- 7 months ago
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Documentary, Ancient Sea Monsters
#Documentary #SeaMonsters #Prehistoric
#Documentary #SeaMonsters #Prehistoric
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AnimalsTranscript
00:01What is today a dry and dusty landscape in Nevada was once an ocean paradise.
00:11240 million years ago, huge prehistoric reptiles swam here beneath an ancient sea.
00:18They would have been truly scary animals to have seen in the ocean.
00:23Now a stunning new discovery in the desert hills has revealed evidence of one of the most ferocious creatures ever found.
00:32The Sharptooth Pickles.
00:37This animal was the top predator in this ecosystem.
00:41This would have been the Tyrannosaurus of the oceans at that time.
00:45And it may change our understanding of how life evolved in Earth's prehistoric seas.
00:53A group of paleontologists are on the hunt in the wilderness of Nevada.
01:11These dry desert hills are a prehistoric graveyard.
01:14But this team isn't searching for ancient life that lived above ground.
01:18240 million years ago, Nevada was an underwater paradise.
01:24And home to ichthyosaurs, the first reptiles to leave land and evolve into ocean creatures.
01:31They know they're here, because they found them before.
01:41In July 2008, another team of paleontologists unearthed the nearly complete remains of a giant ichthyosaur in the nearby Augusta Mountains.
01:49The ichthyosaur was about 35 feet long and it was a pretty slender animal.
01:59It had a long tail.
02:02The skull itself was actually pretty large.
02:05What we think right now may be up to five feet or a little more actually.
02:10So that's a good size.
02:12The size of the ichthyosaurs was definitely very surprising.
02:16Because what we had known thus far, the earlier ichthyosaurs were maximum,
02:20maybe 10, 11 feet long, maybe a little larger than that, but 35 feet.
02:27That was definitely something absolutely unexpected of that size.
02:34But one feature made this ichthyosaur unlike any other of its time.
02:39It's team.
02:41They were diamond-shaped with sharp cutting edges.
02:47This creature was pure carnivore, able to tear apart the flesh of its victims.
02:53So when we first got to the specimen, I actually saw it right there in the field.
02:56It was just stunning.
02:58Because there it was and there was a skull that we could see.
03:01It was weathering out and we saw the teeth being exposed.
03:04There was a few teeth that were actually laying on the surface right there.
03:08All weathered out, we could pick them up and we saw the large teeth with cutting edges.
03:12So they were actually there.
03:14And it totally confirmed what we were hoping for, ichthyosaur that had cutting edges on the teeth.
03:23So this is the regular tooth type for middle Triassic ichthyosaurs,
03:27you know, with a circular cross-section and really pointed piercing type tooth,
03:31which would have been great, worked great on, you know, slippery prey items like fish to just like, you know,
03:36pierce them, hang on to them and then swallow them and pull.
03:39Right, right.
03:41And then the teeth of our ichthyosaur now really contrast this.
03:45I mean, it's much stronger.
03:47It almost has like a diamond-shaped cross-section because of this really sharp cutting edge running right over the tip.
03:53So this tooth would have worked really well, you know, just slashing through muscle fibers
03:59and, you know, biting out chunks of large and meaty and bony prey items.
04:04It wouldn't be necessary to swallow the prey item as whole, but actually be able to cut it in parts and eat it separately.
04:12Yeah, just like a steak knife, you know, going right through it.
04:16I don't think that this guy had any natural enemies in the ecosystem.
04:22This was at the very top of the group chain.
04:32When it was found, the fossil was encased in dozens of pieces of heavy rock, making it possible to carry out the aspirin.
04:44This is exciting.
04:45The remote location required special equipment, a helicopter.
04:56The use of a helicopter in the field is rather uncommon.
04:59It's pretty expensive and sometimes it's also pretty difficult for the helicopter pilot to actually maneuver into the area.
05:06The orgasamons are rather steep and there are some deeper canyons cutting into it.
05:13And the specimen is at the flank of one of these canyons.
05:16And there's no area that's pretty flat or so.
05:23The helicopter came up and let down a net where we placed these individual blocks.
05:28And to protect them against bumping into each other, we also wrapped them in soft tissues and blankets.
05:40The ichthyosaur was sent to the Field Museum in Chicago.
05:44There, the team could study and decode the fossil in greater depth.
05:47This creature was at the top of the ocean's food chain, just as some sharks and killer whales are today.
06:00But this giant reptile wasn't always a sea creature.
06:04More than 250 million years ago, it lived on land.
06:08Scientists can trace the ichthyosaur's evolution through the fossil record left behind.
06:19Here we have one of the oldest hands of ichthyosaur.
06:25And you can see that this is already flipper sheep.
06:28But if you look closely, you can see that there are five fingers, just like our hand.
06:33And also, each finger bone is hourglass shaped with shafts in the middle.
06:39And again, it's like ours.
06:42So, you can see that this animal came from something living on land.
06:47And if you fast forward five million years, and you get the next stage, and get something looking like this.
06:54And here, again, you have five fingers, but the bones are no longer hourglass shaped.
07:00They are tightly packed into squarish elements, mostly.
07:05As the bone structure changed in the hands and feet, limbs once used for swimming became more like rudders on a ship.
07:14But the changes continued, and over millions of years, ichthyosaurs began to look less like reptiles and more like fish.
07:22Then over time, they started to modify their body plan, and it took about 35 million years before they completely became fishing.
07:35Paleontologists were shocked at the appearance of the sharp-toothed creature so early in ichthyosaur evolution.
07:41It was further evidence that the first ichthyosaurs were much more diverse than previously known.
07:50When I first heard about sharp tooth ichthyosaur, I was honestly surprised.
07:55We knew that some ichthyosaurs from later days had sharp teeth.
08:00But not this early.
08:02This is only five million years after ichthyosaurs appeared.
08:05So that's a big surprise.
08:08And this is just a phenomenal example of how quickly evolution can actually happen.
08:14And quickly, in geological terms, can be a few million years.
08:18For paleontologists, five million years or ten million years.
08:22It's a very short period of time.
08:23The first ichthyosaurs appeared not long after the Earth had just experienced a planet-wide catastrophe called the Permian-Triassic extinction.
08:40The Permian-Triassic extinction occurred approximately 250 million years ago, maybe a little bit older.
08:45And it was the major mass extinction that happened in Earth history.
08:49And it had a huge effect on all life on Earth.
08:54It was most likely caused by extensive volcanism, which then had obviously results on changes in the atmosphere temperature-wise.
09:06Which then obviously would have resulted in major impact on life in the seas.
09:11Scientists estimate that 95% of all marine species and 70% of all terrestrial species perish.
09:19But a new evolutionary cycle began, and the reptiles that survived took separate paths.
09:29Those which stayed on land, and those which made their way into the oceans.
09:36All life on land originally came from the oceans, but primitive fish began to develop limbs, allowing them to walk out of the seas.
09:52Now the first reptiles were going back.
09:55The exact reason why the reptiles started going back to the ocean is not well known.
10:02But there are a few good possibilities, and probably the strongest one is that they were after the food.
10:08Reptiles able to adapt to the water confronted few enemies in the near-empty seas.
10:13In just a few million years, they became fully aquatic creatures and evolved into something new, ichthyosaurs.
10:24There's no large fishes. The sharks were relatively small.
10:27They just were able to go in without any pushback, if you will, from the predators that were already there.
10:36So ichthyosaurs kind of went into this virgin environment, and with no competition, and were able to take advantage of the sea life at the time, and develop pretty rapidly.
10:48Scientists now hope to explain how this land-based reptile evolved into a fully aquatic creature.
10:57But to do so, they'll need to find the fossil that demonstrates that transition.
11:05One of the major questions, of course, is the origin of ichthyosaurs, and to narrow down and eventually hopefully pinpoint the group of terrestrial animals that they evolved from,
11:16and to get a better picture of how this evolutionary process from a fully terrestrial animal to these very highly adapted marine animals took place, step by step.
11:29In five to ten million years, ichthyosaurs diversified into about a dozen different species as they conquered the world beneath the waves.
11:38But none of those ever found were thought to be savage flesh-eaters. Until now.
11:46And the investigation is on to understand just what this creature is, and what it may tell us about the Earth's prehistoric seas.
11:57The python hunters are going global.
12:04I thought I had a nice black guard.
12:07And this time, it's not just snakes they're hunting.
12:10You got a ten-foot crocodile. Everything's dangerous.
12:14That's a wild dragon right there.
12:16Follow the reptile catching trio as they climb, jump, and crawl their way around the world in search of the world's deadliest animals.
12:24I found my soulmate. Brand new.
12:27acetyosaurs are on the hunt in Earth's ancient ocean...
12:28...these creatures aren't your average carnivores.
12:30Icthyosaurs are on the hunt in Earth's ancient ocean.
12:41These creatures aren't your average carnivores.
12:44They're cutting edge teeth, making the top planetes believe the whales.
12:48Small fish won't satisfy their habitat.
12:51Scientists believe they have the height and the ability to eat much larger prey.
12:57Sometimes, even each other.
13:00Within seconds, a large ichthyosaur sinks his sharp teeth into the flesh of a smaller one.
13:06And this killer claims another one.
13:16But scientists want to know exactly where this sharp-toothed creature fits in early ichthyosaur evolution.
13:22That information could help them solve the mystery of how ichthyosaurs evolved from some as yet unidentified land-based species.
13:38The sharp-toothed ichthyosaur roamed the seas at a time when the Earth looked dramatically different.
13:43If you'd had a time machine to go back 250 million years, you'd see this huge continental mass and a giant ocean on the other side.
13:50You wouldn't recognize it as the Earth.
13:53The continents were fused together into one gigantic landmass called Pangea.
13:58It had a general sea shape, like the letter C, and it was surrounded by a giant ocean as well, the Patellasin Ocean.
14:09All ichthyosaurs derived from one reptile that took its first steps off Pangea and into the sea over 245 million years ago.
14:18One could think, oh, they live in the oceans. They're just like fish, but they're actually not.
14:24They're definitely reptiles. They are tetrapods, which means that they are animals with four legs.
14:33They evolved into fully aquatic creatures once they made their home in the ocean.
14:38The way evolution works is that mutation happens, bringing in a new feature.
14:44And as long as it doesn't get in the way, it'll stay.
14:47But if it gets in the way, then it's eliminated.
14:51So that's how new designs sort of come about.
14:54The ichthyosaurs are just one piece of puzzle in the grand picture of evolution, obviously.
14:59But ichthyosaurs are a great group to study because they start out with very simple forms and then have this explosive radiation.
15:08Radiation is a term for the expansion of a species into a variety of new forms.
15:16It took between 5 and 10 million years for about a dozen species of ichthyosaurs to evolve from that first land reptile.
15:24By then, there was no turning back.
15:27They became unadapted, if you will, to coming back on the shore.
15:31Over a period of millions of years, their bone structures simply would not support their body.
15:36If they were beached, they'd be like a beached whale today.
15:39If they couldn't wiggle their way off the beach, they'd be dead in a matter of hours or a couple of days just from overheating or suffocation.
15:48The sharp-toothed ichthyosaur had an advantage over other marine life in the ocean.
15:53It used its size and cutting-edge teeth to rise to the top of the food chain.
16:03In any group of animals, you'll find a variation.
16:08And if a group of animals has a mutation, if you will, or a change that produces teeth that are more efficient for a certain kind of feeding, those are the animals that are successful in living and reproducing.
16:22And the animals simply live longer, reproduce more, have more descendants.
16:33It's definitely an important ecological role that was waiting to be filled by some animal.
16:40And obviously, in this case, it was for the first time a marine reptile, and specifically this really large ichthyosaur.
16:51Scientists look to solve the mystery of where the sharp-toothed creature fits in ichthyosaur evolution.
16:56Now an expedition is heading to Nevada in search of more answers, hard evidence only a dig can provide.
17:11Ichthosaur remains have been found all over the world, but one place has been a magnet for paleontologists for more than a century.
17:19Fossil Hill.
17:21Fossil Hill is historically very important because it's actually the site where they found the first ichthyosaurs.
17:32They collected quite a few marine reptiles there.
17:36So is that 30? Is that the paddle?
17:39Yeah.
17:41Fossil Hill is only 80 kilometers away from where the sharp-toothed ichthyosaur was found in 2008.
17:47Now Ryosuke Mortani, along with colleagues Lars Schmitz, Pat Embry and Neil Kelly, has come to Fossil Hill in the hope of learning more about the sharp-tooth and other ichthyosaurs.
18:05The Augusta Mountains, Fossil Hill, are actually rather close to each other, about 50 miles apart in northwestern Nevada.
18:16Both localities expose rocks of approximately the same age.
18:20And we know both localities have delivered fossils, fossil ichthyosaurs.
18:28And so there's a chance that at Fossil Hill we'll find other ichthyosaurs that might tell us and help us to resolve the mystery of our sharp-tooth ichthyosaurs.
18:38As the paleontologists head into the hills of Nevada, they hope for the discovery of a lifetime, of uncovering a second ichthyosaur specimen.
18:53But the holy grail for paleontologists is to find the fossil of the missing link, an early ichthyosaur that lived during the time they transitioned between land and sea.
19:12We don't know exactly how long it took them to get used to the life in the water completely.
19:27Because the first ichthyosaur fossil that they find is already adapted to the life in water.
19:33But getting to their destination, known as Fossil Hill, isn't easy.
19:40The trek is an arduous drive on unpaved roads and dangerous terrain.
19:53Fossil Hill is located in north central Nevada in the Humboldt mountain range.
19:57Its elevation is a little over 5,000 feet. It's considered high desert.
20:02We get cold, very cold winters and hot summers.
20:05You should have a four-wheel drive to get close to the property.
20:11The topography is fairly steep.
20:13You never know what kind of weather conditions you're going to expect.
20:17So we can have dust storms, you can have blizzards, blazing sun.
20:23You just never know what to expect.
20:25Understanding the evolution of any prehistoric species requires a series of fossils that often needs to span millions of years.
20:32But fossils are very hard to come by.
20:39The odds of any fossil being created at all are so great that all fossil finds could be considered remarkable.
20:47Becoming a fossil is like winning the lottery for the first thing.
20:53It's very rare for any animal's carcass or body to survive long enough to be buried and then preserved as a fossil.
21:02Over millions of years, the remains are protected and preserved as the sediment layers build and leave it deeper and deeper beneath the surface.
21:12It has to survive long enough to reach an area where it can be covered up.
21:19It has to remain undisturbed for a long enough period to have these sediments build up on top.
21:25So, you know, it's a calm environment, the bones don't get spread around, you don't have a lot of scavengers tearing the carcass apart.
21:32The sharp toothed ichthyosaur must have died in perfect conditions when it fell to the Nevada seabed 240 million years ago.
21:41Because a nearly complete skeleton was recovered in 2008.
21:45It is very rare that we actually find a complete skeleton, like, including every single bone that there was.
21:55I mean, this is almost never happening.
21:58The sharp toothed ichthyosaur lay deep beneath the Earth's surface.
22:03Then, over millions of years, continental plates buckled and lifted the western United States.
22:12Terrain once underwater transformed into the Nevada mountains.
22:19Gradually, rock and sediment were exposed until eventually the fossilized remains became visible at the surface.
22:30But it's not only winning the lottery for a fossil to become a fossil in the first place.
22:36It's winning the lottery again to actually be found by someone that is able to collect the fossil before it turns to dust.
22:44When they weather out and you get frost freeze and rain and wind and everything else attacking these bones,
22:51they'll be destroyed in a matter of two to three years.
22:54The nearly perfect preservation of the sharp toothed fossil gives scientists a good chance to discover where it fits in the ichthyosaur evolutionary timeline.
23:10But the discovery is only the beginning.
23:14The process continues in the lab.
23:16So now that we have this ichthyosaur here in the Field Museum, it's not entirely prepared yet.
23:21And it's a large specimen. We have 10 to 12 meters of body length.
23:25So it takes a lot of time to prepare it.
23:27The fossils of dinosaurs and other ancient creatures in museums did not begin their journey as pristine bones ready to be assembled.
23:35At Chicago's Field Museum, experts removed the bones of the sharp toothed ichthyosaur from the solid rock tomb that encased them for over 240 million years.
23:53There are several challenges on this ichthyosaur project.
23:57Number one is the size. It's big. So it's really time consuming to do.
24:04Akiko Shinya prepares fossils at the museum.
24:09It's her task to carefully help reconstruct the ichthyosaur from what looks like a pile of rubble.
24:14The ichthyosaur is encased in many pieces of solid rock.
24:18Its reconstruction becomes a prehistoric jigsaw puzzle.
24:22And carving bone out of rock is extremely delicate and time consuming work.
24:28Most of the tools we use are hand tools like these ones.
24:38It's essentially like a miniature jackhammer that you see in the road construction.
24:42So this one, this part goes back and forth and piston.
24:46And it just knocks the rock away from the fossil.
24:50And hopefully there is a good separation between the rock and the fossil that just chips right off.
24:57I need to work on this part.
24:59Nadia and Yol told me that this part is quite important.
25:02They want to know how the bones are connected to bone.
25:05Akiko's first task is to find the cranial sutures, the connection points between the different pieces of the skull.
25:13But 240 million years can blur the line between fossil and rock.
25:25Some parts of the ichthyosaur are very similar color.
25:29Rock itself is somewhat gray and then maybe a little bit darker, maybe a little bit lighter.
25:36It contains lots of shells because the ichthyosaur was in the marine environment.
25:45So it has like a lot of shells and snails and those clam bones.
25:50And they are very similar to ichthyosaur itself.
25:54So it's hard to differentiate, yeah.
26:00They'll need the entire skeleton in order to determine where this creature fits in ichthyosaur evolution.
26:05But so far, only 60% of the sharp tooth fossil is prepared.
26:14While this painstaking process goes on in Chicago, the team in Nevada makes an unexpected discovery.
26:26Is this a tooth? Is this where a tooth was?
26:29I see.
26:34The search continues in Nevada.
26:40Fossil Hill is well known for the dozens of ichthyosaurs found here over the past 100 years.
26:48But so far, the sharp tooth specimen is one of a kind.
26:51And paleontologists need more evidence to better understand the discovery's impact on evolutionary history.
27:02One of our main wishes would be to find another sharp tooth ichthyosaur.
27:05It's not uncommon that we only have one individual per species.
27:11So it's even more important to study that specimen in great detail.
27:15And we have to put in more effort and go out in the field and do more field work.
27:20Find more specimens and be lucky to find more.
27:23The potential for finding ichthyosaur fossils is very great.
27:29I would say there's somewhere around at least 100 ichthyosaur specimens that have been found around Fossil Hill.
27:39Not long into their search, the team finds something located at the base of the hill.
27:43Riosuke Motani spots a discoloration in a piece of rock.
27:53These small black lines in the rock might be considered just another mineral to the untrained eye.
28:00But the ability to distinguish a fossil from rock is an art for paleontologists.
28:05Motani instantly recognizes this as an ichthyosaur fossil.
28:09So here's a quiz.
28:14Which part of the body is this one?
28:16What region of the vertical column?
28:19Yeah.
28:20Oh wow, okay.
28:24So here's an isolated backbone right there.
28:26There's the hole in the middle.
28:28Which is actually not the hole, but it looks like that here.
28:32Then we have the rib.
28:34And the rib around here.
28:36And what else?
28:39Have you spotted anything else?
28:42Judging by the size and shape of its backbone,
28:45Motani believes this ichthyosaur fossil dates from about 245 million years ago.
28:50Not old enough for this investigation.
28:58But it's not just the creature's anatomy that helps determine its age.
29:01Its placement on fossil hill is also an important factor.
29:06Paleontologists can determine how old a fossil is depending on where they find it.
29:10As the team climbs the slope, they head deeper and deeper into the past.
29:21Just a little further up, they locate a second ichthyosaur fossil.
29:28Its smaller size indicates it's an older, more primitive creature.
29:32So these are, as you can see, small ichthyosaurs.
29:33Yeah.
29:34Much smaller than the one we saw before.
29:35Right, right.
29:36So, and this one's older too.
29:37Because as we walk down that way, up that way, along the hill, we are traveling back in time.
29:51Older and older.
29:52Okay.
29:53So we saw one that's bigger back there.
29:55Yeah.
29:56But this one's probably less than a million years older.
30:00One of the nice things of fossil hill is that we can walk through time, essentially, right there.
30:05So from the base of the hill, we can walk up and we cover about five million years.
30:14The forces that created this time machine are plate tectonics.
30:18The continents are sitting on a somewhat liquid, partially molten material of the inner of the earth.
30:25And they're floating on that surface.
30:28And over time, continents drift.
30:31When the first reptiles left land and evolved into ichthyosaurs, there was only one continent, called Pangaea.
30:39Then, Pangaea began to break apart.
30:41These plates move maybe up to five centimeters per year.
30:49But if you accumulate that over millions and millions of years, you can cover a lot of distance in that time.
30:55The earth itself is a very dynamic entity.
31:01And that we actually have an earth that looks like today is maybe only 50, 60 million years ago.
31:10The bottom of the sea was pushed upward and transformed into mountains over millions of years.
31:17And when the sea floor rose, it took fossil evidence of its watery past.
31:24Towards the crest of Fossil Hill, the team discovers what may be a key artifact of these tectonic forces.
31:33Pat Embry locates an ichthyosaur fossil, embedded in a small patch of rock jutting out of the hillside.
31:45What do we have?
31:46Oh, wow.
31:47Look at that.
31:51Wow, that's great.
31:53It's very similar in shape.
31:55Look at that backbone.
31:57It's not that wide in diameter.
32:00It's sort of really cylindrical still.
32:03That's the basal feature.
32:05But this one's pretty complete.
32:07So which way is this facing?
32:08Where's the head?
32:09I think head that way.
32:11And the hip must be around there, somewhere hidden.
32:15Yeah.
32:16If we expose the rest, we might see more.
32:18So gauging from this vertebrae, can you tell how long this guy was?
32:21Yeah, it could be about, let's say, seven to eight feet.
32:26That's the total length.
32:28Although it's not a sharp tooth fossil, Matani is convinced they've found some type of ichthyosaur.
32:35And it's older than what they had expected to find.
32:38Yeah, that's a very nice one.
32:40We've got a vertebrae right here.
32:42There's another one here.
32:44But that's the clearest one.
32:46Yeah, this one is not like a disc in the later ichthyosaurs.
32:50This is much more like cylinder.
32:53That's really nice.
32:55Yeah, it's turning along.
32:57The narrow cylindrical shape of the vertebrae dates the fossil a few million years before the sharp tooth ichthyosaur.
33:04And then there's another one.
33:06Thinner backbones in early ichthyosaurs suggest that they swam by moving their entire body like an eel.
33:12Like an eel.
33:16Scientists believe this motion allowed for speed and maneuverability in shallow waters.
33:22But the backbones became stronger as ichthyosaurs evolved.
33:29The sharp tooth had a thick disc-shaped vertebrae and swam by swinging its huge tail back and forth, giving it the strength it needed to hunt in the open ocean.
33:38And the specimen that they found in the Augusta mountains, the vertebrae, how is it shaped?
33:47Oh, it's a disc-shaped, right?
33:48Yeah, they're disc-shaped.
33:49Yeah.
33:50A typical ashtray shape.
33:51So quite different than this one.
33:52Yes.
33:53Yeah.
33:54Clearly different.
33:55This is really primitive.
33:56Yeah.
33:58This fossil is older than expected, but half of it is still buried in the side of the hill.
34:03Okay.
34:04The paleontologists continue the search, hoping to create a picture of how the ichthyosaur evolved from a land creature.
34:20So I'm getting up this corner because there might be the skull.
34:26But almost 2,000 kilometers away, fossils of a much later giant marine reptile have already revealed more about that creature's own transition from land to sea.
34:36The creature is called a mosasaur, and it once swam what is now Kansas, in a body of water called the Western Interior Sea.
34:49Large limestone columns hold evidence of this watery past.
34:53The rocks that I'm walking on right now were actually the bottom of the Western Interior Sea about 85 million years ago.
35:03The Western Interior Sea, at that point, stretched from, say, Missouri on out to Arizona, Nevada, all the way from the Gulf of Mexico on up to the Arctic Circle.
35:13It was a vast, mid-continent ocean about the size of the Mediterranean Sea.
35:17Where we're standing would have been about 600 foot deep.
35:20But ichthyosaurs did not rule these waters.
35:25They had been extinct for over 15 million years.
35:31We don't know why ichthyosaurs disappeared at this point of time.
35:36They may have just reached the end of their successful run, and then the last forms disappeared from the fossil record.
35:44A variety of factors can lead to the extinction of the species.
35:49Climate change, competition from other groups, or possibly collapse of food resources.
36:00But nature abhors a vacuum, and another sea reptile emerged in the oceans of the world.
36:06The mosasaur.
36:07These were very large, lizard-like marine reptiles that grew to lengths of over 30 feet, and were capable of eating just about anything else that swam in the seaway.
36:19It was a very dangerous place to be alive at that time.
36:23Their lizard relatives, a very successful group.
36:28They had a very mobile jaw joint, so they could open up their jaws extremely, and had a huge gape.
36:37A very successful group.
36:39At 10 meters long, the sharp-toothed ichthyosaur was the largest creature in the ocean 240 million years ago.
36:49And of all the mosasaurs, the one who could easily match the sharp-toothed size and ferocity was a species called Tylosaurus.
37:00The Tylosaurus was huge, the length of a bus.
37:04Larger even than one of the most feared dinosaurs of the time.
37:08These animals were, lengthwise, bigger than the largest Tyrannosaurus.
37:13And they were able to eat anything and everything that they encountered, including other mosasaurs or turtles, big fish, birds.
37:24For 20 million years, mosasaurs dominated the world's oceans.
37:32But their reign would also come to an end in yet another extinction event.
37:3865 million years ago, an asteroid the size of a city screamed through the heavens and slammed into Mexico's Yucatan Peninsula.
37:50The impact sent up a gigantic plume of fiery ash, equivalent to the explosion of 100 million megatons of TNT,
37:57or nearly a billion times the size of the Washington atomic bomb.
38:04Dust and debris blocked out the sun, sending temperatures plunging below freezing.
38:0970% of all life on Earth was wiped out.
38:12It's an event we call the KT extinction.
38:21The KT extinction event was a massive extinction event in Earth's history.
38:25It had a massive impact on the atmospheric composition, on temperatures, on obviously life in the oceans and on land.
38:35The most famous casualties of this disaster were the dinosaurs.
38:41But ocean life suffered a similar fate.
38:44It signaled the final blow for the mosasaurs and many other marine life forms.
38:49The big rock falling out of the sky didn't kill them directly, but it may have been responsible for wiping out this extensive food web that supported thousands of these very large predators.
39:04And when that food disappears, the mosasaurs are basically going to starve to death.
39:13But the KT extinction opened the door to a new migration from land to sea, this time by mammals.
39:24Fossils show a creature much like a tiny deer may have evolved into today's whales.
39:34The evolutionary journey from land to sea is emerging for whales and becoming clear for mosasaurs.
39:41But scientists have yet to find the ichthyosaurs missing link.
39:45Now the expedition team makes a discovery they hope could help give them an answer.
39:50Near the crest of Fossil Hill, a team of paleontologists has made an exciting new discovery.
40:05The remains of an ichthyosaur.
40:10And although this fossil isn't a sharptooth ichthyosaur, no one is disappointed.
40:15It appears to be five to six million years older than the sharptooth specimen.
40:23What gives it its primitive characteristics?
40:28So one of the things is the vertebra that we just talked about, this backbone.
40:32That's cylindrical, not disc-like yet.
40:35And then the rest are actually not difficult to see at this point.
40:40So that's why I want to see it exposed.
40:44So we should move all this off and get it swept off?
40:48Yeah, that would be nice.
40:50All right, let's do it.
40:53But they need to work fast.
40:55The wind is kicking up and a storm is on the way.
40:59Oh, sorry.
41:00I should have secured the bones during the hurry.
41:06We'll wash it off.
41:08I'm too excited.
41:10Yeah, I kind of want to expose the entire thing now.
41:12Yeah.
41:14After excavating the outer edges of the rock, the team gets a closer look at the fossil.
41:19I guess there's no end to it, really.
41:23So we have to stop somewhere.
41:25Wash until we have?
41:26Yeah, that's one way, yeah.
41:29Then we'll know where we are.
41:32The difficulty of distinguishing between rock and fossil is a typical problem.
41:37That embryo washes down the rock to help separate out the bone.
41:41But exactly what kind of ichthyosaur this is remains to be seen.
41:48Really, look at that.
41:50Awesome.
41:51There's way more ribs than we thought there were.
41:52So that's the backbone that we saw earlier, and these are the ribs that we saw.
42:04Some bones here and there, but they're not very well defined.
42:09It's difficult to tell at this point what they are.
42:11So these things are called gastrilia.
42:14So these are not the true ribs.
42:16But these are additional rib looking thin that covers the belly of the animal.
42:22There.
42:24We don't have it, but the reptiles do have it.
42:27So that's what these are.
42:28Yeah, so we have to find out the extent of this animal, how far it goes back, and if the skull is there or not.
42:35Then, once we expose everything, then we can secure the surface and collect it.
42:42So would you say this is one of the oldest ichthyosaurs in North America?
42:46Oh yeah, for sure. There's no doubt about it.
42:48I think it would be totally worthwhile getting it out of the field.
42:52It will take a lot though.
42:55They'd like to remove the fossil and get it to the lab.
42:59But with a storm brewing and a need for heavier equipment, recovery will have to wait.
43:04The team holds out hope that this ichthyosaur could in fact show an early transformation from land to sea creature.
43:16With a limb resembling a hand more than a flipper.
43:22The jackpot might be right there, actually.
43:26If it's just like the oldest ichthyosaurs, then we'll see flippers.
43:30But there's a chance that this might be even more primitive, right?
43:34We might have to go a little bit further back in time to find a more basal ichthyosaur,
43:40a more primitive ichthyosaur that does show that more terrestrial land feature that we are looking for.
43:47And there's probably only one place in the world that has it.
43:51Just like the whales, all the earliest whales come from Pakistan.
43:55That's the only place, because they enter water there.
43:58For ichthyosaurs, we don't know where they enter the water.
44:02Could have been here, could have been somewhere else.
44:05But if it was here, then there's a chance that we find something really primitive.
44:11So that's what we want.
44:15The discovery of this early fossil is one piece of the ichthyosaurs' evolutionary puzzle.
44:20But no one is sure what role the sharp-toothed creature plays in that story.
44:29The answer must wait until it can be fully prepared and studied.
44:34At this point, our investigation of this animal is just not complete enough to make any really firm conclusions of to which group it belongs within ichthyosaurs.
44:49So we'll have to await all the data that we collect to investigate this further.
44:57But it's already clear that the sharp-toothed ichthyosaur and its role as the top predator has changed what scientists thought they knew about these first seed reptiles.
45:07What are these first seed reptiles?
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