By Scarlett Hunt

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Footprints Trackways

• By Scarlett Hunt

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For many years palaeontologists focused on
finding bones. The problem is that a dinosaur
has only one skeleton. The skeleton has a few
hundred bones and thats it some get washed
away, others get eaten some rot before they can
turn into fossils.
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But The same dinosaur can make hundreds of
thousands of footprints in its lifetime. So
palaeontologists have millions of possible
footprints out there waiting to be discovered.
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Just finding the footprint is not enough.
Palaeontologists try to figure out which type
of dinosaur made the footprints. Then they try
to find out extra information about the dinosaur
from examining its tracks.
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Here are some tips for identifying a dinosaur by
its footprints.
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• The size of the footprint is close to the
  size of the foot which made it. Some sauropod
  tracks are over a metre long and are as deep as
  bathtubs. One of the smallest theropod tracks
  ever found is from Nova Scotia.

www.ldeo.columbia.edu
www.ourworld.compuserve.com
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The shape of the footprint is similar to the
shape of the foot which made it.
Palaeontologsts will sometimes place pictures
of bones over top of a picture of the footprint
to help identify it.
REPRINT FROM DINOSAUR TRACKS by TONY THULBORN
Chapman Hall, 1990
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Number of toes (digits) helps palaeontologists
tell who the track maker was.
Scientists use Roman Numerals to count fingers
and toes. They are numbered from the inside to
the outside. For example your thumb would be I
and baby finger would be V.
Small Raptor Foot
Small Allosaurus Hand
Each finger or toe is also part of a phalangeal
formula for the hand or foot. A human hand is
2,3,3,3,3 because the thumb has 2 bones and
each other finger has 3. A theropod foot has the
formula 3,4,5.
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Sometimes not all the toes make a mark in the
footprint. Most two-legged (bipedal) dinosaurs
actually had 4 toes on each foot. One, called
the hallux, was small and held up in the air.
Hallux marks rarely show up in a footprint.
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The soft parts of an animals foot can change the
shape of a footrpint. For example, Robert Bakker
thinks that duckbilled hadrosaurs had plump paws
and would have a webbed footprint.
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Each kind of dinosaur had different shapes of
feet so they made different shapes of footprints.
Dinosaur tracks known from Broome, Western
Australia
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Footprints can tell us whether the animal
walked on 2 legs, 4 legs or switched back
forth
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Two-legged (bipedal) dinosaur trackways
contain similarly sized and shaped prints in
pairs. Each print switches from left to right.
They usually make very narrow trackways which
appear to be in a straight line.
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The feet of a four-legged (quadrupedal) animal
are different sizes and shapes. The front foot
is called the manus. The back foot is called the
pes. The pes (back) prints are larger and wider
in shape than the manus (front) prints. The front
print is usually slightly in front of the back
print on each side of the trackway.
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• By studying dinosaur footprints,
  palaeontologists now know that quadrupedal
  dinosaurs walked diagonally. Trackways show the
  front (manus) print slightly in front of the back
  (pes) print on each side of the trackway.

Animation of the foot order of a preserved
sauropod trackway. www.projectexploration.org/
jobaria/Rearing4.html
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• Quadrupeds tend to walk in a palm-first
  (plantigrade) manner.
• Their toes are usually blurry. Bipeds usually
  walk in a toe-first (digitgrade) manner. These
  tracks have easy-to-see toes.

• Chart taken from An Overview of Dinosaur
  Tracking by Glen Kuban

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Fossilized tracks can show skin texture, claws
and skin creases. The clearest footprints are
those made on slightly wet ground. The muddier
the ground was when the footprint was made, the
fuzzier the footprint is.
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• Palaeontologists examine patterns in footprint
  tracks. They try to figure out if the dinosaur
  was alone, with a group of the same kind of
  dinosaurs, or was being followed by someone else.

In Davenport Ranch in Texas, tracks of 24
apatosaurus are preserved in a group. The
largest prints are on the outside while the
smaller prints are in the middle of the group.
Robert Bakker thinks that the bulls or senior
cows may have guarded the young. From looking
at tracks, Martin Lockley believes that large
sauropods led their herds and walked in a
staggered (or spearhead) formation.
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Site in Eastern Utah NOTE A theropod track is
perpendicular to the sauropod trackway
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The figure below is taken from Fossil Footprints
of the Dinosaur Ridge Area. This new map of the
main Dinosaur Ridge tracksite was completed in
December 1994, by Dr. Martin Lockley of the
University of Colorado at Denver. The map shows
many more tracks (335) and trackways (at least
37) than on previous maps. Ornithopod (e.g.
Iguanodon) tracks are shown in blue theropod
(e.g. Coelurus) tracks are shown in red. Also
shown is a trackway orientation diagram for all
trackways and arrows marking the travel
directions of small- and large ornithopods. This
main tracksite marks where planned new
construction will upgrade viewing and teaching
facilties at the site, which is now surrounded by
a protective fence. This tracksite is located on
the east side of Dinosaur Ridge -- see the track
symbol on the area map
Dinosaur Ridge is geographically located west of
Denver, Colorado
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• R. McNeil Alexander discovered that dinosaur
  hip height equals 4 times the foot print length.
  He then figured out how to calculate a dinosaurs
  speed by measuring only its footprints.
• V 0.25(stride length)1.67(leg length)
• -1.17(gravitational constant)0.5

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According to Professor Paul Eric Olsen in his
lecture notes on www.ldeo.columbia.edu
On-line calculator for determining dinosaur
speeds on the University of Sheffield, England
webpage www.shef.ac.uk/es/DINOC01/
dinocal1.html
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By looking at footprints, palaeontologists can
tell a lot about the animal who made the tracks.
However, there will always be some guessing
because no one has ever found a footprint with a
dinosaurs foot bones still in it.
Thulborn, 1990
Image Stephen Gatesy, Brown University
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