Andrew Davis> Despite their designation as "strangeness bearers" of the sea, these ancient odontocete whales were anything but!

Scott Persons> "Xeno" is Greek for strange.

Doctor Kellogg, the guy who named the first xenorophid doesn't actually specify what he meant by the name.

But probably what he was referring to was the strangeness of their teeth.

Xenorophids we think are some of the oldest whales known to have the ability to echolocate.

Davis> Sometimes it can be a visual treat to spot a pod of whales while out on the ocean, or even seeing a whale up close in an aquarium.

All whales fall into one of two sub-orders: baleen whales or "filter feeders" such as blue whales and humpback whales, or toothed whales like dolphins or orca.

A long time ago, South Carolina's Coastal Plain regions were underwater.

During that time, ancient ancestors of dolphins lived exclusively in the southeastern region of North America.

These predecessors were called Xenorophids.

A rather unusual name for whales, don't you think?

But what exactly makes these whales so fascinating?

I'm your host, Andrew Davis.

Today's journey takes us to the College of Charleston's Mace Brown Museum of Natural History, located in downtown Charleston, South Carolina.

Two special guests join to guide us as we "dive" into the history of these ancient whales.

Persons> I'm Doctor Scott Persons.

I'm the Curator of Natural History at the South Carolina State Museum.

Mike Stoller> Hey there.

My name is Mike Stoller.

I am the Excavations and Collections Manager for the Charleston Center for Paleontology We are a nonprofit working here in association with the Mace Brown Museum of Natural History.

Davis> Hey, Scott, welcome to Curiosity Trek!.

Persons> Thanks for having me.

Davis> Now, the first question I have for you is do xenorophids have any ancestors?

Persons> They do!

So xenorophids belong to a larger group of whales called "odontocetes".

That means they're members of the toothed whale family, and that includes a lot of modern forms like dolphins, killer whales, belugas, and even sperm whales.

But they're part of the larger cetacean family, so they belong to the same group and have the same shared common ancestors as all modern day whales and dolphins.

Xenorophids were around towards the very, very end of what we call the Paleogene period.

That means they date back from about 23 to 30 million years ago.

So during the time of xenorophids, at the end of the Paleogene, where we're standing right now, would've been underwater.

So we were experiencing at the time prehistoric global warming.

The world is warmer, which means that a lot of the water that today is held up in polar ice caps, it melted and flooded the world's oceans so sea level was high.

And that's how we're able to find the bones of these animals preserved here in Charleston.

Because the sea was here, they would sink down to the bottom of it, get preserved in the fine sediments, and now the sea has drifted off, and you can find these ancient, ancient rock layers sitting right on the surface.

The diet of a xenorophid really depends on the particular xenorophid.

Most xenorophids have got teeth at the front of the mouth at least that are long and conical.

They would be really good at clamping down onto and holding tight, slippery prey, things like small fish.

Now others have got no teeth at all and may have been going after soft bodied things like squid.

And still others have larger, more impressive teeth, suggesting they were pushing it towards taking down bigger fish.

Xenorophids did have a lot of natural predators, so they lived at the point in time where there are other large tooth whales swimming through the oceans, and also the time when there is some large scary sharks.

Now, as is the case with most whales, they begin life with a lot more predators than they ended in.

And as xenorophids got larger, the number of animals in the environment that would dare to meddle with them goes down.

Stoller> So lifespan?

We don't have a whole lot of data to work with, but we do know these odontocetes like, say, the bottlenose dolphin can live upwards of 40, 50 years.

So we know that they have probably decent lifespans at the time.

In terms of how big these xenorophids could get.

Some of the larger species would be somewhere in the realm of 8.5 to 10 feet long.

Whereas some of the smaller species, little guys, would have been somewhere in the realm of 3 to 4ft.

So there's quite a range.

As far as we know, right now we have six genuses or geni.

And each one, is very different, but they're all within the same group.

They're all within the xenorophid family.

Davis> Any speculation as to why they chose this particular area to live in?

Yeah.

So, xenorophids would have picked this general area because it was a shallow marine setting.

Like I mentioned, it was this estuarine environment with lots of mud, lots of sand, like shallow water.

Where there's plenty of prey that they could feed on.

So this would have been a good environment for something like an early dolphin.

Davis> Now we get to the part I've personally been looking forward to the most: What made these xenorophid whales so unique?

For that, we'll need to take a closer look at their skulls.

Now, what does the name xenorophid mean in Latin?

Where did that name come from?

Persons> That's a great question!

It's actually a hard question to answer.

So "Xeno" is Greek for strange.

And so when we call them xenorophids, we mean that they're sort of "weirdos", they're "strangeness bearers".

And the origin of that name is a little bit unclear because Doctor Kellogg, the guy who named the first xenorophid doesn't actually specify in his monograph describing it what he meant by the name.

That is, what about xenorophids he found that was so strange, so unusual by comparison to other fossil whales.

But probably what he was referring to was the strangeness of their teeth.

So if you look at the jaw of a modern day dolphin, the teeth that you'll see at the very front of the mouth are the same as the teeth and very back of the mouth.

They all have teeth they've got the same basic form to them.

They're tall, they're conical.

They're good at holding onto fish.

In the skull of a xenorophid, the teeth at the front look fairly similar to the teeth of a modern dolphin, but the teeth at the back have this jagged sort of hacksaw form to them!

And rather than having a single root, they are double rooted.

Xenorophids we think are some of the oldest whales known to have the ability to echolocate.

And we think that based on the structure of their inner ear bones now, a lot of the soft tissue that's associated with being able to echolocate; to produce the sound and hear it doesn't normally fossilize, but the ear bones themselves of xenorophids are very sophisticated and they do wind up being preserved.

In order to echolocate, you've got to do two things: you've got to be able to produce the sound underwater and project it in a concentrated way.

And then you also have to be able to perceive it in a sophisticated enough way that you're able to actually locate distance and position.

And one of the ways you do that is actually by having a little bit of asymmetry in your skull, because you can use that asymmetry as far as where you perceive the sound with one ear and where you perceive it with the other in order to detect the distance.

Davis> Given their abundance in our region, it would have been awesome to see one of these xenorophids up close.

But sadly, we are about 23 million years too late.

It just so happens that the Palmetto State got lucky, in the sense that most xenorophid fossils are found right in our own backyard.

Now, what factors led to the xenorophids' extinction?

Stoller> So at this time in the Oligocene, and kind of the into the Oligocene-Miocene boundary, you had a lot of climactic changes that were happening: we were starting to get colder, sea level was rising and falling, so there were just a lot of things that were happening in the whales environment that weren't very conducive to its survival.

Generally, the skeletons that we find from the xenorophid family tend to be up towards kind of the Summerville-Ridgeville area.

We have a field site up in Ridgeville, and generally you're looking at areas that are kind of 2 to 3 feet below the surface so buried, but discoverable.

Davis> Are xenorophids a common family of whale or are they more on the rare side?

Persons> Xenorophids tend to be more on the rarer side.

They're only found in southeast North America as again, as far as we know that might change in the future.

We might find a xenorophid somewhere else in the world.

But as of right now, we can only really find them in southeast North America.

So places like South Carolina North Carolina and Virginia, which is really fascinating.

Davis> Well, Mike, thank you for this "splash" of enlightenment about xenorophid whales!

Stoller> Of course.

Thanks for having me.

Appreciate it!

On behalf of South Carolina ETV, thank you for joining us!

Persons> My pleasure!

Thanks for having me!

Davis> Thanks to Scott and Mike, we now have a clearer picture on this amazing family of ancient odontocetes found almost exclusively in South Carolina.

If you're an animal lover and find yourself in the Charleston area?

I highly recommend stopping into the Mace Brown Museum to see their impressive collection of xenorophid fossils.

We hope you enjoyed today's dive into these xenorophid whales... And if you did?

All I have to say is... You're "whale-come"!

I'm Andrew Davis.

Thanks for watching, and we hope to see you on our next trip!