Attenborough and the Sea Dragon Page #2

---

must be somewhere here and

they check every rock.

Beautiful shale!

- Lovely!

- Anything interesting?

- Moment of truth...

Nothing.

- Just push it off.

- Yeah.

Is there anything showing?

Nothing else here.

Oh, gosh, that's hard work.

I hope there's something here.

I almost don't want to look!

- Ah!

- What have you found?

- There's a bone.

- Loads of bone going all the way... There's bone there.

- There's something here!

- HE LAUGHS

At long last, the team's

efforts are rewarded.

We've got some bones here!

- There's loads of bones.

- Fantastic!

Ah! What's this?

Is that a vertebrae?

But the bones are not in the position

the team had expected to find them.

Instead of lying across

the face of the cliff,

the skeleton seems to be

bending back into it.

We're going to have to

go down through there.

It means much more work.

And to make matters worse,

a storm is brewing.

The rain is just starting,

but I think we've got to

make a bit of a run for it.

We won't be working any more in this

for the moment. It's torrential.

Beautiful rainbow, though.

A rainbow will be little

comfort if the storm persists.

Rough seas and heavy downpours

can cause landslips,

which could easily destroy any

chance of retrieving the bones.

It was after just such a storm

that Chris found the front limbs,

the paddles of our sea dragon.

They convinced him that the

fossil was something special.

VOICEOVER:
You can see why

when you compare them

VOICEOVER:
to the paddles

of the kind of ichthyosaur

VOICEOVER:
that's usually found here.

This is an adult and this is

the paddle of this creature

and if you compare it to this one...

- Oh, it's huge. Oh, yeah.

- I've never seen anything quite like it.

There are half a dozen rows of

digits there and how many there?

I think there's at least

nine or ten crossways

and obviously, you know,

many more in length.

It's getting on for twice

the number of digits.

- And the whole shape of the fin is completely...

- Quite different.

And must be new, therefore?

- I think so. I've never seen anything quite like it.

- How exciting!

VOICEOVER:
It's extremely rare to find

VOICEOVER:
a new species

of ichthyosaur these days.

Only nine have been discovered

here in the last 200 years.

But can these strange

paddles tell us something

about how this odd ichthyosaur lived?

To try and find out, we are going to

construct a three-dimensional model.

To do that, we first need to

have the paddles scanned.

So, Chris is taking them

to Southampton University.

Here, the engineering department

has one of the largest

high resolution scanners in the country.

It's not every day someone walks in

with a 200-million-year-old sea reptile.

The machine can scan objects of

all different shapes and sizes

from ancient coins to the

components of spacecraft.

To create a picture, the scanner

takes thousands of X-ray images

in cross sections through

the fossil as it rotates.

It's not long before the

first images appear.

That's amazing. It looks really clear.

You can even see the bones

laying underneath the paddle.

At the moment, we're

just doing one section.

We're going to do multiple

scans down the specimen

and build it all back together

into a three-dimensional volume.

The scans of the paddles are

sent to Bristol University.

Here, scientists can isolate the

image of each bone within the rock

and then assemble them to create a

detailed three-dimensional model.

The team is particularly

excited by the shape

and structure of these paddles

and I've come to find out why.

We've got a complete paddle here

taken from the bones itself,

fully reconstructed, rearticulated

so this is as close as we can get

to what it would have looked like.

We can actually start using

this paddle to try and tell us

what species it might have been.

Because of the size of the paddle

and the way that some of these

bones articulate with each other,

it's different to other ichthyosaurus

and so this could be a new species.

- That would be great.

- It would be jolly exciting.

VOICEOVER:
We won't know for sure

until we find the rest of the body,

but can the paddles tell us something

about the way in which this creature swam?

There are a lot of bones in this paddle,

which would have been

good for holding steady

and also for allowing it to

be manoeuvrable in the water.

- There would have been cartilage

round that, wouldn't there? - Yes.

All of the gaps between the bones

would have been filled in with cartilage

and even further around the paddle itself,

giving it a paddle-like shape,

giving it a cross section

a bit like an aerofoil

so that it could cut

straight through the water.

- Could they fold them in to the side?

- Probably not.

Looking at the muscles

and where they attach,

it suggests these are moving up and down,

helping it to turn very quickly

or keeping it on the straight and narrow

when it wants to be a little more sedate.

The shape of the paddles

and the way they moved

seems very like the way an animal

alive today uses its paddles.

That animal usually lives

in tropical waters

like these in the Caribbean.

The sea here is warm

with temperatures much

like they would have been

in Jurassic times around Britain.

And the animal in question...

is the dolphin.

Dolphins, of course, are mammals,

not reptiles like ichthyosaurs.

Nonetheless, the two groups have

bodies shaped in very similar ways.

The front fins or paddles of both

would have helped to steady themselves

as they turn and cut through the water.

And both have similar dorsal fins.

So, although they lived

200 million years apart,

dolphins and ichthyosaurs share

many physical characteristics

and that's because they

evolved in similar ways

as a response to a similar environment.

Like dolphins,

ichthyosaurs evolved from ancestors

that had once lived on land.

As they became adapted to life in water,

they lost the ability to walk,

their bodies became more streamlined

and their forelimbs turned into

paddles to help them swim.

But ichthyosaurs do differ from

dolphins in two striking ways.

Dolphins have tails that

are flattened horizontally

and they drive themselves forward

by beating their tails up and down.

But we know from their fossils

that ichthyosaur tails

were flattened vertically

like those of sharks,

so they must have swum

in the same sort of way

by sweeping their tails from side to side.

Ichthyosaurs, unlike dolphins,

also had back paddles.

They, too, would have helped

stabilise them as they swam.

And what's more, the

paddles of our ichthyosaur

are particularly large and long,

rather like those of the

oceanic whitetip shark.

That shape helps the whitetip

to cruise for long distances

with very little expenditure of

energy in their search for food.

So, it could be that our ichthyosaur

was also a long-distance traveller

and only an infrequent visitor

Rate this script:0.0 / 0 votes