Karma Nanglu

And these are kind of small, worm-like animals building tubes on top of these shelled creatures called brachiopods in order to basically steal the food that they're drawing into their mouths.

They had this weird marking on them.

It looked pretty much like a perfect sort of stylized question mark.

We had no explanation at the time for what this thing could possibly be.

So it just sort of sat there in the back of our minds, kind of like burrowing away at them for, you know, over the course of maybe like two, three years since we first found them.

And we kept on shelving it because we weren't sure what it was, but we knew we'd come back to it because it was super interesting.

Yeah, there's tons of different fossil parasite worms.

There are actually fossils of insects in amber.

I think specifically a group of insects called planthoppers.

And we can actually see nematodes emerging from them in this amber fossil.

So we have not just the host, we also have the parasite.

And in fact, the parasite is actually leaving the body.

It looks basically like if you took a photo of that happening in a modern environment.

Yeah, we were stewing on this for about two, three years.

So once in a while, I would basically go back to the paper or go back to those photos, rather, and do a bit of a search.

And I feel like I was just basically like kind of like like an investigation.

You're knocking off lists of lists of animals or lists of suspects.

Exactly.

Suspects.

And that's not just other animals, but it's like, could it be a feature of the animal's own gut?

Could it be something about their gills?

So we kept on looking at photos of these kinds of structures.

Couldn't see any of them.

And then eventually I wound up with these parasitic modern worms that build tubes that are very, very similar.

Yeah, no, totally.

Well, you know, the first thing to remember is for an animal to enter the fossil record is super rare.

Most things are never going to enter the fossil record at all.

And then to have the association is doubly rare.

And then what's cool about this, the shape of this trace specifically, is it's highly characteristic.

And when we look at their modern day relatives, the spionids who produce these kinds of traces, we actually know quite a lot about their behavior and how they produce the trace because spionids on modern day oysters and mussels and other kinds of commercially important bivalves, you know, for eating, have been really well characterized.

And so we kind of know what must have happened.

The larva must have landed on one of these shells.

It bore in sort of

dissolved away a little bit of the shell, built itself a little home, and then gradually elaborated this long tube out of which the adult worm would have stuck its face and its tentacles to feed on water.

Yeah, you know, 480 million years ago, this group of worms was living inside of basically small clamshells, completely content as can be.

Over the course of basically every major mass extinction, this group has continued to be successful to the point that we still are studying this modern group of organisms.

So it tells you something about parasitic lifestyles, how resilient they can be.

Totally, yeah.

Everyone likes to talk about dinosaurs, but, you know, these worms are, you know, a little bit innocuous, but they're still doing their thing.

I felt crushed.

Absolutely crushed.

Because, you know, it looked like a dynamite thing and leeches I know don't have a fossil record.

I'm not a leech scientist myself, but I knew what a huge discovery that would be.

But no, they were pretty upfront about that, which is what you want in a scientific colleague.

So that's great.

I feel like vindicated sounds too competitive.

I feel really scientifically satisfied that there was... Is that too professional?

You're so Canadian.

Well, yeah, I know.

Danielle's Canadian too, so she's giving me grief.

If you think about the history of life, basically, like a movie that's going through, basically the fossil record, we're not getting a complete picture.

So imagine watching that movie, but you're squinting the entire time.

But once in a while, you get to open your eyes and see the whole picture.

And then you go back to squinting.

And so this site...

in Wisconsin called Waukesha, is one of these sites of exceptional preservation where when watching the movie that's the whole tape of life, you get to open your eyes for a very brief moment and get the totality of the picture, which includes all the soft tissues, things like leeches and stuff.

Yeah, anytime.

It's always fun.

We have fossils as old as about 515, 516 million years old that have evidence of parasites on them.