Meet Fiona, The Pregnant Ichthyosaur Fossil

FLORA LICHTMAN: In the Patagonia region of Chile, Torres Del Paine National Park is a graveyard of ichthyosaurs, ancient dolphin-like reptiles that roamed the oceans when dinosaurs dominated the land. Nearly 90 of these giant reptiles’ fossils have been found amongst the glaciers. But the standout star in the bone heap is Fiona, an ichthyosaur that lived 131 million years ago.

She’s in pristine condition, the only fully preserved ichthyosaur in Chile, and she died pregnant. She’s teaching paleontologists about the evolution of her species, and some of those findings were recently published in The Journal of Vertebrate Paleontology. Joining me to discuss is the lead author, Dr. Judith Pardo-Pérez, paleontologist at the University of Magallanes in Chile. Judith, welcome to Science Friday.

JUDITH PARDO-PÉREZ: Thank you very much. Thank you very much for the invitation.

FLORA LICHTMAN: Judith, you discovered Fiona. Is that right?

JUDITH PARDO-PÉREZ: Yes. It was in 2009.

FLORA LICHTMAN: Did you had something big the minute you laid eyes on her?

JUDITH PARDO-PÉREZ: Yes! No, the first day when we saw it. Because the day when we found her, it was a crazy day because we were there almost three months. And the last day, I was pissed out because I have been in this area since 2004, and every single year we have been there, we have found ichthyosaurs. And that was the only year that we haven’t found any new ichthyosaur, and we were there for three months.

So I say we have to look for ichthyosaurs, and this is the last day. We have to find something new. And then we started exploring, and I just got this what I call the ichthyosaur fever when you get mad and piss out with everybody and you yelling or yelling. And I started and I went alone to look for ichthyosaurs, and the guys were coming afterwards with me.

And then when we were walking in the area that day, we found five ichthyosaurs, actually five new ichthyosaurs. And one of them, the last one was Fiona. We look at from a far distance, and we saw a very large black mark. And when we approached it, we were very amazed because she was completely exposed so we could see the entire leaf from the skull until her tail. And we came back afterwards in the next year in 2010.

So that year, I took a transparent plastic foil, and I put it over the bones. And I started to draw in the bones of the ichthyosaur. And drawing it, I saw very tiny little vertebrae in between the ribs, and I realized that she was pregnant and has a baby and that she was a female ichthyosaur. So that was the discovery.

FLORA LICHTMAN: That’s amazing. It’s like you manifested the find.

JUDITH PARDO-PÉREZ: Yeah, actually the next year when we came back in 2010, I was in my tent in the morning and I say we have found several ichthyosaurs. I found a completely exposed ichthyosaur. Now I want to find a pregnant ichthyosaur.

I say to the universe. And then that morning we realized that the ichthyosaur was pregnant.

FLORA LICHTMAN: You ask, and the fossil gods deliver I guess.

JUDITH PARDO-PÉREZ: Yeah. Yeah.

FLORA LICHTMAN: She died pregnant, which seems very cool to me as a layperson, but what can you learn from this?

JUDITH PARDO-PÉREZ: In this area, we have the ichthyosaur that was pregnant, but we also have found several neonates or newborns and also other ichthyosaurs that are also several newborns, adults, a lot of food. So we think that this area was an area where they came to give birth–

FLORA LICHTMAN: Like a nursery?

JUDITH PARDO-PÉREZ: Yeah, like a nursery area. So in this period of time in the history of ichthyosaurs of what we know worldwide, we don’t have information. So there is a gap in this time, which is during the early Cretaceous, 131 million years ago, and that will help us to understand the evolution of ichthyosaurs.

FLORA LICHTMAN: Wow. Can we learn anything about how they gave birth from looking at the fetus?

JUDITH PARDO-PÉREZ: Mmm hmm. They give birth with the tail first. So the last thing in going out was the skull because these were oxygen breathing animals. So this is the case with Fiona. You can see that the baby was going to be prepared to be born.

But this is very interesting because the first ichthyosaurs, they were giving birth with the head first. So it means that it wasn’t maybe an evolutionary strategy to change that in order to have the tail going out first and the head the last thing and not die during the process of giving birth.

FLORA LICHTMAN: That’s fascinating because basically you want to keep them– because they can’t breathe underwater, you want to keep their oxygen supply going for as long as you can before they’re born.

JUDITH PARDO-PÉREZ: Yeah, yeah, because the anatomy of ichthyosaurs they are very similar to dolphins. They are not related. Ichthyosaurs were marine reptiles, and dolphins are marine mammals. But in anatomy, they are very similar because both animals live and were very adapted to live in the sea.

FLORA LICHTMAN: Got it. Why did you name her Fiona?

JUDITH PARDO-PÉREZ: It was because during the process of excavation, we put a glue that we use to protect the bones because of the vibration of the machine that we were using. And when we were doing it, she turned green– a green color, and we were super scary because, ahhh, what’s happening and why she’s green and she’s supposed to not to be green and everybody will be mad at me.

And then we stopped to analyze what is happening, and with the magnifying glasses, we observed that there were little plants that were living in between the cracks and gave her this green color. So after that, we washed it with acetone, and then she came back to the normal color.

So that night, we started to draw names. And then Dr. Erin Maxwell from the Natural History Museum of Stuttgart, she said, well, maybe can be Fiona for Fiona of Shrek. And everybody liked it.

FLORA LICHTMAN: From Shrek. Yeah, it’s perfect. Yeah, it’s perfect. Give me a sense of a day in your life when you’re on an expedition.

JUDITH PARDO-PÉREZ: Yeah, expeditions here in Patagonia are very extreme because it requires a lot of logistics. So we drive the car for hours until the national park, and then we have to take a– to walk nine hours until the area where we camp. And the horses take some of the loads, and we walk. And the helicopter take the heaviest load.

And in the camp, you try to take data and to not die of cold because it’s– the weather is very complicated. Also it’s cold even in summer. You can have snow. Winds is also extreme. So taking that every day, it’s very demanding and a lot of work and for minimum amount the expeditions that we go.

FLORA LICHTMAN: Wow. Yeah, and you were saying that you were on month three, the end of three months for Fiona.

JUDITH PARDO-PÉREZ: Yeah.

FLORA LICHTMAN: Yeah. That’s a long time. That’s a way of life.

JUDITH PARDO-PÉREZ: Yes. Yeah, but we really like it. And we still have videos out there that we need to excavate because the ichthyosaurs are getting very damaged because of the erosion on the area. So they are going to be in a very short time slowly destroyed. So if we do not protect and see to the material and if we do not excavate them, we are going to lose it, and this is very something extremely, very important material worldwide.

FLORA LICHTMAN: What are you looking for now?

JUDITH PARDO-PÉREZ: I would like to find more pregnant ichthyosaurs. That could be super cool because this will support our hypothesis–

FLORA LICHTMAN: Oh, the nursery hypothesis?

JUDITH PARDO-PÉREZ: Yes, yes, that would help us a lot.

FLORA LICHTMAN: I love that. Well, good luck.

JUDITH PARDO-PÉREZ: Yeah. Thank you very much.

FLORA LICHTMAN: Dr. Judith Pardo-Pérez is a paleontologist at the University of Magallanes in Chile. Judith, thanks so much for joining us today.

JUDITH PARDO-PÉREZ: Thank you very much, Flora, for the invitation. It was very nice.

FLORA LICHTMAN: I agree.

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