The Story of specimen MNN 604*:
The giant skull of Sarcosuchus imperator
by Marco
 If
you were to ask a paleontologist or dinosaur fan about a dinosaur
skull, they would tell you it is the single most infrequent
fossil found in the field. Due to its complexity and delicateness,
the skull of a dinosaur is very fragile and is rarely preserved.
Dinosaur skulls can reveal a great deal about the dinosaur
itself, what it ate, how it ate it, and sometimes to whom
the dinosaur is related. Until a couple of months ago, the
most common fossils in the Dinosaur Lab at the University
of Chicago were skulls. Not dinosaur skulls, but crocodilian
skulls. "Why so many crocodilian skulls?" you ask. The answer
to why crocodilian fossil skulls are more common than dinosaur
skulls lies in their modern-day relatives: crocodiles, alligators,
and gavials. Built solidly with over 60 bones, the skulls
of modern-day crocodiles have powerful jaws used to take down
huge animals. Crocodiles, such as today's Nile crocodile,
are adapted to feeding on big animals, usually sharing a kill.
Like any big predator, crocodiles hunt and tend to also scavenge
as well. If a fellow crocodile were to die, the other crocodiles
would scavenge it leaving no body remains except for the skull.
The discovery continues even as the trip ends….
As any explorer would assure you, the experience does not
end after the trip home, instead it provides extra work. In
this case, for the Niger 1997 Expedition there was a lot of
tedious work ahead. After a short break of sitting in the
floor of the lab, MNN 604 took a trip into the operating table.
There the jacket was opened and assigned to an unsuspecting
undergraduate student: Andrew Gray.
It is not uncommon for a jacketed fossil to be overlooked
for weeks, months, and even years in a typical museum. Many
times these overlooked fossils represent a new species or
a more complete specimen. In this case, it was a fossil skull
that was left sitting in the floor of one of the country's
top fossil labs; the skull of one of the largest crocodilians
to have ever lived.
For months, the jacket containing specimen MNN 604* sat in
the floor of the DinoLab, at the University of Chicago, where
it was used as a side exhibit for lab tours. As anxious visitors
walked by many asked what the jacket contained, the answer
"a croc skull." It is not rare for the person asking the question
at this point to gasp.
Why? Well, because this jacket is about the size of a typical
human being, almost six feet in length! Covered in solid rock
(mostly sandstone and some hematite), the skull is thought
to be the most complete dinosaur skull present at the time.
This is not just any skull; it is the skull of an enigmatic
crocodilian. It is the skull of a crocodilian that is known
from a couple of teeth and bone fragments. Until now no other
drawings have been published about this animal. Until recently,
the largest crocodilian to have ever lived is known from fossils
bearing beds in the Midwestern U.S., the crocodile Deinosuchus.
However, there is a new contender for the title of world's
largest crocodilian: Sarcosuchus imperator. The only
known specimens were jaw fragments discovered in Niger by
French geologists. For the first time ever, the world can
take a close look into the head of the world's largest crocodile
Sarcosuchus imperator.
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