"Coprolite"
means "dung stone", from the Greek kopros (dung) and lithos
(stone). Fossils occur in two forms: body fossils (bones,
shells, teeth), and Trace fossils (footprints, burrows, coprolites).
Studying the trace fossils helps us understand how animals behaved - what
they ate, how they digested it, where they deposited it.
Feces are preserved by being in caves, or
deposited outside which must be quickly covered by sediment under just the
right conditions to preserve it, as it is a soft material (not like
bones). Bacteria change the chemistry of feces, which help it absorb
minerals that changes it to colorful stone over millions of years as it
"lithifies".
How do
we know a rock is really poop?
1) Poop has more phosphorus than other rocks
2) it contains bits of bone, shell, wood or
leaves, sometimes more!
3) It has dung beetle tracks or burrows as
they worked through it
4) often the dinosaur skeletons are found
nearby, or it is a known formation where fossils are found
How do
you decide what critter the poop is from?
1) The age of the rock in which it is found
will limit which critter it could be
2) Are there fossil remains of creatures
nearby?
3) Size and shape of the coprolite
4) compare the appearance and size of the
coprolite to modern animals, if it is not extinct
Can
you give me some examples?
Example 1:
Coprolites were found in the Montana Badlands. They were full of
plant material from redwood trees such as pine cones. They had dung
beetle tracks & burrows in the specimens. The strata of
the rock in which they were found dated to 75 million years ago.
They were the size of basketballs. Maiasaura dinosaur fossils were
nearby, an herbivorous duckbilled dinosaur. Therefore, it was
concluded they were Maiasaura dinosaur coprolites.
Example 2: In
the 1990's, a man in Alberta, Canada found a two foot coprolite. It
tested positive for high amounts of phosphorus, it contained chopped bits
of organic matter. The rock strata dated it to 75 million years
old. The size of it: 2 feet long, meant it was from a large
animal. They also found chopped up bones in it, meaning it came from
a carnivore (meat eating) animal. Based on what was found in the
area, it is most likely the older smaller cousin of a T-Rex. The
surprise? The found FOSSILIZED MUSCLE CELLS in the coprolite from
undigested meat. What a find for these paleontologists!
Example 3: The
first coprolites identified. In the early 1820's, geologist William
Buckland found bones of ancient hyenas, elephants and hippo. He also
found white rocklike blobs about the size of a cherry. He went to
the zoo and examined the feces of living hyenas - it matched! The
shape, size and appearance were similar. Then he compared the
minerals found in the blobs with those found in fresh feces, with the help
of a fellow scientists, and he was correct! The minerals were
similar to those found in the coprolites.
Do
you have more information?
Find and read the
young people's book:
"Dino Dung",
by Dr. Karen Chin
or
go on Amazon and type in "coprolite" for other great books
to read!