Beloved sauropod Dreadnoughtus is featured in the Apple TV+ show PREHISTORIC PLANET, episode 2 "Deserts." Paleontologist Dr. Kenneth Lacovara discusses their presentation and how accurate the dinosaurs were depicted.
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00:00It was quite a long scene of Dreadnoughtus.
00:03Here they are.
00:05A fight scene.
00:06It was a fight scene in this territorial battle
00:11between males.
00:12And I think this was actually kind of based on our science,
00:16because what we found with the two Dreadnoughtus individuals
00:20is that the much larger one, the 65-ton one,
00:24was osteologically, that means its bones,
00:26was osteologically quite young.
00:29You might even think of it as a teenager
00:31who was growing rapidly at the time of its death.
00:34Whereas the one that we found that was one-third smaller,
00:38osteologically, was much, much older.
00:41And so where do you find this in animals today?
00:43Where you find older, smaller individuals
00:46and younger, bigger individuals?
00:47That's in species where you have sexual dimorphism,
00:51where the two sexes are of different sizes.
00:55And usually that happens
00:56where you have male-dominated sexual selection,
00:59which means that two alpha males
01:01are going to compete with each other
01:03to control a territory or a group of females.
01:06There's also female-dominated sexual selection.
01:09That's where you see the males showing off
01:11with all kinds of colors and doing fancy tricks
01:14and buying Corvettes and things like that.
01:17And so with Dreadnoughtus, we have just a hint
01:21that we have sexual dimorphism.
01:24And then kind of a hint, based on a hint
01:27that maybe it was male-dominated sexual selection.
01:30And that's what you are seeing here.
01:32And then-
01:33These air sacs, we gotta talk about these air sacs.
01:35Yeah, let's talk about the air sacs.
01:36What do you think about that?
01:37Well, the air sacs are kind of hard to miss.
01:41I have to tell you that there is zero evidence
01:43that Dreadnoughtus had air sacs.
01:46These are pneumatic gular pouches
01:49like a grouse would have today.
01:51Is it impossible?
01:53No, it's not impossible,
01:55but we don't have any evidence that we've had that.
01:58Now, I was told by the consultant on the show
02:02that they wanted to find a way to illustrate the fact
02:07that extinct animals must have had
02:09amazing soft tissue structures
02:12that will never be preserved in the fossil record,
02:14which is certainly true.
02:15If we only knew elephants from their skeletons,
02:18I probably wouldn't really know what an elephant looked like.
02:22So this is an example of a hypothetical feature
02:26that maybe we're missing completely in the fossil record
02:29that could have existed.
02:31Did they specifically have this?
02:33Probably not.
02:34Is it impossible that they had this?
02:36No, it's also not,
02:38but we don't have any evidence of it.
02:40What we do have though,
02:41is we have their cervical vertebrae,
02:43cervical vertebrae.
02:45And the cervical vertebrae are very pneumatic,
02:48meaning that they have a system of air tubes
02:52and air bladders that invade the bone
02:55over the lifetime of the animal.
02:56So the bone becomes more honeycombed with air over time,
03:00making it very light,
03:01but still retaining most of the strength.
03:03Because if you have a 40 foot long neck,
03:06a 40 foot long lever,
03:07you don't wanna put a lot of weight
03:09at the end of that lever.
03:10So they have these very lightly built pneumatic necks,
03:14which I guess gave them the idea,
03:15okay, there's air in the neck,
03:17there's a lot of air in the neck.
03:19Why not something like male grouses in the breeding season
03:23that have these pneumatic cooler pouches
03:25that pop out like that?
03:27Thinking of a story of Dreadnoughtus.
03:31I know, it's always interesting to draw inspiration
03:34from modern creatures.
03:36There he goes.
03:37But I guess we'll have to hold out
03:39for any more fossil or soft tissue preservation.
03:43Yeah, there's certain things
03:44that we're just never going to know,
03:46and we kind of have to live with that disappointment.
03:50But there are a lot of soft tissue features
03:52that extinct creatures have
03:53that we're just never going to find.
03:56We can make inferences about them.
03:57Sometimes we can do that from molecular work
04:01with modern creatures.
04:02We can look at the DNA from groups of related creatures
04:06and kind of figure out where that trait must have started.
04:10Occasionally you get soft tissue structures preserved
04:15if you have very clay deposits
04:19that can preserve that kind of resolution,
04:21but that's very rare.
04:21And I don't see that scenario happening
04:23for big things like sauropods.
04:25That happens for little things like birds.
04:28And then there's always the promise
04:30of molecular paleontology,
04:31where we routinely cover now,
04:34recover blood vessels and blood cells
04:37and proteins from dinosaurs and other extinct creatures.
04:41A few DNA bases have been recovered.
04:43Is it possible we'll have
04:45a genome of a dinosaur,
04:46an Atlanavian dinosaur in the future?
04:50I don't know.
04:50It's a pretty high mountain to climb,
04:52but I can't say that it's impossible.