(Intro)

Emily: Hey! We're here with Pete Makovicky, who is the associate curator of vertebrate paleontology?

Pete: Dinosaurs.

E: Dinosaurs?

P: Let's just say dinosaurs. So these are the bones of- the mortal remains, so to speak- of a new type of meat-eating dinosaur we call Siats meekerorum. This was published just a few weeks ago, and as you can see, it's nowhere near as complete as Sue.

E: Right.

P: But we have enough to tell us it's a new species, and to tell us what kind of dinosaur it is. So most of the bones are from the vertebral column, so we have a vertebra from the back-

E: That is one- what, is that a thoracic vertebra?

P: That is one- That would be, yeah, in a human being we'd call this a thoracic. So, sort of near the front of the chest. And the top is up here, so this would be- sort of correspond to the bump you'd feel on your back if you ran your thumb down your spine. At least, if you're more flexible than I am.

E: Yeah! I can't...

P: This is the body of the vertebra. This is sort of the bottom, and then through here is actually where the spinal cord would go. That little hole right there.

E: That thing is massive. So what kind of dinosaur is it?

P: So we know that Siats is a meat-eating dinosaur, a Theropod dinosaur, and there are a couple clues in the skeleton that tell us that. Unfortunately, we don't have the business end of this animal. We don't have its skull,

E: Oh, okay.

P: which would be the easiest way to tell.

E: Right.

P: But it has several features that tell us that it is unquestionably a meat-eating dinosaur. So you'll actually see, a cross section of these vertebrae, they're completely honeycombed like that.

E: Oh!

P: and so that's something we see of course in bird skeletons, and we know that birds are derived Theropod dinosaurs. We have also parts of the hip girdle of this animal. There's the hip bone itself, and then the ischium. And the shape of that tells us that we're also dealing with a meat-eating dinosaur. If we look at the tail, we have these big, broad, long extensions that basically overlap the vertebra in front. They create sort of a locking mechanism that makes the tail stiff. And that's another diagnostic feature of certain types of meat-eating dinosaurs.

E: How do those things assist it in its meat-eating ability?

P: In these big animals, you of course have a big front end, with a big torso and a giant head, and so you have to offset it with something, and we think the tail functioned that way. We have to have something that keeps that tail rigid and so these interlocking extensions...

E: Would you find something like that in an herbivore?

P: The herbivorous dinosaurs do slightly different things, so they'll have actually ossified tendons running along their vertebral column.

E: What does that mean?

P: So they basically have tendons, just like we would have around our joints, but they become infused with bone cells and they actually become bony. And that keeps the spine rigid and stiff. And just to give you an idea of size: this is a fairly big animal. This is not a Sue-sized dinosaur, but it would probably have been around 30 feet long, or a little bit longer, and would be up to 3-4 tons.

E: That's pretty big.

P: Yeah, and this is one of the toe bones. This is one of the knuckles in the foot.

E: Woah. Wooah.

P: So that give you just some sense of size.

E: Were they very fast animals? Are you able to tell that from their fossil remains?

P: These animals had huge leg muscles, but they probably needed huge leg muscles just to stabilize the joints in their legs.

E: Yeah.

P: And so these muscles didn't translate to speed, it was just to stand upright.

E: For stability?

P: Yeah.

E: How often is a dinosaur of this kind of caliber- how often is that discovered or unearthed?

P: Well, if we look at North America, which is where this animal comes from- this is from the middle of Utah- it's actually pretty rare. Worldwide, we're actually in sort of a renaissance of dinosaur paleontology, and we probably see up to 30, maybe 40 species named per year.

E: Really? I had no idea.

P: Most of them from China, but also from other parts of the world. But, if we're talking particularly about the North American record, this is pretty unusual. People often ask me, "Do you use some kind of cool remote sensing thing?" and it's like... No, I mean, we use Google Earth a lot now, 'cause you can actually find outcrop, but beyond that it actually just involves walking around and looking at the ground.

E: Really.

P: Sometimes for hours and days. And then at some point, you get lucky and you see bone coming out of the ground. Sometimes you dig in and you find a lot of dinosaur; most often you dig in and you don't find that much, so. The first part of this dinosaur we found is actually the not-so-good looking part of the hip bone that you see down here.

E: Woah.

P: And that's basically the bone crumbling out of the rock. It's been eroded by freeze-thawing, and so it's pretty broken up. And this was kind of spewing out and down the hillside, so the sheer volume of what was there,

E: Yeah.

P: you know, told us we were on to something big. In the field we'll dig around it, but we'll leave a certain amount of rock, and then we cover it in plaster. So over there you have a plaster jacket, also from Utah. Different dinosaur, but nearby. And that's basically our safe carrying case; we can drive it back across the country and bring it here. And then we'll open that up and then actually start the fine preparation process. And that can take a long time, so the rule of thumb is we say about 100 hours of lab time for every hour of- spent in the field collecting.

E: Really?

P: Yeah.

E: Woah!

P: I mean, it's a rough number; it varies a lot between different kinds of fossils, but that's sort of the average. So it takes a long time for a dinosaur to actually be ready for study and a possible exhibit. You know, a lot of people will ask me, like, "Well, you know, you have maybe one tenth of the skeleton. How do you really know this is a new animal?" And so, this of course involves a lot of anatomical knowledge, but here we're looking at the top part of a vertebra from the tail. And you'll see there are these holes on either side, front and back.

E: Yeah. Looks like a little face.

P: But they're very rare in the tails of dinosaurs. You mostly see them in front of the hips. And so only a couple of different kinds of dinosaur have these, but what's unusual is we only have two holes here. Usually if you find them you'll have three. There'll be one in the middle.

E: Oh.

P: But here you have this thick bar.

E: Right.

P: And so that's one of the unique features, so just looking at that we have evidence that it's a megaraptoran, but it's unlike any other megaraptoran we know. So it's that kind of anatomical knowledge we use to tell us whether we're dealing with a new dinosaur or an already known species or what particular group it might belong to.

E: Yeah, that's cool! You have like, pieces of a puzzle and you can kind of map them out where they would go, and from them, draw relations and you know, if the bone is going to be so big, you can have a projection of the rest of the skeleton.

P: Yeah, so one of the ways we estimate mass is, for example, we will look at the girth of a limb bone. This is the fibula, so this is the outside of the shin. 

E: Woah.

P: This is about, I'd say, half the bone or maybe two-thirds.

E: That is huge!

P: And by looking at sort of the girth of it, and comparing to other things where we have more complete skeletons we can come up with a rough size estimate.

E: Do you have an illustration of it?

P: We do.

E: Cool. We might just throw that in the video.

P: Sure.

E: Have a big, nice illustration of it.

P: We are going to put this out, I think, in January. We're actually going to put this out

E: Oh cool!

P: in Stanley Field Hall, so if people want to come and see the new dinosaur and learn a little bit more about it, it'll be out there in one of our cases.

E: Cool! Yeah, come see the dinosaurs!

P: No extra charge!

E: Yeah! At The Field Museum, for $15! New to science!

(Credits)

E: It still has brains on it.