SUNDAY, MARCH 28, 2010
Cervical vertebra
from a spinosaurus
maroccanus
Canadian
Museum of Nature
This is the fourth of a four-part series
on fossils. Collect all four pages and
make a giant poster.
more FOSSIL finds
Part four of four. Trim here and attach to page three of the Fossil series
Ediacara hills
Discovered in
1946, the fossils
found at Ediacara
(pronounced ediakra) Hills in South
Australia represent
one of the largest, Dickinsonia costata
Precambrian era,
best-preserved
Ediacara Hills, Australia.
Precambrian-era
sites. Ediacara
fauna are evidence of the earliest
multicelled animals on earth. About 30
species of soft-bodied marine creatures
have been found locked in the
sandstone of the Ediacara Hills. Many
resemble the modern jellyfish, but
Ediacaran organisms are unique, and
their place on the tree of life is unclear.
burgess Shale
Located in the
Canadian Rockies
of southeastern
British Columbia,
Burgess Shale is a
famous fossil site
and a term used to
describe the type of
fossils found there. Marella specimen
Discovered in 1909 Middle Cambrian era,
British Columbia, Canada
by the American
paleontologist
Charles Doolittle Walcott, the quarry
contains marine plant and animal
fossils that resemble lithographic
pictures on shale. More than 140
species are represented by fossils that
date to the middle Cambrian era. Some
are the ancestors of modern animals,
but others are long extinct and unlike
anything found in oceans today.
Hunsrück-schiefer
Three sites in Germany are wellknown for their
amazing fossils:
Bundenbach,
Wissenbach and
Gemünden. These
fossils are from
the Hunsrück
Shales of the
Mimetaster hexagonalis
lower and middle
Devonian eras. The and Ophiurina lymani
Devonian era,
Hunsrück-schiefer Bundenbach, Germany
fauna include sea
stars, trilobites, other arthropods and
cephalopods.
mazon creek
The area of Mazon Creek in
northeastern Illinois is famous for its
300-million-year-old fossils. These
Carboniferous-age fossils are important
because many have preserved both
hard and soft body parts. Breaking
open a rock near Mazon Creek often
reveals a wonderfully preserved fossil.
Mazon Creek flora consist of more than
400 plant species; its fauna consist of
more than 320 species.
ORTHOCERAS
Orthoceras Plate
Devonian era, Morocco
Orthoceras
Orthoceras was an ancient mollusk (an ancestor
of the modern-day squid) that lived more than 400
million years ago — from the early Ordovician eriod
up to the Triassic period, which covers about 300
million years. They were most prolific during the
Ordovician and Devonian periods.
The word “orthoceras” means “straight shell,”
referring to its long, slender shell.
Orthoceras ranged in size from less than a
centimeter to more than 14 feet long. These
predators swam by propelling themselves with
squirted jets of water. Over time, their shells
accumulated on the ocean floor and were covered
by sediment, eventually changing into stone fossils.
Orthoceras
(polished
single)
Devonian era,
Morocco
Orthoceras fossils are beautiful and common,
with a global distribution. They are often found in
marine rock, especially limestones.
SPINOSAURUS
Spinosaurus lived during the Cretaceous period,
about 100 million years ago. One of the largest
dinosaurs (bigger than T-Rex), spinosaurus had
a long thin snout and large spines along its back.
The spines were covered in a thin layer of skin
that formed a sort of sail. (This was not unusual
for dinosaurs of the time.) “Spinosaurus” means
“spiny lizard.”
The most complete skeleton
of spinosaurus was destroyed
during World War II.
Spinosaurus skull
Cretaceous era,
from a model exhibited at
Chiba, Japan
Spinosaurus
tooth
Canadian
Museum of
Nature
Spinosaurus fossils have been found in Egypt,
the Sahara desert of North Africa, Morocco and
South America.
These carnivores (meat eaters) may have been
scavengers, or they may have fed on fish. They
grew to be 40 to 56 feet (12 to 17 meters) long.
Similar to the crocodile, spinosaurus’ upper and
lower teeth interlocked — this led to speculation
that spinosaurs ate fish.
Spinosaurus
aegyptiacus
Stromatolites
Stromatolites are among the world’s oldest fossils,
some of which are more than 3.5 billion years old.
Many Pre-Cambrian-era fossil specimens have
been collected.
Stromatolites are layered structures formed by the
growth of various algae and cyanobacteria. Like
plants, they photosynthesize their food and for this
reason live only in saline, shallow water.
Stromatolites are prokaryotic (simple-celled)
organisms. Their populations began to decline
about 700 million years ago. This decline may have
been due to the evolution of grazing animals.
Living stromatolites are rare, existing in only a few
places – the most famous location is Shark Bay in
Western Australia.
Living
stromatolites
Shark Bay,
Australia
Growth zone
Older
layers
Stromatolites
Lower Proterozoic era,
Northern Michigan
Base
More than 20,000 species* of trilobites are known to
have lived in ancient seas around the world — some
crawled along the ocean floor, others swam or drifted
with the currents. Some species were herbivores (ate
plants), others were detrivores (ate decayed material),
and some were scavengers (ate carrion).
Most trilobites are about an inch long.
Cutting and polishing rough stromatolites
reveals their color and beauty.
Living
stromatolite
TRILOBITES
A favorite among paleontologists, trilobites were
marine arthropods that became extinct about 250
million years ago (before dinosaurs existed). These
hard-shelled creatures were a diverse group of fossils
that evolved during the Paleozoic era. They thrived
during the Cambrian period, so much so that it is
sometimes called “The Age of Trilobites.”
Gunflint Stromatolite
Pre-Cambrian era,
Ontario, Canada
Arctinurus boltoni,
Silurian era,
Middleport, N.Y.
Cephalon
(head)
Xystridura
trilobite
Middle Cambrian
era, Australia
Thorax
Pygidium
* New species are discovered all the time.
SOURCES: World Book Encyclopedia, World Book Inc.; A Guide to Fossils, Princeton Science Library (1996); A Guide to Rocks & Fossils, Fog City Press (2003).
Huntonia
lingulifer
(Dalmanitid
trilobite)
Lower Devonian era,
Oklahoma, U.S.A.
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