Mini-lecture: Discovering a dinosaur (UCL)


Uploaded by UCLTV on 04.03.2010

Transcript:
My name is Michael Pittman. I'm a PhD student in UCL Earth Sciences.
I study the evolution of the tail
and how it works, its biomechanics, in dinosaurs.
In 2008 me and a team of researchers went to the Gobi Desert
to look for
some new dinosaurs there, to try and understand
the Inner-Mongolian
Late Cretaceous form
this last period of the dinosaurs,
very
poorly known in China but well known
in Mongolia.
Now, we went to
an area that looked like this,
a hummocky ground
in the southern margin of the desert,
very hot, about forty, fifty degrees.
And we were walking around. We spent most of the day walking.
And we eventually found a new taxa. This is how the desert gives way
to a flat
plain.
We didn't find the dinosaur there. We found it in this hummocky area,
where my friend Jonah from George Washington University
saw a claw sticking out of the cliff
and
he showed me this
and he said, what do you think of this? I was like, well, I know, but do you?
And he said, I do. And so
eventually
I told him what it was, a carnivorous dinosaur. And we were both
ecstatic.
Like, everyone
in the area could hear us because they came rushing over thinking something was wrong.
It was a carnivorous dinosaur.
But we didn't know what it was. It's very difficult to tell from just a claw.
Our friend Xu,
the professor
that organised it in China, he
eventually sent us some photos and here's what he sent us. It's a
a fully articulated, complete
dromaeosaur, a type of carnivorous dinosaur.
Its tail is not in this photo. But it's in a separate
jacket
but a complete dromaeosaur. Now,
dromaeosaurs are carnivorous dinosaurs that have
three
bones in the skull that are completely
absent in other carnivorous dinosaurs, like
T. rex.
Now, dromaeosaurs
are very well-known from
skulls
from all over the world
but our best specimen is actually one from Mongolia
and it's a Velociraptor, a well known dinosaur. And this is a picture of it fighting with
a protoceratops. They were actually buried, locked in combat.
So this is basically what our main idea of what a dromaeosaur skeleton is like, just from this one
perfectly preserved animal.

Linheraptor is different from
Velociraptor. This is an original
monograph picture
and
because
if you look at the skull here, this is the orbit, the eye.
In front of it, there's this antorbital fenestra,
which
houses the sinus. And this sinus helps to heat up air, very much like in our own faces.
In Linheraptor,
the anterior portion
called the maxillary fenestra
is particularly anteriorly placed. It's forward in the skull.
And it's also
about the same size as this hole here, the nasal opening associated with the nasal cavity.
So that's what makes it different
but what makes Linheraptor important
is its preservation.
So the actual name of Linheraptor is Linheraptor exquisitus... exquisitus
because
it's a
complete individual. This is actually not fully prepared yet. This has maybe still got months and months of
work to be done
But it's important because now we have this vast database, this vast
source of information from which we can actually understand what other dromaeosaurs look like.

For example,
Tsaangan mangas, which means white monster in Mongolian,
it actually is only know from the skull.
It's very closely related to Linheraptor because they both
share this
anterior placement of the
maxillary fenestra, but Linheraptor's known from the,
this is known from the skeleton, and this,
Tsaangan mangas, is known only from a skull.
So immediately
it's very important because we can
fill in this data and understand what these other dromaeosaurs look like. And that's very important
because it can show us
what the actual relationships were between these animals in much more detail
and how they evolved and diversified like they did.
And finally I'd like to show you an artist's reconstruction. This was done by a colleague,
Nicholas Frankfurt.

It's a black and white drawing and showing
the feathers
on these dromaeosaurs,
and this is
probably what these guys looked like.
Many dinosaurs from China
have shown feathers on various types of carnivorous dinosaurs,
including T. rex ancestor,
and so
this guy here has a
coating of very primitive feathers,
which is what we think these guys looked like.
And what were they eating? Well,
they were eating protoceratops. These are
ancestors of the
horn dinosaurs, like triceratops. They're very ancestral forms.
So they were probably eating these guys, and they were kind of small, like the size of a big dog.
And they were fast and agile, these dromaeosaurs, and they were living in an environment
like
the Kalahari Desert today, so it was
characterized by
alluvial fans, like kind of rock falls, and there's lots of rocks
spread out across the ground and very little vegetation.