTOLOGY OF ASPHALT-PRESERVED BIOTAS Edited By John M. Harris NO. 42 SCIENCE SERIES NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY SCIENTIFIC PUBLICATIONS COMMITTEE Luis M. Chiappe, Vice President for Research and Collections John M. Harris, Committee Chairman Joel W. Martin Gregory Pauly Christine Thacker Xiaoming Wang K. Victoria Brown, Managing Editor Go Online to www.nhm.org/scholarlypublications for open access to volumes of Science Series and Contributions in Science. Natural History Museum of Los Angeles County Los Angeles, California 90007 ISSN 1-891276-27-1 Published on September 15, 2015 Printed at Allen Press, Inc., Lawrence, Kansas PREFACE Rancho La Brea was a Mexican land grant Basin during the Late Pleistocene—sagebrush located to the west of El Pueblo de Nuestra scrub dotted with groves of oak and juniper with Sen˜ora la Reina de los A´ ngeles del Rı´ode riparian woodland along the major stream courses Porciu´ncula, now better known as downtown and with chaparral vegetation on the surrounding Los Angeles. The land grant derived its name hills. Other investigations focused on the function, from the asphaltic seeps that originated from the diet, and behavior of species whose presence in the underlying Salt Lake oilfield and were a source of biota had been established earlier in the century. bitumen for Native Americans and European The beginning of the 21st century has seen settlers. The seeps were known to trap unwary a shift in focus of La Brea studies to anatomical wildlife and domestic animals, but it was not until and behavioral changes through time, aided in 1875 that they were documented as a source of part by an increase in the number and quality of prehistoric fossils. Systematic retrieval of the radiometric dates from specimens collected dur- fossil remains did not take place until the early ing the previous century. New fossil assemblages part of the 20th century. The history of in- recovered during construction at the neighboring vestigation of these important fossil resources Los Angeles County Museum of Art are being took place in three phases. excavated with the same attention to detail as in The first half of the 20th century saw the Pit 91 excavation. These are enabling us to collecting by the University of California, better understand the process of formation of Berkeley, and several local southern California asphaltic fossil deposits, are providing a clearer institutions between 1906 and 1913, after which picture of the local faunal composition, and the Hancock family granted sole right to afford the potential for documenting environ- excavate to the newly established Los Angeles mental changes through time. The Rancho La County Museum and deeded the property to the Brea sequence spans the last phase of global County of Los Angeles in 1924. This early phase cooling and subsequent warming; changes in the focused on well-preserved large specimens of the Rancholabrean biota have much relevance to iconic Late Pleistocene megafauna; poorly pre- environmental changes taking place on earth served specimens were frequently discarded today. during excavation, and smaller elements of the That Rancho La Brea is currently the world’s biota were often flushed away while cleaning the most famous asphaltic fossil deposit–renowned asphalt from the bones. Some 300 species of for the immense number of its fossils and the animals and plants were documented during this diversity of its biota and serving as a standard for interval and these led to the selection of the tar the recovery and interpretation of terrestrial pits as the type locality of the Rancholabrean asphaltic deposits elsewhere–owes much to its Land Mammal Age. geographic location, the foresight of the Hancock The second half of the 20th century saw the re- family to preserve it for posterity, and the opening of Pit 91 in 1969, using similar excava- stewardship of the County of Los Angeles and tion techniques to the 1913–1915 excavations but its Natural History Museum to maintain its enhancing the potential for taphonomic investiga- scientific integrity. This volume is dedicated to tions by documenting the position and orientation the museum’s staff and their many volunteers of all fossils larger than 1 cm. More importantly, who have recovered and curated this scientific the matrix enclosing the bone accumulations was resource over the course of the past century, to treated with solvent to remove the asphalt and, their many scientific associates who have helped specifically, to recover the smaller elements of the with its interpretation, and to the generous biota. This process more than doubled the number donors who have supported different aspects of of known species, and most of the plant, insect, its research and curation programs. and mollusk species from Rancho La Brea were John M. Harris first documented from Pit 91. The plant species June 2015 represent the major habitats of the Los Angeles Pasadena, California CONTENTS Preface ............................................................................................................................... iii John M. Harris Introduction ........................................................................................................................ 1 H. Gregory McDonald, John M. Harris, and Emily Lindsey The Owls (Aves: Strigiformes) of Rancho La Brea .............................................................. 5 Kenneth E. Campbell, Jr., and Zbigniew M. Bochenski Microevolution of Jaw Shape in the Dire Wolf, Canis dirus, at Rancho La Brea .............. 23 Alexandria L. Brannick, Julie A. Meachen, and F. Robin O’Keefe A Pathological Timber Wolf (Canis lupus) Femur from Rancho La Brea Indicates Extended Survival After Traumatic Amputation Injury .............................................................. 33 Eric Scott, Elizabeth Rega, Kim Scott, Bryan Bennett, and Stuart Sumida Dental Microwear Textures of Carnivorans from the La Brea Tar Pits, California, and Potential Extinction Implications ................................................................................ 37 Larisa R. G. DeSantis, Blaine W. Schubert, Elizabeth Schmitt-Linville, Peter S. Ungar, Shelly L. Donohue, and Ryan J. Haupt The Bacula of Rancho La Brea.......................................................................................... 53 Adam Hartstone-Rose, Robert G. Dundas, Bryttin Boyde, Ryan C. Long, Aisling B. Farrell, and Christopher A. Shaw Last Years of Life and Season of Death of a Columbian Mammoth from Rancho La Brea .......................................................................................................... 65 Joseph J. El Adli, Michael D. Cherney, Daniel C. Fisher, John M. Harris, Aisling B. Farrell, and Shelley M. Cox Equus occidentalis Leidy from “Asphalto,” Kern County, California ............................... 81 Kristen E. Brown, William A. Akersten, and Eric Scott The Addition of Smilodon fatalis (Mammalia: Carnivora: Felidae) to the Biota of the Late Pleistocene Carpinteria Asphalt Deposits in California, with Ontogenetic and Ecologic Implications for the Species .......................................................................... 91 Christopher A. Shaw and James P. Quinn Perusing Talara: Overview of the Late Pleistocene Fossils from the Tar Seeps of Peru...... 97 Kevin L. Seymour “Tar Pits” of the Western Neotropics: Paleoecology, Taphonomy, and Mammalian Biogeography ............................................................................................................ 111 Emily L. Lindsey and Kevin L. Seymour vi & Science Series 42 A New Mammal Assemblage from the Late Pleistocene El Breal de Orocual, Northeast of Venezuela............................................................................................. 125 Andre´s Solo´rzano, Ascanio D. Rinco´n, and H. Gregory McDonald Sample Preparation for Radiocarbon Dating and Isotopic Analysis of Bone from Rancho La Brea ........................................................................................................ 151 Benjamin T. Fuller, John M. Harris, Aisling B. Farrell, Gary Takeuchi, and John R. Southon New Technique to Remove Asphalt from Microfossil-rich Matrix from Rancho La Brea ........................................................................................................ 169 Karin Rice, Alex Sessions, Katherine Lai, and Gary T. Takeuchi INTRODUCTION H. Gregory McDonald,1,2 John M. Harris,2,3 and Emily Lindsey4 Humans have utilized naturally occurring surface early twentieth century with the formal excava- deposits of oil in the form of natural asphalt (or tions by the Los Angeles County Museum and the bitumen)