Did Dreadnoughtus Really Have Air Sacs?

Live Science

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.

Transcript

00:00it was a quite a long scene of dreadnoughtus uh here they are um a fight scene there was a fight

00:07scene uh in this um territorial battle between males and i i think this was actually kind of

00:14based on our science because um what we found with the two dreadnoughtus individuals

00:20is that the the much larger one the 65 ton one was osteologically that means its bones was

00:27osteologically quite young you might even think of it as a as a teenager who was growing rapidly at

00:32the time of its death whereas the one that we found that was one third smaller uh osteologically was

00:40much much older and so where do you find this in animals today where you find older smaller

00:45individuals and younger bigger individuals that's in species where you have um sexual dimorphism where

00:51the two sexes are of different sizes and usually that happens where you have male dominated sexual

00:58sexual selection which means that uh two alpha males are going to compete with each other to

01:04control a territory or a group of females there's also female dominated sexual selection that's where

01:09you see the males showing off with all kinds of colors and doing fancy tricks and buying corvettes

01:14and things like that um and so with dreadnoughtus we have just a hint you know that we have sexual

01:23dimorphism and then kind of a hint based on a hint that maybe it was male dominated sexual selection

01:29and that's what you are seeing here and then um these air sacs we got to talk about these air

01:35sacs yeah let's talk about the air sacs what do you think about that well the air sacs are kind of hard

01:39to miss um i have to tell you that there is zero evidence that dreadnoughtus had air sacs uh these

01:46are pneumatic gular pouches like a grouse would have today is it impossible no it's not impossible

01:55but we don't have any evidence that they do have that now i was told by the consultant on the show

02:02that um they wanted to find a way to illustrate the fact that extinct animals must have had amazing

02:10soft tissue structures that will never be preserved in the fossil record which is certainly true if we

02:15only knew elephants from their skeletons i probably wouldn't really know what an elephant looked like

02:22so this is an example of a hypothetical feature that maybe we're missing completely in the fossil

02:28record that could have existed did they specifically have this probably not is it impossible that they

02:36had this no it's also not but we don't have any evidence of it what we do have though is we have

02:41their cervical vertebrae cervical vertebrae and um the cervical vertebrae are very pneumatic meaning that

02:49they have a system of air tubes and air bladders um that invade the bone over the lifetime of the

02:56animal so the the bone becomes more honeycomb with air over time making it very light but still

03:02retaining most of the strength because if you have a 40 foot long neck right a 40 foot long lever

03:07you don't want to put a lot of weight at the end of that lever so they have these very lightly built

03:12pneumatic necks which i guess gave them the idea okay there's there's air in the neck there's a lot of

03:18air in the neck why not something like a like male grouses in the breeding season that have these

03:23pneumatic cooler pouches that pop out like that thinking of a story of droid nanas

03:31i know it's always interesting to draw inspiration from modern creatures there he goes i guess we'll

03:38have to hold out for any more fossil or soft tissue preservation yeah you know there's certain things

03:44that we're just never going to know and we kind of have to live with that disappointment um but there are

03:50a lot of soft tissue features that extinct creatures have that we're just never going to find um we can

03:56make inferences about them sometimes we can do that from um molecular work with modern creatures we can

04:02look at the dna from from groups of related creatures and kind of figure out where that trait must have

04:09started occasionally you get um soft tissue structures preserved if you have very uh clay deposits that can

04:19preserve that kind of resolution but that's very rare and i don't see that scenario happening for big

04:23things like sauropods that happens for little things like birds um and then you know there's always the

04:29promise of molecular paleontology where you know we routinely cover now recover um blood vessels and

04:36blood cells and proteins from dinosaurs and other extinct creatures um a few dna bases have been recovered

04:43is it possible we'll have a genome of a dinosaur of a lion avian dinosaur of the future you know it's

04:50it's a pretty high mountain to climb but i can't say that it's impossible

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