Post on 10-Jun-2020
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.
iv
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
length and circumference measurements. ............................................................. 46
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
length and circumference measurements from an ellipsoid. ................................. 46
Table 10. Results of regressions describing tibial growth during ontogeny in canids using
length and circumference measurements. ............................................................. 47
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
length and circumference measurements from an ellipsoid. ................................. 48
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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
width, measurements along the shaft of the bone. Red circles mark reference
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
Figure 26: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
femora. (A) Allometric slope plots with shaded 95% confidence interval bands. C.
latrans shows positive allometry (slope = 1.423); C. dirus (slope = 1.151). (B)
Residual plots; points fall roughly around (0, 0). (C) Quantile normality plots;
relatively normal distribution of points. ................................................................ 55
Figure 27: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
tibiae. (A) Allometric slope plots with shaded 95% confidence interval bands. C.
latrans shows positive allometry (slope = 1.779); C. dirus (slope = 1.538). (B)
Residual plots; points fall roughly around (0, 0). (C) Quantile normality plots;
relatively normal distribution of points. ................................................................ 56
Figure 28: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
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
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. ..................................... 58
xvii
Figure 30: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
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. ..................................... 59
Figure 31: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
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. ..................................... 60
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
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
xviii
normal distribution of points, but with large steps and gaps from an incomplete or
otherwise small sample size. ................................................................................. 63
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. ................................................................................. 64
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. ................................................................................. 65
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
Figure 39: 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
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
width, measurements along the shaft of the bone. Red circles mark reference
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,
measurements along the shaft of the bone. Red circles mark reference measurement
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
measurements along the shaft of the bone. Red circles mark reference measurement
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.
Taxon N Y-intercept Slope Slope C.I. limits
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
measurements from an ellipsoid.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes
that deviate from isometry are listed in bold.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny).
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
measurements from an ellipsoid.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes
that deviate from isometry are listed in bold.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny).
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
measurements from an ellipsoid.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes
that deviate from isometry are listed in bold.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny).
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
length and circumference measurements.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes
that deviate from isometry are listed in bold.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes
that deviate from isometry are listed in bold.
48
Table 11. Results of regressions describing growth during ontogeny between C. lupus and C. lupus + C. rufus femora using
length and circumference measurements.
Table 12. Results of regressions describing tibial growth during ontogeny between C. lupus and C. lupus + C. rufus using
length and circumference measurements.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes
that deviate from isometry are listed in bold.
Taxon N Y-intercept Slope Slope C.I. limits
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
G denotes positive allometry (increasing gracility of long bones during ontogeny). Species with unusually high slopes
that deviate from isometry are listed in bold.
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
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.
54
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 plots;
points fall roughly around (0, 0). (C) Quantile normality plots; relatively normal
distribution of points.
55
Figure 26: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
femora. (A) Allometric slope plots with shaded 95% confidence interval bands. C. latrans
shows positive allometry (slope = 1.423); C. dirus (slope = 1.151). (B) Residual plots;
points fall roughly around (0, 0). (C) Quantile normality plots; relatively normal
distribution of points.
56
Figure 27: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
tibiae. (A) Allometric slope plots with shaded 95% confidence interval bands. C. latrans
shows positive allometry (slope = 1.779); C. dirus (slope = 1.538). (B) Residual plots;
points fall roughly around (0, 0). (C) Quantile normality plots; relatively normal
distribution of points.
57
Figure 28: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
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
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 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
Figure 30: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
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
Figure 31: SMA regressions of C. latrans (open squares) and C. dirus (open circles)
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
Figure 39: 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 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).
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).
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
MN892 159 60 Lt C. lupus Sub-adult
Rt C. lupus
MN95 144 59 Lt C. lupus Sub-adult
144 59 Rt C. lupus
MN615 110 56 Lt C. lupus Sub-adult
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
MN632 149 65 Lt C. lupus Sub-adult
149 65 Rt C. lupus
MN2392 141 65 Lt C. lupus Sub-adult
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
MN493 76 50 Lt C. lupus Pup
76 50 Rt C. lupus
MN616 146 54 Lt C. lupus 1 yr
146 54 Rt C. lupus
MN1163 156 65 Lt C. lupus Sub-adult
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.
Object ID Shaft Length (mm) Shaft Circumference (mm) Side Species Age
MN235 155 47 Lt C. lupus Sub-adult
155 47 Rt C. lupus
MN892 165 48 Lt C. lupus Sub-adult
Rt C. lupus
MN95 159 44 Lt C. lupus Sub-adult
159 44 Rt C. lupus
MN615 135 47 Lt C. lupus Sub-adult
135 47 Rt C. lupus
MN614 Lt C. lupus 1 yr
173 54 Rt C. lupus
MN1031 170 51 Lt C. lupus Sub-adult
170 51 Rt C. lupus
MN632 178 55 Lt C. lupus Sub-adult
178 55 Rt C. lupus
MN2392 168 54 Lt C. lupus Sub-adult
168 54 Rt C. lupus
MN695 167 54 Lt C. lupus 2 yrs
167 54 Rt C. lupus
MN2118 Lt C. lupus Pup
77 42 Rt C. lupus
MN612 163 51 Lt C. lupus Sub-adult
163 51 Rt C. lupus
MN493 74 46 Lt C. lupus Pup
74 46 Rt C. lupus
MN616 174 45 Lt C. lupus 1 yr
174 45 Rt C. lupus
MN1163 174 55 Lt C. lupus Sub-adult
174 55 Rt C. lupus
PED-047-1 181 44 Lt C. lupus Adult
Rt C. lupus
MN1066 151 39 Lt C. rufus Sub-adult
151 39 Rt C. rufus
Table B.11. Collected femoral data from Canis lupus.
Object ID Shaft Length (mm) Shaft Circumference (mm) Side Species Age
MN235 150 56 Lt C. lupus Sub-adult
150 56 Rt C. lupus
MN892 161 60 Lt C. lupus Sub-adult
Rt C. lupus
MN95 162 51 Lt C. lupus Sub-adult
162 51 Rt C. lupus
MN615 128 54 Lt C. lupus Sub-adult
128 54 Rt C. lupus
MN614 164 63 Lt C. lupus 1 yr
112
164 63 Rt C. lupus
MN1031 157 61 Lt C. lupus Sub-adult
157 61 Rt C. lupus
MN632 168 65 Lt C. lupus Sub-adult
168 65 Rt C. lupus
MN2392 173 67 Lt C. lupus Sub-adult
173 67 Rt C. lupus
MN695 158 60 Lt C. lupus 2 yrs
158 60 Rt C. lupus
MN2118 79 47 Lt C. lupus Pup
79 47 Rt C. lupus
MN612 156 63 Lt C. lupus Sub-adult
156 63 Rt C. lupus
MN493 75 58 Lt C. lupus Pup
75 58 Rt C. lupus
MN616 146 55 Lt C. lupus 1 yr
146 55 Rt C. lupus
MN1163 172 59 Lt C. lupus Sub-adult
172 59 Rt C. lupus
PED-047-1 179 55 Lt C. lupus Adult
Rt C. lupus
MN1066 144 46 Lt C. rufus Sub-adult
144 46 Rt C. rufus
Table B.12. Collected tibial data from Canis lupus.
Object ID Shaft Length (mm) Shaft Circumference (mm) Side Species Age
MN235 140 51 Lt C. lupus Sub-adult
140 51 Rt C. lupus
MN892 172 55 Lt C. lupus Sub-adult
Rt C. lupus
MN95 162 50 Lt C. lupus Sub-adult
162 50 Rt C. lupus
MN615 136 53 Lt C. lupus Sub-adult
136 53 Rt C. lupus
MN614 175 60 Lt C. lupus 1 yr
175 60 Rt C. lupus
MN1031 179 56 Lt C. lupus Sub-adult
179 56 Rt C. lupus
MN632 183 62 Lt C. lupus Sub-adult
183 62 Rt C. lupus
MN2392 184 60 Lt C. lupus Sub-adult
184 60 Rt C. lupus
MN695 167 58 Lt C. lupus 2 yrs
167 58 Rt C. lupus
MN2118 88 46 Lt C. lupus Pup
88 46 Rt C. lupus
MN612 164 58 Lt C. lupus Sub-adult
164 58 Rt C. lupus
113
MN493 86 57 Lt C. lupus Pup
86 57 Rt C. lupus
MN616 179 52 Lt C. lupus 1 yr
179 52 Rt C. lupus
MN1163 178 62 Lt C. lupus Sub-adult
178 62 Rt C. lupus
PED-047-1 206 50 Lt C. lupus Adult
Rt C. lupus
MN1066 136 45 Lt C. rufus Sub-adult
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
118
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