LULU GARCIA-NAVARRO, HOST:
Coprolites - they're ancient and important for scientific discovery.
MARTIN QVARNSTROM: If you look at the fossil droppings, sometimes they are remarkably similar to something that, you know, our dogs produce in the park, just that they're mineralised, of course. So they don't smell, and they're very solid and hard.
GARCIA-NAVARRO: That's paleontologist Martin Qvarnstrom. And yes, he's talking about dinosaur poop - 230-million-year-old dinosaur poop. He's the lead author on a new study of coprolites, fossilized dinosaur feces. And why zoom in on them? Because we want to know...
QVARNSTROM: What this dinosaur relative had for lunch. Like, we could actually see a snapshot of its life and get, like, direct evidence to diets, in this case.
EMMANUEL ARRIAGA VARELA: This is the closest we can get to a time machine. This is like a small time capsule surrounded by dino dung.
GARCIA-NAVARRO: Emmanuel Arriaga-Varela contributed to the study. He's an entomologist. In a square inch of dinosaur scat uncovered in Poland, he found at least 10 intact water beetles and about another 20 fragments of heads and wings. It's a big find in a small specimen.
VARELA: It was - wow, I mean, we can see them - 10 we can see the legs almost intact. This is not possible with other beetles this age.
GARCIA-NAVARRO: And it's not possible because typically, coprolites need to be sliced or crushed in order to extract them.
QVARNSTROM: This poses a little bit of a problem because we want to look inside and see what they contain. The way we've studied the coprolite is by using synchrotron micro-tomography. It sounds complicated, but it's a bit like a CT scanner at the hospital but with a lot more power. So we're able to see small density differences within the fossils.
GARCIA-NAVARRO: Which is what allowed entomologist Varela to make out those legs and antenna and to compare the extinct beetle to its modern cousins, fitting more pieces into the evolutionary puzzle. The beetles, it turns out, were a fortuitous find in the dinosaur dung because scientists believe what was on the menu that day 230 million years ago was algae. And the beetles just had the bad luck to be hanging out in the algae when the dinner bell rang. Coprolites are common enough fossils that there are plenty of them already in museum collections. And Varela says he's getting calls to see if there may be other unexpected finds. Paleontologist Qvarnstrom, though, is looking ahead.
QVARNSTROM: Well, I think it would be really interesting to use this kind of direct evidence of feeding to see what happens before, during and after an extinction event. And this is something that is also, in a way, highly relevant today since we're living in an extinction. So it can tell us about what, could we expect to see in the future?
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