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Biodiversity Response to Climate Change
in the Middle Pleistocene
The publisher gratefully acknowledges the generous contribution to this book provided by
the General Endowment Fund of the University of California Press Associates.
Biodiversity Response to Climate Change
in the Middle Pleistocene
The Porcupine Cave Fauna from Colorado
Edited by
ANTHONY D. BARNOSKY
UNIVERSITY OF CALIFORNIA PRESS
Berkeley Los Angeles London
University of California Press
Berkeley and Los Angeles, California
University of California Press, Ltd.
London, England
© 2004 by The Regents of the University of California
Library of Congress Cataloging-in-Publication Data
Biodiversity response to climate change in the middle Pleistocene : the
Porcupine Cave fauna from Colorado / edited by Anthony D. Barnosky
p. cm.
Includes bibliographical references and index.
ISBN 0-520-24082-0 (cloth : alk. paper)
1. Vertebrates, Fossil—Colorado—Park County. 2. Paleontology—
Pleistocene. 3. Paleoecology—Colorado—Park County. 4. Paleo-
ecology—Pleistocene. 5. Climatic changes—Environmental aspects—
Colorado—Park County—History. 6. Animals, Fossil—Colorado—
Park County. I. Title: Porcupine Cave fauna from Colorado.
II. Barnosky, Anthony D., 1952–
QE881.B535 2004
560′.1792—dc22 2003059592

Manufactured in the United States of America
13 12 11 10 09 08 07 06 05 04
10987654 321
The paper used in this publication meets the minimum requirements
of ANSI/NISO Z39.48-1992 (R 1997) (Permanence of Paper).
To Don Rasmussen, who with his son Larry
found the fossil deposits in Porcupine Cave,
and whose unfailing enthusiasm for
discovery, excavation, and working
with other scientists and volunteers
was essential in moving the project
from concept to reality.
PREFACE ix
ACKNOWLEDGMENTS xi
LIST OF CHAPTER APPENDIXES xiii
LIST OF FIGURES xv
LIST OF TABLES xix
ABBREVIATIONS AND DEFINITIONS xxi
PART ONE
The Discovery and Distribution
of Fossils
1 Climate Change, Biodiversity,
and Ecosystem Health: The Past
as a Key to the Future 3
Anthony D. Barnosky
2 The Pleistocene Fossils of
Porcupine Cave, Colorado:
Spatial Distribution and
Taphonomic Overview 6

Anthony D. Barnosky,
Christopher J. Bell, Robert G.
Raynolds, and Louis H. Taylor
3 The Modern Environment,
Flora, and Vegetation of
South Park, Colorado 27
David J. Cooper
4 The Historical Context of
Porcupine Cave: American
Indians, Spaniards, Government
Surveyors, Prospectors, Ranchers,
Cavers, and Paleontologists in
South Park, Colorado 39
Geraldine J. Rasmussen, Kirk
Branson, and John O. McKelvy
5 The Geology and Speleogenesis
of Porcupine Cave 51
Robert G. Raynolds
6 Magnetostratigraphic Constraints
on the Age of Pleistocene
Fossiliferous Strata in Porcupine
Cave’s DMNH Velvet Room
Excavation 57
S. Julio Friedmann and
Robert G. Raynolds
7 Age and Correlation of Key Fossil
Sites in Porcupine Cave 64
Anthony D. Barnosky and
Christopher J. Bell
8 Biology of Wood Rats as Cave

Dwellers and Collectors 74
Robert B. Finley Jr.
9 Paleopathology and Taphonomic
Modification of Mammalian Bones
from Porcupine Cave 82
C. Suzane Ware and
Elaine Anderson
PART TWO
Systematic Accounts of Taxa
10 A Summary of Fossilized Species
in Porcupine Cave 95
Anthony D. Barnosky
11 Synopsis of the Herpetofauna
from Porcupine Cave 117
Christopher J. Bell, Jason J. Head,
and Jim I. Mead
12 The Early and Middle
Pleistocene Avifauna from
Porcupine Cave 127
Steven D. Emslie
13 The Carnivora from Porcupine
Cave 141
Elaine Anderson
14 Middle Pleistocene (Irvingtonian)
Ochotona (Lagomorpha:
Ochotonidae) from
Porcupine Cave 155
Jim I. Mead, Margarita Erbajeva,
and Sandra L. Swift
15 Leporidae of the DMNH

Velvet Room Excavations
and Mark’s Sink 164
Colleen N. Baxter
16 Identification of Miscellaneous
Mammals from the Pit Locality:
Including Soricidae, Leporidae,
Geomyoidea 169
Anthony D. Barnosky and
Samantha S. B. Hopkins
17 Systematics and Faunal
Dynamics of Fossil Squirrels
from Porcupine Cave 172
H. Thomas Goodwin
18 Fossil Wood Rats of
Porcupine Cave: Tectonic
or Climatic Controls? 193
Charles A. Repenning
CONTENTS
19 Arvicoline Rodents from
Porcupine Cave: Identification,
Spatial Distribution, Taxonomic
Assemblages, and
Biochronologic Significance 207
Christopher J. Bell,
Charles A. Repenning,
and Anthony D. Barnosky
20 Pliocene and Pleistocene Horses
from Porcupine Cave 264
Eric Scott
21 Pleistocene (Irvingtonian)

Artiodactyla from Porcupine
Cave 280
Jim I. Mead and Louis H. Taylor
PART THREE
Effect of Environmental Change
on the Porcupine Cave Fauna
22 Irvingtonian Mammals from the
Badger Room in Porcupine Cave:
Age, Taphonomy, Climate, and
Ecology 295
Alan B. Shabel,
Anthony D. Barnosky,
Tonya Van Leuvan, Faysal Bibi,
and Matthew H. Kaplan
23 Faunal Dynamics of Small
Mammals through the Pit
Sequence 318
Anthony D. Barnosky
24 Stable Carbon and Oxygen
Isotope Analysis of Marmot
Cheek Teeth from the Pit
Locality 327
Robert S. Feranec
25 Assessing the Effect of Middle
Pleistocene Climate Change
on Marmota Populations from
the Pit Locality 332
Anthony D. Barnosky, Matthew
H. Kaplan, and Marc A. Carrasco
26 Effect of Climate Change on

Terrestrial Vertebrate Biodiversity
Anthony D. Barnosky 341
LITERATURE CITED 347
LIST OF CONTRIBUTORS 371
INDEX 373
Since fossil vertebrates were first discovered at Porcupine Cave
on the rim of South Park, Colorado, in 1981, the site has be-
come the world’s most important source of information about
animals that lived in the high elevations of North America in
the middle part of the ice ages, between approximately one
million and 600,000 years ago. Beginning in 1985, teams of
scientists and volunteers from three major research institutions
—the Carnegie Museum of Natural History, the Denver Mu-
seum of Nature and Science, and the University of California
Museum of Paleontology—spent some 15 field seasons exca-
vating and studying tens of thousands of fossil specimens that
have opened a window onto past evolutionary and ecological
adjustments. This window into the past allows us to visualize
how ongoing global change could affect our living commu-
nities. This book reports the results of nearly two decades of
research and has been written to appeal to three overlapping
audiences.
The first target audience is made up of scholars, students, and
others interested in paleontology and in how paleontological
data are applied to solving ecological and evolutionary ques-
tions. The second audience consists of ecologists and conser-
vationists concerned with understanding and preserving
biodiversity and other natural ecological dynamics. To serve
these first two audiences, the book strives to illustrate the
critical role paleontology plays in understanding ecosystem

dynamics, such as the maintenance of biodiversity, and to
document carefully the scientific data from Porcupine Cave
so that this unique data set can be used now and in the future
to illuminate ecological processes.
The third audience is the caving community, which has
increasingly used Porcupine Cave and others like it for both
scientific and recreational purposes over the past 20 years.
The book endeavors to highlight the importance of the frag-
ile but irreplaceable paleontological resources to be found in
caves.
The book is divided into three parts. The chapters in part 1
articulate some scientific questions that the data from the
cave can help answer; document the location, modern envi-
ronment, and geological setting of the site as a context in
which to interpret the fossil data; and relate the history of the
discovery of Porcupine Cave, the spatial distribution and age
of the fossil deposits, and the cause of the accumulation of so
many fossils. Part 2 documents the identification and occur-
rence of various taxonomic groups from the many different
localities within the cave. Part 3 synthesizes the information
presented in the other two parts into a series of analyses de-
signed to explore the implications of the Porcupine Cave fauna
for understanding how terrestrial mountain ecosystems react
in the face of environmental change, how climate change
affects patterns of biodiversity in mammals, and, in light of
these processes, how we might expect ecosystems to respond
to human-induced global warming.
Given the astounding numbers of fossils that Porcupine
Cave has produced—more than 20,000 specimens have been
identified, and many times that number are stored in mu-

seum drawers awaiting identification—it is impossible to ex-
plore all their implications in a single publication. This book
should be viewed as a foundation for further research rather
than the final word on the matter. We hope that the data and
ideas presented herein stimulate debate and provide impetus
for a new cohort of scholars to continue the work we have just
begun.
ix
PREFACE
Excavating, analyzing, and publishing the Porcupine Cave
data has been an arduous task that has taken nearly 20 years
and involved more than 30 scientists, more than 100 field
hands, and the cooperation of the three major museums where
specimens reside: the Carnegie Museum of Natural History
(CM), the Denver Museum of Nature and Science (DMNH),
and the University of California Museum of Paleontology
(UCMP). Thanks are due to all who lent a hand, and especially
to the following individuals and institutions.
The kindness of Frank and Connie McMurry (McMurry
Land and Livestock Company) in allowing us to excavate in
their cave and spend field seasons at their cow camp made the
whole project possible. I am deeply indebted to them. The
project would also not have been possible without financial
support from the U.S. National Science Foundation (grants
BSR-9196082 in the early years and EAR-9909353 during the
synthesis stage), the UCMP, the CM, and the DMNH.
Don Rasmussen spearheaded the excavation teams for
many years and contributed in innumerable ways to the proj-
ect. He has been a delight to work with. Two colleagues who

contributed essential data to this project died before they saw
the fruits of their labors: Vic Schmidt (paleomagnetics) and
Elaine Anderson (carnivores). Memories of days in the cave
and nights at the campfire with them live on. Betty Hill of the
CM, Logan Ivy of the DMNH, and Pat Holroyd of the UCMP
were extremely helpful in arranging loans of specimens and
dealing with sometimes overwhelming curatorial matters.
Paul Koch graciously ran isotope samples in his lab at the Uni-
versity of California, Santa Cruz. Karen Klitz of the University
of California Museum of Vertebrate Zoology (MVZ) prepared
some of the illustrations, and the MVZ was an essential re-
source for specimen identification.
It is impossible to name here the more than 100 volunteers,
students, and employees who helped excavate the deposits and
pick matrix, but I am grateful to them all. Many of them were
members of the Colorado Grotto of the National Speleologi-
cal Society or the Western Interior Paleontological Society.
Hazel Barton led the cartographic efforts to produce detailed
maps of the cave, and I thank her for making her beautiful
map available.
As editor, my job was made easier by the contributors to this
book, many of whom waited patiently after submission of
their manuscripts for the whole package to come together.
Special thanks are due to Chris Bell, who has been with the
project since the early 1990s and who picked most of the ma-
trix from the Pit. Several scientists gave of their time in pro-
viding detailed reviews of various chapters: Elaine Anderson,
Jill Baron, Chris Bell, Annalisa Berta, Doug Burbank, Jim
Burns, Emmet Evanoff, Bob Feranec, Tom Goodwin, Fred
Grady, Elizabeth Hadly, Bill Harbert, Art Harris, R. Lee Lyman,

Bruce MacFadden, Bob Martin, David Polly, Don Rasmussen,
Bruce Rothschild, Dennis Ruez Jr., Eric Scott, Alan Shabel,
David Steadman, Tom Stidham, Tom Van Devender, Blaire
Van Valkenburgh, Alisa Winkler, Bill Wyckoff, and Richard
Zakrzewski. To them, and to several reviewers who wished to
remain anonymous, I give thanks. Gratitude is also extended
to Timothy Heaton and Karel Rogers, who read the entire
manuscript of the book and provided useful comments.
Discussions with my graduate and postdoctoral students
have been intellectually stimulating. Alan Shabel’s deep think-
ing about ecology and willingness to lend a hand as needed
were a great benefit, as were discussions with Marc Carrasco,
Edward Davis, Bob Feranec, Samantha Hopkins, and Brian
Kraatz. Faysal Bibi curated many of the UCMP Pit specimens
and helped produce some of the spreadsheets used in the
analyses.
Above all, I thank my wife, Liz Hadly, for her help both
scientifically and with living life, and my children, Emma
and Clara, who make me think about why biodiversity might
be important for future generations.
A. D. Barnosky
Palo Alto, California
xi
ACKNOWLEDGMENTS
9.1. Specimens from Porcupine Cave showing taphonomic
or paleopathological modification 90
11.1. Amphibian and reptile specimens recovered from
Porcupine Cave 124
13.1. Carnivore specimens from Porcupine Cave 149

14 .1. Ochotona specimens from Porcupine Cave 160
17.1. List of specimens examined for the four most
abundant sciurids studied 187
18.1. Specimens of Neotoma from the Pit 204
19.1. Specimens of arvicoline rodents from
Porcupine Cave 220
21.1. Artiodactyl remains from Porcupine Cave 291
22.1. Repository numbers of all specimens used in
the Badger Room analyses 316
25.1. Listing of analyzed Marmota specimens 340
xiii
CHAPTER APPENDIXES
1.1. Per-hundred-year temperature change values for
global warming events plotted against the interval
of time over which the temperature change was
measured 4
2.1. Location of Porcupine Cave 7
2.2. View of landscape around the cave entrance as
of 1986 8
2.3. Map of Porcupine Cave 10
2.4. North to south profile through Porcupine Cave 12
2.5. West to east profile through Porcupine Cave 13
2.6. Detailed profiles through cross sections depicted in
figure 2.3 14
2.7. Detailed profiles through cross sections depicted in
figure 2.3 15
2.8. Portion of a fossilized Neotoma midden recovered
from middle Pleistocene strata in the CM Velvet
Room excavation 21

2.9. Plan view of excavation grids for DMNH 644,
Velvet Room 21
2.10. Profile of the east wall of grids 14, 15, and 16 in
DMNH 644, Velvet Room 22
2.11. Southeast to northwest profile through the southern
part of the Velvet Room 25
3.1. Computer image of Colorado terrain, showing the
four Colorado parks 28
3.2. Sketch map indicating the location of Porcupine
Cave and the major features of South Park 28
3.3. Looking southwest across the northern portion of
South Park toward the Mosquito Range 29
3.4. Winter view looking west to Silverheels Mountain
just north of Fairplay 29
3.5. Mean monthly precipitation for the Antero Reservoir
weather station, 1961–97 30
3.6. Mean number of days each month receiving more
than 0.25, more than 1.25, and more than 2.54 cm
of precipitation at the Antero Reservoir weather
station 30
3.7. Monthly maximum and minimum temperatures at
the Antero Reservoir weather station 30
3.8. Wet meadow dominated by sedges 33
3.9. Steppe dominated by blue grama grass, with
flowering paintbrush and other herbaceous
dicots 34
3.10. Salt flats southeast of Antero Reservoir 35
3.11. Tussocks of elk sedge dominating calcareous
peatland 36
3.12. Map showing the circumpolar distribution of

Kobresia simpliciuscula 36
3.13. Map showing the circumpolar distribution of
Ptilagrostis porteri in North America and the closely
related P. mongholica in central Asia 36
3.14. A wet meadow–steppe–conifer forest complex in the
southern portion of South Park 37
4.1. Generalized map of South Park showing key
geographic features, landmarks, Bautista de Anza’s
trail, and location of Porcupine Cave 40
4.2. Old Mose 47
4.3. Generalized map of Porcupine Cave 47
5.1. Geological sketch of the vicinity of
Porcupine Cave 52
5.2. Cross section showing inclined strata and
Porcupine Cave 53
xv
FIGURES
5.3. Stratigraphic section at Porcupine Cave 53
5.4. Panel diagram of the ridge containing
Porcupine Cave 54
5.5. Subsidence profile at Porcupine Cave 54
5.6. Speleothems in the Gypsum Room 55
5.7. Hollow stalagmite in the Velvet Room 55
6.1. Map of the Velvet Room 58
6.2. Stratigraphy and paleomagnetic sampling
in DMNH 644 59
6.3. Characteristic remanences from Velvet Room
strata 60
6.4. VGPs and polarity stratigraphy from the
Velvet Room 60

6.5. Zijdervelt diagrams showing the demagnetization
trajectories of various samples 61
6.6. Detailed stereoplots from sample sites 61
6.7. Zijdervelt diagrams from the 1994 block sample 62
7.1. Stratigraphic ranges of Amphibia, Reptilia,
ochotonids, leporids, sciurids, and geomyids at
the Pit 66
7.2. Stratigraphic ranges of arvicolines and other rodents
at the Pit 67
7.3. Stratigraphic ranges of carnivores, artiodactyls, and
equids at the Pit 68
7.4. Correlation of the Pit sequence with the CM and
DMNH Velvet Room excavations 69
7.5. Potential correlation of the Porcupine Cave
stratigraphic sequences with global climate changes
indicated by the oxygen isotope curve 72
8.1. Bushy-tailed wood rat, Neotoma cinerea 75
9.1. Dimensions of measurements for rodent and
lagomorph specimens 83
9.2. Dimensions of measurements for DMNH 30076,
Canis latrans skull 84
9.3. Dimensions of measurements for DMNH 26646,
Canis latrans femur 85
9.4. Lepus sp. (hare or jackrabbit), DMNH 42146,
innominate fragment from Mark’s Sink 85
9.5. Lepus sp. (hare or jackrabbit), DMNH 42148,
fragmentary thoracic vertebra from Mark’s Sink 86
9.6. Lepus sp. (hare or jackrabbit), DMNH 20052, right
calcaneum from the Badger Room 87
9.7. Canis latrans (coyote), DMNH 30076, skull from the

Badger Room 88
9.8. Rodentia cf. Neotoma (wood rat) or Spermophilus
(ground squirrel), DMNH 41425, right innominate
from the DMNH Velvet Room excavation 88
9.9. Canis latrans (coyote), DMNH 26646, right femur
from the Badger Room 89
9.10. Rodentia cf. Neotoma (wood rat), DMNH 42149,
metapodial from Mark’s Sink 89
9.11. Lepus sp. (hare or jackrabbit), DMNH 42147, gnawed
long bone fragment from Mark’s Sink 90
11.1. UCMP 399996; sacrococcyx referred to
Pelobatidae 118
11.2. DMNH 44766; right maxilla referred to
Phrynosoma 119
11.3. UCMP 399995; left dentary referred to
Phrynosomatidae 120
11.4. Porcupine Cave specimens referred to
Viperidae 120
11.5. DMNH 27888; precloacal vertebra referred to
Natricinae 121
11.6. UCMP 399993; precloacal vertebra referred to
non-natricine Colubridae 122
12.1. Premaxilla (DMNH 12807) of an unidentifiable
goose, cf. Anser or Chen sp.; right tarsometatarus
(DMNH 35864) of Numenius madagascariensis or
N. arquata (Far Eastern or Eurasian Curlew) 130
13.1. Martes species A, DMNH 34569, fragment of right
maxilla with P4 from Mark’s Sink, and DMNH 34570,
right M1 from the Velvet Room 142
13.2. Mustela nigripes, DMNH 11017, right mandible with

m1 from the Velvet Room 143
13.3. Mustela vison, DMNH 27767, left mandible with c-m2
from Will’s Hole 144
13.4. Brachyprotoma obtusata, DMNH 33778, left upper
canine from Mark’s Sink 146
13.5. Canis edwardii, DMNH 18353, left mandible with p1,
p3-m2 from the Badger Room 147
14.1. Map of North America showing fossil localities
containing Ochotona of Hemphillian, Blancan, and
definite Irvingtonian age 156
14.2. Drawings of select Ochotona teeth from Porcupine
Cave 158
15.1. Terminology for leporid p3 morphology 165
15.2. Temporal range of species identified in the DMNH
Velvet Room sites 168
17.1. Fossil teeth of Tamiasciurus, Spermophilus, and
Cynomys 174
17.2. Scatterplot of trigonid and talonid width, p4;
scatterplot of trigonid width versus length
of p4 177
17.3. Stratigraphic and interlocality patterns in trigonid
width of p4 of S. cf. S. elegans and relative frequency
of selected sciurid taxa 179
xvi FIGURES
17.4. Specimens of ?Cynomys andersoni sp. nov. 180
17.5. Relative frequency of three classes of anterior
deflection of hypoconid on m3 among four samples
of prairie dogs; discrimination of modern C.
gunnisoni and C. leucurus based on discriminant
function model using variables of p4-m2 184

17.6. Preliminary age correlation hypothesis for Porcupine
Cave sites based on the sciurid fauna 185
18.1. Left m1 of Neotoma cinerea 195
20.1. Distal metapodial, CM 49179, from the
Badger Room 268
20.2. Rodent (wood rat?) gnawing of a distal metapodial
(DMNH 22083) from the Velvet Room 269
20.3. Apparent etching on an isolated left p4 (DMNH
23074) from the Badger Room 269
20.4. Etching on the labial surface of a deciduous lower
premolar (CM 73357) from the Badger Room 270
20.5. Etching on the lingual surface of a right m1
(DMNH 41172) from the Velvet Room 270
20.6. Etching on the lingual surface of adult lower
premolars (right p2, DMNH 27524; right p3 or p4,
CM 49180) from Fissure Fill A 271
20.7. Left P3 (DMNH 27098) from Fissure Fill A 272
20.8. Right p2 (DMNH 27524) from Fissure Fill A 273
20.9. Bivariate plot of measurements of first phalanges
from Porcupine Cave, compared with like elements
of hemionines from other locations 274
20.10. Bivariate plot of measurements of astragali from
Porcupine Cave, compared with like elements of
hemionines from other locations 274
20.11. First phalanges of Equus (Hemionus) sp. from
Porcupine Cave 275
20.12. First phalanx of Equus (Hemionus) sp. from
Porcupine Cave compared with first phalanx of
E. conversidens 275
20.13. Right P3 (DMNH 27054) from the Badger Room 276

20.14. Right m1 or m2 (DMNH 41172) from Mark’s Sink in
the Velvet Room 276
20.15. Bivariate plot of measurements of second phalanges
of small Equus from Porcupine Cave, compared
with like elements of hemionines from other
locations 277
21.1. Extreme rodent gnawing on a broken mid-diaphysis
of a long bone (DMNH 22021; Velvet Room) 281
21.2. Skeletal elements of Platygonus 283
21.3. Cervids from Porcupine Cave 284
21.4. Fossils of Antilocapra or Tetrameryx, cf. Stockoceros,
Ovis, and Antilocapridae 286
21.5. Fossils of Ovis and Oreamnos harringtoni 287
21.6. Remains of Ovibovini gen. et sp. indet. 289
22.1. Location of the Badger Room within
Porcupine Cave 296
22.2. Paired grooves indicative of rodent gnawing on a left
femur, CM 74771 307
22.3. Damage to CM 74511, a left humerus, indicative of
nonrodent dental scraping and pitting 307
22.4. Tooth puncture mark and pitting on a left proximal
femur, CM 74742 307
22.5. Cortical peeling at an ancient fracture surface,
left humerus, CM 74525 307
22.6. Range maps for the indicator species used in the
quantitative climate analysis 308
22.7. Highest temperature (summer) minima and lowest
temperature (winter) maxima on the climate space
shared by the indicator taxa, using Spermophilus
elegans and S. richardsonii 309

23.1. General location of Porcupine Cave and stratigraphy
in the Pit locality 319
23.2. Rarefaction curves and species-richness-per-level
plotted against NISP for the Porcupine Cave Pit
data set 320
23.3. Species-richness-per-level curves for
Porcupine Cave Pit taxa broken out by
subgroups 320
23.4. Relative percentages of small-mammal taxa
through time in the Porcupine Cave Pit sequence,
based on MNI 322
23.5. Relative percentages of small-mammal taxa
through time in the Porcupine Cave Pit sequence,
based on MNI 323
23.6. Relative percentage of Spermophilus and
arvicolines 323
23.7. Relative percentages of species of arvicolines 324
23.8. Relative percentage of Lemmiscus curtatus
lower first
molars with four triangles versus those with five or
more triangles 324
23.9. Plot of the rodent and lagomorph species richness
expected from the Coleman rarefaction analysis
against the observed richness for stratigraphic
levels with sufficiently high NISP 325
24.1. Schematic stratigraphic column within the Pit
sequence showing sediment type 328
24.2. Oxygen and carbon isotope values obtained from
the different levels within the Pit 329
24.3. Oxygen and carbon isotope values from glacial or

interglacial strata within the Pit 330
25.1. Tooth terminology and measurements 335
FIGURES xvii
25.2. Log of the area (AP × T) of the upper P4 plotted as a
function of skull length 337
25.3. Box plots comparing the measurements of lower p4
across the seven stratigraphic levels 337
25.4. Box plots comparing the measurements of upper P4
across the seven stratigraphic levels 338
25.5. Box plots comparing the measurements of lower m3
across the seven stratigraphic levels 338
25.6. Frequency distributions by level for log(area) of
upper P4 339
xviii FIGURES
2.1. Names and locality numbers of major vertebrate
fossil sites of Porcupine Cave 16
2.2. Conversion from numbered arbitrary levels
applicable only within grids to correlative horizons
labeled by letters traceable across grids in DMNH
644, within the Velvet Room 23
3.1. Weather data from the Antero Reservoir station in
South Park, compared with data from Fairbanks,
Alaska, the Colorado Front Range, and the Khamar-
Daban Mountains of southern Siberia 31
3.2. Plant species characterizing the main vegetation
types in South Park 32
7.1. Percentages of arvicoline rodents identified from the
DMNH Velvet Room excavation 70
8.1. Vertebrate associates of Neotoma cinerea
in Colorado 78

8.2. Vertebrate associates of Neotoma mexicana
in Colorado 79
8.3. Vertebrate associates of Neotoma albigula
in Colorado 80
8.4. Vertebrate associates of Neotoma floridana
in Colorado 80
10.1. Faunal list for the Badger Room 96
10.2. Faunal lists for Badger Dome, Come-A-Long
Room, Cramped Quarters, Crystal Room, and
Damp Room 97
10.3. Faunal lists for the Ferret Room, Fissure Dump,
Fissure Fill A, and Fissure Fill B 98
10.4. Faunal lists for Generator Dome, Gypsum Room,
Gypsum Room SE Corner, KU Digs 1 and 3, and
Memorial Day Room 99
10.5. Faunal lists for New Passage, Tobacco Road, Trailside
Entrance, Velvet Room Last Chance Pit, Velvet Room
Kate’s Cupola, and Velvet Room Will’s Hole 100
10.6. Amphibians, reptiles, and birds from Velvet Room
Mark’s Sink 101
10.7. Mammals from Velvet Room Mark’s Sink 102
10.8. Faunal list for specimens found in Porcupine Cave
that lack more detailed provenance data 103
10.9. Faunal list for upper six levels of the Pit 104
10.10. Faunal list for lower seven levels of the Pit 108
10.11. Faunal list for the Velvet Room CM excavation 110
10.12. Faunal list for upper six horizons of the DMNH
Velvet Room excavation 111
10.13. Faunal list for lower six horizons and
undifferentiated material from the DMNH

Velvet Room excavation 114
11.1. Stratigraphic distribution of amphibian and
reptile remains from the Pit locality 124
12.1. Avian taxa identified from early and middle
Pleistocene deposits from Porcupine Cave 128
12.2. Measurements of premaxillae of Centrocercus
urophasianus compared to the fossil specimen
from Porcupine Cave 133
12.3. Measurements of tarsometatarsi of Numenius species
compared to the fossil specimen from Porcupine
Cave 134
13.1. Taxidea taxus: measurements of P4, M1, and m1 from
the Badger Room and a recent sample 145
13.2. Spilogale putorius: measurements of P4, M1, and m1
from Porcupine Cave and a recent sample 145
xix
TAB LES
13.3 Most common species of carnivores in five areas of
Porcupine Cave 148
14.1. North American fossil Ochotona of Pliocene (latest
Hemphillian and Blancan) and early Pleistocene
(Irvingtonian) age 157
14.2. Numbers of specimens of Ochotona from the
stratigraphic units in the Pit 159
14.3. Locations within Porcupine Cave for the unusual
form of pika here termed Ochotona sp. near Trout
Cave form 159
15.1. Matrix of species presence and absence for the
horizons of the main dig site in the Velvet Room 168
17.1. Comparison of S. lateralis and S. cf. S. elegans on lower

and upper alveolar row measurements 177
17.2. Dimensions of p4 for samples of S. cf. S. elegans 178
17.3. Comparison of ?Cynomys andersoni with other
primitive prairie dogs and prairie dog–like ground
squirrels based on lower dental variables 181
17.4. Comparison of four samples of Cynomys on lower
dental variables 183
18.1. Summary of dental differences among the species
of Neotoma represented in the Porcupine Cave
fauna 198
18.2. Numbers of identified specimens (NISP) and
percentages of NISP by level for Neotoma fossils
in the Pit locality 201
19.1. Known temporal range of arvicoline rodent taxa
recovered from Porcupine Cave 219
21.1. Artiodactyla recovered from Porcupine Cave 281
21.2. Measurements of the humerus and radius of
modern and fossil Antilocapra and fossils from
Porcupine Cave 285
21.3. Measurements of astragali identified as belonging to
antilocaprids from Porcupine Cave 287
21.4. Measurements of the M1-2 of the Porcupine Cave
specimen CM 75510; Oreamnos harringtoni
from Texas; Oreamnos harringtoni from the
Grand Canyon, Arizona; Oreamnos americanus;
and Ovis canadensis 288
22.1. Badger Room faunal list 298
22.2. Relative abundance of mammals in the Badger Room
assemblage 299
22.3. Patterns of representation among skeletal

elements in the Carnegie Museum Badger Room
collection 299
22.4. Patterns of modification and damage to leporid
femora and humeri in the Carnegie Museum
collection 300
22.5. Estimates of the minimum and maximum monthly
temperatures within the geographic ranges of
selected indicator taxa 301
22.6. Estimates for the highest minimum and lowest
maximum monthly precipitation levels based on
selected indicator taxa 302
22.7. Synecological profiles for the Badger Room and
recent historical South Park taxa 304
22.8. Systematic richness of the Badger Room fossil
mammals compared with the recent historical
South Park community 305
22.9. Species richness of the South Park mammal
community broken down by size class and
trophic group 310
22.10. Species deletion and addition information broken
down by size class and trophic group 310
24.1. Oxygen and carbon isotope values for Marmota
tooth enamel 329
25.1. Summary statistics for tooth measurements
in Marmota 336
25.2. ANOVA p-values for each dental dimension
in marmot teeth 336
25.3. Measurements of modern marmot teeth and skulls
from MVZ collections 337
xx TABLES

AF Alternating field
HSDk Highest known stratigraphic datum
Ka Thousands of years
LSDk Lowest known stratigraphic datum
Ma Millions of years
middle In this volume the Pleistocene is considered
Pleistocene to begin at some time slightly younger than
1.77 Ma ago, following the placement of the
boundary in the section at Vrica, Italy, by
International Geological Correlation Project
41 and International Union of Quaternary
Research Subcommission 1d at the 27th
International Geological Congress in
Moscow in 1984 (Bell et al., in press), and
subsequent correlation of the boundary with
the magnetostratigraphic and radiometric
time scales (Cande and Kent, 1995; Berggren
et al., 1995). The use of the term “middle
Pleistocene” in this book is informal and
refers to the middle third of the Pleistocene,
that is, the interval of time from about 600
Ka to 1.2 Ma ago. This is not to be confused
with terminology such as “Middle
Pleistocene subseries” (note the uppercase
M), which as of May 1, 2002, was an informal
working definition, adopted by the
International Commission on Stratigraphy,
that encompasses the time interval from
circa 126 to 780 Ka ago (http://micropress
.org/stratigraphy/gssp.htm).

MNI Minimum number of individuals
NISP Number of identified specimens
pcv Precloacal vertebra
yr BP Radiocarbon years before 1950
Dental abbreviations
C Upper canine
I Upper incisor
M Upper molar
P Upper premolar
c Lower canine
i Lower incisor
m Lower molar
p Lower premolar
1, 2, 3, etc. Position in the toothrow. Thus M1 stands for
the first upper molar and p4 stands for the
fourth lower premolar.
Institution abbreviations
AMNH American Museum of Natural History
CM Carnegie Museum of Natural History
DMNH Denver Museum of Nature and Science
FLMNH Florida Museum of Natural History
GCPM George C. Page Museum of La Brea
Discoveries
GRCA Grand Canyon National Park
HAFO Hagerman Fossil Beds National Monument
IMNH Idaho State Museum of Natural History
KU University of Kansas, Kansas Museum of
Natural History
LACM Natural History Museum of Los Angeles
County

MVZ University of California Museum of
Vertebrate Zoology
SBCM San Bernardino County Museum
xxi
ABBREVIATIONS AND DEFINITIONS
TMM Texas Memorial Museum
UCMP University of California Museum of
Paleontology
UNSM University of Nebraska State Museum
USNM United States National Museum
YPM Yale Peabody Museum
Measurement abbreviations
AP Greatest distance from anterior to posterior
portion of tooth
BD Greatest breadth of the distal end
BP Greatest breadth of the proximal end
DLS Greatest diagonal length of the ventral
surface
GBw Greatest breadth over the wings
GD Greatest depth
GL Greatest length
GLl Greatest length of lateral edge
GLm Greatest length of medial edge
Glpe Greatest length of proximal end
LD Length of dorsal surface
SD Smallest breadth of diaphysis
T Greatest transverse distance (i.e., width) of
tooth measured perpendicular to AP
xxii ABBREVIATIONS AND DEFINITIONS
PART ONE

THE DISCOVERY AND
DISTRIBUTION OF FOSSILS