Close your eyes.
Now imagine a dinosaur walking down the street of your neighborhood. The dinosaur towers above you,
its enormous head peeking over the roof of your house. A sudden shadow causes you to look up at
a flock of flying pterosaurs, blocking out the sun and casting long shadows down your street.
In the distance a mighty roar seems to vibrate the air. You are living in a world of dinosaurs.
Dinosaurs no longer walk the Earth, but their fossils buried underground continue to give us
a fascinating glimpse of their world. In today’s art and movies we can see seemingly real-life
dinosaurs, and yet all we have left of them are bones. How do paleontologists take scattered,
incomplete fossil remains found in the ground and reassemble them into complete skeletons?
When new species of dinosaurs are discovered, paleontologists often have an incomplete skeleton.
Perhaps they find just the skull, a few vertebrae, and a leg bone. Scientists
have to put together what they have and fill in the holes of what is missing.
How do they figure out which bones are missing? One of the most common techniques is to compare
dinosaur skeletons with modern animal skeletons. For example, when the T-Rex was first discovered
Paleontologists noticed the bones had some similarities to the skeleton of a chicken,
with an s-shaped spine, three forward pointing toes,
and large back legs. Using the placement of the bones in the chicken skeleton for reference, they
pieced together the bones they had and then filled in the gaps with bones they believed would fit.
We now have a much larger database of fossils on record, as more and more new species continue to
be found. This allows paleontologists to compare newly discovered dinosaur fossils to other
dinosaur fossils on record, as well as living animals, when an incomplete skeleton is found.
Sometimes a particular species’ skeleton can be completed using multiple fossils of
the same dinosaur found in different locations. Like puzzles, fossils are often missing pieces,
which is why it is so important to find more than one fossil of a species.
Paleontologists also team up with geologists, biologists, engineers, and computer experts
to learn even more about these dinosaurs. Geologists look at the Earth surrounding
the fossils. Did the animal live in a swampy environment by an ancient river,
or did it live in a desert with very little vegetation? Biologists study the fossils,
looking for scratches or damage that could tell them how the dinosaur might have died.
Engineers recreate the skeleton in a 3D model to see how the dinosaur might have moved.
Computer experts create computer models to see what they might have looked like and what
their capabilities might have been. For example, looking at a re-creation of a T-Rex, scientists
can determine how fast it would have been able to run based on the muscle and bone structure.
These methods also give us a pretty good idea of what dinosaurs may have looked like. Let’s take a
look at some dinosaurs and what we know about them from the research gathered by these scientists.
This is Megalosaurus. A fossilized jaw bone discovered in 1824 by William Buckland
was the first fossil that was correctly identified as belonging to a dinosaur, although the term
“dinosaur” wouldn’t be used until years later. A smaller version of the T-Rex, Megalosaurus had a
square- shaped head and generally grew to be about 7 meters, or twenty-two feet long. This species is
a type of therapod, a dinosaur that stands on two legs and has short arms and a long tail.
In the late 1900s there was a rush to discover the world’s largest dinosaur.
Exciting fossil discoveries, thought to be massively large dinosaurs,
led to names like “Supersaurus” and “Ultrasaurus”. However, initial estimates were often incorrect
and these super-sized dinosaurs were frequently downsized once the incomplete skeletons were taken
back to the lab. What we do know is that all of the world’s biggest dinosaurs belong to a group
of four-legged herbivores called sauropods. This family of dinosaurs is easily recognizable by
their large bodies and small heads, not to mention their long necks and tails.
The most famous sauropod is the well-known brachiosaurus, whose name translates to “arm
lizard”. This references the fact that its front legs were longer than its rear legs.
Discovered in 1903, scientists assume that brachiosaurus used its long neck
to browse the vegetation of high trees, and that they traveled in family packs.
One sauropod currently holds the distinction of being considered the largest dinosaur
of all time. This is the massive Argentinosaurus,
named for its discovery in Argentina. Only a small portion of this skeleton has been found,
but using reconstruction methods, paleontologists estimate that this behemoth stretched about thirty
to forty meters from head to tail. That’s anywhere from one hundred to
one hundred thirty feet long. From ground to head it stood 20 meters, or about 65 feet tall.
Some other sauropods are believed to have been larger than Argentinosaurus,
but there is not enough evidence yet to support this,
so Argentinosaurus remains the record holder for the time being.
While dinosaurs roamed the earth, their cousins the pterosaurs dominated the skies. The word
pterosaur means 'winged lizard’, and while they are related to dinosaurs, they are not actually
dinosaurs themselves. Belonging to this group of flying reptiles is the fan favorite pterodactylus,
the first pterosaur to be discovered. The Italian scientist who discovered it thought he had found a
new marine animal. Soon, however, paleontologists realized they had unearthed an entirely new group
of animals. One of the most exciting discoveries in this group was the massive Quetzalcoatlus.
This pterosaur boasted a wingspan of nearly 40 feet, and may have weighed 500 pounds or more.
Because of its immense size scientists are not sure if this particular reptile
was capable of flight, or if it spent its life on the ground.
In the early 1800s, Mary Anning and her brother Joseph lived on the coast of England,
a place rich with fossils. Their father taught them how to locate and excavate the fossils,
which they sold to help provide for their family. Mary and Joseph discovered the intact skeleton
of a marine reptile, similar in shape to a modern-day dolphin.
It was named ichthyosaur, which translates to “fish lizard”. This sharp-toothed animal
was generally around ten feet long and likely propelled itself with a long, fish-like tail.
This skeleton was not the only discovery that Mary would make. In 1823 she came across the skeleton
of a plesiosaur, the first time this particular reptile had been found. The fossil of this
long-necked swimming reptile was thought to be a fake at first but was soon confirmed by noted
paleontologists. Sadly, Mary’s discoveries were often not credited to her at the time,
because she was a woman. Today, however, you can see Mary’s plesiosaur hanging in the Natural
History Museum in London. Mary would go on to find many more fossils in the cliffs near her home,
proving that the massive reptiles were not limited to the land or air, but ruled the seas as well.
Fossil discoveries give us a fascinating glimpse into the past, its inhabitants, and their lives.
Often we only have a few key pieces of a particular skeleton
and the rest of the picture is left to science, informed guesses, and imagination.
Every day paleontologists are discovering, and uncovering, more pieces of this endless puzzle.