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  • Natural History Museum of Los Angeles County

    Science Series 42 September 15, 2015

    La Brea and Beyond: The Paleontology of

    Asphalt-Preserved BiotasEdited by John M. Harris

  • Cover Illustration: Pit 91 in 1915An 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 ByJohn M. Harris

    NO. 42SCIENCE SERIES

    NATURAL HISTORY MUSEUMOF 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 90007ISSN 1-891276-27-1

    Published on September 15, 2015

    Printed at Allen Press, Inc., Lawrence, Kansas

  • PREFACE

    Rancho La Brea was a Mexican land grantlocated to the west of El Pueblo de NuestraSenora la Reina de los Angeles del Ro dePorciuncula, now better known as downtownLos Angeles. The land grant derived its namefrom the asphaltic seeps that originated from theunderlying Salt Lake oilfield and were a source ofbitumen for Native Americans and Europeansettlers. The seeps were known to trap unwarywildlife and domestic animals, but it was not until1875 that they were documented as a source ofprehistoric fossils. Systematic retrieval of thefossil remains did not take place until the earlypart of the 20th century. The history of in-vestigation of these important fossil resourcestook place in three phases.

    The first half of the 20th century sawcollecting by the University of California,Berkeley, and several local southern Californiainstitutions between 1906 and 1913, after whichthe Hancock family granted sole right toexcavate to the newly established Los AngelesCounty Museum and deeded the property to theCounty of Los Angeles in 1924. This early phasefocused on well-preserved large specimens of theiconic Late Pleistocene megafauna; poorly pre-served specimens were frequently discardedduring excavation, and smaller elements of thebiota were often flushed away while cleaning theasphalt from the bones. Some 300 species ofanimals and plants were documented during thisinterval and these led to the selection of the tarpits as the type locality of the RancholabreanLand Mammal Age.

    The second half of the 20th century saw the re-opening of Pit 91 in 1969, using similar excava-tion techniques to the 19131915 excavations butenhancing the potential for taphonomic investiga-tions by documenting the position and orientationof all fossils larger than 1 cm. More importantly,the matrix enclosing the bone accumulations wastreated with solvent to remove the asphalt and,specifically, to recover the smaller elements of thebiota. This process more than doubled the numberof known species, and most of the plant, insect,and mollusk species from Rancho La Brea werefirst documented from Pit 91. The plant speciesrepresent the major habitats of the Los Angeles

    Basin during the Late Pleistocenesagebrushscrub dotted with groves of oak and juniper withriparian woodland along the major stream coursesand with chaparral vegetation on the surroundinghills. Other investigations focused on the function,diet, and behavior of species whose presence in thebiota had been established earlier in the century.

    The beginning of the 21st century has seena shift in focus of La Brea studies to anatomicaland behavioral changes through time, aided inpart by an increase in the number and quality ofradiometric dates from specimens collected dur-ing the previous century. New fossil assemblagesrecovered during construction at the neighboringLos Angeles County Museum of Art are beingexcavated with the same attention to detail as inthe Pit 91 excavation. These are enabling us tobetter understand the process of formation ofasphaltic fossil deposits, are providing a clearerpicture of the local faunal composition, andafford the potential for documenting environ-mental changes through time. The Rancho LaBrea sequence spans the last phase of globalcooling and subsequent warming; changes in theRancholabrean biota have much relevance toenvironmental changes taking place on earthtoday.

    That Rancho La Brea is currently the worldsmost famous asphaltic fossil depositrenownedfor the immense number of its fossils and thediversity of its biota and serving as a standard forthe recovery and interpretation of terrestrialasphaltic deposits elsewhereowes much to itsgeographic location, the foresight of the Hancockfamily to preserve it for posterity, and thestewardship of the County of Los Angeles andits Natural History Museum to maintain itsscientific integrity. This volume is dedicated tothe museums staff and their many volunteerswho have recovered and curated this scientificresource over the course of the past century, totheir many scientific associates who have helpedwith its interpretation, and to the generousdonors who have supported different aspects ofits research and curation programs.

    John M. HarrisJune 2015

    Pasadena, California

  • CONTENTS

    Preface ............................................................................................................................... iiiJohn M. Harris

    Introduction ........................................................................................................................ 1H. Gregory McDonald, John M. Harris, and Emily Lindsey

    The Owls (Aves: Strigiformes) of Rancho La Brea .............................................................. 5Kenneth E. Campbell, Jr., and Zbigniew M. Bochenski

    Microevolution of Jaw Shape in the Dire Wolf, Canis dirus, at Rancho La Brea .............. 23Alexandria L. Brannick, Julie A. Meachen, and F. Robin OKeefe

    A Pathological Timber Wolf (Canis lupus) Femur from Rancho La Brea Indicates ExtendedSurvival 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, andPotential 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.......................................................................................... 53Adam 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 fromRancho La Brea .......................................................................................................... 65

    Joseph J. El Adli, Michael D. Cherney, Daniel C. Fisher, John M. Harris, AislingB. Farrell, and Shelley M. Cox

    Equus occidentalis Leidy from Asphalto, Kern County, California ............................... 81Kristen E. Brown, William A. Akersten, and Eric Scott

    The Addition of Smilodon fatalis (Mammalia: Carnivora: Felidae) to the Biota of the LatePleistocene Carpinteria Asphalt Deposits in California, with Ontogenetic andEcologic 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...... 97Kevin L. Seymour

    Tar Pits of the Western Neotropics: Paleoecology, Taphonomy, and MammalianBiogeography ............................................................................................................ 111

    Emily L. Lindsey and Kevin L. Seymour

  • A New Mammal Assemblage from the Late Pleistocene El Breal de Orocual,Northeast of Venezuela............................................................................................. 125

    Andres Solorzano, Ascanio D. Rincon, and H. Gregory McDonald

    Sample Preparation for Radiocarbon Dating and Isotopic Analysis of Bone fromRancho 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 fromRancho La Brea ........................................................................................................ 169

    Karin Rice, Alex Sessions, Katherine Lai, and Gary T. Takeuchi

    vi & Science Series 42

  • INTRODUCTION

    H. Gregory McDonald,1,2 John M. Harris,2,3 and Emily Lindsey4

    Humans have utilized naturally occurring surfacedeposits of oil in the form of natural asphalt (orbitumen) for thousands of years. The oldestevidence for its use is bitumen-coated flintimplements that date to ca. 40,000 BC (Mouste-rian period) (Boeda et al. 1996; Connan, 1999),and ancient use o