ONTOGENETIC CHANGE IN DISTAL AND PROXIMAL LIMB BONES OF JUVENILE PLEISTOCENE COYOTES … ·...

ONTOGENETIC CHANGE IN DISTAL AND PROXIMAL LIMB BONES OF

JUVENILE PLEISTOCENE COYOTES (Canis latrans) AND DIRE WOLVES

(Canis dirus) FROM THE RANCHO LA BREA TAR PITS, CALIFORNIA

A Thesis

Presented to the

Faculty of

California State Polytechnic University, Pomona

In Partial Fulfillment

Of the Requirements for the Degree

Master of Science

In

Geological Sciences

By

Patrick D. Gillespy

2018

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SIGNATURE PAGE

THESIS: ONTOGENETIC CHANGE IN DISTAL AND

PROXIMAL LIMB BONES OF JUVENILE

PLEISTOCENE COYOTES (Canis latrans) AND

DIRE WOLVES (Canis dirus) FROM THE RANCHO

LA BREA TAR PITS, CALIFORNIA

AUTHOR: Patrick D. Gillespy

DATE SUBMITTED: Spring 2018

Geological Sciences Department

Dr. Jonathan A. Nourse

Thesis Committee Chair

Geological Sciences

Dr. Donald R. Prothero

Geological Sciences

Dr. Bryan P. Murray

Geological Sciences

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ACKNOWLEDGEMENTS

The expertise and help of those around me was invaluable to the completion of

this thesis project, without which I would have had added difficulty to an already

laborious process. I would like to devote this section to those who gave me their time, in

whatever form it may have taken.

Thank you to my advisor, Dr. Don Prothero, for his expertise in paleontology and

willingness to impart that knowledge. Your ability to convey concepts new and old will

continue to keep me interested in the life that has existed in the ancient past, still exists

today, or may exist in the future. Urging me to attend conferences has brought me out of

old comfort zones into the realm of new possibilities.

Thank you to Johnnie French of the U.S. Fish and Wildlife Service for dedicating

time out of your busy day to collect data that was beyond my reach and thereby

contributing to this project.

Thank you to the La Brea Tar Pits and Museum staff, especially collection

managers Aisling Farrell and Gary Takeuchi, for making the time for me to come in and

explore your extensive collections. An additional thank you is in order for the members

of the Department of Vertebrate Paleontology of the Los Angeles County Natural History

Museum, notably Vanessa Rhue, for your insight and skills in training me on how to

properly catalogue, handle, and prepare fossil specimens.

To the faculty and staff of the Geological Sciences department of Cal Poly

Pomona, thank you for putting up with my incessant questions about coursework and this

thesis itself. Hopefully you see some of your advice and geologic teachings imparted

herein, as I took everything to heart and mind.

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Thank you to my family for your company and pushing me to be the first to

achieve what you were unable to. Exposing me to the many experiences and views in this

world broadened my horizons. Your help and life experiences mean a great deal to me.

Thank you to my friends, old and new, for believing in my abilities, even when I

found my own lack of faith disturbing. Some of whom I respectfully follow in your

footsteps, as you have toiled in graduate programs of your own, and others who have

embarked on further studies. It is a dangerous business, stepping out onto this road—

there is no knowing where you might be swept off to.

Finally, thank you to my wife, Caitie, for lending a sympathetic ear to my lengthy

scientific explanations and tangents. It is more appreciated than you could possibly

imagine, even if you do not always understand what I am saying. Thank you for

encouraging all that I love as much as you love the tiny Atelerix albiventris. It may not be

normal, but it is natural. If I could, I would throw a lasso around the moon and give it to

you. Just say the word.

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ABSTRACT

Large sample sizes of juvenile animal fossils are rare compared to their adult

counterparts. The preponderance of adult specimens in the fossil record overshadows the

entire ontogenetic growth series of an organism from the earliest stages of life and

onward. This is partially because the fragile parts of younger individuals are typically

poorly preserved. However, the natural asphalt seeps of the Rancho La Brea Tar Pits have

yielded spectacular quantities of specimens young and old, allowing for a more complete

investigation of ontogenetic growth series. We collected long bone length, thickness, and

circumference data from nearly 800 separate appendicular skeleton elements across three

canid species; Pleistocene coyotes (Canis latrans) and dire wolves (Canis dirus), as well

as modern gray wolves (Canis lupus). Standardized major axis bivariate regressions were

used to determine the ontogenetic change in limb bones and the deviation from the line of

isometry (“same growth”). Using regression slopes as a proxy for long bone allometry,

we were able to compare the growth patterns of the extinct canids to other cursorial

animals and their modern counterparts. We found that C. latrans, C. dirus, and C. lupus

long bone growth series are positively allometric, with bones growing longer faster than

they do thicker. The degree of positive allometry is typically more pronounced in the

distal elements than the proximal elements. This suggests an increasing degree of

gracility in the distal elements compared to the relatively robust proximal elements. As

expected of animals adapted to a running lifestyle, the increasing gracility of long bones

would allow for a much more efficient running locomotion behavior. This would be

beneficial while hunting, much like the modern gray wolf when in pursuit of smaller and

faster prey. These statistical results show that coyote and dire wolf growth series are

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typical of other cursorial animals during ontogeny, regardless of climatic influences on

body size changes during the glacial and interglacial periods of the Pleistocene.

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TABLE OF CONTENTS

SIGNATURE PAGE ......................................................................................................... ii

ACKNOWLEDGEMENTS ............................................................................................ iii

ABSTRACT ....................................................................................................................... v

LIST OF TABLES ........................................................................................................... ix

LIST OF FIGURES ......................................................................................................... xi

CHAPTER 1 – INTRODUCTION .................................................................................. 1

1.1 GEOLOGIC SETTING .......................................................................................... 5

1.1.1 REGIONAL SETTING ........................................................................................ 5

1.1.2 TECTONIC SETTING ........................................................................................ 7

1.1.3 STRATIGRAPHY .............................................................................................. 10

1.1.4 NATURAL RESOURCES .................................................................................. 12

1.1.5 CLIMATE.......................................................................................................... 18

1.1.6 FAUNA ............................................................................................................. 20

CHAPTER 2 – METHODS ........................................................................................... 25

2.1 MEASUREMENT DETAILS .............................................................................. 25

2.2 EQUIPMENT AND SOFTWARE ....................................................................... 33

2.3 ISOMETRY AND ALLOMETRY ...................................................................... 35

2.4 STATISTICS: WHY ALLOMETRIC REGRESSIONS? ................................. 35

CHAPTER 3 – RESULTS .............................................................................................. 40

3.1 DATA ANALYSIS ................................................................................................ 40

3.2 C. latrans ALLOMETRY ..................................................................................... 41

3.3 C. lupus ALLOMETRY ........................................................................................ 41

3.4 C. dirus ALLOMETRY......................................................................................... 42

CHAPTER 4 – DISCUSSION AND INTERPRETATION ........................................ 49

4.1 DISCUSSION ........................................................................................................ 49

4.2 INTERPRETATION ............................................................................................ 49

4.2.1 C. latrans .......................................................................................................... 49

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4.2.2 C. lupus ............................................................................................................. 50

4.2.3 C. dirus ............................................................................................................. 51

4.3 PROXIMAL VS. DISTAL LIMB BONES ......................................................... 61

CHAPTER 5 – CONCLUSIONS AND FUTURE WORK ......................................... 68

5.1 CONCLUSIONS ................................................................................................... 68

5.2 FUTURE WORK .................................................................................................. 68

REFERENCES ................................................................................................................ 70

APPENDIX A – JUVENILE BONE MEASUREMENTS .......................................... 82

APPENDIX B – DATA TABLES .................................................................................. 83

APPENDIX C – KILBOURNE AND MAKOVICKY (2012) TABLE .................... 114

APPENDIX D – INTERSPECIFIC SLOPE C.I. COMPARISON .......................... 115

APPENDIX E – INTRASPECIFIC REGRESSION RESULTS .............................. 116

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LIST OF TABLES

Table 1. Results of regressions describing humeral growth during ontogeny in canids

using length and circumference measurements. ................................................... 43

Table 2. Results of regressions describing humeral growth during ontogeny between C.

lupus and C. lupus + C. rufus using length and circumference measurements. ... 43

Table 3. Results of regressions describing humeral growth during ontogeny in canids

using length and circumference measurements from an ellipsoid. ....................... 43

Table 4. Results of regressions describing growth during ontogeny of canid radii using

length and circumference measurements. ............................................................. 44

Table 5. Results of regressions describing growth during ontogeny between C. lupus and

C. lupus + C. rufus radii using length and circumference measurements............. 44

Table 6. Results of regressions describing growth during ontogeny of canid radii using

length and circumference measurements from an ellipsoid. ................................. 45

Table 7. Results of regressions describing growth during ontogeny of canid femora using


Table 8. Results of regressions describing growth during ontogeny between C. lupus and

C. lupus + C. rufus femora using length and circumference measurements. ....... 46

Table 9. Results of regressions describing growth during ontogeny of canid femora using


Table 10. Results of regressions describing tibial growth during ontogeny in canids using


Table 11. Results of regressions describing tibial growth during ontogeny between C.

lupus and C. lupus + C. rufus using length and circumference measurements. ... 47

x

Table 12. Results of regressions describing tibial growth during ontogeny in canids using


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LIST OF FIGURES

Figure 1: Illustration of various gray wolf (Canis lupus) developmental growth stages.

From newborn pup, 3 weeks old, 2 months old, and adult. Image from (Miren

Leyzaola, 2015; http://www.blog.illustraciencia.info/2015/04/canis-lupus-

occidentalis-etapas-de.html). .................................................................................. 1

Figure 2: Map of Rancho La Brea Tar Pits and Museum in Hancock Park with

generalized subsurface geology and petroleum pathways. Hancock Park is located

in the middle of urban Los Angeles. Inset: regional view of California with Los

Angeles County shaded and location of the La Brea Tar Pits marked. From (Joe

LeMonnier, 2007; naturalhistorymag.com/htmlsite/0607/0607_feature.html). ..... 3

Figure 3: Complete dire wolf (Canis dirus) growth series of right tibiae shown in lateral

view from Rancho La Brea. Arranged oldest (top) to youngest (bottom)

individual. Bones are aligned from the knee joint attachment proximally (left) to

distally (right).......................................................................................................... 4

Figure 4: Geomorphic provinces of Southern California. East-west-trending Transverse

Ranges in green. Northwest-trending Peninsular Ranges in red. Box near middle

of image bounds the Los Angeles Basin. Small star inside marks the approximate

location of the La Brea Tar Pits. Adapted from (Yerkes et al., 1965). ................... 6

Figure 5: Plate-tectonic evolution of the North American West Coast. Early transform

faulting occurred west of the modern San Andreas transform fault system and has

migrated eastward over time. In diagrams before 5 Ma, partial outline of Baja

California and Gulf of California shown for reference. Adapted from (Irwin,

1990). ...................................................................................................................... 9

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Figure 6: Petroleum seeps from rocks of the Miocene Monterey Formation near Morro

Bay, CA. The change of the rocks over time, from diatomite to porcellanite and

chert, created space for the migration of petroleum along fractures. Top of scale in

photo in inches, bottom in centimeters. ................................................................ 11

Figure 7: Petroleum reservoirs of the Los Angeles Basin. Small star near top of map

indicates the approximate location of the La Brea Tar Pits and Museum within the

southern portion of the Salt Lake oil field. Inset: regional view of California with

location of the L.A. Basin. Adapted from (Gayle Olson-Raymer, accessed 2018;

http://users.humboldt.edu/ogayle/hist383/LosAngeles.html). .............................. 13

Figure 8: Rancho La Brea lagerstätte fossil deposit in petroleum saturated sediments.

Multiple disarticulated skulls, ribs, pelvic bones and other mixed elements can be

identified in this assemblage. Note the canid skull near the lower-right of the

image. From (http://www.ucmp.berkeley.edu/quaternary/labrea.php). ................ 14

Figure 9: Asphalt seep vents of the McKittrick Tar Pits, western Kern County, CA. Photo

shows an approximately 2m x 2m area. McKittrick seeps are contemporaneous

with deposits of the La Brea Tar Pits. ................................................................... 15

Figure 10: Various ways in which natural asphalt seeps may be obscured. Left: layers of

dust, leaves, and twigs partially cover an active vent at Rancho La Brea. Image

adapted from (https://reference.com/science/tar-pits-a64ec47e7687119e). Right:

McKittrick oil seeps covered by stream flow that acts as a natural draw for

animals while hiding the true extent of the asphalt............................................... 16

Figure 11: Generalized cross-sectional illustration of the inverted cone-shape of an

asphalt vent with accumulated animal remains. Mixing of bones is common as the

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asphalt is churned over time, with 11,000-year-old bones found next to those that

are 30,000 years old. From (Natural History Museum of Los Angeles County,

2002). .................................................................................................................... 18

Figure 12: Average global surface air temperatures over the last 2.588 million years.

Large peaks correspond to interglacial periods while troughs represent glacial

periods. Small bone symbol on timescale denotes the oldest fossil bones found at

Rancho La Brea (~45 ka). Marked in red lettering are the last interglacial

(Eemian), the Last Glacial Maximum (LGM), the Younger Dryas (YD), and

Holocene. Adapted from (G. Fergus, 2014;

https://en.wikipedia.org/wiki/File:All_palaeotemps.svg). .................................... 19

Figure 13: Artist’s depiction of a coyote (Canis latrans) with accompanying skeleton

collected from Rancho La Brea deposits. Modern coyotes stand approximately 58

– 66 cm (1.9 – 2.2 ft) at the shoulder. Pleistocene individuals were slightly larger

than this. Adapted from (tarpits.org/la-brea-tar-pits/timeline). ............................ 21

Figure 14: Drawing of a dire wolf (Canis dirus) with its skeleton, as excavated from the

Rancho La Brea deposits. At the shoulder, C. dirus would have stood on average

between 68 – 80 cm (2.2 – 2.6 ft) tall. The largest modern gray wolves may stand

from 65 – 85 cm (2.1 – 2.8 ft) tall in comparison. Adapted from (tarpits.org/la-

brea-tar-pits/timeline). .......................................................................................... 22

Figure 15: Growth series selection of C. dirus right femora shown in anterior view. Bones

are aligned from the knee joint to hip joint attachments, distally (left) to

proximally (right), and from oldest (top) to youngest (bottom) individual. ......... 26

xiv

Figure 16: Random assortment of 30 C. dirus juvenile and sub-adult right radii in anterior

view. Bones are each positioned top to bottom, proximally to distally, from the

elbow joint attachment to the carpus (wrist). ........................................................ 27

Figure 17: Adult C. dirus left humerus in medial view (left) and posterior view (right).

Arrows indicate length and circumference, plus mediolateral and anteroposterior

width, measurements along the shaft of the bone. Red circles mark reference

measurement landmarks. Juvenile equivalent in Appendix A, Figure A.1. ......... 28

Figure 18: Adult C. dirus left radius in posterior view (left) and lateral view (right).

Arrows indicate length and circumference, as well as mediolateral and

anteroposterior width, measurements along the shaft of the bone. Red circles mark

reference measurement landmarks. ....................................................................... 29

Figure 19: Adult C. dirus left femur in posterior (left) and lateral (right) views. Arrows

indicate length and circumference, in addition to mediolateral and anteroposterior


measurement landmarks. Juvenile equivalent in Appendix A, Figure A.2. ......... 30

Figure 20: C. dirus juvenile (left) and adult (right) right tibiae in lateral view. Arrows

indicate length, circumference, and mediolateral and anteroposterior width

measurements along the shaft of the bone. Red circles mark reference

measurement landmarks........................................................................................ 31

Figure 21: Equation for the closest approximation of the circumference of an ellipse, in

lieu of the use of integration. Where a and b are the different radiuses of the

ellipsoid. From (Zafary, 2006). ............................................................................. 32

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Figure 22: C. dirus left radii in anterior view annotated with anatomical references. When

epiphyses are fused (left), measurements are made up to the epiphyseal line

(middle) so as to keep length and circumference measurements of the shaft (right)

equivalent between juveniles and adults. The shaft of the bone here refers to the

diaphysis and metaphysis, excluding the epiphyses. ............................................ 34

Figure 23: Left: isometric and allometric growth trends of a round shape with a central

pore for a hypothetical organism. When n=1, the change in shape is constant

between the total diameter and the pore width and is considered isometric. When

n > 1, then the change in shape is faster as the pore increases compared to the total

diameter and is considered allometric. Adapted from (Prothero, 2013; Figure 2.8

(A)). Right: Isometric growth vs. allometric growth. Isometry is the same scaling

(linear) growth and shape of an organism (i.e. salamander). Allometry is the

change of shape of an organism as a response to a change in size during growth

(i.e. humans). Adapted from (Prothero, 2013; Figure 2.8 (B and C)). ................. 36

Figure 24: SMA regressions of C. latrans (open squares) and C. dirus (open circles)

humeri. (A) Allometric slope plots with shaded 95% confidence interval bands. C.

latrans shows positive allometry (slope = 1.576); C. dirus (slope = 1.255). (B)

Residual plots; points fall roughly around (0, 0). (C) Quantile normality plots;

relatively normal distribution of points. ................................................................ 53

Figure 25: SMA regressions of C. latrans (open squares) and C. dirus (open circles) radii.

(A) Allometric slope plots with shaded 95% confidence interval bands. C. latrans

shows positive allometry (slope = 1.633); C. dirus (slope = 1.462). (B) Residual

xvi

plots; points fall roughly around (0, 0). (C) Quantile normality plots; relatively

normal distribution of points. ................................................................................ 54


femora. (A) Allometric slope plots with shaded 95% confidence interval bands. C.





tibiae. (A) Allometric slope plots with shaded 95% confidence interval bands. C.





humeri using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence

interval bands. C. latrans shows positive allometry (slope = 1.407); C. dirus

(slope = 1.224). (B) Residual plots; points fall roughly around (0, 0). (C) Quantile

normality plots; relatively normal distribution of points. ..................................... 57

Figure 29: SMA regressions of C. latrans (open squares) and C. dirus (open circles) radii

using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence




xvii


femora using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence





tibiae using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence




Figure 32: SMA regressions of C. lupus (open triangles) humeri. (A) Allometric slope

plot with shaded 95% confidence interval bands. C. lupus shows a high degree of

positive allometry (slope = 2.609). (B) Residual plot; points fall roughly around

(0, 0), but a rough linear trend may be discernable as well as notable outliers near

the left side of the graph. (C) Quantile normality plots; relatively normal

distribution of points, but with large steps and gaps from an incomplete or

otherwise small sample size. ................................................................................. 62

Figure 33: SMA regressions of C. lupus (open triangles) radii. (A) Allometric slope plot

with shaded 95% confidence interval bands. C. lupus shows a high degree of


(0, 0), but a rough linear trend may be discernable as well as notable outliers

towards the bottom-left of the graph. (C) Quantile normality plots; relatively

xviii

normal distribution of points, but with large steps and gaps from an incomplete or


Figure 34: SMA regressions of C. lupus (open triangles) femora. (A) Allometric slope

plot with shaded 95% confidence interval bands. C. lupus shows a high degree of


(0, 0), but a rough linear trend may be discernable as well as notable outliers to

the left and bottom of the graph. (C) Quantile normality plots; relatively normal



Figure 35: SMA regressions of C. lupus (open triangles) tibiae. (A) Allometric slope plot

with shaded 95% confidence interval bands. C. lupus shows a high degree of


(0, 0), but a rough linear trend may be discernable as well as notable outliers near

the left and bottom of the graph. (C) Quantile normality plots; relatively normal



Figure 36: SMA regressions of C. lupus and C. rufus combined data of proximal limb

long bones with shaded 95% confidence interval bands. Humeri (left) display

highly allometric trends (slope = 2.138). Femora (right), show similar increasing

allometry (slope = 2.364). ..................................................................................... 66

Figure 37: SMA regressions of C. lupus and C. rufus combined data of distal limb long

bones with shaded 95% confidence interval bands. Radii (left) display highly

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allometric trends (slope = 2.451). Tibiae (right), show similar increasing

allometry (slope = 2.476). ..................................................................................... 66

Figure 38: Combined SMA regressions of C. latrans (red open squares), C. dirus (black

open circles), and C. lupus (blue open triangles) long bones during growth.

Allometric slopes show increasingly gracile trends when comparing the proximal

femur (left: C. latrans slope = 1.423; C. dirus slope = 1.151; C. lupus slope =

2.808) to the distal tibia (right: C. latrans slope = 1.779; C. dirus slope = 1.538;

C. lupus slope = 2.880). ........................................................................................ 67


open circles), and C. lupus (blue open triangles) long bones during growth.

Allometric slopes show increasingly gracile trends when comparing the proximal

humerus (left: C. latrans slope = 1.576; C. dirus slope = 1.255; C. lupus slope =

2.609) to the distal radius (right: C. latrans slope = 1.633; C. dirus slope = 1.462;

C. lupus slope = 3.024). ........................................................................................ 67

1

CHAPTER 1 – INTRODUCTION

The development of an organism from the earliest stage to maturity, or ontogeny

(Figure 1), requires a number of adaptations to long-bone geometry. Material changes in

bone during ontogeny can change the structural characteristics of the bone as an organism

matures. By developing more ossified and lamellar bone to maintain structural rigidity

mammals accommodate for increased mechanical stresses on long bones, a result of

larger body masses and locomotor behaviors as individuals mature (Currey, 1977;

Carrier, 1983). In the case of juvenile and subadult mammals, relatively thicker bones

must develop to compensate for these stresses because of their weaker, flexible woven-

bone composition (Carrier, 1996). It has been shown that an increase in long bone length

Figure 1: Illustration of various gray wolf (Canis lupus) developmental growth stages.

From newborn pup, 3 weeks old, 2 months old, and adult. Image from (Miren Leyzaola,

2015; http://www.blog.illustraciencia.info/2015/04/canis-lupus-occidentalis-etapas-

de.html).

2

relative to thickness will occur during ontogeny in many mammalian species (Carrier,

1996; Kilbourne and Makovicky, 2012). Whether a bone shows this increasing gracility

or if it grows thicker and more robust during ontogeny warrants further attention,

especially in regards to interspecific comparisons. We expect mammals with a cursorial

(running) life style to have limbs that grow long faster than they grow thick, ending up as

gracile limbs, while large mammals like elephants might be expected to have limbs that

grow thicker faster than they grow long.

The preservation of fossil bone in the geologic record is sporadic at best. It is

never fully complete except in rare circumstances, yet still important for understanding

the changes in organisms and their environment throughout Earth history. Prothero

(2013) notes how fossil preservation is fairly selective, often favoring the hard elements

of organisms (e.g., shells or bones) over soft and delicate parts. This means that the

delicate and poorly mineralized bones of juvenile animals in particular are often missing

from the fossil record (Torzilli et al., 1982). The development of an organism during

ontogeny can be a difficult process to observe in this context.

There are few places where large samples of well-preserved juvenile bones can be

found that detail the complete ontogenetic growth series of a species. The Rancho La

Brea (RLB) tar seeps of southern California, located in Hancock Park, Los Angeles

(Figure 2), are one of the few fossil deposits in the world that offer an extraordinary

opportunity to sample large quantities of well-preserved bones of juvenile animals. With

over 200,000 specimens of dire wolves (Merriam, 1912; Kurtén and Anderson, 1980;

Stock and Harris, 1992; Dundas, 1999) representing around 4000 individuals, numerous

Pleistocene coyotes, and a few specimens of gray wolves (mostly from modern,

3

comparative museum collections), this collection is unparalleled for its sampling of rare

specimens, like juvenile bones. Access to the fossil collections housed in the La Brea Tar

Pits Museum (formerly the Page Museum), situated in the Hancock Park, allowed for

more detailed undertakings of comparisons between juveniles and adults, such as the

scaling relationship of long bone proportions during ontogeny (Figure 3). Therefore, it is

the purpose of this study to investigate the ontogenetic change in proximal and distal limb

bone growth series of Pleistocene fossil juvenile coyotes (Canis latrans) and dire wolves

(Canis dirus) to determine whether they develop like other cursorial animals, with limbs

becoming long faster than they grow thick, and also whether the extinct canids have the

same growth patterns as living canids.

Figure 2: Map of Rancho La Brea Tar Pits and Museum in Hancock Park with

generalized subsurface geology and petroleum pathways. Hancock Park is located in the

middle of urban Los Angeles. Inset: regional view of California with Los Angeles County

shaded and location of the La Brea Tar Pits marked. From (Joe LeMonnier, 2007;

naturalhistorymag.com/htmlsite/0607/0607_feature.html).

4

Figure 3: Complete dire wolf (Canis dirus) growth series of right tibiae shown in lateral

view from Rancho La Brea. Arranged oldest (top) to youngest (bottom) individual. Bones

are aligned from the knee joint attachment proximally (left) to distally (right).

5

1.1 GEOLOGIC SETTING

1.1.1 REGIONAL SETTING

Los Angeles sits atop a sedimentary basin that is positioned between two

geomorphic provinces that arose during a complex tectonic history; the Peninsular

Ranges and the Transverse Ranges (Figure 4). The Peninsular Ranges province extends

south into Baja California and, along with the Coast Ranges north of latitude 34°30’ N, is

a predominantly northwest-trending feature typical of the structural grain of the region

(Yerkes et al., 1965). The east-west-trending mountains, ridges, valleys, and plains of the

Transverse Ranges province diverge from this general trend as a result of tectonic forces.

The Los Angeles basin is bounded to the south by the Peninsular Ranges province and

the associated Santa Ana Mountains that lie to the east and the San Joaquin Hills to the

southeast; to the northwest, the basin is bounded by the Santa Monica Mountains of the

southern Transverse Ranges. The sedimentary thickness of the basin can be as much as

9100 m (Yerkes et al., 1965). The basin is dominated by northwest-trending strike-slip

faults, such as the Whittier, Newport-Inglewood, and Palos Verdes faults (Bilodeau et al.,

2007). The structural boundary between the basin and the Transverse Ranges province is

an east–west-trending zone of faults, dominated by the Santa Monica-Hollywood-

Raymond fault system (Wright, 1991; Ingersoll and Rumelhart, 1999).

Peninsular Ranges Province

The Peninsular Ranges province consists of groups of mountain ranges that

stretch south from the Los Angeles basin to Baja California for ~1500 km, with peak

6

elevations ranging from 152 to 3302 m (i.e., San Jacinto Peak). Northwest-trending

ridges and sediment-filled valleys are the predominant characteristic of the province.

Much of the province is submerged offshore and consists of similar ridges and closed

basins formed during the early and middle Miocene (Yerkes et al., 1965; Legg, 1991;

Wright, 1991; Crouch and Suppe, 1993), with water depths from ~850 to ~2100 m. The

province has been uplifted by Cenozoic age northwest- to west–northwest-trending fault

Figure 4: Geomorphic provinces of Southern California. East-west-trending Transverse

Ranges in green. Northwest-trending Peninsular Ranges in red. Box near middle of

image bounds the Los Angeles Basin. Small star inside marks the approximate location of

the La Brea Tar Pits. Adapted from (Yerkes et al., 1965).

7

zones that die out, merge with, or terminate against east-trending reverse and thrust faults

north towards the Transverse Ranges.

Transverse Ranges Province

The Transverse Ranges province is a group of mountainous peaks and ridges that

run east-west, north of the Los Angeles basin with peak elevations varying from ~150 to

3506 m (i.e., San Gorgonio Mountain). Uplift of the province began between 3.9 to 3.4

Ma due to transpressional forces related to the SAF development that began ~5 Ma

(Woodford et al., 1954). The northern and southern boundaries of the province are

bounded by the east-trending Santa Ynez and Santa Monica fault zones respectively.

1.1.2 TECTONIC SETTING

Los Angeles is located within the active transform boundary zone between the

eastern edge of the Pacific Plate and the North American plate (Atwater, 1970). Major

fault systems of northwest-trending, right-lateral strike-slip faults (e.g., the San Jacinto

and Elsinore faults) similar in style to the dominant fault feature of the region, the San

Andreas fault (SAF), comprise this boundary zone. Roughly east–west oriented, largely

left-lateral or thrust faults (e.g., the Santa Ynez or San Fernando faults) bound the

Transverse Ranges. The SAF is located 56 km northeast of downtown Los Angeles and

marks the boundary between the two tectonic plates; with the Pacific plate moving

northwest at a rate of 48-52 mm/yr relative to the North American plate to the east

(Atwater and Stock, 1998).

The current tectonic regime that eventually gave rise to the Los Angeles basin

started during the Mesozoic with the formation of a continental margin subduction zone

west of the North American plate with the Farallon plate between 150-145 Ma (Bilodeau

8

et al., 2007 and referenced therein). Magmatic arc and forearc basin development

continued during the Cretaceous (ca. 120-80 Ma), depositing volcaniclastic sediments in

the forearc basins, emplacing granitic rocks in the magmatic arcs, or metamorphosing

rocks to blueschist and greenschist in the accretionary prism (Wright, 1991; Crouch and

Suppe, 1993; and Ingersoll, 2001). An increase in the North American plate motion

trenchward (Engebretson et al., 1984) and subduction of the Shatsky Rise oceanic plateau

during the Cretaceous-Paleogene (ca. 80-40 Ma) is believed to have caused flat-slab

subduction (Liu et al., 2010) of the Farallon plate and the resulting Laramide orogeny and

forearc.

At about 30 Ma, two triple junctions formed (Figure 5) as the Pacific plate

collided with the North American plate; with the northern Mendocino triple junction

(MTJ) and the southern Rivera triple junction (RTJ) migrating away from each other,

separated by the proto-San Andreas fault (Atwater 1970; Irwin, 1990). This continued

collision of the East Pacific Rise of the MTJ during the early Miocene altered the plate

boundary from predominantly subduction and convergence to transform motion

(Ingersoll, 2008; Atwater, 1989; and Atwater and Stock, 1998). Formation of other right-

lateral faults in the region separated crustal blocks from the North American plate and

onto the Pacific plate, which then experienced clockwise-transrotational and

transtensional stresses (Luyendyk, 1991; Dickenson, 1996; Ingersoll and Rumelhart,

1999) during much of the middle Miocene (ca. 18-12 Ma) and late Miocene (ca. 12-6

Ma). These processes formed many of the extensional features of the Los Angeles basin

where the majority of sediments filling the basin were deposited and rapid deposition

initiated tectonic subsidence (Yeats and Beall, 1991; and Ingersoll, 2001).

9

Inboard migration eastward of the Pacific–North American plate boundary during

the Miocene-Pliocene (ca. 6-4 Ma) and initiation of the modern SAF as a result of

extreme torsional stresses from the opening of the Gulf and California (Atwater, 1998;

Singer, 2005) gave rise to the “Big Bend” area of transpression in the SAF. The uplift of

the now-rotated Tranverse Ranges (ca. 3.9-3.4 Ma) partially accommodates those

Figure 5: Plate-tectonic evolution of the North American West Coast. Early transform

faulting occurred west of the modern San Andreas transform fault system and has

migrated eastward over time. In diagrams before 5 Ma, partial outline of Baja California

and Gulf of California shown for reference. Adapted from (Irwin, 1990).

10

transpressional stresses, while other east-west left-lateral, reverse, and thrust faults in the

region formed along reactivated Miocene faults (Crouch and Suppe, 1993), creating

many of the modern topographic features of the Los Angeles basin. This would facilitate

the accumulation sediments that eventually gave rise to the RLB tar pits within the basin.

1.1.3 STRATIGRAPHY

The stratigraphic sequence of the Los Angeles basin is heavily influenced by the

tectonic processes that shaped it. It consists of igneous and metamorphic basement rocks

of the San Gabriel and Santa Monica Mountains, Upper Cretaceous marine clastic

sedimentary rocks, mostly marine sedimentary and volcanic rocks from the Paleogene

and Neogene, and clastic marine and nonmarine Quaternary sediments (Bilodeau et al.,

2007). The RLB deposits originate during the Miocene from the diagenesis of organic-

rich sediments.

Miocene Rocks

Lower Miocene rocks composed of strata of the upper Sespe and Vaqueros

Formations were deposited with the opening of the Los Angeles basin during the

Miocene. Lower-middle Miocene strata of the Topanga Formation consist of mostly

marine clastic sandstone, siltstone, and basaltic volcanic rocks (of the Conejo and

Glendora Volcanics) (Dibblee, 1982, 1991; Fritsche, 1993; McCulloh et al., 2002). The

Modelo, Monterey, and Puente Formations make up the strata of the upper Miocene,

consisting of marine organic-rich siliceous shales and sandstones up to 2600 m thick, that

were deposited in shallow to moderately deep waters (Dibblee, 1982, 1991; Wright,

1991) during a phase of accelerated subsidence and deposition (Yerkes et al., 1965).

11

These upper Miocene rocks are the source of the majority of the petroleum reserves in the

region (Figure 6); a result of the thermal alteration of kerogens, the fossilized organic

material from organisms such as diatoms.

Pliocene Rocks

Clastic marine strata of the Fernando, Pico, and Repetto Formations consist of

mudstone and siltstone interbedded with silty sandstone, overlain by friable sandy-

siltstone, sandstone, and pebble conglomerate that thickens from 760 m to 4270 m

towards the south in the Los Angeles basin (Yerkes et al., 1965; Dibblee, 1982). The

sandstones of these formations act as petroleum reservoir rocks.

Figure 6: Petroleum seeps from

rocks of the Miocene Monterey

Formation near Morro Bay,

CA. The change of the rocks

over time, from diatomite to

porcellanite and chert, created

space for the migration of

petroleum along fractures. Top

of scale in photo in inches,

bottom in centimeters.

12

Pleistocene Deposits

Marine silt, sand, and gravel of the San Pedro and Lakewood Formations

(Dibblee, 1991) account for most of the fill of the Los Angeles basin as a result of marine

transgressions-regressions caused by climatic changes during the Pleistocene. Cooling

periods during glacial cycles of the Ice Age resulted in worldwide glaciation and uptake

of oceanic water that was locked into large ice sheets, dropping sea levels as much as

125-130 m. Warming trends during interglacial cycles would result in sea level rise,

depositing fine-grained marine and estuarine sediments (Bilodeau et al., 2007). These

units vary in thickness from 126 m to 1310 m and are exposed as marine terraces along

the coast (Yerkes et al., 1965). Nonmarine sediments deposited during the Late

Pleistocene (> 40 kyr) of mostly sands and gravels are the major fossil-bearing units of

this study.

Holocene Alluvium

Modern alluvial fans, stream channels and flood plains consisting of cobble and

pebble lenses and sheets with sand, silt, and clay interbeds make up the local Holocene

cover material. Derived from the highlands, these sediments can vary in thickness from

30 m to 60 m (Bilodeau et al., 2007).

1.1.4 NATURAL RESOURCES

Oil and Gas

Petroleum and gas deposits (Figure 7) were used by the indigenous Native

American Chumash and Tongva people who found a use for the tar (more appropriately,

asphalt) in the construction and sealing of baskets, boats, other projects, and trade goods.

13

The Los Angeles area was commonly used in the excavation of asphalt for similar uses as

well as for petroleum production from the Salt Lake oilfields during the early 1900’s,

with upwards of 1150 producing oil wells in 1904. Natural seeps of petroleum provided

an economical boost to the region, while also preserving the Pleistocene fossil remains of

140 plant species and 420+ animal species (Natural History Museum of Los Angeles

County, 1998), such as those found at the La Brea Tar Pits.

Figure 7: Petroleum reservoirs of the Los Angeles Basin. Small star near top of map

indicates the approximate location of the La Brea Tar Pits and Museum within the

southern portion of the Salt Lake oil field. Inset: regional view of California with location

of the L.A. Basin. Adapted from (Gayle Olson-Raymer, accessed 2018;

http://users.humboldt.edu/ogayle/hist383/LosAngeles.html).

14

La Brea Tar Pits

The Rancho La Brea (RLB) tar pits are a remarkable lagerstätte whereby fossils

are exceptionally preserved in sediments that are permeated by naturally occurring

asphalt originating from Miocene strata (Figure 8). William Denton was the first to

describe fossils (a saber-toothed cat canine) from RLB in 1875. The importance of the

RLB fossil deposits was not recognized until around 1901 when Union Oil geologist, W.

W. Orcutt rediscovered and recognized the fossil bones preserved in asphalt at Hancock

Ranch (now Hancock Park). Over 2 million fossil specimens were collected from RLB

Figure 8: Rancho La Brea lagerstätte fossil deposit in petroleum saturated sediments.

Multiple disarticulated skulls, ribs, pelvic bones and other mixed elements can be

identified in this assemblage. Note the canid skull near the lower-right of the image.

From (http://www.ucmp.berkeley.edu/quaternary/labrea.php).

15

between 1901 and 1915, primarily after the Hancock family gave exclusive excavation

rights to the newly established Los Angeles County Museum in 1913. The path to fossil

preservation and subsequent study would not be possible without the aforementioned

tectonic and sedimentary processes that formed the Los Angeles basin and surrounding

areas.

The RLB tar pits originate from sedimentary reservoir rocks and associated

structures that were fractured due to tectonic movement on the San Andreas Fault and

other nearby faults of the system, namely the local 6th Street Fault. The natural petroleum

migrates through these fractures until it reaches the surface in vents and fissures (Figure

Figure 9: Asphalt seep vents of the McKittrick Tar Pits, western Kern County, CA. Photo

shows an approximately 2m x 2m area. McKittrick seeps are contemporaneous with

deposits of the La Brea Tar Pits.

16

9). At the surface, the lighter volatile fraction of the petroleum dissipates once in contact

with the atmosphere (Campbell and Bochenski, 2014), either through evaporation or

bacterial biodegradation. The heavier compounds are left behind in a sticky, viscous ooze

called asphaltum (also known as bitumen, pitch, tar, or brea in Spanish) which flows into

topographic lows, such as stream beds, forming shallow (tens of centimeters) pools

known colloquially as “tar pits.”

It is this sticky asphalt that entrapped now-extinct animals, and continues to trap

modern extant species, that blundered into the seeps. This entrapment was likely

facilitated by an obscuring layer of dust, leaves, and water (Figure 10). When an animal,

bird, or insect came to drink the pooled water or otherwise attempted to cross over the

Figure 10: Various ways in which natural asphalt seeps may be obscured. Left: layers of

dust, leaves, and twigs partially cover an active vent at Rancho La Brea. Image adapted

from (https://reference.com/science/tar-pits-a64ec47e7687119e). Right: McKittrick oil

seeps covered by stream flow that acts as a natural draw for animals while hiding the

true extent of the asphalt.

17

obscured seep, it would become ensnared in the shallow asphalt and struggle close to the

surface before it succumbed to thirst or starvation. A struggling herbivore or other prey

animal would attract disproportionately large numbers of predators and scavengers which

would become trapped in the asphalt themselves as they attempted to prey on the doomed

and dying animal, creating what is deemed as a “predator trap.” This predator/prey

interaction can be observed in the fossil deposits of RLB where there are around 10

predators to every prey animal present (McDonald et al. 2015). The deposited asphalt

would then gradually cover the deceased animals and penetrate their bones, slowing or

completely stopping decay and weathering. This is why over the last 10,000 to 50,000

years (O’Keefe et al. 2009) the RLB seeps have accumulated large quantities of well-

preserved, unaltered fossil bones from Pleistocene animals. However, it was not as if the

asphalt seeps trapped animals every day; Harris and Jefferson (1985) and others have

estimated that one individual trapped each decade is enough to explain the abundance of

bones. The vast majority of these fossil bones are found in the inverted cone-shaped

deposits as disarticulated remains (Figure 11), suggesting extensive post-mortem

rearrangement that makes stratigraphic and radiocarbon dating difficult. Still, the

extraordinary foresight to excavate and preserve these fossils is what allows for the

investigation of extinct North American megafauna and more relevantly, Pleistocene

coyotes and dire wolves.

18

1.1.5 CLIMATE

The climate of the Pleistocene as a whole fluctuated between glacial and

interglacial cycles that were dominated by highland continental ice sheets of the glacial

periods. These glacial-interglacial transitions were heavily influenced by Milankovitch

cycles, such as those driven by the 100,000-year eccentricity cycle (Shackleton, 2000) as

well as shorter 40,000- and 20,000-year cycles. 11 major Pleistocene glacial-interglacial

cycles are further divided between relatively colder stadials and warmer interstadials

(Richmond, 1986). Dates for glacial-interglacial periods that define the Pleistocene

(2.588 million to 11,700 BP; Subcommission of Quaternary Stratigraphy, 2016) have

been derived from ice cores obtained from projects such as the Greenland Ice Core

Project (GRIP) and Greenland Ice Sheet Project (GISP) (Figure 12). This means that the

Figure 11: Generalized cross-sectional illustration of the inverted cone-shape of an

asphalt vent with accumulated animal remains. Mixing of bones is common as the asphalt

is churned over time, with 11,000-year-old bones found next to those that are 30,000

years old. From (Natural History Museum of Los Angeles County, 2002).

19

flora and fauna during this time were adapting to changing climates, with the Los

Angeles basin and coastal regions being composed of pine-cypress conifer forests

(Axelrod, 1983) and grasslands that transitioned to oak-chaparral forests and scrubland,

then further to sage-chaparral scrublands as the climate warmed to a Mediterranean

climate (Johnson, 1977).

The North American mammalian megafauna experienced an extinction of 33

genera as the climate during the end Pleistocene went through a period of change.

Mammoths, mastodons, short-face bears and sabre-tooth cats all went extinct along with

dire wolves during the Younger Dryas interval (12.7-11.7 ka) (Barnosky et al., 2004).

The Younger Dryas interval marked an abrupt return to cooler glacial conditions

Figure 12: Average global surface air temperatures over the last 2.588 million years.

Large peaks correspond to interglacial periods while troughs represent glacial periods.

Small bone symbol on timescale denotes the oldest fossil bones found at Rancho La Brea

(~45 ka). Marked in red lettering are the last interglacial (Eemian), the Last Glacial

Maximum (LGM), the Younger Dryas (YD), and Holocene. Adapted from (G. Fergus,

2014; https://en.wikipedia.org/wiki/File:All_palaeotemps.svg).

20

(Carlson, 2013) that dominated much of the rest of the Pleistocene and a reversal from a

warming trend at the end of the last glacial maximum (26.5-20 ka in the Northern

Hemisphere and 26.5-14.5 ka in Antarctica) heading into the Holocene (Clark et al.,

2009). The cause of this abrupt change in climate ranges from a controversial bolide

impact event (Firestone et al., 2007a; Kennett et al., 2009a,b) to much more accepted,

non-catastrophic natural mechanisms such as a decline in the strength of ocean current

conveyors (i.e. the Atlantic meridional overturning circulation) due to a large influx of

meltwater (Pinter et al., 2011).

1.1.6 FAUNA

Many animals called RLB home during the Pleistocene, when the Los Angeles

basin experienced several wet and cool glacial cycles, with some continuing on (coyotes

and gray wolves) into modern times and others becoming extinct (dire wolves). The

modern coyote (C. latrans) is an extremely adaptable, small-bodied (7-21 kg) carnivoran

canid (Bekoff, 1977); smaller than a modern wolf, but larger than a fox (Figure 13). It is a

solitary to pack hunter whose primary prey base is small mammals. Pleistocene C.

latrans was likely larger that its modern Holocene counterpart due to competition for a

larger megafaunal prey-base (Meachen et al., 2015b). On the other hand, the gray wolf

(C. lupus) has changed little through this time range. C. lupus is the largest of the extant

canid species and is a larger bodied (23-80 kg) pack hunter that specializes in long

distance chases of large prey items such as deer and elk (Mech, 1981). The extinct dire

wolf (C. dirus) roamed the Americas between 125,000-10,000 years ago. It was similar in

size to and stockier (34-110 kg) than its modern cousin (Anyonge and Roman, 2006;

Sorkin, 2008) (Figure 14) and likely fulfilled the same ecological niche as the extant C.

21

lupus, hunting in competition with the saber-toothed cat (Smilodon fatalis) and American

lion (Panthera leo atrox) for large prey such as bison, camels, and horses (Coltrain et al.,

2004).

1.2 PREVIOUS STUDIES

Cranial allometric studies of domestic dogs (Canis familiaris), dire wolves,

coyotes, and other carnivorans are often used to determine body mass, mechanical bone

forces, and feeding habits (Morey, 1992; Anyonge and Roman, 2006; Meachen et al.,

2015b). However, postcranial investigations may also elucidate similar issues and those

Figure 13: Artist’s depiction of a coyote (Canis latrans) with accompanying skeleton

collected from Rancho La Brea deposits. Modern coyotes stand approximately 58 – 66

cm (1.9 – 2.2 ft) at the shoulder. Pleistocene individuals were slightly larger than this.

Adapted from (tarpits.org/la-brea-tar-pits/timeline).

22

of locomotor habits: whether an animal is cursorial (walking or running) with gracile or

robust limb bones, arboreal (climbing), or even fossorial (digging). Meachen et al.

(2015a) found certain relationships exist between postcranial adaptations and climate in

carnivorans, with canids showing adaptations towards cursoriality and open, dryer

climates. As cursorial mammals, it is expected that C. dirus and C. latrans would show

more gracility, similar to C. lupus. Carrier (1983) proposed that juvenile and subadult

mammals will have relatively thicker limb bones that act to mechanically support the

animal at early stages of life when the bones are composed of weaker material, which

Figure 14: Drawing of a dire wolf (Canis dirus) with its skeleton, as excavated from the

Rancho La Brea deposits. At the shoulder, C. dirus would have stood on average between

68 – 80 cm (2.2 – 2.6 ft) tall. The largest modern gray wolves may stand from 65 – 85 cm

(2.1 – 2.8 ft) tall in comparison. Adapted from (tarpits.org/la-brea-tar-pits/timeline).

23

then become more gracile with age so as to support the locomotor behavior of the larger

adult animal.

The degree of sexual dimorphism in mammals is typically driven by the

competition of males for access to females (Short and Balaban, 1994; Weckerly, 1998)

and is an important factor in body mass estimations. Carnivorans and primates tend to

show a marked increase in the body mass of males compared to females (Ewer, 1973;

Martin et al., 1994). Long-bone proportions in primates and canine dentition size in

Pleistocene carnivorans (Ruff et al., 1989; Van Valkenburgh and Sacco, 2002) have been

used to study the degree of sexual dimorphism in mammals. It is shown that C. dirus, like

most other canids, exhibit a low level of sexual dimorphism (Van Valkenburgh and

Sacco, 2002) and the body mass differences associated with these proportional changes

would have little effect on bone growth during ontogenesis.

Kilbourne and Makovicky (2012) obtained ontogenetic samples of length and

circumference data for 22 species of mammals differing in clade and in body mass. They

suggest that most cursorial, or running, animals tend to display more rapid growth of the

length compared to the cross-sectional area in the distal limb bones. The distal limb

elements (tibia and radius) of running animals become more gracile (elongate) compared

to the proximal limb bones (femur and humerus).

Meachen and Samuels (2012) found that Pleistocene coyotes of Rancho La Brea

were morphologically larger and more robust than their modern counterparts while

remaining rather cursorial and particularly well adapted for running. They also argue that

coyotes do not follow trends in changes of larger body size as a response to cooling

climates (i.e., Bergmann’s rule) and that this morphological change is possibly a response

24

to larger competitors (i.e., dire wolves) instead of a response to climatic changes

occurring throughout the last glacial-interglacial cycle. As determined through cross-

sectional geometric properties, C. dirus was similar in size to the modern gray and timber

wolf (C. lupus) with more robust jaws and larger individuals likely exceeding the body

masses observed in their extant cousins (Anyonge and Roman, 2006). Unlike the coyotes,

dire wolves show changes in body size with a changing climate through time, with other

factors, such as cranial allometry, fluctuating (Brannick et al., 2015). However, dire

wolves have also been found to show no significant change in size and shape of their

limb bones through the entire previous 35,000 years of climate changes during the last

glacial maximum (Prothero et al., 2012).

These studies focused on primarily adult specimens and the majority of dire wolf

growth series trends omit large samples of juvenile and subadult specimens. Further

investigation that includes this end of the age spectrum is warranted so as to develop a

more complete picture of the species.

25

CHAPTER 2 – METHODS

2.1 MEASUREMENT DETAILS

To determine the ontogenetic growth changes in populations of coyote (Canis

latrans), dire wolf (Canis dirus), and gray wolf (Canis lupus) long bones, length,

midshaft circumference, and mediolateral and anteroposterior measurements were taken

for humeri, femora, radii, and tibiae. Ulnar measurements were not taken because the

ulna is not a major weight bearing element in canids and the identification of epiphyseal

sutures is problematic. A range of juvenile to adult specimens (Figure 15; Figure 16)

were sampled at random from collection drawers and inspected for signs of damage and

pathology. The completeness of specimens can be greatly affected by the presence of

these defects and any measurements made at the affected sites will be less accurate, if at

all possible. Incomplete and damaged specimens, as well as uncertain element

measurement landmarks, were avoided for the purpose of making more accurate

measurements.

Mediolateral width and anteroposterior thickness measurements were taken as

close to midshaft of the diaphysis as possible. Humeral measurements (Figure 17) were

made distally to the deltoid tuberosity, and radial measurements (Figure 18) were made

distally of the pronator teres attachment. Femoral measurements Figure 19) were made

directly midshaft, and tibial measurements (Figure 20) were made distally of the tibial

crest.

26

Figure 15: Growth series selection of C. dirus right femora shown in anterior view.

Bones are aligned from the knee joint to hip joint attachments, distally (left) to

proximally (right), and from oldest (top) to youngest (bottom) individual.

27

Figure 16: Random assortment of 30 C. dirus juvenile and sub-adult right radii in

anterior view. Bones are each positioned top to bottom, proximally to distally, from the

elbow joint attachment to the carpus (wrist).

28

Figure 17: Adult C. dirus left humerus in medial view (left) and posterior view (right).

Arrows indicate length and circumference, plus mediolateral and anteroposterior width,

measurements along the shaft of the bone. Red circles mark reference measurement

landmarks. Juvenile equivalent in Appendix A, Figure A.1.

29

Figure 18: Adult C. dirus left radius in posterior view (left) and lateral view (right).

Arrows indicate length and circumference, as well as mediolateral and anteroposterior


measurement landmarks.

30

Figure 19: Adult C. dirus left femur in posterior (left) and lateral (right) views. Arrows

indicate length and circumference, in addition to mediolateral and anteroposterior width,


landmarks. Juvenile equivalent in Appendix A, Figure A.2.

31

Figure 20: C. dirus juvenile (left) and adult (right) right tibiae in lateral view. Arrows

indicate length, circumference, and mediolateral and anteroposterior width


landmarks.

32

Mediolateral and anteroposterior measurements are substituted as variables in the

equation for an ellipse (Figure 21) in order to calculate a separate approximate

circumference value of the appendicular element. Circumference here is used as a proxy

for the cross-sectional area of a measured element because long bones effectively

function as hollow elliptical beams. This allows for analyses of only two variables (i.e.,

length vs. circumference), creating a single scaling relationship following Kilbourne and

Makovicky (2012) so as to determine ontogenetic growth patterns. Circumference

measurements were taken similarly.

Length measurements were made along the diaphysis and metaphysis of the

appendicular elements, excluding the epiphysis where it is fused at the epiphyseal growth

plate suture, as delineated by the epiphyseal line (Figure 22), so as to keep measurements

equivalent between juvenile and adult specimens. Humeral lengths were measured along

a line following posterior from the greater tubercle towards the lateral condyle (Figure

17), and radial lengths were measured following the center of the proximal articular

surface towards the styloid process (Figure 18). Femoral lengths were measured

following a line from the femoral head towards the medial condyle (Figure 19), and tibial

lengths were measured in line from the intercondylar eminence towards the center of the

Figure 21: Equation for the closest approximation of the circumference of an ellipse, in

lieu of the use of integration. Where a and b are the different radiuses of the ellipsoid.

From (Zafary, 2006).

33

distal articular surface (Figure 20). Long bone lengths, midshaft circumferences, and

mediolateral and anteroposterior thicknesses are provided in Appendix B (Table B.1-4;

Table B.5-8; Table B.9-12).

2.2 EQUIPMENT AND SOFTWARE

Measurements of length and mediolateral width and anteroposterior thickness that

were 150 mm or less were made with 150 mm long digital calipers which could be zeroed

at any point and that are sensitive to an accuracy of 0.02 mm and a precision of 0.01 mm.

Abbe’s Principle of Alignment was considered so as to reduce the measurement error

introduced while using the digital calipers (Zhang, 1989). Abbe’s Offset, a second order

error, is negligible when the measurement is taken parallel to the line along the element

being measured. The Abbe Error, a first-order error, occurs when parallelism is not

accounted for and magnifies the angular error over distance. Both errors were minimized

when making measurements by insuring the calipers were in line with the measurement

axis of the element and that the element was as close to the fixed scale as possible for

proper measurements but are otherwise not quantified herein. Length measurements over

150 mm and measurements of midshaft circumference were made using a flexible, metric

measuring tape.

Testing for allometry was accomplished by a natural log transformation (base e)

of the length and circumference measurements before processing the data in two primary

programs for regression analysis so as to remove extreme effects due to size variations.

RMA for JAVA (v. 1.21) by Andrew J. Bohonak and Kim van der Linde and the

statistical program R with the SMATR package (Warton et al., 2011), visualized with the

opensource program RStudio for ease of use, were used to compare and confirm

34

Figure 22: C. dirus left radii in anterior view annotated with anatomical references.

When epiphyses are fused (left), measurements are made up to the epiphyseal line

(middle) so as to keep length and circumference measurements of the shaft (right)

equivalent between juveniles and adults. The shaft of the bone here refers to the diaphysis

and metaphysis, excluding the epiphyses.

35

regression analyses. Ontogenetic trends in long bone growth were determined by

comparing the slopes of the regression lines with the slope predicted by isometry.

2.3 ISOMETRY AND ALLOMETRY

If a regression trend shows a departure from the standard isometric growth line,

then it can be said that the trend is allometric. Isometric trends would produce a slope

near unity (1.0) and suggest a “same” rate of change in the shape of a bone (Prothero,

2013), while allometric trends will fall to either side of unity (Figure 23). With the

circumference plotted on the X-axis and the length on the Y-axis, a slope less than 1.0

suggests negative allometry and an increasing robustness of the bone during ontogeny;

with the circumference growing at a faster rate than the length of the bone. A slope

greater than 1.0 suggests positive allometry and an increasing slenderness of the bone

(Kilbourne and Makovicky, 2012); the length of the bone growing at a faster rate than the

circumference. Ontogenetic trends of C. latrans were compared to previous work by

Kilbourne and Makovicky (2012) (Appendix C) to determine the reproducibility of the

measurement and analysis procedures in addition to producing a more robust sample size.

C. dirus trends were compared to the predicted slopes of the aforementioned ontogenetic

trends to determine if they display isometry, negative allometry, or positive allometry of

corresponding bone shape during ontogeny. Finally, C. dirus results are compared to the

results from the C. latrans and C. lupus analyses to infer if any similarities or differences

exist between extinct and extant canid relatives.

2.4 STATISTICS: WHY ALLOMETRIC REGRESSIONS?

In order to determine the empirical relationship between the cross-sectional area

and length measurements of limb bones from C. latrans, C. dirus, and C. lupus a

36

statistical analysis is necessary. Among the quantitative analyses available (univariate,

bivariate, and multivariate), univariate, one variable, and multivariate, more than one

variable, analyses are not considered for this study as a simpler analytical case exists

where two variables are involved. An inferential bivariate analysis is therefore the best

method by which to analyze the measurement data. It is then necessary to determine

whether there is a dependent variable, by which its value is partially determined by the

independent variable, if there are no dependent variables, or if both variables are

Figure 23: Left: isometric and allometric growth trends of a round shape with a central

pore for a hypothetical organism. When n=1, the change in shape is constant between the

total diameter and the pore width and is considered isometric. When n > 1, then the

change in shape is faster as the pore increases compared to the total diameter and is

considered allometric. Adapted from (Prothero, 2013; Figure 2.8 (A)). Right: Isometric

growth vs. allometric growth. Isometry is the same scaling (linear) growth and shape of

an organism (i.e. salamander). Allometry is the change of shape of an organism as a

response to a change in size during growth (i.e. humans). Adapted from (Prothero, 2013;

Figure 2.8 (B and C)).

37

dependent to some degree on one another. Does y change as x increases (or vice versa)?

Do both variables change at rates relative to each other? In the case of ontogeny with

respect to allometric studies, neither variable is independent and both are dependent

relative to one another, with one scaling at a rate governed by a particular ratio between

the two variables.

The basic principle of allometry begins with Huxley’s (1932) simple allometry

derivation of the power function

y = bxα

that is called the “allometric equation” (Reiss, 1989) or “allometric relation” (Harvey and

Pagel, 1991), and which is then natural log-transformed,

ln y = ln b + α ln x,

and re-expressed as,

y = b + αx,

with x and y representing biological measurements, and α and b are the constants of the

slope and the intercept, respectively (Huxley, 1932; Gould, 1966). This transformed

equation is used to more easily view and infer the linear relationship that is related by the

biological size variables. It is also reasonably useful for interpreting size variables

because growth is a multiplicative process (Huxley, 1932). It is then necessary to

determine a reasonable method of line-fitting, or regression, to interpret the allometric

results.

Regression is best used when fitting lines (e.g., linear regression) for the

prediction of the Y-variable based on the value of the X-variable, with predicted values

falling closer to the mean than the observed values. It is generally used because many

38

problems are posed so as to answer if Y is associated with X or how strongly Y is

associated with X (Fuller, 1987). One such linear regression technique, least mean

squares (LMS), is commonly used by programs such as Microsoft Excel to fit linear lines

that maximize the normal distribution while minimizing the sum of the squared errors

between the predicted (Y) and observed (X) values. Another regression is ordinary least

squares (OLS) where the sum of the squared vertical or horizontal deviations is

minimized. Both consider a bivariate dataset where there is one dependent variable and

one independent variable; as the Y-axis (dependent) changes, the X-axis (independent)

will change accordingly. Allometry, however, is more concerned with the value of the

slope of the line-of-best-fit and linear regression towards the mean is not appropriate for

such an analysis (Warton et al., 2006).

With a bivariate dataset, standardized major axis (SMA), also referred to as

reduced major axis (RMA), model II regression can be used to describe a line-of-best-fit

and is the preferred method for this study since the slope of the regression line is of

primary interest. SMA minimizes the sum of the product of the horizontal and vertical

deviations, effectively summarizing the relationship between the Y and X variables

instead of predicting Y from X. SMA considers a bivariate dataset where both variables

are dependent on each other, with the Y and X variables changing at a rate relative to

each other, as in the case of ontogeny. When using this regression method for allometry

there are a couple of considerations that must be taken into account.

• Samples should be randomly selected so as to not bias the slope of the line-of-

best-fit (Fuller, 1987) because both Y and X values are considered random

variables that warrant sampling at random (Warton et al., 2006).

39

• It should be assumed that equation error will be present and measurement

error information should not be used. Measurement error, or observational

error, is an error whereby the measured values of subjects do not represent the

true values of the subjects being measured and may include sampling error.

However, equation error is typically much larger compared to measurement

error and it may be reasonable to assume that there is no measurement error

instead of no equation error (Warton et al., 2006). Equation error is where the

actual values of the subjects do not fall along a straight line and is

synonymous with “natural variation” (Sokal and Rohlf, 1995) or “intrinsic

scatter” (Akritas and Bershady, 1996).

These errors can be assumed and minimized by choosing the most appropriate

regression method. The final regression model may be validated by the presence of

neither systematically high or low observed errors (residuals) with a constant spread

throughout their range and the presence of normally distributed quantiles. Additionally, a

p-value ≤ 0.05 would indicate strong evidence against the null hypothesis and allow for

the rejection of the null hypothesis.

40

CHAPTER 3 – RESULTS

3.1 DATA ANALYSIS

Analyses were derived from length, circumference, mediolateral width, and

anteroposterior thickness bone measurements of C. latrans collected from 50 humeri and

femora each, and from 53 radii and 79 tibiae; of C. dirus obtained from 120 each of

humeri, radii, and tibiae and 123 separate femora; and with C. lupus length and

circumference measurements, provided by Johnnie French of the U.S. Fish and Wildlife

Service, from 25 humeri, 26 radii, and 28 femora and tibiae of 15 individuals from New

Mexico. Mediolateral and anteroposterior measurements were not available in the C.

lupus data and ellipsoid calculations and comparisons to C. latrans and C. dirus are

omitted from the relevant analyses. It should be noted that an additional set of 2 length

and circumference measurements were provided for each limb bone from one individual

of the wolf species Canis rufus, or red wolf. This modern wolf species is taxonomically

unresolved but is often considered synonymous with C. lupus (Wozencraft, 2005), hence

its inclusion in some of the analyses herein. However, genetic studies have suggested that

C. rufus is an independent species from C. lupus that may have diverged from an ancient

wolf ancestor (Vonholdt et al., 2011; Hinton et al., 2013; and Rutledge et al., 2015) or as

a result of gray wolf-coyote hybridization (Vonholdt et al., 2016). With those

assumptions, some results are presented with C. rufus data omitted.

RMA for Java vs. SMATR Package for R

SMA analyses between the RMA for Java and SMATR package for R programs

yielded nearly the same results, with only the 95% confidence interval (C.I.) limits

41

differing between the two programs. The SMATR package for R has an additional output

for the p-value.

3.2 C. latrans ALLOMETRY

Humeral Slopes. Coyote humeral slopes of length vs. circumference from RMA

for Java and SMATR package for R (Table 1) are identical at 1.576. For the analyses of

length vs. circumference from an ellipsoid (Table 2), the slopes are the same at 1.407.

Radial Slopes. Slopes for radial growth series between the two statistical

programs from the analysis of length vs. circumference are the same at 1.633 (Table 3),

while lowering to 1.314 from the analyses of length vs. circumference of an ellipse

(Table 4).

Femoral Slopes. Slopes for coyote femoral growth series are equivalent at 1.423

between the two programs for length vs. circumference (Table 5). The slope changes to

1.355 for length vs. circumference of an ellipse (Table 6).

Tibial Slopes. Likewise, tibial results do not differ between the two programs,

with values at 1.779 for the length vs. circumference analyses (Table 7) and 1.519 for the

length vs. circumference from an ellipse (Table 8).

3.3 C. lupus ALLOMETRY

Humeral Slopes. Similarly, gray wolf humeral slopes do not change between

RMA for Java and R results, holding at 2.609 (Table 1). If C. rufus is included however,

then the slope changes to 2.138 (Table 9).

Radial Slopes. Slope results for the radius growth series are the same at 3.024

(Table 3) and 2.451 with C. rufus included (Table 10).

42

Femoral Slopes. There is no difference in the slopes of the femora with values

identical at 2.808 (Table 5). This value decreases to 2.364 when C. rufus is made part of

the dataset (Table 11).

Tibial Slopes. Tibial analyses yield slopes that are indistinguishable between the

two programs, with both having an output of 2.880 (Table 7). The inclusion of C. rufus

alters the slope to a lower value of 2.476 (Table 12).

3.4 C. dirus ALLOMETRY

Humeral Slopes. Dire wolf humeral slopes are also equal between the two

programs, with a value of 1.255 for length vs. circumference (Table 1). For length vs.

circumference of an ellipse, the slope changes to 1.224 (Table 2).

Radial Slopes. Radial growth series slopes are similar at 1.462 for length vs.

circumference analyses (Table 3). Slopes fall to 1.397 when using the circumference of

an ellipse (Table 4).

Femoral Slopes. The slopes from femoral analyses are interchangeable between

the two statistical programs with a value of 1.151 from length vs. circumference (Table

5). The slope changes to 1.302 based on analyses using the circumference from an ellipse

(Table 6).

Tibial Slopes. Furthermore, tibial results show no change with either program,

with slopes equal at 1.538 (Table 7). Circumference from an ellipse analyses yielded

equivalent slopes of 1.482 (Table 8).

43

Table 1. Results of regressions describing humeral growth during ontogeny in canids using length and circumference

measurements.

Table 2. Results of regressions describing humeral growth during ontogeny in canids using length and circumference

measurements from an ellipsoid.

Taxon N Y-intercept Slope Slope C.I. limits

R2 P RMA Java SMATR

Carnivora

C. latrans 50 -0.9345 1.576 (G) 1.375, 1.776 1.388, 1.788 0.8084 < 2.22x10-16

C. lupus 25 -5.7481 2.609 (G) 1.935, 3.284 2.021, 3.369 0.6410 1.54x10-06

C. dirus 120 -0.1218 1.255 (G) 1.161, 1.349 1.165, 1.352 0.8328 < 2.22x10-16

G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes

that deviate from isometry are listed in bold.


R2 P RMA Java SMATR

Carnivora

C. latrans 50 -0.2501 1.407 (G) 1.232, 1.583 1.243, 1.593 0.8157 < 2.22x10-16

C. dirus 120 0.0126 1.224 (G) 1.133, 1.315 1.137, 1.318 0.8351 < 2.22x10-16

G denotes positive allometry (increasing gracility of long bones during ontogeny).

44

Table 3. Results of regressions describing growth during ontogeny of canid radii using length and circumference

measurements.

Table 4. Results of regressions describing growth during ontogeny of canid radii using length and circumference



R2 P RMA Java SMATR

Carnivora

C. latrans 53 -0.8412 1.633 (G) 1.422, 1.844 1.436, 1.857 0.7894 < 2.22x10-16

C. lupus 26 -6.7720 3.024 (G) 1.909, 4.139 2.108, 4.338 0.2342 1.22x10-02

C. dirus 120 -0.6397 1.462 (G) 1.305, 1.620 1.314, 1.628 0.6522 < 2.22x10-16




R2 P RMA Java SMATR

Carnivora

C. latrans 53 0.4462 1.314 (G) 1.150, 1.478 1.160, 1.488 0.8031 < 2.22x10-16

C. dirus 120 -0.3289 1.397 (G) 1.238, 1.556 1.247, 1.564 0.6127 < 2.22x10-16


45

Table 5. Results of regressions describing growth during ontogeny of canid femora using length and circumference

measurements.

Table 6. Results of regressions describing growth during ontogeny of canid femora using length and circumference



R2 P RMA Java SMATR

Carnivora

C. latrans 50 -0.3120 1.423 (G) 1.242, 1.604 1.253, 1.615 0.8089 < 2.22x10-16

C. lupus 28 -6.4453 2.808 (G) 1.852, 3.764 2.011, 3.922 0.2870 3.30x10-03

C. dirus 123 0.5254 1.151 (G) 1.064, 1.237 1.068, 1.240 0.8259 < 2.22x10-16




R2 P RMA Java SMATR

Carnivora

C. latrans 50 0.0616 1.355 (G) 1.144, 1.565 1.161, 1.581 0.7144 1.17x10-14

C. dirus 123 -0.0665 1.302 (G) 1.193, 1.411 1.198, 1.415 0.7850 < 2.22x10-16


46

Table 7. Results of regressions describing tibial growth during ontogeny in canids using length and circumference

measurements.

Table 8. Results of regressions describing tibial growth during ontogeny in canids using length and circumference



R2 P RMA Java SMATR

Carnivora

C. latrans 79 -1.4500 1.779 (G) 1.567, 1.992 1.579, 2.003 0.7241 < 2.22x10-16

C. lupus 28 -6.5261 2.880 (G) 1.846, 3.915 2.026, 4.095 0.2061 1.52x10-02

C. dirus 120 -1.0507 1.538 (G) 1.381, 1.696 1.389, 1.704 0.6856 < 2.22x10-16




R2 P RMA Java SMATR

Carnivora

C. latrans 79 -0.3553 1.519 (G) 1.347, 1.691 1.357, 1.700 0.7520 < 2.22x10-16

C. dirus 120 -0.7849 1.482 (G) 1.330, 1.635 1.338, 1.642 0.6827 < 2.22x10-16


47

Table 9. Results of regressions describing humeral growth during ontogeny between C. lupus and C. lupus + C. rufus using

length and circumference measurements.

Table 10. Results of regressions describing growth during ontogeny between C. lupus and C. lupus + C. rufus radii using



R2 P RMA Java SMATR

Carnivora

C. lupus 25 -5.7481 2.609 (G) 1.935, 3.284 2.021, 3.369 0.6410 1.54x10-06

C. lupus

C. rufus 27 -3.7982 2.138 (G) 1.486, 2.790 1.583, 2.887 0.4519 1.23x10-04




R2 P RMA Java SMATR

Carnivora

C. lupus 26 -6.7720 3.024 (G) 1.909, 4.139 2.108, 4.338 0.2342 1.22x10-02

C. lupus

C. rufus 28 -4.4971 2.451 (G) 1.542, 3.361 1.705, 3.524 0.1528 3.97x10-02



48

Table 11. Results of regressions describing growth during ontogeny between C. lupus and C. lupus + C. rufus femora using


Table 12. Results of regressions describing tibial growth during ontogeny between C. lupus and C. lupus + C. rufus using



R2 P RMA Java SMATR

Carnivora

C. lupus 28 -6.4453 2.808 (G) 1.852, 3.764 2.011, 3.922 0.2870 3.30x10-03

C. lupus

C. rufus 30 -4.6052 2.364 (G) 1.545, 3.183 1.683, 3.321 0.1991 1.36x10-02




R2 P RMA Java SMATR

Carnivora

C. lupus 28 -6.5261 2.880 (G) 1.846, 3.915 2.026, 4.095 0.2061 1.52x10-02

C. lupus

C. rufus 30 -4.8763 2.476 (G) 1.619, 3.332 1.763, 3.476 0.2015 1.28x10-02



49

CHAPTER 4 – DISCUSSION AND INTERPRETATION

4.1 DISCUSSION

Since the RMA for Java and SMATR package for R programs yielded nearly

identical regression slopes, it becomes redundant to interpret the results from both

programs and one should be chosen. For this reason, the SMATR package for R is the

program of choice because it allows for outputs that include a p-value for testing the null

hypothesis and graphical representations of SMA plots, residual plots, and normality

quantile-quantile (Q-Q) plots that all allow for determining validity of the analyses.

4.2 INTERPRETATION

4.2.1 C. latrans

Allometric analyses of C. latrans were first compared to previous work from

Kilbourne and Makovicky (2012) to determine if similar results are recorded from

comparable methods and regressions. First-pass linear regressions of the data did not fit

well with the expected values from the previous study, with Pleistocene coyotes

displaying a surprising degree of robust growth during ontogeny. After personal

correspondence with Dr. Kilbourne, the regression models were corrected to more

accurately reflect their methods (i.e. plotting the correct variables on the appropriate axes,

as is described in the methods). The new results (Table 1; Table 4; Table 7; Table 10)

were more in line with the previous study (Appendix Table C.1); percent difference of

humeral slopes only differing by 8.74%, femoral slopes differing by 14.17%, and tibial

slopes differing by 10.69%. No data for radial slopes were previously recorded for C.

50

latrans by Kilbourne and Makovicky (2012). With similar slopes, it can be concluded

that the methods followed were appropriate.

Allometric slopes from directly measured cross-sectional area of humeral (Figure

24a), radial (Figure 25a), femoral (Figure 26a), and tibial elements (Figure 27a) of C.

latrans show positive allometry. Slopes from mathematically computed cross-sectional

area of the same skeletal elements (Figure 28a; Figure 29a; Figure 30a; Figure 31a) are

also shown to be positively allometric, suggesting an increasing gracility during growth.

Residuals (Figure 24b; Figure 25b; Figure 26b; Figure 27b and Figure 28b; Figure 29b;

Figure 30b; Figure 31b) from the analyses appear to be randomly and unpredictably

distributed about the (0,0) line, showing no clear pattern. This suggests that the analyses

models are valid. Furthermore, Q-Q plots (Figure 24c; Figure 25c; Figure 26c; Figure 27c

and Figure 28c; Figure 29c; Figure 30c; Figure 31c) seem to be normally distributed with

slight steps likely due to incomplete sampling from the entire growth spectrum during

ontogeny, suggesting a “goodness of fit” of the models. Despite differences in body size

through time (Meachen and Samuels, 2012), ontogenetic growth in C. latrans has

retained positive allometry, resulting in a cursorial animal particularly well-adapted to

chasing down small prey items.

4.2.2 C. lupus

The allometric slopes of C. lupus are significantly larger than that of C. latrans

with R2 values between ~20% (tibia) to ~60% (humerus). The humeral (Figure 32a),

radial (Figure 33a), femoral (Figure 34a), and tibial (Figure 35a) slopes are all positively

allometric. While p-values are much larger than those for the other two canids, the values

fall below P < 0.05 and are still statistically significant, allowing us to reject the null

51

hypothesis. However, residual plots are not scattered randomly and appear to group to the

right of the graphs (Figure 32b; Figure 33b; Figure 34b; Figure 35b). On the other hand,

the Q-Q plots suggest a normally distributed dataset (Figure 32c; Figure 33c; Figure 34c;

Figure 35c) with gaps likely due to sampling. Perhaps either sampling bias or insufficient

data points unduly affected the results.

Results that include C. rufus data also show positive allometry for all skeletal

elements; proximal (humerus and femur) slopes (Figure 36) and distal (radius and tibia)

slopes (Figure 37) being smaller than when compared to C. lupus alone. With increasing

genetic data suggesting that C. rufus is a separate species from C. lupus (Vonholdt et al.,

2011; Hinton et al., 2013; and Rutledge et al., 2015; Vonholdt et al., 2016), and from the

variable results presented here, it is unlikely that C. rufus data can be appropriately

applied to C. lupus analyses without acting as outliers that disproportionately weight the

slope of the allometric line.

Regardless, modern wolves are cursorial animals and an increasing gracility

during growth is expected. Therefore, the high slopes may suggest such a gracile trend,

though the data are not fully explained by the analytical models.

4.2.3 C. dirus

Similar to the other canids, C. dirus ontogenetic slopes display positive allometry.

Slope values are lower for the distal bones of the limbs, the humerus (Figure 24a) and

femur (Figure 25a), and higher for the proximal elements, the radius (Figure 26a) and

tibia (Figure 27a), as is typically found in cursorial animals. With values of P < 2.22x10-

16, there exists an association between the rate of growth of the length and thickness of

the limb, allowing for a rejection of the null hypothesis. Further support of a reliable

52

positive allometric slope is that the residuals (Figure 24b; Figure 25b; Figure 26b; Figure

27b) are randomly distributed about the (0,0) line and show no clear grouping or pattern.

Distribution of quantiles along a line suggest normality (Figure 24c; Figure 25c; Figure

26c; Figure 27c), with small steps in the points likely due to incomplete sampling from

the entire spectrum of growth trends as a result of the natural fossil preservation process.

The validity of the models and “goodness of fit” lends further credence to the inference

that C. dirus benefited from an increasing gracility of the long bones during ontogeny as

there was likely a need to run after large prey that required coordinated pack hunting to

effectively subdue.

Compared to C. latrans and C. lupus, the smaller and larger canids respectively,

C. dirus exhibits more robustness of the limb bones, yet retains overall gracility. This

relative robustness may be the result of a mechanical need to support the larger mass of

the animal as opposed to an adaptation to colder climates during the Pleistocene such as

Bergman’s rule or Allen’s rule, which predicts shorter and more robust limbs in the face

of such climatic conditions. C. dirus existed on both sides of the last glacial maximum,

enduring both warming and cooling climate changes, yet does not display any significant

changes in limb-bone size and shape (Prothero 2013). Results from C. lupus do not

appear to be consistently reliable to compare to C. dirus, in part because of the large

range in the slope confidence intervals (C.I.) about the predictions. If there is no overlap

between the 95% confidence intervals for the means of two independent populations,

then there is statistical significance. If there is overlap in the C.I. bands (Appendix D)

however, then the p-value is used to determine significance. Still, the dire wolf is

expected to be very similar in behavior and physiology to its extant relative.

53


humeri. (A) Allometric slope plots with shaded 95% confidence interval bands. C. latrans

shows positive allometry (slope = 1.576); C. dirus (slope = 1.255). (B) Residual plots;

points fall roughly around (0, 0). (C) Quantile normality plots; relatively normal

distribution of points.

54


radii. (A) Allometric slope plots with shaded 95% confidence interval bands. C. latrans




55


femora. (A) Allometric slope plots with shaded 95% confidence interval bands. C. latrans




56


tibiae. (A) Allometric slope plots with shaded 95% confidence interval bands. C. latrans




57


humeri using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence

interval bands. C. latrans shows positive allometry (slope = 1.407); C. dirus (slope =

1.224). (B) Residual plots; points fall roughly around (0, 0). (C) Quantile normality

plots; relatively normal distribution of points.

58


radii using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence interval

bands. C. latrans shows positive allometry (slope = 1.314); C. dirus (slope = 1.397). (B)

Residual plots; points fall roughly around (0, 0). (C) Quantile normality plots; relatively

normal distribution of points.

59


femora using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence

interval bands. C. latrans shows positive allometry (slope = 1.355); C. dirus (slope =

1.302). (B) Residual plots; points fall roughly around (0, 0). (C) Quantile normality

plots; relatively normal distribution of points.

60


tibiae using an ellipsoid. (A) Allometric slope plots with shaded 95% confidence interval

bands. C. latrans shows positive allometry (slope = 1.519); C. dirus (slope = 1.482). (B)

Residual plots; points fall roughly around (0, 0). (C) Quantile normality plots; relatively

normal distribution of points.

61

4.3 PROXIMAL VS. DISTAL LIMB BONES

Proximal and distal limb bone allometry of the three canid species holds true to

the ontogenetic trends proposed by Kilbourne and Makovicky (2012). The proximal

bones (humerus and femur) display relatively more robust allometric slopes than those of

the distal bones (radius and tibia). While results from direct measurements are clearer,

those from the mathematically derived cross-sections still generally match with what is

expected (see Appendix E for intraspecific comparisons). The increased gracility of the

radii compared to the humeri (Figure 39) are apparent as well as the gracility of the tibiae

compared to the femora (Figure 38).

Canids are digitigrade animals, standing on their toes, as opposed to plantigrade

(with carpals and tarsals flat on the ground) or unguligrade (standing on the tips of the

phalanges). Digitigrade animals have a proportionally longer distal limb compared to the

proximal limb. This lengthens the stride of the animal and, thus, the speed of locomotion

(Polly, 2007; Young et al., 2014). An increase in the gracility of the distal elements

would be expected where speedier movement is advantageous and facilitated by longer

limb bones, such as in running animals like canids.

62

Figure 32: SMA regressions of C. lupus (open triangles) humeri. (A) Allometric slope plot with shaded 95% confidence

interval bands. C. lupus shows a high degree of positive allometry (slope = 2.609). (B) Residual plot; points fall roughly

around (0, 0), but a rough linear trend may be discernable as well as notable outliers near the left side of the graph. (C)

Quantile normality plots; relatively normal distribution of points, but with large steps and gaps from an incomplete or

otherwise small sample size.

63

Figure 33: SMA regressions of C. lupus (open triangles) radii. (A) Allometric slope plot with shaded 95% confidence interval

bands. C. lupus shows a high degree of positive allometry (slope = 3.024). (B) Residual plot; points fall roughly around (0, 0),

but a rough linear trend may be discernable as well as notable outliers towards the bottom-left of the graph. (C) Quantile

normality plots; relatively normal distribution of points, but with large steps and gaps from an incomplete or otherwise small

sample size.

64

Figure 34: SMA regressions of C. lupus (open triangles) femora. (A) Allometric slope plot with shaded 95% confidence

interval bands. C. lupus shows a high degree of positive allometry (slope = 2.808). (B) Residual plot; points fall roughly

around (0, 0), but a rough linear trend may be discernable as well as notable outliers to the left and bottom of the graph. (C)

Quantile normality plots; relatively normal distribution of points, but with large steps and gaps from an incomplete or

otherwise small sample size.

65

Figure 35: SMA regressions of C. lupus (open triangles) tibiae. (A) Allometric slope plot with shaded 95% confidence interval

bands. C. lupus shows a high degree of positive allometry (slope = 2.880). (B) Residual plot; points fall roughly around (0, 0),

but a rough linear trend may be discernable as well as notable outliers near the left and bottom of the graph. (C) Quantile

normality plots; relatively normal distribution of points, but with large steps and gaps from an incomplete or otherwise small

sample size.

66

Figure 37: SMA regressions of C. lupus and C. rufus combined data of distal limb long

bones with shaded 95% confidence interval bands. Radii (left) display highly allometric

trends (slope = 2.451). Tibiae (right), show similar increasing allometry (slope = 2.476).

Figure 36: SMA regressions of C. lupus and C. rufus combined data of proximal limb

long bones with shaded 95% confidence interval bands. Humeri (left) display highly

allometric trends (slope = 2.138). Femora (right), show similar increasing allometry

(slope = 2.364).

67


open circles), and C. lupus (blue open triangles) long bones during growth. Allometric

slopes show increasingly gracile trends when comparing the proximal humerus (left: C.

latrans slope = 1.576; C. dirus slope = 1.255; C. lupus slope = 2.609) to the distal

radius (right: C. latrans slope = 1.633; C. dirus slope = 1.462; C. lupus slope = 3.024).


open circles), and C. lupus (blue open triangles) long bones during growth. Allometric

slopes show increasingly gracile trends when comparing the proximal femur (left: C.

latrans slope = 1.423; C. dirus slope = 1.151; C. lupus slope = 2.808) to the distal tibia

(right: C. latrans slope = 1.779; C. dirus slope = 1.538; C. lupus slope = 2.880).

68

CHAPTER 5 – CONCLUSIONS AND FUTURE WORK

5.1 CONCLUSIONS

Although the climate changed much during the Pleistocene and many of the

animals and plants adapted to these fluctuating conditions, this thesis statistically shows

that the allometric growth of coyotes and dire wolves has changed little and is typical of

canids, showing increasing gracility during growth. This is similar to their extant

relatives, the modern coyote and gray wolf. Gray wolves are known to be running

animals that likely exhibit the same increase in bone gracility as a means to promote a

faster running locomotor behavior that arose as a response to the hunting of smaller and

faster prey items as part of a more diversified diet. Likewise, dire wolves show a positive

allometric rate of bone growth during ontogeny that supports a similar running locomotor

behavior. Despite the larger proposed body masses (Anyonge and Roman, 2006) and

possible changes in body size of dire wolves with changing climatic conditions, no true

robustness is observed as might be expected from colder climates experienced throughout

the Pleistocene.

5.2 FUTURE WORK

Given the sheer number of specimens recovered from the Rancho La Brea tar

seeps, there is plenty of opportunity to expand on this study by increasing the sample

sizes of the measurements made for C. latrans and C. dirus as well as other canids

housed in the museum collections, including C. lupus, the domestic dog (C. familiaris),

and the gray fox (Urocyon cinereoargenteus).

69

It is worth noting that the cortical thickness of long bones can be useful in the

determination of locomotor modes (Meachen, 2010) because its compact structure is

critical to body structure and weight bearing due to its resistance to bending and torsional

stresses. The cortical bone may be taken into account when measuring cross-sectional

area since the long bone shaft functions as a hollow elliptical beam with symmetrical

cross-sectional areas (Anyonage, 1993; Runestad et al., 1993; Runestad and Ruff, 1995;

Runestad, 1997) and the empty space could be taken into consideration. Because

destructive sampling is typically required to measure the internal extent of this bone

layer, it was deemed impractical for this study. Future analysis using x-ray radiographic

imaging would prove useful as a noninvasive method for measuring cortical thickness, as

in Anyonge (1993) and Runestad (1997). Magnetic resonance imaging (MRI) may also

be helpful as a noninvasive measurement technique for the true cross-sectional area of

bones by accounting for the internal structure of the bone shaft. However, these methods

require the use of specialized and expensive medical equipment that may be immobile

(e.g., MRI) which would be best suited to a study conducted in coordination with a

medical center.

Correlations to life history and organismal traits (Kilborne and Makovicky, 2012)

may also benefit from additional measurements added to this dataset in part or in whole.

OLS bivariate regressions between SMA slopes and size related variables of adult and

birth body mass, ontogenetic range of body mass, and growth rate, as well as OLS

bivariate regressions between SMA slope and cursoriality and mass-specific basal

metabolic rate, should it be discernible, could provide further clues about these extinct

animals and/or their extant relatives during ontogeny.

70

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APPENDIX A

Figure A.1: C. dirus juvenile left

humerus in medial (left) and

posterior (right) view. Arrows

indicate length, circumference,

and mediolateral and

anteroposterior width

measurements along the shaft of

the bone. Measurements were

made equivalently between adult

and juvenile specimens.

Figure A.2: C. dirus juvenile left

femur in posterior (left) and

lateral (right) view. Arrows

indicate length, circumference,

and mediolateral and

anteroposterior width

measurements along the shaft of

the bone. Measurements were

made equivalently between adult

and juvenile specimens.

83

APPENDIX B

Table B.1. Collected humeral data from Canis latrans.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

LACMHC

9811 72 27 9.67 7.34 LT Humerus 10

LACMHC

9792 84 29 9.68 7.94 LT Humerus 10

LACMHC

9810 81 31 10.28 8.22 LT Humerus 10

LACMHC

9809 82 32 9.53 8 LT Humerus 10

LACMHC

9807 109 33 10.28 8.74 LT Humerus 10

LACMHC

9793 109 33 10.86 8.7 LT Humerus 10

LACMHC

9819 99 34 11.02 9.03 LT Humerus 10

LACMHC

9818 107 35 11.34 9.27 LT Humerus 10

LACMHC

9808 109 36 12.08 9.88 LT Humerus 10

LACMHC

9806 110 36 12.02 10 LT Humerus 10

LACMHC

9791 114 35 11.14 9.36 LT Humerus 10

LACMHC

9817 124 34 11.12 9.61 LT Humerus 10

LACMHC

9804 124 32 9.56 8.82 LT Humerus 10

LACMHC

9803 117 38 13.01 10.05 LT Humerus 10

LACMHC

9838 123 38 12.95 10.45 RT Humerus 10

LACMHC

9824 124 35 11.88 9.86 RT Humerus 10

LACMHC

9856 133 39 12.76 11.48 RT Humerus 10

LACMHC

9841 125 38 12.83 10.43 RT Humerus 10

LACMHC

9840 136 39 13 10.63 RT Humerus 10

LACMHC

9839 126 37 12.12 9.68 RT Humerus 10

LACMHC

9837 137 40 13.84 11.05 RT Humerus 10

LACMHC

9836 132 39 12.8 10.49 RT Humerus 10

84

LACMHC

9835 139 38 12.72 11.07 RT Humerus 10

X9632 153 44 14.96 11.82 RT Humerus

(Ad) 10

X9635 142 46 15.19 13.01 RT Humerus

(Ad) 10

X9631 155 46 15.34 12.58 RT Humerus

(Ad) 10

LACMHC

9867 68 26 7.85 7.09 RT Humerus 10

LACMHC

9830 77 30 9.51 8.05 RT Humerus 10

LACMHC

9845 82 32 9.93 7.97 RT Humerus 10

LACMHC

9846 75 29 9.15 7.62 RT Humerus 10

LACMHC

9864 82 33 10.18 8.15 RT Humerus 10

LACMHC

9847 85 33 11.02 8.97 RT Humerus 10

LACMHC

9865 103 34 10.93 9.31 RT Humerus 10

LACMHC

9827 101 35 11.46 9.68 RT Humerus 10

LACMHC

9862 106 33 10.69 9.36 RT Humerus 10

LACMHC

9863 102 34 11.5 9.07 RT Humerus 10

LACMHC

9829 90 32 10.35 8.46 RT Humerus 10

LACMHC

9850 105 37 12.05 9.76 RT Humerus 10

LACMHC

9849 106 35 11.34 9.28 RT Humerus 10

LACMHC

9844 112 37 12.4 9.88 RT Humerus 10

LACMHC

9848 96 32 10.69 8.5 RT Humerus 10

LACMHC

9852 98 36 11.63 9.7 RT Humerus 10

LACMHC

9851 111 36 11.76 9.66 RT Humerus 10

LACMHC

9833 121 34 10.75 9.55 RT Humerus 10

LACMHC

9861 126 39 13.54 10.92 RT Humerus 10

X9772 143 45 14.71 13.09 RT Humerus

(Ad) 16

X9773 134 42 13.42 12.63 RT Humerus

(Ad) 16

85

X9774 135 45 15.26 13.68 RT Humerus

(Ad) 16

X9762 154 46 15.2 11.92 LT Humerus

(Ad) 13

X9765 151 46 14.69 12.44 LT Humerus

(Ad) 13

Table B.2. Collected radial data from Canis latrans.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

LACMHC

10109 74 25 4.76 7.71 RT Radius 10

LACMHC

10111 85 28 5.34 8.32 RT Radius 10

LACMHC

10108 87 29 5.14 9.08 RT Radius 10

LACMHC

10130 90 29 5.79 9.74 RT Radius 10

LACMHC

10134 109 30 6.02 10.23 RT Radius 10

LACMHC

10128 105 27 5.11 9.04 RT Radius 10

LACMHC

10131 113 32 6.07 10.69 RT Radius 10

LACMHC

10105 116 32 6.35 10.27 RT Radius 10

LACMHC

10129 123 32 6.01 10.95 RT Radius 10

LACMHC

10126 118 28 5.67 9.17 RT Radius 10

LACMHC

10127 129 31 6.52 10.68 RT Radius 10

LACMHC

10123 132 31 6.06 10.72 RT Radius 10

LACMHC

10124 131 32 7.29 10.28 RT Radius 10

LACMHC

10110 70 22 4.54 7.52 RT Radius 10

LACMHC

10136 75 25 4.84 8.37 RT Radius 10

LACMHC

10092 79 26 5.04 8.52 LT Radius 10

LACMHC

10095 114 29 5.77 10.06 LT Radius 10

LACMHC

10091 108 29 5.85 9.85 LT Radius 10

LACMHC

10088 101 29 6.47 9.45 LT Radius 10

86

LACMHC

10085 103 27 5.48 9.09 LT Radius 10

LACMHC

10083 126 29 6.37 9.56 LT Radius 10

LACMHC

10089 92 29 5.58 9.51 LT Radius 10

LACMHC

10090 90 27 5.6 9.04 LT Radius 10

W235 163 42 10.25 14.93 LT Radius

(Ad) 16

W233 163 41 9.16 15.02 LT Radius

(Ad) 16

W228 166 43 9.73 15.95 LT Radius

(Ad) 16

W227 162 36 7.68 13.53 LT Radius

(Ad) 16

W232 165 39 7.89 14.15 LT Radius

(Ad) 16

W229 155 34 6.84 12.16 LT Radius

(Ad) 16

W231 154 37 8.25 13.31 LT Radius

(Ad) 16

W230 152 34 7.26 11.83 LT Radius

(Ad) 16

LACMHC

10104 138 33 7.28 11.39 RT Radius 10

LACMHC

10140 132 33 6.45 10.52 RT Radius 10

LACMHC

10122 132 30 6.13 10.3 RT Radius 10

LACMHC

10132 137 31 6.1 10.27 RT Radius 10

LACMHC

10143 132 31 5.63 10.33 RT Radius 10

LACMHC

10144 136 32 6.19 10.84 RT Radius 10

W250 106 31 6.52 10.73 LT Radius 61

W258 119 30 6.06 9.92 LT Radius 61

W249 129 33 6.78 10.81 LT Radius 61

W244 148 35 7.49 12.07 LT Radius 61

W257 137 32 6.52 10.35 LT Radius 61

W241 140 32 7.21 10.92 LT Radius 61

W247 136 35 7.45 11.7 LT Radius 61

W246 137 35 7.2 12.12 LT Radius 61

W259 141 32 6.97 11.18 LT Radius 61

W254 140 36 8.03 12.81 LT Radius 61

W245 143 37 8.35 12.4 LT Radius 61

W265 142 32 6.61 11.61 LT Radius 61

W252 145 38 8.75 12.89 LT Radius 61

W110 151 36 7.92 12.5 LT Radius 61

W240 159 39 8.13 13.25 LT Radius 61

87

W251 155 40 8.31 14.76 LT Radius 61

Table B.3. Collected femoral data from Canis latrans.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

W 552 164 45 13.3 13.29 LT Femur

(Ad) 4

W 544 162 41 11.78 10.93 LT Femur

(Ad) 4

W 468 157 44 12.92 13.07 RT Femur

(Ad) 3

W 551 153 40 12.34 11.68 LT Femur

(Ad) 4

W 545 164 48 14.57 14.31 LT Femur

(Ad) 3

W 541 168 45 13.29 12.88 LT Femur

(Ad) 3

W 480 158 48 14.17 14.61 RT Femur

(Ad) 4

W 473 167 45 13.29 12.95 RT Femur

(Ad) 4

W 475 160 42 11.15 12.63 RT Femur

(Ad) 4

W 478 157 44 12.84 11.89 RT Femur

(Ad) 4

LACMHC

9924 95 32 9.11 8.71 LT Femur 10

LACMHC

9927 94 31 9.09 8.57 LT Femur 10

LACMHC

9930 108 33 9 9.14 LT Femur 10

LACMHC

9926 109 32 9.05 8.92 LT Femur 10

LACMHC

9913 123 35 10.29 10.1 LT Femur 10

LACMHC

9928 125 37 11.05 10.19 LT Femur 10

LACMHC

9934 121 36 10.07 9.87 LT Femur 10

LACMHC

9929 127 33 9.47 9.02 LT Femur 10

LACMHC

9931 132 38 11.07 10.52 LT Femur 10

LACMHC

9914 146 37 10.61 10.35 LT Femur 10

W597 112 32 9.53 8.98 LT Femur NA

W601 117 37 11 10.67 LT Femur NA

W605 72 25 7.77 7.66 LT Femur NA

W610 82 29 8.26 8.9 LT Femur NA

88

LACMHC

120090 100 33 10.65 10.19 LT Femur NA

LACMHC

120089 107 34 9.92 10.73 LT Femur NA

W591 94 30 8.39 9.32 LT Femur NA

W593 100 29 8.18 9.04 LT Femur NA

W594 103 32 9.15 9.39 LT Femur NA

LACMHC

120087 119 34 9.69 9.26 LT Femur NA

LACMHC

120086 109 36 11.64 10.14 LT Femur NA

LACMHC

120085 115 37 10.98 9.81 LT Femur NA

LACMHC

120084 115 37 10.65 10.25 LT Femur NA

LACMHC

120083 125 34 10.11 9.2 LT Femur NA

LACMHC

120082 123 34 9.55 9.9 LT Femur NA

LACMHC

120081 130 38 11.55 10.59 LT Femur NA

LACMHC

120080 124 37 10.46 10.31 LT Femur NA

LACMHC

120264 95 33 9.51 9.26 RT Femur NA

LACMHC

120263 106 39 11.88 10.66 RT Femur NA

LACMHC

120262 96 33 8.94 9.36 RT Femur NA

W 596 106 34 9.81 10.14 RT Femur NA

LACMHC

120261 113 36 10.06 11.35 RT Femur NA

LACMHC

120260 118 34 9.6 9.44 RT Femur NA

LACMHC

120259 116 37 11.19 10.32 RT Femur NA

LACMHC

120242 140 35 9.54 10 RT Femur NA

LACMHC

120241 139 42 12.32 12.07 RT Femur NA

LACMHC

120240 132 43 12.79 12.67 RT Femur NA

LACMHC

120234 147 40 12.05 11.91 RT Femur NA

LACMHC

120228 154 41 11.66 11.63 RT Femur NA

LACMHC

120221 147 44 14.13 13.78 RT Femur NA

89

Table B.4. Collected tibial data from Canis latrans.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

LACMHC

10,040 130 34 8.6 9.9 RT Tibia 10

LACMHC

10,058 153 40 11 11.3 RT Tibia 10

LACMHC

10,043 124 32 8.7 8.6 RT Tibia 10

LACMHC

10,038 119 32 8.5 8.9 RT Tibia 10

LACMHC

10,060 75 27 6.6 7.3 RT Tibia 10

LACMHC

10,039 99 30 7.86 7.74 RT Tibia 10

LACMHC

10,044 93 28 8.14 7.7 RT Tibia 10

LACMHC

10,022 98 32 9 8.64 RT Tibia 10

LACMHC

10,041 101 34 8.69 9.18 RT Tibia 10

LACMHC

10,037 145 32 9.69 8.9 RT Tibia 10

LACMHC

10,021 118 33 9.42 9.12 RT Tibia 10

LACMHC

120346 115 31 8.22 7.89 RT Tibia 10

LACMHC

10,005 74 27 7.52 6.14 LT Tibia 10

LACMHC

9979 74 26 6.73 7.29 LT Tibia 10

LACMHC

10,014 94 30 7.6 8.01 LT Tibia 10

LACHMC

10,000 85 29 8.12 8.38 LT Tibia 10

LACMHC

10,013 99 30 8.37 8.37 LT Tibia 10

LACMHC

9999 116 30 8.45 8.67 LT Tibia 10

LACMHC

9998 118 34 9.8 9.31 LT Tibia 10

LACMHC

10,012 126 38 11.04 11.14 LT Tibia 10

LACMHC

9994 128 33 8.34 9.27 LT Tibia 10

LACMHC

9995 142 36 10.2 10.18 LT Tibia 10

LACMHC

10,011 140 35 9.96 9.8 LT Tibia 10

90

LACMHC

9977 138 35 10.2 8.74 LT Tibia 10

LACMHC

9996 143 36 9.85 10.95 LT Tibia 10

LACMHC

9997 136 32 9.04 8.75 LT Tibia 10

LACMHC

9993 149 34 9.58 9.52 LT Tibia 10

LACMHC

10,002 145 38 10.6 11.01 LT Tibia 10

LACMHC

9978 155 40 11.16 11.74 LT Tibia 10

LACMHC

10,052 141 34 9.15 9.39 RT Tibia 10

LACMHC

10,045 130 33 9.54 10.15 RT Tibia 10

LACMHC

10,036 121 33 9.65 9.4 RT Tibia 10

LACMHC

10,042 141 34 9.8 9.87 RT Tibia 10

LACMHC

10,029 148 36 10.5 10.32 RT Tibia 10

LACMHC

120425 105 31 8.72 8.97 RT Tibia 10

LACMHC

120424 93 28 8.22 7.84 RT Tibia 10

W 747 119 32 8.8 9.02 RT Tibia 10

LACMHC

120689 94 29 8.65 8.33 LT Tibia 10

W 823 102 34 9.56 8.71 LT Tibia 10

LACMHC

120688 120 36 10.08 10.53 LT Tibia 10

LACMHC

120687 124 40 11.54 11.51 LT Tibia 10

LACMHC

120686 147 33 10.15 9.67 LT Tibia 10

LACMHC

120685 155 36 10.6 10.43 LT Tibia 10

LACMHC

120684 156 40 11.32 12.43 LT Tibia 10

LACMHC

120683 64 27 7.22 7.51 LT Tibia 10

LACMHC

120681 75 27 7.82 7.44 LT Tibia 10

LACMHC

120680 76 26 6.93 7.35 LT Tibia 10

W 708 103 28 8.2 7.76 LT Tibia 10

LACMHC

120679 106 33 9.4 8.96 LT Tibia 10

LACMHC

120678 103 35 9.88 9.85 LT Tibia 10

91

LACMHC

120677 110 35 10.3 10.15 LT Tibia 10

LACMHC

120676 118 30 9.01 8.94 LT Tibia 10

W 693 114 28 7.84 8.18 LT Tibia 10

LACMHC

120675 115 35 9.19 10.87 LT Tibia 10

LACMHC

120674 114 31 8.66 9.07 LT Tibia 10

LACMHC

120673 119 32 9.05 8.82 LT Tibia 10

LACMHC

120672 123 34 9.68 9.68 LT Tibia 10

LACMHC

120671 124 35 9.35 10.47 LT Tibia 10

LACMHC

120670 127 34 9.21 9.92 LT Tibia 10

LACMHC

9973 167 41 11.5 12.29 LT

Tibia

(Ad) 10

LACMHC

9987 170 38 10.89 10.54 LT

Tibia

(Ad) 10

LACMHC

9984 161 37 10.9 10.12 LT

Tibia

(Ad) 10

LACMHC

9985 154 35 9.74 10.32 LT

Tibia

(Ad) 10

W 733 167 42 11.73 12.45 LT Tibia

(Ad) 4

W 732 174 43 13.02 12.67 LT Tibia

(Ad) 4

W 723 170 41 13.36 13.41 LT Tibia

(Ad) 4

W 729 181 44 12.33 13.62 LT Tibia

(Ad) 4

W 720 173 42 12.32 12.86 LT Tibia

(Ad) 3

W 719 183 45 12.26 12.86 LT Tibia

(Ad) 3

LACMHC

120669 123 35 9.86 9.77 LT Tibia NA

LACMHC

120668 128 37 10.68 10.64 LT Tibia NA

W 812 135 33 9.89 9.17 LT Tibia NA

W 821 136 33 9.99 9.75 LT Tibia NA

LACMHC

120667 134 38 10.42 10.73 LT Tibia NA

LACMHC

120666 135 32 9.57 9.07 LT Tibia NA

LACMHC

120665 139 39 10.51 11.61 LT Tibia NA

LACMHC

120664 129 32 9.33 9.52 LT Tibia NA

92

LACMHC

120663 148 36 10.29 10.29 LT Tibia NA

LACMHC

120662 138 41 12.22 11.95 LT Tibia NA

Table B.5. Collected humeral data from Canis dirus.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

LACMHC

93682 146.32 53 18.35 16.1 RT Humerus NA

LACMHC

93695 124.46 54.5 17.77 16.66 RT Humerus NA

LACMHC

93662 142.76 56 18.01 18.33 RT Humerus NA

LACMHC

93638 139.47 57.5 19.1 18.04 RT Humerus NA

LACMHC

93639 135.64 52.5 17.86 14.67 RT Humerus NA

LACMHC

93663 141.52 57 19.08 17.19 RT Humerus NA

LACMHC

93640 125.56 50 16.56 15.22 RT Humerus NA

LACMHC

93641 129.49 55 18.33 14.48 RT Humerus NA

LACMHC

93642 137.99 55 17.5 15.46 RT Humerus NA

LACMHC

93685 138.22 56.3 18.71 15.77 RT Humerus NA

LACMHC

93697 129.02 50.5 16.78 14.36 RT Humerus NA

LACMHC

93686 135.56 57 18.71 15.72 RT Humerus NA

LACMHC

93668 143.84 54 18.12 16.03 RT Humerus NA

LACMHC

93645 132.77 51.5 17.07 15.62 RT Humerus NA

LACMHC

93670 154.64 61 20.52 17.37 RT Humerus NA

LACMHC

93669 143.03 51 16.51 14.82 RT Humerus NA

LACMHC

93646 134.88 55 19.06 16.82 RT Humerus NA

LACMHC

93647 131.46 52 17.8 15.79 RT Humerus NA

LACMHC

93687 132.85 53.5 18.06 15.34 RT Humerus NA

LACMHC

93648 135.35 49.5 16.82 14.64 RT Humerus NA

93

LACMHC

93671 149.39 60 19.27 17.8 RT Humerus NA

LACMHC

93649 120.57 54 17.93 16.23 RT Humerus NA

LACMHC

93672 142.7 53.5 19.08 15.39 RT Humerus NA

LACMHC

93688 134.46 53.5 18.01 15.78 RT Humerus NA

LACMHC

93651 125.3 53 17.96 15.56 RT Humerus NA

LACMHC

93673 144.13 56 18.83 16.89 RT Humerus NA

LACMHC

93696 120.76 50 16.34 15.25 RT Humerus NA

LACMHC

93702 106.78 46.5 15.18 13.99 RT Humerus NA

LACMHC

93652 127.62 53 16.79 17.07 RT Humerus NA

LACMHC

93674 149.67 58 18.91 16.9 RT Humerus NA

LACMHC

93653 143.46 56 18.55 15.64 RT Humerus NA

LACMHC

93690 128.63 57.5 19.52 17.06 RT Humerus NA

LACMHC

93675 146.97 63.5 20.74 18.73 RT Humerus NA

LACMHC

93691 131.12 52 16.91 15.21 RT Humerus NA

LACMHC

93676 136.69 53 17.82 16.81 RT Humerus NA

LACMHC

93654 132.03 56 19.57 16.71 RT Humerus NA

LACMHC

93655 131.96 53 17.85 15.82 RT Humerus NA

LACMHC

93677 139.56 54.5 18.9 16.08 RT Humerus NA

LACMHC

93692 126.18 52.5 18.08 16.38 RT Humerus NA

LACMHC

93693 121.74 51.5 17.01 14.94 RT Humerus NA

LACMHC

93656 123.65 52 16.67 15.84 RT Humerus NA

LACMHC

93678 145.95 58 18.4 16.83 RT Humerus NA

LACMHC

93657 132.65 49 16.49 15 RT Humerus NA

LACMHC

93679 127.84 56 19.53 17.57 RT Humerus NA

LACMHC

93680 141.62 56.5 19.33 16.43 RT Humerus NA

94

LACMHC

93658 125.84 52 17.64 15.56 RT Humerus NA

LACMHC

93659 127.04 49 16.97 14.94 RT Humerus NA

LACMHC

93681 150.58 54 18.33 15.46 RT Humerus NA

LACMHC

93694 120.53 53.5 17.06 16.16 RT Humerus NA

LACMHC

93660 157.1 65 21.9 18.8 RT Humerus NA

LACMHC

93733 105.93 46.5 15.11 14.12 RT Humerus NA

LACMHC

93732 112.59 47 16.03 14.44 RT Humerus NA

LACMHC

93731 112.21 53.4 17.11 16.04 RT Humerus NA

LACMHC

93730 113.5 50 16.18 14.84 RT Humerus NA

LACMHC

93699 118.62 56 17.86 15.66 RT Humerus NA

LACMHC

93728 112.51 48 15.81 13.76 RT Humerus NA

LACMHC

94455 152.8 56.5 19.78 16.72 RT Humerus NA

LACMHC

93729 113.3 48 15.08 14.56 RT Humerus NA

LACMHC

93706 120.72 52 16.71 16.24 RT Humerus NA

LACMHC

93723 88.63 44 14.1 15.49 RT Humerus NA

I-6201 158.3 64 22.62 18.23 RT Humerus 91

I-6200 177.07 68 24.6 19.42 RT Humerus 91

I-6186 174.98 65 22.93 19.75 RT Humerus NA

LACMHC

10718 123.49 53 18.2 15.69 RT Humerus NA

LACMHC

10716 172.38 60.5 20.41 18.1 RT Humerus NA

LACMHC

10717 149.48 61 21 17.31 RT Humerus NA

I-6197 188.24 69 23.39 20.1 RT Humerus NA

I-6194 157.81 63 22.09 17.73 RT Humerus NA

I-6193 179.22 68 23.89 18.78 RT Humerus NA

LACMHC

10712 176.24 69 24.24 19.47 RT Humerus NA

LACMHC

10762 168.17 61 21.11 17.65 RT Humerus NA

I-6189 185.55 67 23.85 18.99 RT Humerus NA

LACMHC

10703 165.28 68 23.66 18.33 RT Humerus NA

LACMHC

10285 178.65 67 23.84 19.35 LT Humerus NA

95

LACMHC

10700 176.61 68 24.78 18.5 RT Humerus NA

I-6188 161.08 57 19.47 15.8 RT Humerus NA

LACMHC

10701 173.17 64 23.79 17.45 RT Humerus NA

LACMHC

10710 171.8 67.5 23.6 19.43 RT Humerus NA

LACMHC

10702 189.12 70.5 25.02 19.56 RT Humerus NA

LACMHC

10704 166.26 64 23.35 18.2 RT Humerus NA

LACMHC

10711 177.91 67 24.88 19.49 RT Humerus NA

I-6765 173.78 65 22.66 20.35 LT Humerus NA

I-6760 173.41 71 23.67 20.79 LT Humerus NA

I-6763 163.22 65 24.18 18.5 LT Humerus NA

I-6758 160.69 64 22.95 18.9 LT Humerus NA

LACMHC

10390 169.5 63 21.5 18.46 LT Humerus NA

I-6762 155.8 67 22.34 18.8 LT Humerus NA

I-6759 176.68 62 22.38 17.44 LT Humerus NA

I-6769 163.37 62 21.36 17.5 LT Humerus NA

I-6755 167.38 64.5 22.19 18.83 LT Humerus NA

I-6770 171.97 65 23.71 18.37 LT Humerus NA

I-6756 170.26 73 25.06 21.17 LT Humerus NA

LACMHC

10386 171.34 61 19.63 18.2 LT Humerus NA

LACMHC

10387 149.4 63 21.52 17.16 LT Humerus NA

LACMHC

10388 120.85 49 15.57 14.26 LT Humerus NA

LACMHC

10709 164.15 64 22.5 18.17 RT Humerus NA

LACMHC

10706 164.34 67 23.28 18.31 RT Humerus NA

I-6192 164.31 64 22 18.76 RT Humerus NA

I-6191 159.05 63 22.11 18.73 RT Humerus NA

LACMHC

10705 163.33 63 22.45 18.14 RT Humerus NA

LACMHC

10713 171.78 69 24.92 19.38 RT Humerus NA

LACMHC

10714 174.73 65 22.12 19.31 RT Humerus NA

LACMHC

10708 165.1 69 23.25 19 RT Humerus NA

LACMHC

10707 161.24 63 21.12 18.26 RT Humerus NA

I-6195 163.46 66 23.32 18.17 RT Humerus NA

I-6187 167.4 64 22.92 18.24 RT Humerus NA

LACMHC

10283 172.24 71.5 22.44 19.38 LT Humerus NA

96

I-6757 153.18 67 21.97 18.04 LT Humerus NA

LACMHC

10282 168.37 67 22.56 18.72 LT Humerus NA

LACMHC

10287 167.25 65 22.37 18.51 LT Humerus NA

LACMHC

10286 177.57 66 23.07 18.2 LT Humerus NA

I-6764 170.74 66 24.2 17.56 LT Humerus NA

LACMHC

10279 163.2 68 23.59 19.61 LT Humerus NA

LACMHC

10278 174.06 66 22.83 19.56 LT Humerus NA

I-6761 159.29 68 22.61 18.74 LT Humerus NA

I-6767 170.32 68 23.33 18.97 LT Humerus NA

I-6768 174.11 70.5 25.24 20.15 LT Humerus NA

LACMHC

10280 172.37 65.5 22.78 19.2 LT Humerus NA

LACMHC

10284 169.68 68 24.57 19.75 LT Humerus NA

LACMHC

10281 175.79 71.5 25.32 20 LT Humerus NA

Table B.6. Collected radial data from Canis dirus.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

LACMHC

98089 120 41 14.4 10.16 LT Radius NA

LACMHC

98072 130 41 14.79 9.45 LT Radius NA

LACMHC

98071 131 42 15.25 10.42 LT Radius NA

LACMHC

98074 120 43 15.58 10.95 LT Radius NA

LACMHC

98073 129 41 14.38 9.91 LT Radius NA

LACMHC

98056 146 49 17.66 11.45 LT Radius NA

LACMHC

98057 138 48 17.87 11.7 LT Radius NA

LACMHC

98070 128 43 15.16 9.58 LT Radius NA

LACMHC

98034 125 47 16.93 11.17 LT Radius NA

LACMHC

98055 140 47 16.65 11.08 LT Radius NA

LACMHC

98022 146 51 18.81 11.94 LT Radius NA

97

LACMHC

98020 146 45 16.36 10.6 LT Radius NA

LACMHC

98021 144 45 16.66 11.32 LT Radius NA

LACMHC

98054 138 47 17.43 12.1 LT Radius NA

LACMHC

98068 130 47 17.78 11.69 LT Radius NA

LACMHC

98032 128 46 16.19 10.78 LT Radius NA

LACMHC

98053 150 46 16.08 11.94 LT Radius NA

LACMHC

98067 134 44 16.13 10.14 LT Radius NA

LACMHC

98019 137 44 15.2 11.33 LT Radius NA

LACMHC

98069 138 47 16.73 11.29 LT Radius NA

LACMHC

98052 153 46 16.48 11.71 LT Radius NA

LACMHC

98018 148 44 16.07 10.36 LT Radius NA

LACMHC

98017 142 42 14.89 10.21 LT Radius NA

LACMHC

98087 116 42 15.3 10.08 LT Radius NA

LACMHC

98077 126 45 16.23 11.66 LT Radius NA

LACMHC

98066 133 43 15.53 10.79 LT Radius NA

LACMHC

98051 153 46 16.77 11.18 LT Radius NA

LACMHC

98065 141 47 16.42 11.44 LT Radius NA

LACMHC

98085 121 42 15.73 9.3 LT Radius NA

LACMHC

98086 120 43 15.84 10.18 LT Radius NA

LACMHC

98064 140 45 16.38 11.47 LT Radius NA

LACMHC

98084 123 40 13.97 9.59 LT Radius NA

LACMHC

98062 140 41 14.79 9.5 LT Radius NA

LACMHC

98063 132 48 17.73 11.15 LT Radius NA

LACMHC

98049 141 45 16.19 10.52 LT Radius NA

LACMHC

98082 128 45 15.94 10.97 LT Radius NA

98

LACMHC

98028 143 48 17.72 12.06 LT Radius NA

LACMHC

98061 132 49 17.05 10.86 LT Radius NA

LACMHC

98048 145 44 16.41 9.83 LT Radius NA

LACMHC

98047 143 43 15.67 10.02 LT Radius NA

LACMHC

98027 145 45 16.89 11.02 LT Radius NA

LACMHC

98010 147 42 15.47 9.19 LT Radius NA

LACMHC

98081 118 45 16.56 10.24 LT Radius NA

LACMHC

98060 129 40 15.47 10.28 LT Radius NA

LACMHC

98011 150 48 17.02 11.19 LT Radius NA

LACMHC

98012 141 50 17.87 12.64 LT Radius NA

LACMHC

98009 146 46 16.25 10.82 LT Radius NA

LACMHC

98059 137 44 15.61 10.32 LT Radius NA

LACMHC

98046 143 46 17.26 12.05 LT Radius NA

LACMHC

98026 134 43 15.36 10.6 LT Radius NA

LACMHC

98080 122 48 16.97 11.73 LT Radius NA

LACMHC

98058 132 45 15.82 11.18 LT Radius NA

LACMHC

98045 141 49 18.29 12.08 LT Radius NA

LACMHC

98008 151 46 16.68 11.75 LT Radius NA

LACMHC

98044 150 41 14.9 8.91 LT Radius NA

LACMHC

98007 142 46 16.69 11.97 LT Radius NA

LACMHC

98025 131 43 16.16 9.69 LT Radius NA

LACMHC

98006 148 48 17.92 11.32 LT Radius NA

LACMHC

98036 122 45 16.54 11.36 LT Radius NA

LACMHC

98000 148 48 17.49 12 LT Radius NA

LACMHC

98040 166 43 15.55 10.8 LT Radius NA

99

LACMHC

97998 148 50 18.38 12.69 LT Radius NA

LACMHC

97993 153 49 17.8 11.14 LT Radius NA

LACMHC

97999 141 47 17.88 11.47 LT Radius NA

LACMHC

98039 162 51 18.68 12.77 LT Radius NA

LACMHC

98001 155 47 17.64 11.25 LT Radius NA

LACMHC

97988 156 50 19.01 11.99 LT Radius NA

LACMHC

98079 123 43 15.96 10.31 LT Radius NA

LACMHC

98041 157 49 17.44 13.42 LT Radius NA

LACMHC

98035 126 45 16.36 11.23 LT Radius NA

LACMHC

98042 149 45 16.68 10.91 LT Radius NA

LACMHC

97991 145 47 17.62 10.98 LT Radius NA

LACMHC

97981 171 55 20.88 12.03 LT Radius NA

LACMHC

97982 167 52 19.46 12.2 LT Radius NA

LACMHC

97985 157 50 18.12 11.88 LT Radius NA

LACMHC

97992 148 45 16.95 10.98 LT Radius NA

LACMHC

97990 154 50 18.42 12.13 LT Radius NA

LACMHC

98023 144 48 17.25 11.96 LT Radius NA

LACMHC

97989 153 51 18.53 12.39 LT Radius NA

LACMHC

97974 173 53 19.38 13.12 LT Radius NA

LACMHC

98165 197 58 20.59 14.81 LT Radius NA

LACMHC

98168 180 55 18.94 14.36 LT Radius NA

LACMHC

98166 182 54 19.25 13.92 LT Radius NA

LACMHC

97975 165 53 19.07 12.84 LT Radius NA

LACMHC

97971 173 48 17.63 12.29 LT Radius NA

LACMHC

97973 161 52 19.57 11.85 LT Radius NA

100

LACMHC

97970 165 54 19.55 13.26 LT Radius NA

LACMHC

97968 159 53 18.88 13.45 LT Radius NA

LACMHC

97967 168 52 19.74 12.49 LT Radius NA

LACMHC

97969 169 53 18.7 12.48 LT Radius NA

I-9157 188 53 19.93 11.95 LT Radius 3

I-9077 180 49 17.36 12.05 LT Radius 3

I-9124 211 59 22.5 13.96 LT Radius 3

I-9209 190 59 21.62 14.84 LT Radius 3

I-9184 200 48 17.67 11.88 LT Radius 3

I-8975 190 63 23.01 14.7 LT Radius 3

I-9102 174 49 17.99 11.98 LT Radius 3

I-9094 179 53 19.33 12.29 LT Radius 3

I-9007 182 53 18.59 13.79 LT Radius 3

I-9185 180 52 18.61 13.69 LT Radius 3

I-9162 188 59 20.89 14.83 LT Radius 3

I-9120 170 48 16.38 10.86 LT Radius 3

I-9010 186 54 19.1 12.5 LT Radius 3

I-9182 179 52 18.31 12.13 LT Radius 3

I-9160 163 46 16.08 10.96 LT Radius 3

I-9035 180 51 17.21 12.35 LT Radius 3

I-9147 181 52 18.83 12.39 LT Radius 3

LACMHC

10851 176 56 19.6 13.46 LT Radius 3

I-9104 176 49 17.68 11.12 LT Radius 3

I-9187 173 53 17.93 12.94 LT Radius 3

I-8347 181 50 17.72 12.38 RT Radius 3

I-8364 175 52 18.24 13.56 RT Radius 3

I-8231 189 54 20.41 13.64 RT Radius 3

I-8243 179 55 19.4 14.46 RT Radius 3

I-8236 180 55 20.28 13.63 RT Radius 3

I-9265 176 52 18.74 12.8 RT Radius 3

I-8344 180 53 19.07 14.57 RT Radius 3

I-8322 176 54 18.97 13.43 RT Radius 3

I-8392 188 58 20.88 14.7 RT Radius 3

I-8196 170 49 16.94 12.54 RT Radius 3

Table B.7. Collected femoral data from Canis dirus.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

LACMHC

87791 195.2 56.5 19.08 18.38 LT Femur NA

LACMHC

87782 197.91 62.9 19.79 20.05 LT Femur NA

101

LACMHC

87773 194.29 60.94 20.36 18.97 LT Femur NA

LACMHC

87780 186.29 56.16 17.83 17.29 LT Femur NA

LACMHC

87781 192.04 53.32 16.71 16.79 LT Femur NA

LACMHC

87783 195.78 59 18.83 17.5 LT Femur NA

LACMHC

87760 206.56 63.7 20.21 19.66 LT Femur NA

LACMHC

87765 198.72 62.02 19.59 19.21 LT Femur NA

LACMHC

87764 206.01 64.2 20.33 20.29 LT Femur NA

LACMHC

87763 201.14 55.6 18 17.72 LT Femur NA

LACMHC

87762 201 59.04 18.57 18.53 LT Femur NA

LACMHC

87761 201.61 67.71 22.31 21.59 LT Femur NA

LACMHC

87770 195.98 61.19 18.53 20.5 LT Femur NA

H-421 197.74 65 20.2 20.04 RT Femur 61

H-318 195.33 63.17 19.26 19.14 RT Femur 61

H-242 201.5 60.31 19.11 18.88 RT Femur 61

H-495 187.55 65.14 19.01 21.75 RT Femur 61

H-367 199.64 63.25 19.94 20.8 RT Femur 61

H-319 201.59 67.46 20.25 20.88 RT Femur 61

H-499 195.68 62.4 19.58 20.55 RT Femur 61

LACMHC

88550 143.22 50 15.04 15.02 RT Femur NA

LACMHC

88563 136.23 49 15.8 16.22 RT Femur NA

LACMHC

88565 158.24 50 16.74 15.23 RT Femur NA

LACMHC

94594 158.63 50 15.81 16.29 RT Femur NA

LACMHC

88577 140.81 45 14.32 14.26 RT Femur NA

LACMHC

88575 142.06 48 15.46 15.18 RT Femur NA

LACMHC

94588 158.07 48.5 15.87 17.17 RT Femur NA

LACMHC

88539 147.43 47 15.84 14.86 RT Femur NA

LACMHC

88524 164.7 51 16.41 17.04 RT Femur NA

LACMHC

88566 142.62 48 15.44 16.3 RT Femur NA

LACMHC

88585 128.83 45 14.25 14.7 RT Femur NA

102

LACMHC

88544 160.35 53.5 17.57 17.65 RT Femur NA

LACMHC

88546 141.93 50.5 16.4 16.6 RT Femur NA

LACMHC

88574 142.99 49 15.81 16.68 RT Femur NA

LACMHC

88551 151.38 48 15.49 16.11 RT Femur NA

LACMHC

88552 149.2 51 16.57 16.4 RT Femur NA

LACMHC

88559 150.51 55 18.18 17.29 RT Femur NA

LACMHC

88538 160.47 50 16.2 15.74 RT Femur NA

LACMHC

88543 158.22 53.5 17.27 17.31 RT Femur NA

LACMHC

94596 152.43 47 15.49 15.49 RT Femur NA

LACMHC

88545 155.06 50 16.45 16.4 RT Femur NA

LACMHC

88536 165.83 56 17.79 18.52 RT Femur NA

LACMHC

88533 173 55 18.37 18.77 RT Femur NA

LACMHC

88534 159.31 55 17.91 17.88 RT Femur NA

LACMHC

88586 129.86 42.5 13.09 14.28 RT Femur NA

LACMHC

88548 159.32 50.5 16.24 17.38 RT Femur NA

LACMHC

88555 139.83 49.5 16.12 16.47 RT Femur NA

LACMHC

94589 159.04 50.5 16.14 15.74 RT Femur NA

LACMHC

94587 175.2 50 16.33 15.94 RT Femur NA

LACMHC

88541 160.42 49.5 16.27 16.28 RT Femur NA

LACMHC

88583 123.51 48 15.04 15.59 RT Femur NA

LACMHC

88589 114.62 44 13.92 14.18 RT Femur NA

LACMHC

88580 136.22 46 14.34 14.98 RT Femur NA

LACMHC

88588 115.66 38 12.09 12.55 RT Femur NA

LACMHC

88556 157.3 46 14.67 14.83 RT Femur NA

LACMHC

88547 146.37 52 16.8 15.91 RT Femur NA

103

LACMHC

94595 155.1 49 15.88 14.49 RT Femur NA

LACMHC

88532 163.6 54 17.27 15.97 RT Femur NA

LACMHC

94593 156.16 47 15.21 14.77 RT Femur NA

LACMHC

88558 148.52 50 15.37 15.47 RT Femur NA

LACMHC

88557 145.18 48 15.39 15.15 RT Femur NA

LACMHC

94598 150.41 48 15 15.02 RT Femur NA

LACMHC

88561 141.65 52 16.27 16.29 RT Femur NA

LACMHC

88582 132.89 47 14.75 14.25 RT Femur NA

LACMHC

88570 140.11 51.5 16.22 16.25 RT Femur NA

LACMHC

88517 158.99 55 17.81 16.71 RT Femur NA

LACMHC

88508 165.41 52 16.62 16.38 RT Femur NA

LACMHC

88496 174.32 52 16.96 16.25 RT Femur NA

LACMHC

88497 174.82 54 17.64 15.84 RT Femur NA

LACMHC

88500 168.38 52 17.04 16.23 RT Femur NA

LACMHC

88499 161.44 53 16.42 16.21 RT Femur NA

LACMHC

88495 180.72 55 17.71 17.29 RT Femur NA

LACMHC

88468 181.16 60 19.69 18.01 RT Femur NA

LACMHC

88453 170.71 51 16.84 15.68 RT Femur NA

LACMHC

88454 176.7 53 17.14 16.37 RT Femur NA

LACMHC

88486 166.37 53 17.53 16.68 RT Femur NA

LACMHC

88494 183.66 59 18.82 18.58 RT Femur NA

LACMHC

88493 190.79 63 20.48 19.82 RT Femur NA

LACMHC

88492 194.47 61 18.95 19.7 RT Femur NA

LACMHC

88487 179.4 54 17.92 16.18 RT Femur NA

LACMHC

88490 178.75 52 17.24 16.33 RT Femur NA

H-559 204 66 20.69 19.97 RT Femur NA

104

H-493 202 69 19.82 22.06 RT Femur NA

H-427 201 62 19.53 19.19 RT Femur NA

LACMHC

12742 207 66 20.79 20.03 RT Femur NA

LACMHC

12743 207 69 20.49 21.63 RT Femur NA

LACMHC

12752 204 62 17.5 18.99 RT Femur NA

H-490 190 63 19.17 18.79 RT Femur NA

LACMHC

12751 203 65 20.01 19.65 RT Femur NA

LACMHC

12746 208 67 20.99 19.64 RT Femur NA

H-558 208 64 19.86 19.26 RT Femur NA

H-893 182 62 17.73 19.99 LT Femur 61

H-637 184 67 20.16 22.19 LT Femur 61

H-642 195 67 20.09 21.61 LT Femur 61

H-874 205 69 21.6 21.18 LT Femur 61

H-685 198 60 17.83 17.87 LT Femur 61

H-711 200 64 19.71 19.16 LT Femur 61

H-892 187 61 18.86 19.37 LT Femur 61

H-591 199 69 22.48 21.16 LT Femur 61

H-853 188 63 18.67 19.26 LT Femur 61

H-759 211 72 21.89 21.62 LT Femur 61

LACMHC

12756 138 49 14.69 14.86 RT Femur NA

LACMHC

12755 167 52 16.53 15.43 RT Femur NA

LACMHC

12754 180 57 17.37 17.41 RT Femur NA

LACMHC

12753 203 62 17.92 18.69 RT Femur NA

LACMHC

87784 196 61 18.73 18.23 LT Femur NA

LACMHC

87795 190 60 17.03 18.59 LT Femur NA

LACMHC

87790 192 62 18.16 18.29 LT Femur NA

LACMHC

87778 204 62 18.03 19.02 LT Femur NA

LACMHC

87772 201 63 18.72 18.8 LT Femur NA

LACMHC

87786 201 66 19.93 19.35 LT Femur NA

LACMHC

87792 203 68 20.76 20.78 LT Femur NA

LACMHC

87785 203 61 18.61 18.26 LT Femur NA

LACMHC

87787 210 64 19.38 19.57 LT Femur NA

105

LACMHC

87777 214 64 20.41 19.57 LT Femur NA

LACMHC

87789 199 63 19.41 19.16 LT Femur NA

LACMHC

87788 194 59 18.14 17.86 LT Femur NA

LACMHC

87776 199 62 18.45 18.95 LT Femur NA

LACMHC

87775 210 62 19.13 19.06 LT Femur NA

LACMHC

87766 208 62 19.06 18.5 LT Femur NA

LACMHC

87767 191 60 18.39 18.14 LT Femur NA

LACMHC

87768 199 64 19.63 19.13 LT Femur NA

LACMHC

87769 209 70 20.23 20.65 LT Femur NA

Table B.8. Collected tibial data from Canis dirus.

Loc #

Shaft

Length

(mm)

Shaft

Circumference

(mm)

Midshaft

Width Ft/Bk

(mm)

Midshaft

Width Side

(mm)

Side Element Pit

H-1195 192 66 20.76 20.02 RT Tibia NA

LACMHC

13768 100 44 12.72 13.61 RT Tibia 4

LACMHC

13761 102 46 12.94 13.83 RT Tibia 4

LACMHC

13765 138 55 16.37 17.12 RT Tibia 4

LACMHC

13763 153 58 17.02 17.66 RT Tibia 4

H-1297 202 60 17.96 19 RT Tibia

(Ad) 4

H-1343 210 70 20.73 22.29 RT Tibia

(Ad) 4

H-1336 194 58 16.69 19.32 RT Tibia 4

H-1298 193 57 17.05 18.11 RT Tibia 4

H-1318 193 60 18.32 18.61 RT Tibia 4

H-1346 203 62 17.81 19.6 RT Tibia

(Ad) 4

H-1264 205 63 19.81 20.21 RT Tibia

(Ad) 4

H-1275 206 62 18.61 19.43 RT Tibia

(Ad) 4

H-1307 201 63 20.1 19.85 RT Tibia

(Ad) 4

H-1273 195 67 20.54 20.67 RT Tibia

(Ad) 4

106

H-1306 207 62 17.1 19.3 RT Tibia

(Ad) 4

H-1312 206 64 20.72 20.19 RT Tibia

(Ad) 4

H-1968 195 55 16.5 17.59 LT Tibia

(Ad) 13

H-1981 195 59 18.86 18.58 LT Tibia

(Ad) 13

H-1935 196 63 18.31 20.28 LT Tibia

(Ad) 13

H-1953 195 60 17.66 19.29 LT Tibia

(Ad) 13

H-1940 198 60 18.17 18.34 LT Tibia

(Ad) 13

H-1219 202 59 19.18 17.53 LT Tibia

(Ad) 13

H-1227 195 62 19.4 20.48 LT Tibia

(Ad) 13

H-1931 200 62 18.17 20.13 LT Tibia

(Ad) 13

H-1996 208 65 19.35 19.98 LT Tibia

(Ad) 13

H-2006 186 54 15.56 16.84 LT Tibia 13

H-1961 167 56 18.19 17.01 LT Tibia 13

H-1977 179 56 16.45 17.88 LT Tibia 13

LACMHC

91450 152 50 14.74 15.87 LT Tibia NA

LACMHC

91453 135 46 14.32 14.4 LT Tibia NA

LACMHC

91466 130 48 14.85 15.17 LT Tibia NA

LACMHC

91457 139 49 14.25 15.42 LT Tibia NA

LACMHC

91454 138 50 15.18 15.8 LT Tibia NA

LACMHC

91451 152 51 15.46 16.01 LT Tibia NA

LACMHC

91458 138 48 13.94 14.37 LT Tibia NA

LACMHC

91476 134 51 15.33 16.73 LT Tibia NA

LACMHC

91439 147 54 15.92 17.01 LT Tibia NA

LACMHC

91849 174 52 17.35 17.49 LT Tibia NA

LACMHC

91440 154 48 14.36 14.9 LT Tibia NA

LACMHC

91455 143 50 15.21 16.19 LT Tibia NA

LACMHC

91465 136 47 14.01 14.5 LT Tibia NA

107

LACMHC

91437 143 53 15.76 17.01 LT Tibia NA

LACMHC

91464 141 50 15.18 15.85 LT Tibia NA

LACMHC

91463 132 51 15.39 16.7 LT Tibia NA

LACMHC

91459 138 54 16.25 17.1 LT Tibia NA

LACMHC

91462 128 48 14.42 15.05 LT Tibia NA

LACMHC

91456 145 48 13.49 15.78 LT Tibia NA

LACMHC

91461 136 46 13.95 14.42 LT Tibia NA

LACMHC

91438 145 50 15.47 16.27 LT Tibia NA

LACMHC

91436 140 55 15.54 16.83 LT Tibia NA

LACMHC

91455 144 50 14.91 15.74 LT Tibia NA

LACMHC

91435 146 45 13.81 14.41 LT Tibia NA

LACMHC

91429 148 52 15.05 16.39 LT Tibia NA

LACMHC

91426 154 54 15.67 16.9 LT Tibia NA

LACMHC

91449 145 53 16.27 17.15 LT Tibia NA

LACMHC

91431 151 56 16.83 17.43 LT Tibia NA

LACMHC

91430 155 50 14.71 15.84 LT Tibia NA

LACMHC

91428 154 54 16.28 17.17 LT Tibia NA

LACMHC

91432 148 55 16.49 16.8 LT Tibia NA

LACMHC

91413 165 50 15.5 16.2 LT Tibia NA

LACMHC

91412 160 49 14.25 15.17 LT Tibia NA

LACMHC

91427 157 53 15.25 16.66 LT Tibia NA

LACMHC

91411 164 55 16.15 17.52 LT Tibia NA

LACMHC

91448 142 50 15.34 16.55 LT Tibia NA

LACMHC

91447 142 49 14.89 14.71 LT Tibia NA

LACMHC

91410 155 53 16.16 16.71 LT Tibia NA

108

LACMHC

91467 122 45 13.62 14.56 LT Tibia NA

LACMHC

91468 118 45 13.44 15.32 LT Tibia NA

LACMHC

91445 140 53 15.48 16.72 LT Tibia NA

LACMHC

91423 155 54 16.41 16.5 LT Tibia NA

LACMHC

91409 160 56 17.23 17.49 LT Tibia NA

LACMHC

91460 140 48 15.36 14.95 LT Tibia NA

LACMHC

91446 134 53 16.62 17.09 LT Tibia NA

LACMHC

91425 162 52 15.39 15.95 LT Tibia NA

LACMHC

91422 160 57 16.28 18.45 LT Tibia NA

LACMHC

91452 149 51 15.23 16.89 LT Tibia NA

LACMHC

91421 161 55 16.41 17.18 LT Tibia NA

LACMHC

91406 157 55 16.81 17.69 LT Tibia NA

LACMHC

91407 156 53 16.04 16.94 LT Tibia NA

LACMHC

91405 173 57 16.61 18.16 LT Tibia NA

LACMHC

91424 153 55 16.45 17.71 LT Tibia NA

LACMHC

91443 136 54 16.29 17.18 LT Tibia NA

LACMHC

91404 169 52 15.62 16.8 LT Tibia NA

LACMHC

91419 154 53 16.28 17.44 LT Tibia NA

LACMHC

91416 155 59 18.39 19.61 LT Tibia NA

LACMHC

91420 150 49 14.85 15.49 LT Tibia NA

LACMHC

91403 161 55 17.14 17.01 LT Tibia NA

LACMHC

91402 161 54 16.21 16.75 LT Tibia NA

LACMHC

91401 164 50 14.76 15.62 LT Tibia NA

LACMHC

91444 142 51 15.92 16.22 LT Tibia NA

LACMHC

91399 160 51 14.87 16.25 LT Tibia NA

109

LACMHC

91442 135 50 15.17 16.46 LT Tibia NA

LACMHC

91418 161 48 14.47 15.52 LT Tibia NA

LACMHC

91398 165 52 15.83 15.95 LT Tibia NA

LACMHC

91417 157 54 16.03 17.49 LT Tibia NA

LACMHC

91415 158 50 14.89 15.49 LT Tibia NA

LACMHC

91441 152 49 14.04 14.81 LT Tibia NA

LACMHC

91414 157 53 16.53 16.82 LT Tibia NA

LACMHC

91397 161 55 17.28 17.63 LT Tibia NA

LACMHC

91396 150 53 15.55 16.69 LT Tibia NA

LACMHC

91395 165 50 14.96 16.3 LT Tibia NA

LACMHC

91394 173 51 15.46 16.47 LT Tibia NA

LACMHC

91391 130 39 11.69 12.44 LT Tibia NA

LACMHC

91390 127 45 13.49 14.14 LT Tibia NA

LACMHC

91381 146 47 14.46 14.93 LT Tibia NA

LACMHC

91382 158 54 15.68 17.66 LT Tibia NA

LACMHC

91383 162 54 16.28 17.28 LT Tibia NA

LACMHC

91384 156 53 16.06 16.85 LT Tibia NA

LACMHC

91374 174 57 17.71 18.14 LT Tibia NA

LACMHC

91365 170 57 17.73 17.79 LT Tibia NA

LACMHC

91344 179 56 17.29 17.88 LT Tibia NA

LACMHC

91347 180 58 17.83 18.79 LT Tibia NA

LACMHC

91352 187 59 18.26 19.14 LT Tibia NA

LACMHC

91354 182 58 16.86 18.26 LT Tibia NA

LACMHC

91346 189 58 17.81 19.45 LT Tibia NA

LACMHC

91345 185 56 16.71 17.94 LT Tibia NA

110

LACMHC

91338 179 56 16.79 17.96 LT Tibia NA

LACMHC

91302 200 58 17.24 19.27 LT Tibia NA

LACMHC

91330 207 61 18.17 19.69 LT Tibia NA

Table B.9. Collected humeral data from Canis lupus.

Object ID Shaft Length (mm) Shaft Circumference (mm) Side Species Age

MN235 137 57 Lt C. lupus Sub-adult

137 57 Rt C. lupus


Rt C. lupus


144 59 Rt C. lupus


110 56 Rt C. lupus

MN614 Lt C. lupus 1 yr

153 63 Rt C. lupus

MN1031 Lt C. lupus Sub-adult

134 60 Rt C. lupus


149 65 Rt C. lupus


141 65 Rt C. lupus

MN695 135 60 Lt C. lupus 2 yrs

135 60 Rt C. lupus

MN2118 79 49 Lt C. lupus Pup

79 49 Rt C. lupus

MN612 Lt C. lupus Sub-adult

134 61 Rt C. lupus


76 50 Rt C. lupus

MN616 146 54 Lt C. lupus 1 yr

146 54 Rt C. lupus


156 65 Rt C. lupus

PED-047-1 162 56 Lt C. lupus Adult

Rt C. lupus

MN1066 125 46 Lt C. rufus Sub-adult

125 46 Rt C. rufus

111

Table B.10. Collected radial data from Canis lupus.



155 47 Rt C. lupus


Rt C. lupus


159 44 Rt C. lupus


135 47 Rt C. lupus

MN614 Lt C. lupus 1 yr

173 54 Rt C. lupus


170 51 Rt C. lupus


178 55 Rt C. lupus


168 54 Rt C. lupus


167 54 Rt C. lupus

MN2118 Lt C. lupus Pup

77 42 Rt C. lupus


163 51 Rt C. lupus


74 46 Rt C. lupus


174 45 Rt C. lupus


174 55 Rt C. lupus


Rt C. lupus


151 39 Rt C. rufus

Table B.11. Collected femoral data from Canis lupus.



150 56 Rt C. lupus


Rt C. lupus


162 51 Rt C. lupus


128 54 Rt C. lupus


112

164 63 Rt C. lupus


157 61 Rt C. lupus


168 65 Rt C. lupus


173 67 Rt C. lupus


158 60 Rt C. lupus


79 47 Rt C. lupus


156 63 Rt C. lupus


75 58 Rt C. lupus


146 55 Rt C. lupus


172 59 Rt C. lupus


Rt C. lupus


144 46 Rt C. rufus

Table B.12. Collected tibial data from Canis lupus.



140 51 Rt C. lupus


Rt C. lupus


162 50 Rt C. lupus


136 53 Rt C. lupus


175 60 Rt C. lupus


179 56 Rt C. lupus


183 62 Rt C. lupus


184 60 Rt C. lupus


167 58 Rt C. lupus


88 46 Rt C. lupus


164 58 Rt C. lupus

113


86 57 Rt C. lupus


179 52 Rt C. lupus


178 62 Rt C. lupus


Rt C. lupus


136 45 Rt C. rufus

114

APPENDIX C

Table C.1. Compiled results of regressions from Kilbourne and Makovicky (2012) of

appendicular skeleton long bone growth during ontogeny in C. latrans.

Element N X Y-intercept Slope Slope C.I. limits R2

Humerus 13 7.5 -1.183 1.72 (G) 1.601, 1.884 0.974

Radius - - - - - -

Femur 13 8.5 -0.7881 1.64 (G) 1.457, 2.087 0.949

Tibia 9 4.4 -1.883 1.98 (I) 0.567, 2.263 0.905

I denotes isometry (constant proportions during ontogeny) and G denotes positive

allometry (increasingly gracile long bones during ontogeny). X is defined as the size

range of ontogenetic samples calculated by dividing the length of the longest specimen

by the length of the shortest specimen.

115

APPENDIX D

A B

C D

Figure D.1: Interspecific comparisons of C. dirus (open, black circles) and C. lupus

(open, blue triangles) limb-bone SMA regressions from SMATR with plotted slope

95% confidence interval bands (gray shaded areas). (A) C. dirus humeral slope =

1.255; slope C.I. limits = 1.161, 1.352. C. lupus humeral slopes = 2.609; slope C.I.

limits = 2.021, 3.369. (B) C. dirus radial slope = 1.462; slope C.I. limits = 1.314,

1.628. C. lupus radial slope = 3.024; slope C.I. limits = 2.108, 4.338. (C) C. dirus

femoral slope = 1.151; slope C.I. limits = 1.068, 1.240. C. lupus femoral slope =

2.808; slope C.I. limits = 2.011, 3.922. (D) C. dirus tibial slope = 1.538; slope C.I.

limits = 1.389, 1.704. C. lupus tibial slope = 2.880; slope C.I. limits = 2.026, 4.095.

116

APPENDIX E

Figure E.1: SMA regression plots of C. latrans long bone growth showing

intraspecific allometric trends between methods. Measurements made with length and

circumference (open squares) vs. those calculated using an ellipse (solid squares) as a

proxy for long-bone cross-sectional area. (A) Humeri trends (slope = 1.576 vs. slope

= 1.407). (B) Radii trends (slope = 1.633 vs. slope = 1.314). (C) Femora trends

(slope = 1.423 vs. slope = 1.355). (D) Tibiae trends (slope = 1.779 vs. slope = 1.519).

A B

D C

117

Figure E.2: SMA regression plots of C. dirus long bone growth showing intraspecific

allometric trends between methods. Measurements made with length and

circumference (open circles) vs. those calculated using an ellipse (solid circles) as a

proxy for long-bone cross-sectional area. (A) Humeri trends (slope = 1.255 vs. slope

= 1.224). (B) Radii trends (slope = 1.462 vs. slope = 1.397). (C) Femora trends

(slope = 1.151 vs. slope = 1.302). (D) Tibiae trends (slope = 1.538 vs. slope = 1.482).

A B

C D

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Figure E.3: SMA regression plots of C. lupus long bone growth showing intraspecific

allometric trends between methods. Measurements made using only data from C.

lupus (larger open triangles) vs. those made including C. rufus (smaller solid

triangles). (A) Humeri trends (slope = 2.609 vs. slope = 2.138). (B) Radii trends

(slope = 3.024 vs. slope = 2.451). (C) Femora trends (slope = 2.808 vs. slope =

2.364). (D) Tibiae trends (slope = 2.880 vs. slope = 2.476).

A B

C D

ONTOGENETIC CHANGE IN DISTAL AND PROXIMAL LIMB BONES OF JUVENILE PLEISTOCENE COYOTES … ·...

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