The skull is usually the most delicate part of a
skeleton and is the part least likely to be found
intact as a fossil. A skull is made from many fragile
bones that easily fall apart after death.
One way crocs are different from most dinosaurs is
that crocodile skulls are made from stout bones filled
with teeth that fuse into a nearly solid block when
the animal matures. The jaw muscles are buried deep
in the skull, making a difficult meal for a predator.
For that reason, we found many fossilized skulls of
Sarcosuchus - more than any other animal in
that part of the Sahara.
The largest skull we found was nearly perfect. The
lower jaws were attached and many of the teeth were
in their sockets. That's why we chose this 6-foot
long skull as the model for the skull reconstruction
you see below.
ROLL OVER THE BONES
to find out where they are found on the skull.
CLICK ON THE BONES
to learn more about Sarcosuchus' specialized
skull anatomy.
Illustration by Paul Sereno and
Carol Abraczinskas
A. Skull (side view)
Some of Sarcosuchus' remarkable adaptations
are easily seen in side view. Look at the teeth in
the bone at the end of the snout (pm, premaxilla).
Not only are they the largest teeth in the skull--the
reverse of many crocodiles and alligators--they are
angled inward. The longest bone in the cranium (m,
maxilla) has 30 teeth. The tenth one is sort of like
a canine, as it is noticeably larger than its neighbors.
B. Skull (top view)
Looking at the skull in "top view," it is
easy to notice the extreme size of the nose opening!
In life the opening of the nose, would have been surrounded
by flesh, called the nostril, and would have appeared
much smaller. The big opening enclosed a cavity, possibly
for enhanced smell or for making unusual calls. Crocs
are very communicative animals; they frequently roar,
grunt, hiss and just splash around.
Also notice that the cavity for the eye, called the
"orbit," faces upward and is in full view.
This means Sarcosuchus' eyes were rotated more
onto the top of the skull than in many living crocs.
The pair of holes behind each orbit is for powerful
jaw muscles.
C. Cranium (view from below)
Now that we can see the skull upside down ("view
from below"), where does the air come out when
Sarcosuchus exhaled? Way back at the back end
of the skull near its throat. Air passed in a tunnel
inside the snout all the way to the back of the skull--surprise!
The snout is hollow! Why have such an air tunnel inside
the snout? This allows crocs to chew and breathe at
the same time--just like us. It would be difficult
for us to eat a meal if we needed to stop breathing
with every bite!
D. Snout end (view from below)
Here is the fearful front end of the jaws of SuperCroc
as seen from below. Look at that overbite! Those huge
overhanging teeth and the fan-shaped end of the lower
jaw are very unusual for a croc. They must have allowed
this fearsome predator to grab anything it wanted
to and drag it under the water.
E. Large tooth in mandible
This is an up-close look at the largest tooth in the
lower jaws--tooth #3 (if we number the teeth from
the front). It is a very strongly built tooth, only
about twice as tall as it is wide. You can see the
shape in the cross-section next to the tooth. Strong
teeth like this are good for lots of things--catching
fish but also for grabbing and dragging, and crushing
bone.
F. Smaller tooth in mandible
Here is a slightly smaller tooth in the lower jaw,
tooth #17. It is also very strongly built, only about
twice as tall as it is wide across its base. Notice
that it has a little more of a curve than the large
tooth and comes to a more slender tip. This tooth--
there are about 30 in a row like it above and below--make
sure that nothing escapes the enormous jaws of the
predator.
Questions
If the scale bar in F is 1/4", how tall is tooth
17t?