Anglerfish Ancestors Once Roamed The Seafloor

Summary

Short Wave: Anglerfish Ancestors Once Roamed The Seafloor

Released June 4, 2025 | Host: Emily Kwong and Regina Barber

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Introduction to Anglerfish Diversity

In the episode titled "Anglerfish Ancestors Once Roamed The Seafloor," hosts Emily Kwong and Regina Barber delve into the intriguing world of deep-sea anglerfish, exploring their diverse morphologies and evolutionary history. The conversation centers around the surprising diversity of anglerfish species despite their shared harsh deep-sea environment.

Personal Encounters and Changing Perceptions

Emily Kwong opens the discussion with a personal anecdote about her first encounter with anglerfish through the lens of popular culture:

Emily Kwong [00:22]: "The first time I ever saw an anglerfish was on the big screen. It appeared first as a warm, glowing light."

This cinematic introduction shapes many listeners' initial perceptions of these enigmatic creatures. Co-host Regina Barber echoes this sentiment, highlighting the memorable depiction of anglerfish in "Finding Nemo."

Co-host [00:34]: "A light. Yeah, over there."

Rose Fauchet from Rice University shares her childhood fear of anglerfish, inspired by the same movie, and how her perspective shifted after engaging in scientific research.

Rose Fauchet [01:13]: "And apparently when the anglerfish scene came on, I was so freaked out by it, I started crying and my mom had to take me out of the theater."

Scientific Exploration of Anglerfish Diversity

Transitioning from personal experiences to scientific inquiry, Rose Fauchet and evolutionary biologist Elizabeth Miller discuss their research on the morphological diversity of anglerfish. They sought to understand why over 200 species of deep-sea anglerfish exhibit such varied body shapes despite inhabiting the uniform conditions of the bathypelagic zone.

Elizabeth Miller [02:22]: "It's a huge expanse of space in total darkness, high pressure, cold temperatures, food limitation."

Their research focuses on quantifying morphological variations to place them within an evolutionary framework, aiming to determine whether these differences evolved rapidly or gradually.

Elizabeth Miller [04:23]: "It is a mystery. It's not clear why one anglerfish species would be shaped one way while a different anglerfish species would be shaped a different way."

Methodology: Building the Anglerfish Family Tree

The team employed a combination of detailed morphological analysis and genetic sequencing to construct a comprehensive family tree of anglerfish species. Rose Fauchet meticulously mapped the skulls of various anglerfish using CT scans, placing 111 landmarks on each model to quantify their structural differences.

Rose Fauchet [04:56]: "I took the CT scans that we had of these anglerfish and first I had to make them into like a 3D model."

Elizabeth Miller handled the genetic aspect, extracting DNA from preserved specimens to assess genetic similarities and differences. This dual approach allowed them to correlate physical diversity with genetic divergence.

Elizabeth Miller [06:04]: "And from there I use fancy statistical models and basically it tells me what the differences are from species to species and the significance of those differences as far as, like, how closely or distantly related the different species are."

Ancestral Origins and Evolutionary Transition

A key revelation from their study is the ancestral lineage of deep-sea anglerfish. The closest living relatives are the "sea toads" or "coffin fishes," suggesting that anglerfish ancestors were benthic, residing on the ocean floor before transitioning into the pelagic water column. This shift opened up new ecological niches, driving the evolution of diverse body forms.

Elizabeth Miller [10:01]: "The bathyplegic anglerfishes seem to have arisen from a deep sea benthic ancestor. And it was this transition off the seafloor that spurred the evolution of all of these new shapes."

Emily Kwong emphasizes the significance of this transition:

Emily Kwong [10:52]: "This seems like one of the biggest takeaways of your study. And it's amazing that anglerfish started from an ancestor that lived on the ocean floor and then made it into the water column to be the anglerfish that we know and love today."

Implications for Evolutionary Biology

The study challenges conventional wisdom by highlighting that the deep sea, often perceived as a biodiversity desert, is actually a hotspot for evolutionary diversification. This newfound understanding broadens the scope of biodiversity studies beyond traditional environments like tropical rainforests and coral reefs.

Elizabeth Miller [12:04]: "We're used to thinking of biodiversity in terms of, like, tropical rainforests and coral reefs, places that have a lot going on. And what we're learning from the evolutionary history of the angler fishes is that also might be a place where you can evolve a lot of biodiversity."

Rose Fauchet reflects on the positive aspects of their research amidst a field often focused on loss:

Rose Fauchet [12:38]: "A lot of this project was celebrating the biodiversity that we do have. And, yeah, it's kind of nice to for once not be like, well, here's a thousand genuses about to go extinct."

Conclusion: Celebrating Deep-Sea Biodiversity

The episode concludes by underscoring the importance of recognizing and celebrating the rich biodiversity of the deep sea. By uncovering the evolutionary history of anglerfish, Rose Fauchet and Elizabeth Miller provide a fresh perspective on the resilience and adaptability of life in one of Earth's most extreme environments.

Emily Kwong [13:52]: "Thank you for listening to Short Wave from NPR."

This exploration not only deepens our understanding of anglerfish but also invites listeners to reconsider the ecological and evolutionary dynamics of the deep ocean.

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Notable Quotes:

• Elizabeth Miller [02:22]: "It's a huge expanse of space in total darkness, high pressure, cold temperatures, food limitation."
• Rose Fauchet [04:56]: "I took the CT scans that we had of these anglerfish and first I had to make them into like a 3D model."
• Elizabeth Miller [10:01]: "The bathyplegic anglerfishes seem to have arisen from a deep sea benthic ancestor."
• Elizabeth Miller [12:04]: "We're used to thinking of biodiversity in terms of, like, tropical rainforests and coral reefs... that also might be a place where you can evolve a lot of biodiversity."

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This comprehensive summary captures the essence of the "Anglerfish Ancestors Once Roamed The Seafloor" episode, highlighting the key discussions, insights, and conclusions drawn by the hosts and guests. It provides a clear understanding of the research on anglerfish diversity and its broader implications for evolutionary biology, making it accessible and engaging for both listeners and those new to the topic.

Transcript

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[NPR Announcer]

You'Re listening to Short Wave from NPR.

[Emily Kwong]

The first time I ever saw an anglerfish was on the big screen. It appeared first as a warm, glowing light. I see a. I see a light.

[Co-host]

A light. Yeah, over there.

[Rose Fauchet]

I see it too.

[Emily Kwong]

Rising out of the dark with bulbous eyes and pointy teeth, this fish gets a villain moment in the 2003 Pixar movie Finding Nemo.

[Co-host]

So pretty.

[Elizabeth Miller]

Good.

[Emily Kwong]

Feeling's gone. And so ENS probably the best underwater chase scene in cinematic history.

[Rose Fauchet]

I remember seeing this movie in the theaters. I was three in 2003.

[Emily Kwong]

This is Rose Fauchet from Rice University.

[Rose Fauchet]

And apparently when the anglerfish scene came on, I. I was so freaked out by it, I started crying and my mom had to take me out of the theater.

[Emily Kwong]

But Rose has had a change of heart about anglerfish because this past year she did research about them alongside evolutionary biologist and ichthyologist Elizabeth Miller at UC Irvine. Now, Elizabeth says this moment in Finding Nemo, where dory and marlin are enthralled by the anglerfish's bioluminescent light, is pretty accurate to how it happens in the deep sea.

[Elizabeth Miller]

The idea is that the prey are drawn to the lure and they don't see the anglerfish attached to it and they get eaten.

[Emily Kwong]

There are over 200 species of deep sea anglerfish. The one in Vine Nemo is modeled after what's known as the football fish. But Elizabeth and Rose told me others look very different. Some are long and thin like eels. Some are squat. Some have huge prehistoric looking teeth, while others have big eyes set far back into their heads. And the majority of them live in the bathypelagic zone, the deep, deep sea.

[Elizabeth Miller]

It's a huge expanse of space in total darkness, high pressure, cold temperatures, food limitation.

[NPR Announcer]

But in this zone that is so.

[Emily Kwong]

Cold, so homogenous, and so devoid of sunlight, somehow the anglerfish still ended up looking very diverse. And researchers wanted to know why.

[Elizabeth Miller]

It is a mystery. It's not clear why one anglerfish species would be shaped one way while a different anglerfish species would be shaped a different way.

[Emily Kwong]

So today on the show, the big anglerfish mystery. Why do these science fictiony fish look so different from one another? What spurred this divergence in Anglerfish body shape and size. And what can that tell us about the deep sea as a whole? I'm Emily Kwong, and you're listening to Shortwave, the science podcast from npr.

[Co-host]

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[Emily Kwong]

All right, Rose and Elizabeth, the deep sea pelagic anglerfish. What were the big question marks for you and what did you want to what'd you want to figure out?

[Elizabeth Miller]

So we can look at images of anglerfish? And it seems obvious to our eyes that they're different shapes, but we needed to quantify that variation so that we can analyze it in an evolutionary framework. And what I mean by an evolutionary framework is understanding how all of that diversity evolved. Did it evolve very quickly? Did it evolve gradually? Those are the big questions.

[Emily Kwong]

And Rose, at the time you were an undergrad student at Rice University in Elizabeth's colleague's lab. Can you explain what you did on this project? What was your role?

[Rose Fauchet]

So my part of the project was looking at the morphology of anglerfish skulls. I had to look at the skeletons of the anglerfish and then determine which bones are which and like the edges of all the bones and, and things like that. So I took the CT scans that we had of these anglerfish and first I had to make them into like a 3D model. And then we have this very fun software that basically lets me put a, a little dot on certain points of that skull model we settled on. I believe it's 111 landmarks that I put onto each of these skulls.

[Elizabeth Miller]

Yeah, I will say 111 points is a lot. It's even more difficult when you've got these fish that have such bizarre skulls. The work that Rose did is really tremendous. And it was all done by hand.

[NPR Announcer]

So you all set about building a family tree for anglerfish. So cool. How do you even go about building something like that?

[Elizabeth Miller]

So to back up a little bit, the big family tree is what links all of these species together.

[NPR Announcer]

Yeah.

[Elizabeth Miller]

And the methods to do this are the same for pretty much any organism. You extract DNA from the tissues of these specimens. What makes it difficult in the case of the anglerfish is getting those tissues.

[Emily Kwong]

Right. This isn't a 23andMe situation. You can't just ask anglerfish to spit into a tube for you so you can collect their DNA.

[Elizabeth Miller]

That's correct. And finding the fish is no small feat, as you can imagine. It relies on careful planning of people who regularly go out to sea to do surveys of fishes in general, not necessarily targeting anglerfishes and making sure when an angler fish is found that it's preserved in the property. It needs to be kept on ice and kept cold pretty much as soon as it's brought up. It needs to be preserved in alcohol and put on a shelf in a museum. And that, that's the basis of the CT scans or the three dimensional X rays that we used. And then the tissues were the basis of the family tree.

[NPR Announcer]

Okay.

[Emily Kwong]

So while Rose was mapping all these three dimensional X rays, plotting points onto the skulls to see where the anglerfish were visually similar. It sounds like, Elizabeth, you were extracting the DNA and seeing where they were genetically similar.

[Elizabeth Miller]

That's right. That's exactly right. And so from there I use fancy statistical models and basically it tells me what the differences are from species to species and the significance of those differences as far as, like, how closely or distantly related the different species are.

[Co-host]

Wow.

[NPR Announcer]

Okay, Rose, can you talk a little bit about how you and Elizabeth got access to all these specimens and CT scans? I heard all this was done with museum collections. Kind of like an interlibrary loan, but for museums.

[Rose Fauchet]

So all these different museums across the world have like, fantastic collections of fish that are basically just preserved in ethanol. And there is like an online database where you can search for, you know, whatever species of fish you're looking for, and it will show you. And the fish world is actually, it's pretty small. It feels kind of like everybody knows everybody. And so if you ask nicely enough, they'll FedEx you fish that have been sitting in a jar since like 1965. And if you're a very lucky undergrad, you get to open up a package in lab one day and you're holding one of the rarest fish on Earth.

[Emily Kwong]

Were you one of these lucky undergrads.

[NPR Announcer]

Who got to do this?

[Rose Fauchet]

I did get to be an undergrad who opened up a box from FedEx one day and there's a football fish, you know, wrapped in cheesecloth, soaked in ethanol. And I picked up the fish and I was so excited, I ran down the halls of this building to, like, go and show all of my friends that I had a football fish. Also, I'm sure it's, you know, shocking to hear, but 60 year old fish sitting in ethanol do have a particular smell about them.

[Elizabeth Miller]

Delicious.

[NPR Announcer]

So you are going deep into anglerfish hay history in a way. In looking at these samples, I want to go all the way back to the original anglerfish ancestor. What did that ancestor look like, the one that started it all?

[Elizabeth Miller]

I'll give some context. That anglerfish, the deep sea anglerfish we've been talking about, are all part of this group with the scientific name lophiaformes.

[Emily Kwong]

Lophiaformes.

[Elizabeth Miller]

Yes.

[NPR Announcer]

Okay.

[Elizabeth Miller]

So the deep sea anglerfish, their closest relative within this broader group is a fish called the sea toad.

[NPR Announcer]

The sea toad, yes.

[Elizabeth Miller]

That's another fun one to Google, if you have access to Google. The sea toad.

[NPR Announcer]

Oh, I am, I am. Coffin fishes. Is that another word for sea toads? Yeah, they look very grumpy. They're literally frowning.

[Elizabeth Miller]

Exactly.

[NPR Announcer]

And hanging out on the bottom of the ocean floor.

[Elizabeth Miller]

Yep. Coffin fish is another word for them. So that's the closest relative, the closest living relative to the deep sea anglerfishes we've been talking about. And so what did the direct ancestor of the anglerfishes look like? It most likely looked something like that sea toad, although perhaps something intermediate. We can't know for sure. But what it implies is that the broader group, Lopheiformes has always been in the deep sea in some capacity. But the more significant transition was off the seafloor and into the water column.

[NPR Announcer]

Yeah.

[Emily Kwong]

This seems like one of the biggest takeaways of your study. And it's amazing that anglerfish started from an ancestor that lived on the ocean floor and then made it into the water column to be the anglerfish that we know and love today.

[Elizabeth Miller]

That's correct. The bathyplegic anglerfishes seem to have arisen from a deep sea benthic ancestor. And it was this transition off the seafloor that spurred the evolution of all of these new shapes.

[NPR Announcer]

And what does that tell us about, like, the conditions of this part of the ocean that made that so, like, it's just. Is it just that they had to adapt super quickly in order to survive?

[Elizabeth Miller]

I think the way to think about it is opportunity. They came off the seafloor into the water column, the bathyplagic zone, and presumably there are new ways of living, new ecological opportunities, even if we don't know necessarily what they are. And so they potentially evolved these new shapes to take advantage of those new opportunities.

[NPR Announcer]

Yeah. I want to ask you both one last question. Why do you think this is so important to study? How does it change how you think about this field of evolutionary biology?

[Elizabeth Miller]

I think this is critical for our understanding of the conditions that diversity evolves in. We're used to thinking of biodiversity in terms of, like, tropical rainforests and coral reefs, places that have a lot going on. And we look at a place like the deep sea and we see the opposite of that. And what we're learning from the evolutionary history of the angler fishes is that also might be a place where you can evolve a lot of biodiversity. And that's a totally new way of looking at that environment.

[NPR Announcer]

Rose.

[Rose Fauchet]

Well, so I think especially natural history and marine biology at this point in time can be a pretty devastating field to work in. You know, so much of what we do and what we think about is how much we are constantly losing that's already gone. But there's something about the scope of this project that felt positive and kind of like a nice reprieve from that. Yeah, I think a lot of this project was celebrating the biodiversity that we do have. And, yeah, it's kind of nice to for once not be like, well, here's a thousand genuses about to go extinct.

[NPR Announcer]

No, here's a thousand genuses being opportunistic hunters in the ocean. Yeah, I love that. Well, thank you both so much for spending time with me and helping shortwavers everywhere learn more about these incredible fish.

[Elizabeth Miller]

It was my pleasure. Thank you.

[Rose Fauchet]

Thanks.

[Emily Kwong]

This episode was produced by Hannah Chin. It was edited by Burleigh McCoy and fact checked by Tyler Jones. The audio engineer was Kwesi Lee. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Emily Kwong. Thank you for listening to Short Wave from.

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