Category Archives: extinct

Episode 255: Reptiles with Something Extra

Posted on by

Podcast: Play in new window | Download (Duration: 12:13 — 13.9MB)

Subscribe: RSS | More

Sign up for our mailing list! We also have t-shirts and mugs with our logo!

Thanks to Ethan and Simon this week for their suggestions! This week we’re looking at some extinct reptiles that each have a little something extra (and unexpected).

Further reading:

Two Extinct Flying Reptiles Compared

Cretaceous ‘Four-Limbed Snake’ Turns Out To Be Long-Bodied Lizard

Kuehneosaurids may have resembled big Draco lizards although they weren’t related:

Big turtle:

Purussaurus was big enough to eat even really big turtles (from Prehistoric Wildlife):

Meiolania had a pointy head and a pointy tail:

Not a snake with legs after all:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week we’ll learn about an extinct reptile suggested by Ethan, some extinct turtles suggested by Simon, and an extinct snake that might not be a snake at all. All these animals had physical details you wouldn’t expect, as we’ll see.

First, though, a reminder that I have five Kickstarter backers who haven’t sent me their birthday shout-out names and birthdays yet! I sent messages to them last month and haven’t heard back, so if you backed the Kickstarter and added on the birthday shout-out, but never got the opportunity to send me your names and birthdays, please message me as soon as possible! The shout-outs start in January!

So, on to the extinct reptiles that each have something a little extra. Let’s start with Ethan’s suggestion, the kuehneosaurids. Kuehneosaurus, kuehneosuchus, and their relations lived around 225 million years ago in what is now England. The first dinosaurs lived around the same time but kuehneosaurids weren’t dinosaurs. They were lizard-like reptiles that grew about two feet long, or 70 cm, including a long tail, and probably lived in trees and ate insects. Oh, and they had wings.

They weren’t technically wings but extended ribs. Kuehneosaurus’s wings weren’t all that big, although they were big enough that they could act as a parachute if the animal fell or jumped from a branch. Kuehneosuchus’s wings were much longer. In a study published in 2008, a team of scientists built models of kuehneosuchus and tested them in a wind tunnel used for aerospace engineering. It turned out to be quite stable in the air and could probably glide very well.

We don’t know a whole lot about the kuehneosaurids because we haven’t found all that many fossils. We’re not even sure if the two species are closely related or not. We’re not even sure they’re not the same species. Individuals of both were uncovered in caves near Bristol in the 1950s, and some researchers speculate they were males and females of the same species. Despite the difference in wings, otherwise they’re extremely similar in a lot of ways.

Generally, researchers compare the kuehneosaurids to modern Draco lizards, which we talked about in episode 237, even though they’re not related. Draco lizards are much smaller, only about 8 inches long including the tail, or 20 cm, and live throughout much of southeastern Asia. They have elongated ribs that they use to glide efficiently from tree to tree, and they eat insects. Draco lizards can fold their wings down and extend them, which isn’t something the kuehneosaurids appear to have been able to do.

Next, let’s look at Simon’s turtles. Stupendemys geographicus lived a lot more recently than the kuehneosaurids, only about 6 million years ago in northern South America. It was a freshwater turtle the size of a car: 13 feet long, or 4 meters. As if that wasn’t impressive enough, the males also had horns—but not on their heads. The male Stupendemys had projections on its shell, one on either side of its neck, that pointed forward and were probably covered with keratin sheaths to make them sharper and stronger. Males used these horns to fight each other, and we know because some of Stupendemys’s living relations do the same thing, although no living species actually have horns like Stupendemys. They’re called side-necked turtles and most live in South America, although they were once much more widespread.

Stupendemys probably grew to such a huge size because there were so many huge predators in its habitat. It lived in slow-moving rivers and wetlands, where it probably spent a lot of time at the river’s bottom eating plants, worms, crustaceans, and anything else it could find. It was too big and heavy to move very fast, but a full-grown turtle was a really big mouthful even for the biggest predator in the rivers at the time, Purussaurus.

Purussaurus was a genus of caiman, related to crocodiles, that might have grown up to 41 feet long, or 12.5 meters. We don’t know for sure since the only Purussaurus fossils found so far are skulls. It ate anything it could catch, and we even have Stupendemys fossils with tooth marks that show that Purussaurus sometimes ate giant turtles too. One Stupendemys fossil has a 2-inch, or 5 cm, crocodile tooth embedded in it.

Stupendemys is the largest freshwater turtle known and the second-largest turtle that ever lived. Only Archelon was bigger, up to about 15 feet long, or 4.6 meters. Archelon was a marine turtle that lived around 70 million years ago. We talked about it in episode 75.

Simon also told me about another turtle genus, Meiolania, which lived in what is now Australia and parts of Asia around 15 million years ago. It might even have remained in some areas as recently as 11,000 years ago. The shell, or carapace, of the largest species grew over 6.5 feet long, or 2 meters. Even the smallest species had a carapace over 2 feet long, or about 70 cm. Since the fossils of smaller species have only been found on islands, researchers think the small size may have been due to island dwarfism. It probably lived on land and ate plants. It also had horns, but not on its shell. These horns were actually on its head, although they aren’t technically horns.

The horn-like projections pointed sideways and its tail also had spikes at its end. That meant it couldn’t pull its head under its shell to protect it like most other turtles can, but on the other hand, anything that tried to bite its head or tail would get a painful mouthful of spikes.

We don’t know a whole lot about Meiolania, including if it’s related to living species of turtle. When the first fossils were found, early paleontologists thought they were lizards, not turtles. What we do know, though, is that people ate them. Bones of some species appear in the middens, or trash sites, of ancient people in Australia, and there’s evidence that they were hunted to extinction within a few hundred years after humans settled where the turtles lived. That would also explain why the island-dwelling species seemed to have lived longer than the mainland species, since people didn’t live on the islands where they’ve been found.

Finally, we’ll finish with Tetrapodophis amplectus, leading to the philosophical question about whether a snake with legs is really a snake. That’s the same question researchers were asking themselves too until very recently. Tetrapodophis was only described in 2015 and was initially determined to be an early snake that had four legs.

Tetrapodophis lived around 120 million years ago in what is now Brazil in South America. It grew about a foot long, or 30 cm, and had a slender, elongated body with small but well-developed legs. Is it a lizard with snake-like characteristics or an early snake that hadn’t completely lost its legs yet?

It had hooked teeth and we know it ate small animals because one specimen actually has the fossilized remains of its last meal in its fossilized digestive system. Initially researchers thought it might have been a burrowing animal, using its small legs to help it grab onto items and push itself forward.

The type specimen was a complete skeleton, which is really rare. Unfortunately it was illegally exported and the paleontologist who described the species didn’t bother to at least invite a Brazilian paleontologist to study the Brazilian fossil. He was also incredibly rude when asked about it so I’m not going to give you his name, but he seems to be a really sketchy guy, which is too bad.

He also made some mistakes that might not have been mistakes. If a person is dishonest in one area, they’re probably dishonest in other areas too. When he described Tetrapodophis, he mischaracterized some aspects of its anatomy to make it seem more snake-like. A new study published in November 2021 corrects those mistakes and determines that instead of being a flashy exciting snake with legs, Tetrapodophis was most likely just a small member of the lizard family Dolichosauridae. I’m happy to report, by the way, that one of the lead authors of the new study is named Tiago Simões, a paleontologist from Brazil.

Dolichosaurs were marine lizards with small legs and snake-like bodies and were actually pretty closely related to mosasaurs. You know, the marine reptiles that lived at the same time as dinosaurs and could grow more than 50 feet long in some species, or 15 meters.

There’s some controversy in the mosasaur camp too, because some researchers think mosasaurs were most closely related to snakes while others think they were most closely related to monitor lizards. It just goes to show that scientific knowledge is forever growing and adapting to new information as it comes to light, but that answers aren’t always clear.

What is clear is that extinct reptiles are awesome, but you probably already knew that.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 240: The End of the Dinosaurs

Posted on by

Podcast: Play in new window | Download (Duration: 24:51 — 28.7MB)

Subscribe: RSS | More

Sign up for our mailing list! We also have t-shirts and mugs with our logo!

Here we go. It’s the big one, the Cretaceous-Paleogene extinction event!

Further reading:

How Birds Survived the Asteroid Impact That Wiped Out the Dinosaurs

How an asteroid ended the age of dinosaurs

Extinction event that wiped out dinosaurs cleared way for frogs

How life blossomed after the dinosaurs died

66-million-year-old deathbed linked to dinosaur-killing meteor

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Here it is, the extinction event episode that everyone’s been waiting for, or at least that everyone knows about. It’s the one that killed off the dinosaurs and ushered in the age of mammals. It’s probably the one we know most about and it’s certainly the one we have the most paintings of, usually of a T. rex staring into the sky at an approaching comet.

In episode 227 we talked about the end-Permian extinction event, which took place about 250 million years ago. The Cretaceous-Paleogene extinction event, or end-Cretaceous, took place just over 66 million years ago, which means that for almost 200 million years there was more or less smooth sailing in the world. Dinosaurs evolved during that time, and I think we can all agree that dinosaurs are fascinating animals.

The largest terrestrial animals ever to live were dinosaurs, specifically the sauropods. Sauropods were just unimaginably huge. They were like walking buildings that ate plants, and even that doesn’t give a good idea of their size. Some sauropods had extremely long tails as well as very long necks, which increased their length. Right now the largest sauropod known was probably Argentinosaurus that might have grown as long as 118 feet, or 36 meters, but paleontologists keep finding bigger and bigger sauropods. Some sauropods had extremely long necks that they held up like a giraffe. The tallest was probably Barosaurus, estimated as being 72 feet tall, or 22 meters. And we won’t even get into estimates of how much these massive animals weighed. They make the biggest elephant that ever lived look like a toy elephant.

Sauropods ate plants, with the low-necked species eating low-growing plants and the high-necked species eating tree leaves, although even saying that much is controversial. There’s a lot we don’t know about sauropods in general, since most sauropod fossils are incomplete and many species are only known from one or a few bones. But we do know some surprising things about sauropods. We have a lot of sauropod tracks, which helps us understand how their feet looked and whether they had claws, but it also tells us that some species of sauropod traveled in herds. Paleontologists do generally agree that many sauropods migrated, since animals that big would soon exhaust all the food in one area if they didn’t.

Sauropods were extremely successful and lived all over the world. There were plenty of sauropods alive 66 ½ million years ago, and then…there were no sauropods alive ever again.

These days, there’s so much evidence that a massive asteroid killed off the dinosaurs that pretty much everyone agrees, but when the idea was first proposed in 1980, it was extremely controversial. When I was a kid I remember reading dinosaur books that still said the extinction of the dinosaurs was a mystery but that many scientists thought it was due to disease or volcanoes.

The asteroid strike hypothesis was proposed by the physicist Luis Alvarez and his son, Walter. They worked with a small team of other scientists, including two chemists, Helen Michel and Frank Asaro, to investigate a strange anomaly in rock strata. Rocks dating to the end of the Cretaceous period and the beginning of the Paleogene period are separated by a thin layer of clay that’s visible throughout the world, or at least wherever the rocks remain and can be examined. It’s called the Cretaceous-Paleogene boundary, or K-Pg boundary, although in older books and websites it’s called the K-T boundary. It occurred just over 66 million years ago. The Alvarezes were curious about this layer, and during their investigations they found out that the clay is full of an element called iridium.

Iridium is a silvery-white metal chemically related to platinum, and it’s rare. At least, it’s rare on Earth. It’s a common component of asteroids, which was one of the main reasons why the Alvarezes came to their hypothesis that the K-Pg boundary was the result of a massive asteroid impact. Other scientists had made similar suggestions in the decade or so leading up to the Alvarezes’ theory, but the iridium discovery provided the proof everyone wanted.

Iridium wasn’t the only thing found in the K-Pg boundary layer, either. There were other platinum-group metals present in high concentrations—much higher than found on Earth, and in fact these elements are referred to as rare-earth metals for that reason. In some places, the K-Pg boundary contains grains of shocked quartz and microtektites. We’ll discuss those in a minute.

As we’ve discussed before in various episodes, the earth’s surface is always moving around. It’s slow to us, with continents moving around at the same dizzying speed that our fingernails grow, but over millions of years that adds up. Continents move around and crash into each other, forming new mountain ranges that then wear down to plains, and where continental plates pull apart or push together the crust can weaken and allow magma to erupt through as volcanoes. Ocean levels rise and fall. In other words, a crater made 66 million years ago might have disappeared as all this geologic activity goes on.

But then, we found the crater. The crater.

The Chicxulub crater is in Mexico, specifically the Yucatán Peninsula at the southern portion of the Gulf of Mexico. You can’t see it when you’re walking around because it’s buried under 2,000 feet of soil, or 600 meters, that has built up over the last 66 million years. Two geophysicists found it in the 1970s while surveying for petroleum, but it wasn’t until 1990 that they were able to verify that it was a crater. Asteroid impacts leave clues behind that the geophysicists recognized.

The first clue is shocked quartz. Quartz is a common crystalline mineral throughout the world, and it has a certain structure that’s familiar to geologists. In shocked quartz, that structure has been deformed by intense pressure, but not high temperature. It was first noticed after nuclear bomb tests, and after that scientists recognized it in meteor craters.

The second clue is little pieces of glass called tektites. They’re different from obsidian, which is a type of glass formed by volcanic activity. Tektites are usually shaped like droplets or little blobs, but sometimes they’re round. They’re only found around big impact sites and only for relatively recent meteor impacts, because they don’t last forever.

The Chicxulub crater is actually kind of old for its tektites to still be around, except for two things. First, the tiniest tektites, the microtektites, ended up in the K-Pg boundary layer, as I mentioned earlier. Second, we actually have a fossil site in North Dakota, in the middle of North America up near Canada, that seems to date to literally the day of the asteroid impact, and there are tektites all over the site, including clogging the gills of fish. The tektites match the chemical signatures of the Chicxulub crater so we know that’s where they came from.

Before we talk about the North Dakota fossil bed, let’s discuss what exactly happened on the day the asteroid hit the earth. Because we’ve found the asteroid’s crater, we know a lot about the asteroid itself. Most researchers estimate that it was about 6 miles across, or 10 km. It approached the earth at an angle, traveling about 12 km a second. That’s 7.5 miles per second. It hit the earth right on the coast, partly in the ocean, partly on land, forming a crater about 110 miles across, or 180 km, and 12 miles deep, or 19 km.

The asteroid smashed into the Earth so fast that it was completely buried in about the time it takes you to blink. There really wasn’t time for any dinosaurs to look up and wonder what that bright light was, because the time between the asteroid entering earth’s atmosphere and smashing into the earth was maybe five seconds.

The megatsunami resulting from the impact would have been unbelievably huge. Waves may have been a mile high, or over 1.5 km. The initial impact would have thrown water more than 7.5 miles into the air, or 12 km, and when that water fell back down it would have set up another megatsunami. Not only that, the impact actually shook the whole earth like a massive earthquake, which caused landslides all over the place and set up even more tsunamis. It’s like shaking a snowglobe to watch the fake snow swirl around and around, only instead of fake snow it was ocean.

At the same time, everything near the impact site was instantly on fire. It was on fire because the asteroid was traveling so fast that it was glowing white-hot with incandescent heat just from pushing against air molecules, and when it hit the Earth, all that heat had to go somewhere. Also, everything exploded. The water exploded up and outward, the land exploded up and outward. A lot of water turned instantly to steam. The asteroid itself disintegrated and tiny bits of it were carried high into the atmosphere along with ash, dust, molten glass created by the blast, and anything else that was nearby and not instantly incinerated.

The shockwaves from the impact acted as a magnitude 12 earthquake, with follow-up shocks estimated at about magnitude 9 occurring across the entire planet. Volcanoes erupted as a result, pumping even more ash and gases into the atmosphere. All the trees were flattened for about 930 miles around the impact, or 1500 km.

Within a few hours of the impact, fireballs of molten rock and glass were falling across the world, setting fires on land and heating the surface of the ocean to boiling temperature in many areas. And it was already getting really dark as the massive amounts of debris and dust and ash and smoke and everything else spread across the earth.

Okay, deep breath. This happened a long, long time ago and most animals died so quickly they didn’t feel anything. Look out the window if you’re feeling stressed and see how calm it is? Maybe it’s raining where you live or maybe it’s night-time and you can hear frogs or crickets calling, maybe an owl if you’re lucky. It might be daytime and you can hear cars passing by, or a dog barking somewhere, people talking. Whew. Okay, back we go to that awful day 66 million years ago, back to the fossil site found in North Dakota.

Back then, the middle of North America was a shallow sea. The first tsunami wave was probably 30 feet tall, or 9 meters, when it reached the mouth of a river emptying into the sea. It pushed the river backwards and washed hundreds of freshwater fish onto a sand bar. To add insult to injury, or just injury to injury, while the fish were stranded and flopping around trying to get back in the water, globs of molten glass and rocks rained down on them. Then another wave pushed up the river and covered the dead and dying fish with a lot of sand and sediment, which preserved them.

The site was discovered in 2013 and the findings were published in 2019. It’s not just fish at the site, although there are unbelievable numbers of fish. There are also tree trunks and branches that show evidence of burning, ammonites and other marine animals that were washed up the river, even part of a triceratops and a hadrosaur. One charred trunk is covered in amber, which is fossilized tree resin. The amber is full of tektites, which were caught in the resin when it was soft.

Every time I say tektite I think of those spidery things in Zelda, which makes this whole situation seem even worse.

None of the animals at the site show evidence of being eaten by anything. Some researchers estimate that the event took place less than an hour after the asteroid impact. There’s also a layer of clay on top of the sediment that contains high levels of iridium.

In all, roughly 75% of all life on earth went extinct following the asteroid impact. Many animals that survived the immediate aftermath of the impact died out months or years later, and many more scraped along for hundreds or thousands of years before finally going extinct. The massive amounts of dust and ash in the atmosphere blocked sunlight for the next several years or even longer, which means plants died throughout the world. Poisonous gases in the atmosphere led to acid rain that killed more plants and animals. The ocean temperature dropped considerably, as did the overall temperature of the earth, leading to freezing temperatures that would have killed off even more animals. Deep-sea animals fared better than most, but many plankton went extinct very soon after the impact and that meant animals that ate the plankton also went extinct.

But, of course, not everything went extinct. If it had, I wouldn’t be recording this episode and you wouldn’t be listening to it. Awful as it sounds, the Cretaceous-Paleogene extinction event wasn’t nearly as bad as the end-Permian extinction. Full recovery is estimated to have taken as much as 9 million years, when it took 50 million years for the earth to fully recover from the end-Permian extinction.

One thing that isn’t generally known is that things had been getting rough on earth for a couple of million years before the asteroid hit. Some species were already in decline due to climate change. The asteroid just made everything intensely worse.

The first plants to recolonize the blasted wastelands were ferns, lots and lots and lots of ferns. Ferns are tough plants and thrive in areas where nothing else can grow, and ferns grow quickly and provide food for lots of animals. Within a hundred years of the impact the world was carpeted with ferns.

Some dinosaurs did survive, of course, but we call them birds. They would have looked very birdlike even 66 million years ago. Most birds that survived were ones that lived on the ground instead of in trees. Researchers think many birds survived because they were able to eat seeds, which would have remained as a food source even after the plants that dropped the seeds had all died. Insects and other invertebrates that eat rotting leaves would have been just fine, and many birds could find and eat them too.

Mammals also survived the asteroid impact, of course. Look, here we are! We’ve done quite well for ourselves. 66 million years ago most mammals were small and rodent-like, and the ones that survived probably mostly lived in burrows and ate seeds and other plant material or small animals like insects.

Surprisingly, frogs did really well after the asteroid impact. Frogs are small and can survive in small microhabitats. While most of the frogs in North America went extinct, plenty of frogs survived in other parts of the world that weren’t so close to the impact site, and as soon as conditions improved, more species evolved than ever before. That’s why frogs across the world look so similar. They may not all be closely related, but they all faced the same environmental pressures at the same time.

Once plants started to recover, things took a turn for the better as birds, fish, mammals, reptiles, amphibians, insects, and other animal groups suddenly didn’t have to watch out for dinosaurs or the other big predators that had gone extinct. Sauropods and other giant herbivores weren’t eating up all the plants. Life evolved rapidly to fill the available ecological niches, and animals started getting bigger and bigger.

In late 2019, scientists released details of a fossil site found in Colorado, in the western United States. It has an unbroken record of rocks dating from before the asteroid impact to about a million years afterwards. It gives us an excellent record of the changes that took place.

In the years after the impact, there’s not a lot to see, just lots of ferns and some rat-sized mammals. Within 200,000 years palm forests had replaced the ferns and cat-sized mammals were common. By 400,000 years after the impact, plants and trees with nuts evolved and many mammals were the size of dogs. By 700,000 years after, the relatives of modern bean and pea plants appeared, forests were varied and healthy, and the mammals were the size of wolves or bigger. There were animals other than mammals too, including a five-foot-long crocodilian, or 1.5 meters, with teeth adapted to crush turtle shells.

The ancestors of whales evolved about 50 million years ago around what is now India and its neighbors, when a little animal called Indohyus spent a lot of time in the water. It was about the size of a raccoon, which it resembled in some ways, except that its bones were unusually heavy for its size. This helped it stay underwater without effort. The hippopotamus has the same kind of heavy bones for the same reason, and Indohyus was actually related to the hippo’s distant ancestor. Within five million years, descendants of animals like Indohyus were fully aquatic and looked a lot like dolphins with small legs. As whales got bigger and faster, predators evolved too, including the largest shark that ever lived, Megalodon. The first baleen whales evolved around 25 million years ago and ultimately grew to the gigantic sizes of some of the whales alive today.

Every time you feel sad that you’ll never see a real live dinosaur like a sauropod, remember that you live at the same time as the undisputed largest animal that has ever lived, the blue whale. It can grow up to 98 feet long, or 30 meters, and possibly longer. That’s as long as a ten-story building is high. It’s twice the length of Megalodon! If you have the money and time, you can actually charter a boat that will take you out to look at blue whales because they’re still alive!

I guarantee you that millions upon millions of years from now, in some far-distant future that we can’t even imagine, there will be scientists who study whales and write whatever those future people use as books, and there will be young people who read those books and look longingly at drawings of whales. They’ll know about dinosaurs, sure, and those will always be popular, but it’ll be the whales that really catch people’s imagination. There will be the far-future equivalent of movies where people successfully clone whales or bring them back from the past, and the details will be all wrong but no one will know because no one in that far future time will actually know what whales really look like! But you know, and that is the most amazing fact I can ever share with you.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes. There are links in the show notes to join our mailing list and to our merch store.

Thanks for listening!

Episode 236: Updates 4 and a Mystery Snake!

Posted on by

Podcast: Play in new window | Download (Duration: 17:33 — 19.4MB)

Subscribe: RSS | More

Sign up for our mailing list! We also have t-shirts and mugs with our logo!

It’s our fourth annual updates and corrections episode! I’ve already had to make a correction to this episode!

Further reading:

Cassowary, a rare emu-like bird, attacks and kills Florida man, officials say

The dog Bunny’s Facebook page

3D printed replicas reveal swimming capabilities of ancient cephalopods

Enormous ancient fish discovered by accident

A rare observation of a vampire bat adopting an unrelated pup

Pandemic paleo: A wayward skull, at-home fossil analyses, a first for Antarctic amphibians

Neanderthals and Homo sapiens used identical Nubian technology

Entire genome from Pestera Muierii 1 sequenced

Animal Species Named from Photos

Cryptophidion, named from photos:

The sunbeam snake showing off that iridescence:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

 

It’s our fourth annual updates and corrections episode, and to keep it especially interesting we’ll also learn about a mystery snake. Make sure to check the show notes for lots of links if you want to learn more about these updates.

 

First, we have a small correction from episode 222. G emailed with a link about a Florida man who was killed by a cassowary in 2019, so cassowaries continue to be dangerous.

 

We also have a correction from episode 188, about the hyena. I called hyenas canids at one point, and although they resemble canids like dogs and wolves, they’re not canids at all. In fact, they’re more closely related to cats than dogs. Thanks to Bal for the correction!

 

In response to the talking animals episode, Merike told about a dog who uses computer buttons to communicate. The dog is called Bunny and she’s completely adorable. I’ll link to her facebook page. I have my doubts that she’s actually communicating the way it looks like she is. She’s obviously a clever dog but I don’t think she understands the English language so well that she can choose verbs like “is” from her list of words. I think she’s probably mostly taking unconscious cues from her owner. But I would be happy to be proven wrong.

 

Following up from our recent deep-sea squid episode, a team of paleontologists studying ancient cephalopods 3-D printed some replicas of what the animals would have looked like while alive. Then they took the models into a swimming pool and other water sources to study how their shells affected the way they could move through the water. They discovered that a type of cephalopod with a straight shell, called an orthocone, probably mostly moved up and down in the water to find food and could have moved extremely fast in an upward or downward direction. A type of cephalopod with a spiral shaped shell, called a torticone, also spun slightly as it moved around. The same team has previously worked with 3-D models of ammonoids, which we talked about in episode 86. The models don’t just look like the living animals, they have the same center of balance and other details, worked out mathematically.

 

Speaking of ancient animals, a collector in London bought a fossil found in Morocco thinking it was part of a pterodactyl skull. When the collector asked a palaeontologist to identify it, it turned out to be a fossilized coelacanth lung. The collector donated the fossil for further study, and the palaeontologist, David Martill, worked with a Brazilian coelacanth expert, Paulo Brito, to examine the fossil.

 

The fossil dates to the Cretaceous, about 66 million years ago, and is bigger than any coelacanth lung ever found. Modern coelacanths grow a little over six feet long at most, or 2 meters, but the estimated length of this Coelacanth is some 16 ½ feet, or 5 meters. The fossil is being donated to a university in Morocco.

 

We talked about vampire bats way back in episode 11, and I love bats and especially vampire bats so I try to keep an eye on new findings about them. Everyone thinks vampire bats are scary and creepy, but they’re actually social, friendly animals who don’t mean to spread rabies and other diseases to the animals they bite. It just happens.

 

Vampire bats live in colonies and researchers have long known that if a female dies, her close relations will often take care of her surviving baby. Now we have evidence that at least sometimes, the adoptive mother isn’t necessarily related to the birth mother. It’s from a recently published article based on a study done in 2019.

 

A team researching how unrelated vampire bats form social bonds captured 23 common vampire bats from three different colonies and put them together in a new roost where their interactions could be recorded by surveillance cameras. One particular pair of females, nicknamed Lilith and BD, became good friends. They groomed each other frequently and shared food. If you remember from episode 11, vampire bats share food by regurgitating some of the blood they drank earlier so the other bat can lap it up. Since vampire bats can starve to death in only a few nights if they can’t find blood, having friends who will share food is important.

 

During the study, Lilith gave birth to a baby, but shortly afterwards she started getting sick. She had trouble getting enough food and couldn’t groom or take care of her baby as well as a mother bat should. Her friend BD helped out, grooming the baby, sharing food with Lilith, and eventually even nursing the baby when Lilith got too sick to produce milk. After Lilith died, BD adopted the baby as though it was her own. By the time the study ended, BD was still caring for the baby bat.

 

We talked about spiders in the Antarctic in episode 221, and mentioned that Antarctica hasn’t always been a frozen wasteland of ice and snow. In a new study of fossils found in Antarctica, published in May of 2021, the first Antarctic amphibian skull has been identified. It lived in the early Triassic, not long after the end-Permian mass extinction 252 million years ago. It’s been named Micropholis stowi and is a new species of temnospondyl that was previously only known from South Africa. The skull, along with other fossils from four individuals, was discovered in the Transantarctic Mountains in 2017 and 2018, and the research team studied them from home during the 2020 pandemic lockdowns.

 

In news about humans and our extinct close relations, a new finding shows that Neanderthals and humans used the same type of tools. Researchers studied a child’s tooth and some stone tools, all found in a cave in the mountains of Palestine, and determined that the tooth was from a Neanderthal child, not a human. The tooth was discovered in 1928 but was in a private collection until recently, so no one had been able to study it before now. The tools are a specific type developed in Africa that have only been found associated with humans before. Not only that, but until this finding, there was no evidence that Neandertals ever lived so far south.

 

The child is estimated to have been about nine or ten years old, which is the age when you’re likely to lose a baby tooth as your adult teeth start growing in. I like to think about the child sitting next to their Mom or Dad, who were either creating new tools or using ones they’d already made to do something like cut up food for that evening’s dinner. Maybe the child was supposed to be helping, and they were, but they had a loose tooth and kept giving it a twist now and then, trying to get it to come out. Then, finally, out it popped and bounced onto the cave floor, where it was lost for the next 60,000 years.

 

Researchers have just announced that they’ve sequenced the genetic profile of a woman who lived in what is now Romania about 35,000 years ago. Judging from her skull shape and what is known about ancient humans in Europe, the team had assumed she would be rather restricted in her genetic diversity but that she would show more Neanderthal ancestry than modern humans have. Instead, they were surprised to find that the woman had much more genetic diversity than modern humans but no more Neanderthal genes than most human populations have these days.

 

This was a surprise because modern humans whose prehistoric ancestors migrated out of Africa show much less genetic diversity than modern humans whose ancestors stayed in Africa until modern times. Researchers have always thought there was a genetic bottleneck at some point during or not long after groups of humans migrated out of Africa around 80,000 years ago. Lots of suggestions have been made about what might have caused the bottleneck, including disease, natural disaster, or just the general hardship of living somewhere where humans had never lived before. A genetic bottleneck happens when a limited number of individuals survive long enough to reproduce—in other words, in this case, if so many people die before they have children that there are hardly any children left to grow up and have children of their own. To show in the general population as it does, the bottleneck has to be widespread.

 

Now researchers think the genetic bottleneck happened much later than 80,000 years ago, probably during the last ice age. Humans living in Europe and Asia, where the ice age was severe, would have had trouble finding food and staying warm.

 

I’m getting close to finishing the Strange Animals Podcast book, which I’ll talk about a little more in our Q&A episode later this week. It’s a collection of the best mystery animals we’ve covered on the podcast, along with some new mystery animals, and I’m working hard to update my research. If you remember back in episode 83, about mystery big cats, we discussed the Barbary lion, which was thought to be an extinct subspecies of lion that might not actually be extinct. Well, when I looked into it to see if any new information had turned up, I found more than I expected. I rewrote those paragraphs from episode 83 and I’ll read them here as an update:

 

Lions live mostly in Africa these days, but were once common throughout southern Asia and even parts of southern Europe. There even used to be a species called the American lion, which once lived throughout North and South America. It only went extinct around 11,000 years ago. The American lion is the largest species of lion ever known, about a quarter larger than modern African lions. It probably stood almost 4 feet tall at the shoulder, or 1.2 meters. Rock art and pieces of skin preserved in South American caves indicate that its coat was reddish instead of golden. It lived in open grasslands like modern lions and even in cold areas.

 

Much more recently, the Barbary lion lived in northern Africa until it was hunted to extinction in the area. The Barbary lion was the one that battled gladiators in ancient Rome and was hunted by pharaohs in ancient Egypt. It was a big lion with a dark mane, and was thought to be a separate subspecies of lion until genetic analysis revealed in 2006 that it wasn’t actually different from Panthera leo leo.

 

The last wild Barbary lion was sighted in 1956, but the forest where it was seen was destroyed two years later. The lions in a few zoos, especially in Ethiopia and Morocco, are descended from Barbary lions kept in royal menageries for centuries.

 

Lions are well known to live on the savanna despite the term king of the jungle, but they do occasionally live in open forests and sometimes in actual jungles. In 2012 a lioness was spotted in a protected rainforest in Ethiopia, and locals say the lions pass through the reserve every year during the dry season. That rainforest is also one of the few places left in the world where wild coffee plants grow. So, you know, extra reason to keep it as safe as possible.

 

Finally, we’ll finish with a mystery snake. In 1968, during the Vietnam War, the United States Naval Medical Research Unit discovered a small snake in central Vietnam. It was unusual enough that they decided to save it for snake experts to look at later, but things don’t always go to plan during wartime. The specimen disappeared somewhere along the line. Fortunately, there were photographs.

 

The photos eventually made their way to some biologists, and in 1994 a paper describing the snake as a new species was published by Wallach and Jones. They based their description on the photos, which were good enough that they could determine details like the number of scales on the head and jaw. They named it Cryptophidion annamense and suggested it was a burrowing snake based on its characteristics.

 

Other biologists thought Cryptophidion wasn’t a new species of snake at all. In 1996 a pair of scientists published a paper arguing that it was just a sunbeam snake. The sunbeam snake is native to Southeast Asia, including Vietnam, and can grow over 4 feet long, or 1.3 meters. It’s chocolate-brown or purplish-brown but has iridescent scales that give it a rainbow sheen in sunshine. It’s a constricting snake, meaning it squeezes the breath out of its prey to kill it, but it only eats small animals like frogs, mice, and other snakes. It’s nocturnal and spends a lot of its time burrowing in mud to find food.

 

Wallach and Jones, along with other scientists, argued that there were too many differences between the sunbeam snake and Cryptophidion for them to be the same species. But without a physical specimen to examine, no one can say for sure if the snake is new to science or not. If you live in or near Vietnam and find snakes interesting, you might be the one to solve this mystery.

 

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

 

Thanks for listening!

Episode 228: Monkey Lizards and Weird Turtle…Things

Posted on by

Podcast: Play in new window | Download (Duration: 14:27 — 15.0MB)

Subscribe: RSS | More

Sign up for our mailing list!

We have a merch store now too!

Thanks to Ethan for this week’s topic, two weird animals that developed after the Great Dying we talked about last week!

Further reading:

Monkey Lizards of the Triassic

Placodonts: The Bizarre ‘Walrus-Turtles’ of the Triassic

Drepanosaurus (without a head since we haven’t found a skull yet, but with that massive front claw):

Drepanosaurus’s tail claw:

Hypuronector had a leaf-like tail:

Placodus was a big round-bodied swimmer:

Some placodonts [art by Darren Naish, found at the second article linked above]:

Henodus was the oddball placodont that probably ate plant material:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

 

Last week we talked about the end-Permian mass extinction, also called the Great Dying. This week let’s follow up with a couple of weird and interesting animals that evolved once things got back to normal on Earth. Thanks to Ethan who suggested both animals.

 

The great dying marks the end of the Permian and the beginning of the Triassic period, which lasted from about 251 million years ago to 201 million years ago. In those 50 million years, life rebounded rapidly and many animals evolved that we’re familiar with today. But some animals from the Triassic are ones you’ve probably never heard of.

 

We’ll start with a reptile called the drepanosaur. Drepranosaurs are also sometimes called monkey lizards for reasons that will soon become clear. Paleontologists only discovered the first drepanosaur in 1980, Drepanosaurus, and within a few years they recognized a whole new family, Drepanosauridae, to fit that first discovery and subsequent closely related specimens. Drepanosaurs were weird little reptiles that probably looked like lizards in many ways, although they weren’t lizards.

 

How weird was Drepanosaurus? Very weird. Very, very weird.

 

It was obviously a climbing animal that probably spent all of its life in the treetops. It had lots of adaptations to life in trees, such as hind feet where all the toes pointed in the same direction and were somewhat curved, sort of like a spider monkey’s hand. That would help it get a good grip on branches. But those hind feet aren’t why it’s called the monkey lizard.

 

Drepanosaurus and its relatives are called monkey lizards because of their tails. Many monkeys have prehensile tails, which act as a fifth limb and help keep the monkey stable in a tree by curling around branches and hanging on. Drepanosaurus had something similar. Instead of being mobile from side to side like most reptile tails, Drepanosaurus’s tail could mostly only curve downward. Modern chameleons have an even more pronounced downward-curving tail that helps them climb. But the chameleon’s tail is still just a tail. The end of Drepanosaurus’s tail had several modified caudal bones that were probably exposed through the skin. Those modified bones acted as a claw to help the animal grab onto tree trunks and branches. So Drepanosaurus had claws on its front feet, claws on its hind feet, and a claw on its tail. It’s sort of like having five feet.

 

As if that wasn’t weird enough, let’s talk about those claws on the front feet. It had five toes on each foot, and four of them had ordinary claws. They were sharp but fairly small, about what you’d expect from an animal that grew about 19 inches long at most, or 50 cm. But the second toe on each foot, which corresponds to the pointer finger on a human hand, had a much bigger claw. MUCH BIGGER CLAW. It was as big as its whole hand! Most researchers think it used the claw to dig into rotting wood, insect nests, and bark to find insects and other small animals to eat.

 

But that’s not all. Drepanosaurus also had a structure called a supraneural bone at the base of its neck, made up of fused vertebrae, that would have made it look like it had a little hunch on its shoulders. While we don’t have a skull of Drepanosaurus, since we only have three specimens so far, this structure is also present in other drepanosaur species where we do have the neck and head, and they all have fairly long, slender necks and birdlike skulls with large eyes. It’s possible that the supraneural bone was the attachment site for special muscles that helped Drepanosaurus extend its neck very quickly to grab insects and other small animals.

 

Drepanosaurs in general shared many of the traits seen in Drepanosaurus, although with some differences. Many drepanosaurs had opposing toes on the feet that would help them grasp branches and twigs more securely. Most don’t have the giant claw on the front feet although most do have the tail claw. But one monkey lizard doesn’t live up to its name at all.

 

A little drepanosaur called Hypuronector limnaios, which only grew about five inches long, or 12 cm, had a much different tail from its relations. Its tail didn’t curve downward at all—in fact, it stuck up behind it and was probably not very flexible. Not only was the tail longer than the body and head together, it had long points growing down from the vertebrae, called haemal arches, which made the tail extremely large top to bottom but flattened from side to side.

 

In other words, its tail looked like a leaf. The drepanosaur could cling to a branch with its tail sticking up, and any nearby predators would probably think it was just another leaf growing from the branch, especially if the tail was covered in green skin. Some researchers speculate that it could have used its tail as a sail to glide from branch to branch too, or it might have acted as a parachute if it had to jump from a branch to escape a predator. Hypuronector’s front legs were longer than its hind legs, unlike other drepanosaurs, which suggests it might have had a flap of skin that helped it glide.

 

Drepanosaur fossils have been found in parts of the United States and western Europe, but were probably more widespread than that. We still don’t know a whole lot about them, so every new specimen that’s found can give paleontologists lots of new information. Most drepanosaurs resembled weird chameleons with birdlike heads, but they weren’t related to birds or chameleons. We don’t actually know what they were closely related to.

 

Ethan also suggested placodonts, another reptile that evolved in the Triassic. Don’t confuse them with placoderms, the armored fish that went extinct in the great dying. The “placo” part of both words means tablet or plate. Therefore, placoderms have skin—that’s the “derm” part—covered in plates, while placodonts have flattened teeth, because the “dont” part refers to teeth. That’s why you get braces on your teeth at the orthodontist but you go to the dermatologist for skin problems.

 

What did placodonts do with their flattened teeth? They used them to crush the shells of shellfish and crustaceans. From that you can infer that they were marine reptiles, and you would be right. The earlier species had big round bodies with heavy bones, which helped them dive to the ocean floor to find food. They lived in shallow coastal waters and had large flattened ribs that helped protect them from injury if currents pushed them into rocks. While the teeth in the back of the mouth were flattened to crush shells, the teeth in the very front of the mouth were sharp and pointed forward to grab prey.

 

One of the most common early placodonts was Placodus [PLAK-oh-dus], which grew nearly six and a half feet long, or 2 meters. Its long tail was flattened laterally to help it swim and it probably had webbed toes. Since its legs were small and relatively weak considering how heavy its body was, it probably couldn’t get around very well on land, so it would have stayed close to the water. It probably looked kind of like the modern marine iguana, which we talked about in episode 92, but with longer jaws. On the other hand, unlike the marine iguana, placodus had a third eye.

 

THIRD EYE ALERT! If you remember way back in episode 3, where we talked about the tuatara, we learned a little bit about the parietal eye, or third eye. Parietal eyes are found on the top of a few animals’ heads, including the tuatara, but they aren’t the same as ordinary eyes. They’re very small photoreceptive eyes that can only sense light and dark. In Placodus’s case, researchers think that ability helped it figure out which way was up more easily when it was underwater. If you’ve ever been knocked down by a wave you’ll understand how easy it is to get disoriented underwater.

 

Placodus and other early placodonts had a ridge of bony scutes on the back to help protect it from predators. In later placodonts those scutes were bigger and bigger until they were more like armor, which added weight to the body and meant that the bones didn’t have to be so dense. This meant that instead of having barrel-like bodies, later placodonts were a little more streamlined. Their bodies were more flattened than round, but still broad across with big plates protecting the back. Their legs were more like flippers.

 

Does this make you think of something? Something like a sea turtle?

 

Later placodonts looked a lot like turtles, a classic case of convergent evolution because they weren’t related to turtles at all. If you saw Placochelys, for instance, you’d probably just think it was a weird sea turtle, unless you got a really close look at it. It grew about three feet long, or 90 cm, with a triangular head, a knobby shell, and flippers with clawed toes at the ends. It had a beak like a turtle’s instead of Placodus’s forward-pointing teeth, but unlike a turtle it also had teeth in the back of the mouth. These were still big flat teeth used for crushing shellfish, but like other placodonts the upper teeth grew from the palate, or the roof of the mouth.

 

Other placodonts would have looked strange to us, like Psephoderma. It grew up to six feet long, or 180 cm, and instead of a single turtle shell, it had two shells. One covered its body from the back of the head down to the pelvis. The other covered its pelvis and was smaller. It had a long tail and a pointy nose.

 

At least one placodont didn’t live in the ocean and didn’t eat shellfish and crustaceans. Henodus grew about three feet long, or one meter, and lived in brackish water or possibly freshwater. Its shell was twice as broad as it was long. It also had a lower shell, or plastron, on its belly. Its nose was short and squared-off and it had a turtle-like beak, and instead of teeth it had denticles on the sides of its jaws. Some researchers think it was a filter feeder, filtering tiny animals from the water through the denticles, while other researchers think it may have eaten water plants. It might have done both.

 

There’s a lot we don’t know about placodonts. We don’t know if they laid eggs or gave birth to live young, and we don’t know what exactly they ate. Obviously their teeth were best suited to crushing shells, but we don’t actually know what kind of shellfish they preferred or if they only ate crustaceans or something else. Placodont remains have been found in Europe, the Middle East, and China, but they were probably more widespread than that. During the Triassic, as the supercontinent Pangaea broke up, it created lots of shallow oceans and island chains that would have been ideal for placodonts.

 

Unfortunately for the placodonts, as the landmasses moved farther apart over millions of years, the shallow seas became deeper. Populations would have become isolated from each other. Eventually placodonts went extinct, probably by a combination of habitat loss and competition from other animals as dinosaurs and their relatives spread throughout the world.

 

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

 

Thanks for listening!

Episode 227: The Great Dying

Posted on by

Podcast: Play in new window | Download (Duration: 16:20 — 17.2MB)

Subscribe: RSS | More

Sign up for our mailing list!

It’s another extinction event episode! This one’s about the end-Permian AKA the Permian-Triassic AKA the GREAT DYING.

Further Reading:

Ancient mini-sharks lived longer than thought

Lystrosaurus’s fossilized skeleton:

Lystrosaurus may have looked something like this but I hope not:

This artist’s rendition of lystrosaurus looks a little less horrific but it might not be any more accurate:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

It’s time for our next extinction event episode, and this week it’s the big one. Not the extinction event that killed the dinosaurs, but one you may not have heard of, one that almost destroyed all life on earth. I mean, obviously it didn’t and things are fine now, but it was touch and go there for a while. It’s the Permian-Triassic extinction event, or end-Permian, which took place just over 250 million years ago. It was so bad that scientists who aren’t given to hyperbole refer to it as the Great Dying.

Don’t worry, we won’t talk about extinction the whole time. We’ll also learn about some interesting animals that survived the extinction event and did just fine afterwards.

We have a better idea of what happened at the end of the Permian than we have about the earlier extinction events we talked about in episodes 205 and 214. Right about 252 million years ago, something caused a massive volcanic eruptive event in what is now Siberia. Some researchers speculate that the cause of the volcanic eruptions may have been a huge asteroid impact on the other side of the Earth, which was so powerful that it caused magma to move away from the impact like water sloshing in a jostled glass. The magma rose up toward the earth’s crust and eventually through it onto the surface.

The result was probably the largest volcanic event in the last half-billion years and it continued for an estimated two million years. Most of the eruptions were probably pretty low-key, just runny lava pouring out of vents in the ground, but there was just so much of it. Lava covered almost a million square miles of land, or 2.6 million square km. Ash and toxic gases from some eruptions also ended up high in the atmosphere, but one big problem was that the lava poured through sediments full of organic material in the process of turning into coal. Lava, of course, is molten rock and it’s incredibly hot. It’s certainly hot enough to burn a bunch of young coal beds, which added more ash and toxic gases to the air—so much ash that shallow water throughout the entire world became choked with ash.

The carbon dioxide released by all that burning coal caused severe ocean acidification and ocean anoxia—a lack of oxygen in the water. But it gets worse! A lot of lava erupted into the ocean right at the continental shelf, where the shallow coastal water becomes much deeper. This is exactly the place where you find methane deposits in the sediments on the ocean floor. When those deposits were suddenly disturbed by lava flowing into them, all the methane in the formerly tranquil depths was released and bubbled to the surface. Methane is a powerful greenhouse gas, meaning that if a whole lot of it ends up in the atmosphere in a short amount of time, it can cause rapid global warming—much faster than that caused by carbon dioxide. This global warming would have happened after a period of global cooling due to reduced sunlight reaching the earth through ash clouds, which lasted long enough and was severe enough that sea levels dropped as glaciers formed. Then everything heated way, way up. The ice caps melted, which may have led to a stagnation of ocean currents. This in turn would have contributed to the water’s anoxicity and toxicity. The average temperature of the ocean would have increased by almost 15 degrees Fahrenheit, or 8 degrees Celsius. Atmospheric warming may have been as much as 68 degrees Fahrenheit in places, or 20 degrees Celsius. That’s not the average temperature of the world, that’s the temperature increase.

So, basically, everything was terrible and it happened very quickly in geologic terms. A 2018 study found that everything looked pretty much fine for the 30,000 years leading up to the great dying. Some researchers even think the initial extinction event might have taken place over just a few centuries.

Marine animals were affected the most, especially marine invertebrates. Trilobites and placoderms went extinct, eurypterids went extinct, and corals went extinct until about 14 million years later when modern corals developed. Some researchers estimate that 95% of all marine species went extinct.

Things were better on land, but not that much better. At the end of the Permian, life was good on land and it was especially good for insects because of the high percentage of oxygen in the air and the variety of plant life in huge swamps around the supercontinent Pangaea. The largest insects that ever lived were buzzing around in the Permian. This included an order of insects called Meganisoptera, or griffinflies. Griffinflies looked like dragonflies and may be related to them. Some species had a wingspan 28 inches across, or 71 cm. The arthropod Anthopleura, sometimes called the giant millipede, lived in the Permian too. Some species grew six feet long, or 2.5 meters, and were about 18 inches wide, or 45 cm. It looked like a millipede but had even more legs. It probably looked scary, but it only ate plants as far as we know.

Instead of actively breathing the way most vertebrates do, most invertebrates use a passive system to absorb oxygen from the air. This is great when there’s a lot of oxygen. When the level of oxygen drops, though, the largest species can’t absorb enough oxygen to function and die out rapidly. That’s one reason why you don’t have to worry about spiders the size of bears. So all the large invertebrates and a lot of the smaller ones went extinct as oxygen was replaced with carbon dioxide, methane, and other toxic gases in the atmosphere.

The acid rain caused by toxic gases and the reduced sunlight caused by ash in the atmosphere also killed off plants. Forests died, so that the fossil record during and after the extinction event contains massive amounts of fungal spores from fungi that decompose trees. Some researchers think all of the world’s trees died. Forests disappeared for some four million years. Since trees absorb carbon dioxide from the atmosphere and release oxygen, the lack of trees made oxygen levels drop even more.

Animals that depended on forests to survive also went extinct, including about two-thirds of all amphibians, reptiles, and therapsids. Therapsids were proto-mammals and it’s a good thing they didn’t all die out because they eventually gave rise to mammals.

Everything I’ve described sounds so incredibly bad, you may be wondering how anything survived. One stroke of luck was probably the size of Pangaea. That was the supercontinent made up of most of the world’s landmasses all smushed together. Before the extinction event, the middle of Pangaea was probably pretty dry with swampier climates around the edges. After the extinction event, the interior of the supercontinent was the safest place to be.

One of the most common land animals after the extinction event was a herbivore called Lystrosaurus. Lystrosaurus was a therapsid, and it was nothing exciting to look at unless you were also a lystrosaurus. Some species were the size of a cat while some were much larger, up to 8 feet long, or 2.5 m. It had a short snout, a short tail, and a semi-sprawling gait. A lizard walks with its legs stuck out to the sides, while a dog or cat or pig walks with its legs underneath its body. Lystrosaurus was somewhere between the two.

It probably lived in burrows that it dug with its strong front legs. While it had a pair of tusks that grew down from the upper jaw, those were its only teeth. Instead it probably had a turtle-like beak that helped it bite off pieces of vegetation.

Lystrosaurus lived in the central part of Pangaea, in what is now Asia, Antarctica, South Africa, and eastern Europe back when all those areas were all scrunched up close together. It survived the extinction event and expanded its range, and for millions of years it was almost the only big land animal in the world. It had almost no predators because they’d all gone extinct, and it had very few competitors for food because they’d all gone extinct. Lystrosaurus made up 90% of all land vertebrates for millions of years.

How did it survive when so many other animals died out? There are several theories, but the most important factor was probably its lack of specialization. It could survive on any kind of plant instead of needing to feed on specific species of plant. There’s also evidence that it could enter a torpor similar to hibernation where its metabolism slowed way down. This would have been a literal lifesaver during the time when the air and water were toxic and very little plant life survived. Lystrosaurus could hunker down in its burrow for long stretches of time, then come out and find enough food and water to keep it going for another stretch of torpor.

Just imagine the world back then, after the initial extinction event but before the world had recovered—say, a million years after the volcanic activity stopped. Picture a series of gentle rolling hills dotted with grazing animals. It’s peaceful and very open because there are no trees. Grass hasn’t evolved yet so the ground is covered in fern-like plants from the genus Dicroidium, which lives in dry conditions. As you look closer with your mind’s eye, you realize that every single one of those grazing animals—thousands of them visible in every direction—are the same kind of animal that looks sort of like a fuzzy pig with a stumpy lizard tail, clawed feet, and a turtle’s beak. Lystrosaurus, living the good life.

In the ocean, the situation was similar. The shallows were toxic waste dumps of ash where the water had so little oxygen that nothing could survive. But the deeper ocean was still livable for some animals.

For a long time, scientists thought a group of early sharks called cladodontomorphs had gone extinct during the great dying. Their distinctive teeth had been common in the fossil record, but after the extinction event they disappeared. Cladodontomorphs only grew about a foot long at most, or 30 cm, and may have had a weird-shaped dorsal fin that pointed forward. They lived in shallow coastal waters. You know, the worst possible place to be 252 million years ago.

Then palaeontologists found some of those teeth in rocks that were in much deeper water 135 million years ago. It turns out the little sharks had survived the extinction event by moving into the open ocean where conditions were better. And they didn’t just survive, they lasted for another 120 million years.

So let’s break it down. It was probably four million years before trees developed again from different plants. It was some 14 million years before coral reefs could rebuild as modern corals developed after their cousins went extinct. It took 30 million years for terrestrial vertebrates to recover from the great dying and 50 million years for all the ocean’s ecosystems to fully recover. That’s a colossally long time. But it did recover.

So what animals arose once the recovery was well underway? Icthyosaurs. Archosaurs, which eventually evolved into pterosaurs, crocodilians, dinosaurs, and birds. And therapsids that eventually gave rise to modern mammals.

I don’t usually tease the following week’s show, but next week we’re going to learn about some weird and interesting animals that developed in the early to mid Triassic, after the extinction event was over and life started evolving in new directions. As I’ve said in the previous extinction event episodes: no matter how bad things get, there’s always going to be some little animal stumping along out of the carnage to get on with the business of surviving and thriving.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 218: More Unusual Hoofed Animals

Posted on by

Podcast: Play in new window | Download (Duration: 25:03 — 26.0MB)

Subscribe: RSS | More

So many interesting hoofed animals in this episode, so many awesome suggestions! Thanks to Page, Elaine, Pranav, Richard E., Richard from NC, and Llewelly!

Further Reading:

Meet the Takin: The Largest Mammal You’ve Never Heard Of

New hope for the elusive okapi, the Congo’s mini giraffe

The Resurrection of the Arabian Oryx

Eucladoceros was not messing around with those antlers:

Megaloceros and Thranduil’s elk in the Hobbit movies. COINCIDENCE?

The stag-moose. What can I say? This thing is AWESOME:

Hoplitomeryx. Can you have too many horns? No, no you cannot:

The gerenuk, still beautiful but freaky-looking:

The golden takin looking beautiful [pic from the article linked above]:

The elusive okapi:

Okapi bums [pic from the article linked above]:

The giraffe being really tall and a baby giraffe being somewhat less tall:

A giraffe exhibiting dwarfism but honestly, he is still plenty tall:

The Arabian oryx is just extra:

The weird, weird tusks of the babirusa. Look closely:

Show Transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Back in episode 116, we talked about some amazing hoofed animals. This week we’re going to look at some more amazing hoofed animals that you may have never heard about. Some are extinct but some are running around out there looking awesome even as we speak! Thanks to Page, Elaine, Pranav, Richard E., Richard from NC, and Llewelly for their suggestions! If you’re a Patreon subscriber you may recognize part of the end of the episode as largely from a Patreon episode, by the way.

Let’s start with an extinct deer with amazing antlers. Llewelly suggested it, or more accurately replied to a Twitter conversation mentioning it. That counts as a suggestion. It’s been a while but I think the conversation was about the Hobbit movies.

Eucladoceros was a deer the size of a moose but with much weirder antlers. We’re not talking about the Megaloceros, often called the Irish elk, although it was distantly related. Eucladoceros’s antlers were much different. They branched up and out but were spiky like an ordinary deer’s antlers instead of palmate like a moose’s or Megaloceros’s antlers. But they were seriously big, with up to twelve points each and over five and a half feet across, or 1.7 meters. The deer itself stood just under 6 feet tall at the shoulder, or 1.8 meters. It’s often called the bush-antlered deer because the antler’s many points look like the branches of a bush.

Eucladoceros lived in Eurasia but we’re not completely sure when it went extinct or why. We don’t really know that much about it at all, in fact, which is surprising because it was such a big animal. It was one of the earliest deer with branching antlers and it probably went extinct before humans encountered it, but we don’t know that for sure either.

Another deer relation is a gigantic animal called the stag moose that lived at the very end of the Pleistocene, or ice age, until around 13,000 years ago. It probably looked a lot like a huge, muscular deer more than a moose, but had moose-like antlers that grew up to 6 1/2 feet across, or 2 meters. The animal itself stood almost six feet tall at the shoulder, or 1.8 m, which is about the size of the modern moose. It lived in northern North America until melting glaciers allowed other animals to migrate into the area, and the modern moose outcompeted its cousin.

Early deer and deer relations looked a lot different from the deer we’re familiar with today. For instance, Hoplitomeryx. It was a ruminant and therefore related to modern deer, but while it probably looked a lot like a deer, it didn’t have antlers. It had horns. Antlers grow every year from the skull and the animal sheds them later, usually after breeding season. Horns are permanent, usually made of a bony core with a keratin sheath over it.

Hoplitomeryx lived around 11 to 5 million years ago in one small area of Europe. Specifically, it lived on a large island near what is now Italy, although the island is now part of a little peninsula. It probably also lived on other, smaller islands nearby. While some specimens found are quite small, probably due to island dwarfism, some grew as big as the bush-antlered deer, over 5 ½ feet tall, or 1.7 meters.

It had a pair of horns that were shaped like a modern goat’s, that grew from the top of its head and curved backwards. And it had a smaller pair of horns underneath those horns that grew outward. And it had a single horn that was about the same size or bigger and shaped the same as the goat-like horns, but which grew in the middle of the forehead like a really weird unicorn. Also, it had fangs. I am not making this up. It’s sometimes called the five-horned deer for obvious reasons.

We also don’t know much about Hoplitomeryx except that it was really awesome, so let’s move on to our next strange hoofed animal. This one is a suggestion by Page, who wanted to know more about the gerenuk. We talked about it in episode 167 but it’s such an interesting animal that there’s more to learn about it.

The gerenuk is an antelope that lives in East Africa. It’s considered a type of gazelle, although it’s not very closely related to other gazelles. It’s slender with long legs and a long neck, and stands about three feet tall at the shoulder, or 105 cm. The male has a pair of S-shaped, ridged black horns that can grow up to 18 inches long, or 45 cm, while the female doesn’t have horns at all. It’s reddish-brown with a pale belly and a pale stripe down its sides, a short tail, and a white patch around each eye. But as we talked about in episode 167, its legs are extremely thin—so thin that they look like sticks, especially the front legs.

The gerenuk is the only type of antelope that can stand on its hind legs, which it does all the time. It will even use its front legs to pull branches down closer to its mouth while standing on its hind legs. As a result, even though it’s not very big, it can reach leaves that other antelopes can’t. Not only does this mean it can find food where other antelopes can’t, it also means it doesn’t need very much water because it can reach tender leaves with a higher moisture content.

Like many gazelles, the gerenuk marks its territory with scent glands. It has scent glands on its knees, covered with tufts of hair, and scent glands in front of its eyes. So if you see a gerenuk rubbing its knees or face on a branch, that’s why.

Our next hoofed animal is the golden takin, which looks kind of like a musk ox except that it has pale golden fur. But it isn’t a musk ox although it is in the family Bovidae. It’s actually most closely related to sheep but is sometimes referred to as a goat-antelope. It does resemble the mountain goat in some respects, which makes sense because it lives in the Himalayan Mountains in China. As a result, it has a lot of adaptations to intense cold.

It has a thick coat that grows even thicker in winter, with a soft, dense undercoat to trap heat next to the body. It also has large sinus cavities that warm the air it breathes before it reaches the lungs, which means it has a big snoot. Its skin is oily, which acts as a water repellent during rain and snowstorms. In spring it migrates to high elevations, but when winter starts it migrates back down to lower elevations where it’s not quite as cold.

Like the gerenuk, the golden takin will stand on its hind legs to reach leaves, but it has to balance its front legs against something to stay upright. It will eat just about any plant material it can reach, including tree bark, tough evergreen leaves, and bamboo. Yes, bamboo. It sometimes shares the same bamboo forests where pandas live. The golden takin is a strong animal that will sometimes push over small trees so it can eat the leaves. It visits salt licks regularly, and some researchers think it needs the minerals available at salt licks to help neutralize the toxins found in many plants it eats.

Both male and female golden takins have horns, which grow sideways and back from the forehead in a crescent and can be almost three feet long, or 90 cm. It has a compact, muscular build and can stand over four feet tall at its humped shoulder, or around 1.4 m. Baby golden takins are born with dark gold-brown fur that helps camouflage it, but as it ages, it fur grows more and more pale gold. A full-grown golden takin is big enough and strong enough that it doesn’t have many predators. If a bear or wolf threatens it, it can run fast if it needs to or hide in dense underbrush.

Next, let’s learn about an animal requested by both Elaine and Pranav. In the 19th century and earlier, Europeans exploring central Africa kept hearing about an elusive animal that lived deep in the remote forests. It was supposed to be a kind of donkey or zebra, but it was so little-known that some Europeans started calling it the African unicorn because they didn’t even think it existed.

In 1899, a British man named Harry Johnston decided to get to the bottom of the African unicorn mystery. When he asked the Pygmy people about it, they knew exactly what he was talking about and showed him some hoof prints. Like most Europeans at the time, Johnston thought the African unicorn was a zebra, so he was surprised to learn that it had cloven hooves.

The Pygmy people also gave Johnston some strips of skin from the animal, and later he bought two skulls and a complete skin. He sent these to England where the animal was identified as a giraffe relation. It was named Okapia johnstoni, and is known by the name okapi.

The okapi’s discovery by science was as astounding in its way as the coelacanth’s discovery a few decades later. Until it was described in 1901, scientists thought all the giraffe relations had died out long ago. Paleontologists had found fossils that showed how the giraffe evolved from a more antelope-like animal, and suddenly there was a living animal with those same features. It was mind-blowing!

The okapi is the giraffe’s closest living relation, but it doesn’t look much like a giraffe. For one thing, it’s not quite five feet tall at the shoulder, or 1.5 meters, and while it does have a long neck, it’s nothing like as long as a giraffe’s. It looks more like an antelope than a giraffe, at least at first glance. It’s dark reddish-brown with pale gray markings on its face, and its lower legs are white and its rump and upper legs are striped black and white. It also has a tail with a tuft at the end like a giraffe’s. Females are usually larger than males.

The male okapi has a pair of ossicones on his head, but they’re not very long compared to giraffe ossicones. As you may remember, an ossicone is a bony projection from the skull that’s covered with skin and hair. The female has little forehead bumps instead of actual ossicones.

The okapi lives in rainforests in central Africa and is a solitary animal. It has a long tongue like a giraffe which it uses to grab leaves. Its tongue is almost as long as the giraffe’s, up to 18 inches long, or 46 cm, whereas the giraffe’s tongue is 20 inches long, or 56 cm. A female okapi has one calf every two years or so, and in the first month of life, the calf doesn’t defecate at all. Not a single baby okapi poop. Some babies may hold it until they’re ten weeks old. Scientists aren’t sure if this same behavior is found in the wild, since okapis are hard to observe in the wild and most behavioral observations come from captive animals, but the hypothesis is that by not defecating, the baby is less likely to attract the attention of leopards who would smell the poops.

For a long time scientists thought the okapi didn’t make any sounds at all, just some whistles and chuffing sounds. It turns out, though, that a mother okapi communicates with her baby with infrasound, which is below the range of human hearing.

Speaking of giraffes, in March of 2021 a study of the giraffe genome was published, focusing on the giraffe’s adaptations for growing so extremely tall. One interesting discovery is that the giraffe has very little sense of smell although it has excellent eyesight. This makes sense considering that the giraffe’s head is so far above the ground. Most scents left by predators will be on or close to the ground, not high up in the air. The giraffe also doesn’t sleep very much and it shows a lot of genetic adaptations for extremely high blood pressure. It needs that high blood pressure to push blood up its long neck to its brain. Researchers are especially interested in the genetics of blood pressure, since high blood pressure in humans is a serious problem that can lead to all sorts of medical issues.

We’ve talked about giraffes before, especially in episode 50, about the tallest animals. Giraffes have extremely long necks and legs and a big male can stand 19.3 feet high, or 5.88 m, measured at the top of his head. Even a short giraffe is over 14 feet tall, or 4.3 meters. To put that into perspective, the average height of a ceiling in an average home is 8 or 9 feet high, or just over 2.5 meters. This means a giraffe could look into an upstairs window to see if you have any giraffe treats, and not only would it not need to stretch to see in, it would probably need to lower its head.

But in 2015, a team of biologists surveying the animals in the Murchison Falls National Park in Uganda, which is in eastern Africa, noticed a male giraffe that had much shorter legs than usual. They nicknamed him Gimli after one of the dwarf characters from Lord of the Rings, and estimated his height as just over nine feet tall, or about 2.8 meters. Gimli would not be able to peek into an upstairs window, but he was still a fully grown giraffe.

Since dwarfism affects the length of an animal’s limbs, it was obvious that Gimli was actually a dwarf giraffe, the first ever documented.

Then, in 2018, a different team of scientists found a different giraffe in a different place, Namibia in southwest Africa, who was fully grown but also had short legs. He was also a male, nicknamed Nigel, and was hanging around with some other giraffes on a private farm. The farmer had seen Nigel plenty of times over several years. Nigel’s height was estimated at 8 ½ feet tall, or 2.6 meters.

In animals, dwarfism can result from inbreeding, which is sometimes done on purpose by humans trying to breed cute pets. It also just sometimes happens, a random mutation that affects growth hormones. In the wild, an animal with unusually short legs usually doesn’t live very long. Either it can’t run fast enough to escape a predator or it can’t run fast enough to catch prey. Both Gimli and Nigel appear healthy, though, and even a short giraffe is still a large animal that can kick and run pretty fast.

Next, Richard from North Carolina suggested the Arabian oryx, and it is a beautiful and amazing hoofed animal. It’s a large antelope and used to live throughout the Middle East, but by the 1930s, habitat loss and hunting had restricted it to the desert in northwestern Saudi Arabia. Then oil company employees and Arabian princes both discovered the fun that is to be had when you have a car and a machine gun and can just drive around shooting everything you see. Such fun, driving animals to extinction, I’m being sarcastic of course. The last few Arabian oryx survived to 1972, but they were effectively extinct decades before then.

But. Zoos to the rescue. The Arabian oryx is a beautiful animal that does well in captivity, so lots of zoos had them on display. In 1960 conservationists realized they had to act fast if the oryx wasn’t going to go extinct completely, and they started a captive-breeding project called Operation Oryx at the Phoenix Zoo in Arizona, which is in the southwestern United States. They managed to capture three of the remaining wild animals and added to the herd with captive-bred oryxes donated by other zoos.

Operation Oryx was such a success that in only twenty years they were able to reintroduce oryx into the wild. Currently there are an estimated 1,200 oryxes in the wild with another 7,000 or so in zoos and conservation centers around the world. It’s still vulnerable, but it’s not extinct.

The oryx is white with dark brown or black markings, including dark legs and a pair of long, straight, slender black horns. Both males and females have these horns, which can grow up to two and a half feet long, or 75 cm. Since the oryx itself only stands a little over three feet high at the shoulder, or 1 meter, the horns are sometimes longer than the animal is tall. The oryx lives in small herds of mixed males and females, which travel widely in their desert habitat to find food and water. During the hot part of the day, the oryx digs a shallow nest under a tree or bush to lie in. It also has a short tufted tail. I just noticed the tail in a picture I’m looking at. It’s so cute.

In the last weird hoofed animals episode, we ended with a pig relation, so we’re going to end this episode with a pig relation too. Richard E. suggested the babirusa, and you definitely need to know about this weird piggy.

The babirusa is native to four islands in Indonesia. It’s related to pigs, but researchers think it split off from other pigs early on because of how different it is. Females have only one pair of teats, for instance, and usually only one piglet is born at a time, sometimes two. Females make a nest of branches to give birth in.

The babirusa also lacks the little bone in the snout that helps most pig species root. The babirusa only roots in very soft mud, but sometimes it digs for roots with its hooves. It eats plants of all kinds, including cracking nuts with its strong jaws, and will eat insect larvae, fruit, mushrooms, and even occasionally fish and small animals when it can catch them. Unlike most pigs, the babirusa is good at standing on its hind legs to reach branches, much like deer, which is why it’s sometimes called the deer-pig. Its stomach is more like a sheep’s than a pig’s, with two sacs that help it digest fibrous plant material, and it has relatively long, slender legs compared to most pigs.

Most pigs have tusks of some kind, but the babirusa’s are really weird. At first glance they’re just surprisingly long tusks that curve up and back, but when you look closer, you see that the upper pair actually grows up through the top of the snout.

The babirusa boar has two pairs of tusks, which are overgrown canine teeth. The lower pair jut out from the mouth the way most pig tusks do. The upper pair are the weird ones. Before a male babirusa is born, the tooth sockets for its upper canines are normal, but gradually they twist around and the teeth grow upward instead of down. They grow right up through the snout, piercing the skin, and then continue to grow up to 17 inches long, or 43 cm, curving backwards toward the head. In at least one case, a tusk has grown so long it’s actually pierced the boar’s skull.

For a long time researchers assumed males used their tusks to fight, but males fight by rearing on their hind legs and kicking each other with their forehooves. Then researchers decided the tusks were actually for defense during fights, to keep a boar from getting its face kicked. But the tusks aren’t actually very strong and don’t appear to be used for much of anything. Most likely, it’s just a display for females.

The babirusa does well in captivity, even becoming quite tame. Many zoos keep them, which is a good thing because they’re becoming more and more endangered as their island habitats are taken over by farming and development.

So that’s it for the second episode about strange hoofed animals. I guarantee you that we’re going to have a third because there are so many.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 217: Three (Small) Mystery Animals

Posted on by

Podcast: Play in new window | Download (Duration: 14:15 — 14.9MB)

Subscribe: RSS | More

This week we’re going to look at three small mystery animals! Well, the mysteries are small. The animals are not particularly small.

Further Reading:

Long-Extinct Gibbon Found Inside Tomb of Chinese Emperor’s Grandmother

Ancient Egypt’s Mona Lisa? An elaborately drawn extinct goose, of course

A case of mistaken identity for Australia’s extinct big bird

Bones of a mystery gibbon found in a noblewoman’s tomb:

Gibbons painted about a thousand years ago by artist Yi Yuanji:

A couple of gibbons at MAX FLUFF:

The mystery goose painting (left) compared with a modern version of the painting (middle) and a red-breasted goose (right):

All the geese from the painting:

A red-breasted goose, not historically known from Egypt:

The mystery bird rock art:

An emu (with babies):

Genyornis compared to a human:

Genyornis leg bones compared to emu leg bones (right), but on left is a comparison of a so-called Genyornis (actually not) egg and an emu egg:

A couple of megapodes in their egg field:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

We’re long overdue for an episode about a mystery animal, so this week let’s look at not one, not two, but three mysteries! They’re all small scientific mysteries, not big spooky ones, but I think you’ll find them interesting.

We’ll start at an archaeological dig in China. In 2004, archaeologists excavated a noblewoman’s tomb in northwestern China, which they dated to about 2,200 to 2,300 years old. The tomb might have been for a woman called Lady Xia, who was the grandmother of the first emperor of China. So, kind of a big deal.

The archaeologists discovered twelve pits in the tomb, and each pit contained the skeletons of various animals, some of them domesticated animals but some of them wild. Having a private menagerie was a status symbol back then, as it sometimes has been in other cultures around the world. In pit #12, they found remains of a leopard, a black bear, a crane, a lynx, and a type of small ape called a gibbon.

The gibbon remains were a surprise, because today all species of gibbon in China live only in the very southern areas and are critically endangered by habitat loss and hunting. Either a gibbon had been transported hundreds of miles over difficult terrain 2,300 years ago, or gibbons lived in the area.

Gibbons are small apes and there are 16 species alive today. They all live in southern Asia. We talked about the siamang in episode 76, and the siamang is a type of gibbon. Many gibbons, including the siamang, have inflatable resonant chambers in the throat to amplify their calls, but all gibbons make loud, often musical sounds to communicate with each other. They spend most of the time in treetops and mostly eat fruit, along with other plant material.

Because this part of northwestern China is subtropical, and because it’s been so long since the animals died, the skeletons aren’t complete. The only gibbon bones left were part of a cranium and mandible. Obviously, scientists had to be careful with the bones and couldn’t run any tests that might damage them. They made a 3D scan of the bones and used the scan to compare the gibbon’s skull and jaw with those of living species of gibbon, to determine what species it was.

It turned out that not only was it a species unknown to science, it was different enough from other gibbons that it belonged in its own genus.

According to experts in Chinese history and literature, gibbons were considered noble animals that often appeared in paintings and poetry. Various species of gibbon lived throughout much of China until around the 14th century. After the 14th century, though, habitat loss and hunting drove the gibbons farther south until now there are almost no gibbons left in China. Lady Xia’s pet gibbon is the first species known that definitely went extinct in the modern era, which makes it even more important that the gibbons still alive today are protected along with their habitats.

Speaking of ancient paintings of animals, 4,600 years ago, an artist made a painting of some geese for a tomb in Egypt. The painting is five feet long, or 1.5 meters, and is a fragment of a larger wall decoration that has been lost. It’s called the “Meidum Geese.” It’s a lovely painting and the geese are incredibly lifelike—so lifelike, in fact, that it should be easy to identify them.

But maybe not quite so easy after all.

There are three species of geese in the painting. Two are probably the graylag goose and the greater white-fronted goose. The third looks similar to the red-breasted goose, but there are enough differences that researchers aren’t sure. No red-breasted goose remains have ever been found in Egypt; it only lives in Europe and Asia.

It’s quite likely that the mystery goose is an extinct species. Other animal species depicted in Egyptian art are extinct now, even though they were common when the art was made. Egypt’s climate is much dryer than it was thousands of years ago, so naturally there were different animals back then even if you don’t factor in human activity like hunting.

The painting was discovered in 1871. One Italian archaeologist named Francesco Tiradritti claims it’s a hoax, painted by one of the curators at the Cairo Museum back when it was first found. One of the reasons he thinks it’s a hoax is that the red-breasted goose isn’t known in Egypt. This isn’t a very good argument to me. First of all, the goose doesn’t exactly match the red-breasted goose, while a hoaxer would probably work from a model or a picture to get the details right. Second of all, a hoaxer would probably have been careful to only include goose species that are known to live in Egypt. Tiradritti’s argument basically seems to be that the Meidum geese are too good and therefore could only possibly be painted by someone who had trained in Italy. In reality, though, ancient people of all cultures were perfectly capable of being masterful artists even though they were not European.

Other experts have rebutted Tiradritti’s claim and point out that he’s not an art historian and that many actual art historians have studied the Meidum geese and declared them genuine. Not only that, but scenes carved in other tombs seem to depict the same types of geese that are in the painting.

Speaking of geese and artwork, let’s move on to our final mystery animal. This one’s complicated, because it’s not just one mystery, it’s two.

Ancient artwork sometimes gives scientists useful information about when and where an animal lived and what it looked like. Sometimes, though, the artwork reveals more mysteries than it solves. For instance, some rock art found in Australia’s Northern Territory.

The art depicts two birds with long goose-like necks, drawn with a pigment called red ochre. It’s sort of a rusty color. The birds have legs that are about as long as the neck, and small heads with short, blunt bills.

At first the archaeologists studying the site thought the art depicted emus. Then they took a closer look and realized the details were wrong for emus, but they did match a different bird. Genyornis newtoni was distantly related to modern ducks and geese, but was flightless and really big. It stood seven feet tall, or over two meters. It had strong but relatively short legs, a goose-like neck, tiny wings, and a short, blunt bill. It probably ate fruit and small animals.

The finding excited the palaeontologists, because Genyornis was supposed to have gone extinct around 45,000 years ago. That meant that if the art really did depict the bird, the art had to be that old too.

The reason that researchers dated the extinction of Genyornis to about 45,000 years ago is because that’s when its eggshells stop being found, even though until then they were fairly common in ancient sand dunes.

But something didn’t add up. Genyornis was a little taller but six times heavier than the emu, but its eggs were no larger than an emu’s egg. A 2016 study suggested that the eggshells identified as Genyornis eggs were actually from a completely different bird, specifically a type of megapode.

Megapodes are birds that live in Australia and some nearby islands, including New Guinea. In fact, I think we’ll learn about some megapodes in an upcoming episode about more weird New Guinea birds. One interesting thing about megapodes is the way they incubate their eggs. Instead of keeping the eggs warm by sitting on them, megapodes build nest mounds. Most make a big mound of leaves and other vegetation, because as vegetation decays, it releases heat. The female lays her eggs on the mound and the male guards and tends the eggs, placing more leaves over them as needed or sometimes removing it to keep the eggs from getting too hot. Other megapodes lay their eggs in warm sand or even in volcanic areas where the ground stays warm. In other words, it makes sense that lots of these old eggshells would be found in what were once sand dunes, since the eggs were most likely buried in the sand to start with. Researchers think the sand dune eggs belonged to an extinct species of megapode called the giant malleefowl.

So that’s one mystery solved, but it leaves us with other mysteries. When did the Genyornis actually go extinct? How old is the rock art and does it really depict Genyornis?

Since its discovery around 2010, the so-called Genyornis rock art has been carefully studied. Geologists have determined the age of the rock face where the painting appears, and it’s not nearly as old as 45,000 years. Right about 13,800 years ago, a rock overhang collapsed, exposing a rock surface. Then some people came along and decided that rock surface would be the perfect place to paint two birds. So the painting can’t be any older than that.

A close analysis of the painting shows that there’s more than meets the eye, too. The initial painting was of a person with animal characteristics, called an anthropomorph, and at some point later someone painted the birds over it. The painting also contains the image of a barbed spear piercing one of the birds. So whatever the birds are, they were birds that people hunted.

Meanwhile, other experts were studying Genyornis. The current determination is that it went extinct around 25,000 or 30,000 years ago.

So we have rock art that cannot be older than a tad under 14,000 years old, but it appears to be art of a bird that went extinct at least 25,000 years ago. What’s going on?

It’s probable that Genyornis actually lived a lot more recently than 25,000 years ago. Scientists can only make determinations of when an animal went extinct by the fossils and subfossil remains they find or don’t find. There aren’t a lot of Genyornis fossils to start with, but the ones we do have mostly come from the same area where the rock art was found.

If the rock art really is of Genyornis, and it does seem to be, then people were most likely hunting Genyornis less than 14,000 years ago and possibly much more recently. Hopefully soon researchers will find more recent evidence so we can get a better idea of when it really went extinct and why.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 216: Gentle Giant Sharks

Posted on by

Podcast: Play in new window | Download (Duration: 18:46 — 19.4MB)

Subscribe: RSS | More

Let’s learn about some of the biggest sharks in the sea–but not sharks that want to eat you!

Further reading:

‘Winged’ eagle shark soared through oceans 93 million years ago

Manta-like planktivorous sharks in Late Cretaceous oceans

Before giant plankton-eating sharks, there were giant plankton-eating sharks

An artist’s impression of the eagle shark (Aquilolamna milarcae):

Manta rays:

A manta ray with its mouth closed and cephalic fins rolled up:

Pseudomegachasma’s tooth sitting on someone’s thumbnail (left, photo by E.V. Popov) and a Megachasma (megamouth) tooth on someone’s fingers (right):

The megamouth shark. I wonder where its name came from?

The basking shark, also with a mega mouth:

The whale shark:

Leedsichthys problematicus (not a shark):

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week we’re going to look at some huge, weird sharks, but they’re not what you may expect when you hear the word shark. Welcome to the strange world of giant filter feeders!

This episode is inspired by an article in the brand new issue of Science, which you may have heard about online. A new species of shark is described in that issue, called the eagle shark because of the shape of its pectoral fins. They’re long and slender like wings.

The fossil was discovered in 2012 in northeastern Mexico, but not by paleontologists. It came to light in a limestone quarry, where apparently a quarry worker found it. What happened to it at that point isn’t clear, but it was put up for sale. The problem is that Mexico naturally wants fossils found in Mexico to stay in Mexico, and the authors of the study are not Mexican. One of the authors has a history of shady dealings with fossil smugglers too. On the other hand, the fossil has made its way back to Mexico at last and will soon be on display at a new museum in Nuevo León.

Fossils from this quarry are often extremely well preserved, and the eagle shark is no exception. Sharks don’t fossilize well since a shark’s skeleton is made of cartilage except for its teeth, but not only is the eagle shark’s skeleton well preserved, we even have an impression of its soft tissue.

The eagle shark was just slightly shorter than 5 ½ feet long, or 1.65 meters. Its tail looks like an ordinary shark tail but that’s the only ordinary thing about it. The head is short and wide, without the long snout that most sharks have, it doesn’t appear to have dorsal or pelvic fins, and its pectoral fins, as I mentioned a minute ago, are really long. How long? From the tip of one pectoral fin to the other measures 6.2 feet, or 1.9 meters. That’s longer than the whole body.

Researchers think the eagle shark was a filter feeder. Its mouth would have been wide to engulf more water, which it then filtered through gill rakers or some other structure that separated tiny animals from the water. It expelled the water through its gills and swallowed the food.

The eagle shark would have been a relatively slow swimmer. It glided through the water, possibly flapping its long fins slowly in a method called suspension feeding, sometimes called underwater flight. If this makes you think of manta rays, you are exactly correct. The eagle shark occupied the same ecological niche that manta rays do today, and the similarities in body form are due to convergent evolution. Rays and sharks are closely related, but the eagle shark and the manta ray evolved suspension feeding separately. In fact, the eagle shark lived 93 million years ago, 30 million years before the first manta remains appear in the fossil record.

The eagle shark lived in the Western Interior Seaway, a shallow sea that stretched from what is now the Gulf of Mexico straight up through the middle of North America. Because it’s the only specimen found so far, we don’t know when it went extinct, but researchers suspect it died out 65 million years ago at the same time as the non-avian dinosaurs. We also don’t have any preserved teeth, which makes it hard to determine what sharks it was most closely related to. Hopefully more specimens will turn up soon.

Now that we’ve mentioned the manta ray, let’s talk about it briefly even though it’s not a shark. It is big, though, and it’s a filter feeder. If you’ve never seen one before, they’re hard to describe. If it had gone extinct before humans started looking at fossils scientifically, we’d be as astounded by it as we are about the eagle shark—maybe even moreso because it’s so much bigger. Its body is sort of diamond-shaped, with a blunt head and short tail, but elongated fins that are broad at the base but end in drawn-out points.

Manta rays are measured in width, sometimes called a wingspan since their long fins resemble wings that allow it to fly underwater. There are two species of manta ray, and even the smaller one has a wingspan of 18 feet, or 5.5 meters. The larger species can grow 23 feet across, or 7 meters. Some other rays are filter feeders too, all of them closely related to the manta.

The manta ray lives in warm oceans, where it eats zooplankton. Its mouth is wide and when it’s feeding it moves forward with its mouth open, letting water flow into the mouth and through the gills. Gill rakers collect tiny food, which the manta ray swallows. It has a pair of fins on either side of the mouth that are sometimes called horns, but which are properly called cephalic fins. Cephalic just means “on the head.” These fins help direct water into the mouth. When a manta ray isn’t feeding, it closes its mouth just like any other shark, folding its shallow jaw shut. For years I thought it closed its mouth by folding the cephalic fins over it, but that’s not the case, although it does roll the fins up into little points. The manta ray is mostly black with a white belly, but some individuals have white markings on the back and black speckles and splotches underneath. We talked about some mysteries associated with its coloring in episode 96.

The eagle shark isn’t the only filter feeding shark. The earliest known is Pseudomegachasma, the false megamouth, which lived around 100 million years ago. It was only described in 2015 after some tiny shark teeth were found in Russia. The teeth looked like those of the modern megamouth shark, although they’re probably not related. The teeth are only a few millimeters long but that’s the same size as teeth from the megamouth shark, and the megamouth grows 18 feet long, or 5.5 m.

Despite its size, the megamouth shark wasn’t discovered until 1976, and it was only found by complete chance. On November 15 of that year, a U.S. Navy research ship off the coast of Hawaii pulled up its sea anchors. Sea anchors aren’t like the anchors you may be thinking of, the big metal ones that drop to the ocean’s bottom to keep a ship stationary. A sea anchor is more like an underwater parachute for ships. It’s attached to the ship with a long rope on one end, and opens up just like a parachute underwater. The tip of the parachute has another rope attached with a float on top. When the navy ship brought up its sea anchors, an unlucky shark was tangled up in one of them. The shark was over 14 ½ feet long, or 4 ½ m, and didn’t look like any shark anyone had ever seen.

The shark was hauled on board and the navy consulted marine biologists around the country. No one knew what the shark was. It wasn’t just new to science, it was radically different from all other sharks known. Since then, only about 100 megamouth sharks have ever been sighted, so very little is known about it even now.

The megamouth is dark brown in color with a white belly, a wide head and body, and a large, wide mouth. The inside of its lower lip is a pale silvery color that reflects light, although researchers aren’t sure if it acts as a lure for the tiny plankton it eats, or if it’s a way for megamouths to identify each other. It’s sluggish and spends most of its time in deep water, although it comes closer to the surface at night.

The basking shark is even bigger than the megamouth. It can grow up to 36 feet long, or 11 meters. It’s so big it’s sometimes mistaken for the great white shark, but it has a humongous wide mouth and unusually long gill slits, and, of course, its teeth are teensy. It’s usually dark brown or black, white underneath, and while it spends a lot of its time feeding at the surface of the ocean, in cold weather it spends most of its time in deep water. In summer, basking sharks gather in small groups to breed, and sometimes will engage in slow, ponderous courtship dances that involve swimming in circles nose to tail.

But the biggest filter feeder shark alive today, and possibly alive ever, is the whale shark. It gets its name because it is literally as large as some whales. It can grow up to 62 feet long, or 18.8 meters, and potentially longer.

The whale shark is remarkably pretty. It’s dark gray with a white belly, and its body is covered with little white or pale gray spots that look like stars on a night sky. Its mouth is extremely large and wide, and its small eyes are low on the head and point downward. Not only can it retract its eyeballs into their sockets, the eyeballs actually have little armored denticles to protect them from damage. The body also has denticles, plus the whale shark’s skin is six inches thick, or 15 cm.

The whale shark lives in warm water and migrates long distances. It mostly feeds near the surface although it sometimes dives deeply to find plankton. It filters water differently from the megamouth and basking sharks, which use gill rakers. The whale shark has sieve-like filter pads instead. The whale shark doesn’t need to move to feed, either. It can gulp water into its mouth by opening and closing its jaws, unlike the other living filter feeders we’ve talked about so far.

We talked about the whale shark a lot in episode 87, if you want to know more about it.

All these sharks are completely harmless to humans, but unfortunately humans are dangerous to the sharks. Even though they’re all protected, they’re vulnerable to getting tangled in nets, killed by ships running over them, and killed by poachers.

One interesting thing about these three massive filter feeding sharks is their teeth. They all have tiny teeth, but the mystery is why they have teeth at all. Their teeth aren’t just tiny, they have a LOT of teeth, more than ordinary sharks do. It’s the same for the filter feeding rays. They have hundreds of teensy teeth that the animals don’t use for anything, as far as researchers can tell. One theory is that the babies may use their teeth before they’re born. All of the living filter feeders we’ve talked about, including manta rays, give birth to live pups instead of laying eggs. The eggs are retained in the mother’s body while they grow, and she can have numerous babies growing at different stages of development at the same time. The babies have to eat something while they’re developing, once the yolk in the egg is depleted, and unlike mammals, fish don’t nourish their babies through umbilical cords. Some researchers think the growing sharks eat the mother’s unfertilized eggs, and to do that they need teeth to grab hold of slippery eggs. That still doesn’t explain why adults retain the teeth and even replace them throughout their lives just like other sharks. Since all of the filter feeders have teeth although they’re not related, the teeth must confer some benefit.

So, why are these filter feeders so enormous? Many baleen whales are enormous too, and baleen whales are also filter feeders. Naturally, filter feeders need large mouths so they can take in more water and filter more food out of it. As a species evolves a larger mouth, it also evolves a larger body, and this has some useful side effects. A large animal retains heat even if it’s not actually warm-blooded. A giant fish can live comfortably in cold water as a result. Filter feeding also requires much less effort than chasing other animals, so a giant filter feeder has plenty of energy for a relatively low intake of food. And, of course, the larger an animal is, the fewer predators it has because there aren’t all that many giant predators. At a certain point, an adult giant animal literally has no predators. Nothing attacks an adult blue whale, not even the biggest shark living today. Even a really big great white shark isn’t going to bite a blue whale. The blue whale would just bump the shark out of the way and probably go, “HEY, STOP IT, THAT TICKLES.” The exception, of course, is humans, who used to kill blue whales, but you know what I mean.

Let’s finish with a filter feeder that isn’t a shark. It’s not even closely related to sharks. It’s a ray-finned fish that lived around 165 million years ago, Leedsichthys problematicus. Despite not being related to sharks and being a member of what are called bony fish, its skeleton is partially made of cartilage, so fossilized specimens are incomplete, which is why it was named problematicus. Because the fragmented fossils are a problem. I’m genuinely not making this up to crack a dad joke, that’s exactly why it got its name. One specimen is made up of 1,133 pieces, disarticulated. That means the pieces are all jumbled up. Worst puzzle ever. Remains of Leedsichthys have been found in Europe and South America.

As a result, we’re not completely sure how big Leedsichthys was. The most widely accepted length is 50 feet long, or 16 meters. If that’s anywhere near correct, it would make it the largest ray-finned fish that ever lived, as far as we know. It might have been much larger than that, though, possibly as long as 65 feet, or 20 meters.

Leedsichthys had a big head with a mouth that could open extremely wide, which shouldn’t surprise you. Its gills had gill rakers that it used to filter plankton from the water. And we’re coming back around to where we started, because like the eagle shark, Leedsichthys had long, narrow pectoral fins. Some palaeontologists think it had a pair of smaller pelvic fins right behind the pectoral fins instead of near the tail, but other palaeontologists think it had no pelvic fins at all. Because we don’t have a complete specimen, there’s still a lot we don’t know about Leedsichthys.

The first Leedsichthys specimen was found in 1886 in a loam pit in England, by a man whose last name was Leeds, if you’re wondering where that part of the name came from. A geologist examined the remains and concluded that they were part of (wait for it) a type of stegosaur called Omosaurus. Two years later the famous early palaeontologist Othniel Marsh examined the fossils, probably rolled his eyes, and identified them as parts of a really big fish skull.

In 1899, more fossils turned up in the same loam pits and were bought by the University of Cambridge. IA palaeontologist examined them and determined that they were (wait for it) the tail spikes of Omosaurus. Leeds pointed out that nope, they were dorsal fin rays of a giant fish, which by that time had been named Leedsichthys problematicus.

In 1982, some amateur palaeontologists excavated some fossils in Germany, but they were also initially identified as a type of stegosaur—not Omosaurus this time, though. Lexovisaurus. I guess this particular giant fish really has been a giant problem.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 214: Armored Fish and the Late Devonian Mass Extinctions

Posted on by

Podcast: Play in new window | Download (Duration: 21:53 — 22.6MB)

Subscribe: RSS | More

It’s the next in our short series of episodes about mass extinctions! Don’t worry, it won’t be boring, because we’re going to learn about a lot of weird ancient fish too.

Further reading:

Titanichthys: Devonian-Period Armored Fish was Suspension Feeder

Behind the Scenes: How Fungi Make Nutrients Available to the World

Dunkleosteus was a beeg feesh with sharp jaw plates that acted as teeth:

Titanichthys was also a beeg feesh, but it wouldn’t have eaten you (picture from the Sci-News article linked above):

Pteraspis: NOSE HORN FISH:

Cephalaspis had no jaws so it couldn’t chomp you:

Bothriolepis kind of looked like a fish in a mech suit:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Here’s the second in our small series of episodes about extinction events, this one the Late Devonian extinction. We’ll also learn about some weird and amazing fish that lived during this time, and a surprising fact about ancient trees.

The Devonian period is often called the Age of Fish because of the diversity of fish lineages that arose during that time. It lasted from roughly 420 million years ago to 359 million years ago. During the Devonian, much of the earth’s landmasses were smushed together into the supercontinent Gondwana, which was mostly in the southern hemisphere, and the smaller continents of Siberia and Laurussia in the northern hemisphere. The world was tropically warm, ocean levels were high, and almost all animal life lived in the oceans. Some animals had adapted to living on land at least part of the time, though, and plants had spread across the continents. The first insects had just evolved too.

Shallow areas of the ocean were home to animals that had survived the late Ordovician extinctions. There were lots of brachiopods, bivalves, crinoids, trilobites, and corals. Eurypterids were still thriving and ammonites lived in deeper water. But while all these animals are interesting, we’re mainly here for the fish.

The fish of the Devonian were very different from modern fish. Most had armor. Way back in episode 33 we talked about the enormous and terrifying dunkleosteus, which lived in the late Devonian. It might have grown up to 33 feet long, or 10 meters. Since we still don’t have any complete specimens, just head plates and jaws, that’s an estimate of its full size. However long it grew, it was definitely big and could have chomped a human in half without any trouble at all. It’s probably a good thing mammals hadn’t evolved yet. Instead of teeth, dunkleosteus had jaw plates with sharp edges and fanglike projections that acted as teeth.

Another huge fish from the Devonian is called titanichthys, which might have grown as long as dunkleosteus or even bigger, but which was probably not an apex predator. Its jaw plates were small and blunt instead of sharp, which suggests it wasn’t biting big things. It might not have been biting anything. Some researchers think titanichthys might have been the earliest known filter feeder, filtering small animals from the water by some mechanism we don’t know about yet. Filter feeders use all sorts of adaptations to separate tiny food from water, from gill rakers to baleen plates to teeth that fit together closely, and many others. A study published in 2020 compared the jaw mechanisms of modern giant filter feeders (baleen whales, manta rays, whale sharks, and basking sharks) to the jaw plates of titanichthys, as well as the jaw plates of other placoderms that were probably predators. Titanichthys’s jaws are much more similar to those of modern filter feeders, which it isn’t related to at all, than to fish that lived at the same time as it did and which it was related to.

Titanichthys and dunkleosteus were both placoderms, a class of armored fish. That wasn’t unusual, actually. In the Devonian, most fish ended up evolving armored plates or thick scales. What was unusual in placoderms were their jaws. Specifically, the fact that they had jaws at all. Placoderms were probably the first fish to evolve jaws.

Pteraspis, for instance, was an armored fish that wasn’t a placoderm. It had no fins at all but it was a good swimmer, streamlined and possibly a predator, although it might have been a plankton feeder at the surface of the ocean. It grew about 8 inches long, or 20 cm. It used its tail to propel itself through the water, and instead of fins it had spines growing from its armor that helped keep it stable. A spine on its back, near the rear of the body armor, acted as a dorsal fin, while spines on the sides of its armor, just over its gills, acted like pectoral fins. It also had some smaller spines along its back and a big spike on its nose. Probably not a good fish to swallow whole.

Cephalaspis lived in the early Devonian, around 400 million years ago in fresh water. It wasn’t very big, maybe a foot long, or 30 cm. Basically, it would have fit nicely on a dinner plate, but it wouldn’t have looked much like a trout other than its size. It wasn’t a placoderm either although it did have armor. It was probably a bottom feeder and was flattened in shape with a broad, roughly triangular head covered in armor plates. Its eyes were at the top of its head and its mouth was underneath. The rest of its body was thinner and tapered to a thin tail. It probably used its head to dig around in the mud and sand to find small invertebrates, which it slurped up and swallowed whole because it had no jaws to bite with.

In comparison, the placoderm bothriolepis was about the same size as cephalaspis and was also a bottom feeder in fresh water, but that’s where the resemblance ends. It lived later, around 375 million years ago, and probably ate decomposing plant material. Like other placoderms, it had armored plates on its head and the front part of its body. The armor at the front of its head had a little opening for its eyes, which were really close together. Its tail wasn’t armored and was probably only covered in skin without scales. Bothriolepis also had long armored pectoral fins that look sort of like spikes. Its head armor was so heavy that it probably used these spike-like fins to help push itself off the bottom. The pectoral fins of some bothriolepis species had an elbow-like joint as well as a joint at the top of the fin, making them more arm-like than fin-like. Basically, bothriolepis looks like a fish wearing a mech suit that doesn’t cover its tail. It looks like an armored box with a fish tail and spikes for arms. It looks weird.

Bothriolepis was really common throughout the world with lots of species known. The largest was B. rex, which grew up to 5 1/2 feet long, or 1.7 meters, and which had thicker armor than other placoderms. Researchers think its heavy armor would have kept it from being swept to the surface by currents. Most bothriolepis species were much smaller, though.

Because it was so common, we know quite a bit about bothriolepis. In addition to the fossilized armor plates, we have some body impressions and even fossilized internal organs. This is really rare, and the reason it’s happened more than once in bothriolepis is that the internal organs were protected by the armor plates long enough for fine sediment to fill the body before the organs decomposed or were eaten by other animals. We know that the digestive system was simple compared to modern fish but the gut was spiral shaped, which allowed more time for the plant material it ate to stay in the body so more nutrients could be extracted from it. The gills were likewise primitive, and it may have also had a pair of primitive lungs. Yes, lungs! Not all palaeontologists agree that the sacs were actually lungs, but those who do think the fish would have gulped air at the surface like a lungfish. Since most, if not all, bothriolepis species seem to have lived in freshwater, it’s possible it needed lungs to breathe air if the water where it lived was low in oxygen. Some researchers think it might even have been able to use its pectoral fins to move around on land, at least enough to move to a new water source if its home dried up. Because bothriolepis remains are sometimes found in marine environments, some researchers also speculate that it may have migrated from or to the ocean to spawn, and that it used its possible land-walking ability to navigate around obstacles while migrating along rivers.

At least some bothriolepis individuals also had a pair of weird frills at the base of the tail. They might have acted as fins but they might have had something to do with mating, like a male shark’s claspers. It’s not clear if all individuals had them or only some.

Placoderms were the first fish to develop jaws, teeth, and pelvic fins. Pelvic fins were important not just because it made the fish more stable in the water, but because they correspond to hind legs in tetrapods. Here’s something to think about: if pelvic fins hadn’t evolved in fish, would land animals have eventually evolved four legs or would all land animals have just two legs and a tail? Would humans look like mermaids and mermen, or weird seals? Would birds have evolved wings even if it meant they had no feet?

Okay, so, back to the Devonian. There were lots more fish than just the placoderms, of course. Coelacanths, lungfish, and early sharks evolved at this time and are still around, as are ray-finned fish that are the most common fish today.

But maybe with all this talk of weird fish, you’ve forgotten this is an episode about an extinction event. Ocean life in the Devonian was chugging along just fine–but then something happened, something that resulted in the same loss of oxygen in the oceans that caused so many extinctions in the late Ordovician. But no one’s sure what that was.

The extinction event actually took place in several waves millions of years apart. Researchers generally think that the same events that caused the late Ordovician extinction events may have caused the late Devonian extinction events. Toward the end of the Devonian the Earth did appear to go through several rapid temperature changes, and some researchers think the cause of these temperature changes might have been trees.

At the beginning of the Devonian, there were lots of plants on land, but they were all small. You could walk from one side of a continent to another and never encounter a plant taller than knee-high. But plants were evolving rapidly, and before long the first trees appeared. They were related to ferns, club moss, and a type of plant called horsetails, which wouldn’t have looked much like trees to us. The progymnosperms also evolved during this time, and they were ancestors of modern gymnosperms, a group which includes conifers, gingkos, and cycads. Some of these early trees didn’t even have leaves, while some had what looked like fern fronds. Some grew almost 100 feet tall, or 30 meters.

Tall trees need strong roots, and roots loosened the soil and underlying rocks to great depths. This made it more likely that heavy rains would wash soil into the water, potentially causing microbial blooms. All these trees also absorbed enormous quantities of carbon dioxide and released oxygen into the atmosphere. This sounds great, because animals need oxygen to breathe! But as trees spread across the land, growing bigger and taller, they absorbed as much as 90% of the available carbon dioxide, so much that it actually caused the earth to cool enough to cause glaciers to form.

One interesting thing about trees. Trees and other plants contain complex polymers called lignin that harden the cells. Lignin is why trees have bark and wood. Lignin is also really resistant to decay, which is why it takes so long for a fallen tree to rot down into nothing. There are specialized bacteria and fungi that can break down lignin, but most bacteria and fungi can’t affect it at all.

Plants first evolved lignin around 400 million years ago, and early trees contained a lot of it, way more than modern trees have. It took bacteria and fungi a long time to evolve ways to break that lignin down to extract nutrients from it—around 100 million years, in fact. So for 100 million years, whenever a storm knocked over a tree and it died, its trunk just…stayed there forever–or at least for a really long time, becoming more and more buried over the centuries. Lignin isn’t water soluble either, so even trees that fell into a lake didn’t rot, or at least the lignin in the trunks didn’t rot. All those tree trunks were eventually compressed by the weight of the soil above them into coal beds.

Anyway, the peak of this cycle of trees absorbing carbon dioxide and releasing oxygen actually happened in the Carboniferous period, which occurred just after the final wave of the Devonian extinctions. That’s why insects could grow so incredibly large during the Carboniferous, because the atmosphere contained so much oxygen.

But in the build-up to the late Devonian extinction events, there were periods of colder and warmer climate worldwide, possibly caused by trees, possibly by other factors, most likely by a combination of many factors. Glaciers would form and melt rapidly, possibly leading to the same issues that caused the late Ordovician extinction events.

I’ll quote a bit from episode 205 to remind you what scientists think happened in the Ordovician when a whole lot of glaciers suddenly melted:

As the glaciers melted, cold fresh water flowed into the ocean and may have caused deep ocean water to rise to the surface. The deep ocean water brought nutrients with it that then spread across the ocean’s surface, and this would have set off a massive microbial bloom.

Microbial blooms happen when algae or bacteria that feed on certain nutrients suddenly have a whole lot of food, and they reproduce as fast as possible to take advantage of it. The microbes use up oxygen, so much of it that the water can become depleted.

Rivers were also a major source of nutrients flowing into the ocean, as tree roots continued to break up rock and soil, which made its way into the water.

Whatever the cause or causes, the result was that the ocean lost most or all of its oxygen, especially in the deep sea. Oxygen, of course, is what animals breathe. Fish push water over their gills and absorb oxygen from it by a chemical process the same way we absorb oxygen from the air with our lungs. The air contains a lot of other gases in addition to oxygen, but it’s the oxygen we need.

The first wave of extinctions in the Devonian is called the Taghanic Event. A lot of brachiopods and corals went extinct then, among many other animals. About the time life started to rebound from that wave, the Kellwasser Event killed off more brachiopods and corals, a lot of trilobites, and jawless fish. Finally, the biggest and worst wave of all was the Hangenberg Event.

The Hangenberg Event was really bad. Really, really bad. In the late Ordovician extinction event, some researchers think it took three million years for the oceans to recover from their lack of oxygen. In the late Devonian extinction event, it may have taken 15 million years for the oceans to fully recover. Some researchers think that in addition to everything else going on in the world, a nearby star may have gone supernova and damaged the ozone layer that protects the earth, which would have damaged plants and animals that lived on land.

The end result of the late Devonian extinction event was that 97% of all vertebrate species went extinct, especially those that lived in shallow water, and 75% of all animal species. All placoderms went extinct and almost all corals went extinct.

Most people think that oil—you know, the stuff we use to make gasoline and plastic—came from dead dinosaurs, but that’s not the case. A lot of oil actually formed from the animals that died in the Devonian extinction events. Fish and other animals suffocated as the water lost oxygen, and the lack of oxygen at the bottom of the ocean meant that all those bodies that sank into the depths didn’t rot. They were buried by sediment and as the years and then centuries and millennia passed, more and more sediment piled up, causing pressure and heat that transformed the organic remains into a substance called kerogen. Kerogen is still an organic material and if it’s exposed to oxygen it will oxidize and decay, but if it remains deep underground for millions of years the heat and pressure will eventually transform it chemically into hydrocarbons that make up oil. Don’t ask me to explain this in any more detail than that. My mind is still blown about tree trunks not decomposing for 100 million years; there’s really no room left in my brain to wonder about how oil forms.

Anyway, luckily for us, by the time of the late Devonian extinction events, the first land vertebrates had already evolved and they survived. They spread throughout the world and thrived for 110 million years until the next major extinction event, which was so profound it’s called “the great dying” by palaeontologists. We’ll learn about that one in a few months. Next week I promise we’ll have a light, happy episode where nothing goes extinct!

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 212: The River of Giants

Posted on by

Podcast: Play in new window | Download (Duration: 15:38 — 16.1MB)

Subscribe: RSS | More

Thanks to Pranav for his suggestion! Let’s find out what the river of giants was and what lived there!

Further reading:

King of the River of Giants

Spinosaurus was a swimming dinosaur and it swam in the River of Giants:

A modern bichir, distant relation to the extinct giants that lived in the River of Giants:

Not actually a pancake crocodile:

A model of Aegisuchus and some modern humans:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

A while back, Pranav suggested we do an episode about the river of giants in the Sahara. I had no idea what that was, but it sounded interesting and I put it on the list. I noticed it recently and looked it up, and oh my gosh. It’s amazing! It’s also from a part of the world where it’s really hot, as a break for those of us in the northern hemisphere who are sick of all this cold weather. I hope everyone affected by the recent winter storms is warm and safe or can get that way soon.

The Sahara is a desert in northern Africa, famous for its harsh climate. Pictures of the Sahara show its huge sand dunes that stretch to the horizon. This wasn’t always the case, though. Only about 5,500 years ago, it was a savanna with at least one lake. Lots of animals lived there and some people too. Before that, around 11,000 years ago, it was full of forests, rivers, lakes, and grasslands. Before that, it was desert again. Before that, it was forests and grasslands again. Before that, desert.

The Sahara goes through periodic changes that last around 20,000 years where it’s sometimes wet, sometimes dry, caused by small differences in the Earth’s tilt which changes the direction of the yearly monsoon rains. When the rains reach the Sahara, it becomes green and welcoming. When it doesn’t, it’s a desert. Don’t worry, we only have 15,000 more years to wait until it’s nice to live in again.

This wet-dry-wet pattern has been repeated for somewhere between 7 and 11 million years, possibly longer. Some 100 million years ago, though, the continents were still in the process of breaking up from the supercontinent Gondwana. Africa and South America were still close together, having only separated around 150 million years ago. The northern part of Africa was only a little north of the equator and still mostly attached to what is now Eurasia.

Near the border of what is now Morocco and Algeria, a huge river flowed through lush countryside. The river was home to giant animals, including some dinosaurs. Their fossilized remains are preserved in a rock formation called the Kem Kem beds, which run for at least 155 miles, or 250 km. A team of paleontologists led by Nizar Ibrahim have been working for years to recover fossils there despite the intense heat. The temperature can reach 125 degrees Fahrenheit there, or 52 Celsius, and it’s remote and difficult to navigate.

For a long time researchers were confused that there were so many fossils of large carnivores associated with the river, more than would be present in an ordinary ecosystem. Now they’ve determined that while it looks like the fossils were deposited at roughly the same time from the same parts of the river, they’re actually from animals that lived sometimes millions of years apart and in much different habitats. Bones or even fossils from one area were sometimes exposed and washed into the river along with newly dead river animals. This gives the impression that the river was swarming with every kind of huge predator, but it was probably not quite so dramatic most of the time.

Then again, there were some really fearsome animals living in and around the river in the late Cretaceous. One of the biggest was spinosaurus, which we talked about in episode 170. Spinosaurus could grow more than 50 feet long, or 15 m, and possibly almost 60 feet long, or 18 m. It’s the only dinosaur known that was aquatic, and we only know it was aquatic because of the fossils found in the Kem Kem beds in the last few years.

Another dinosaur that lived around the river is Deltadromeus, with one incomplete specimen found so far. We don’t have its skull, but we know it had long, slender hind legs that suggests it could run fast. It grew an estimated 26 feet long, or 8 meters, including a really long tail. At the moment, scientists aren’t sure what kind of dinosaur Deltadromeus was and what it was related to. Some paleontologists think it was closely related to a theropod dinosaur called Gualicho, which lived in what is now northern Patagonia in South America. Remember that when these dinosaurs were still alive, the land masses we now call Africa and South America had been right in the middle of a supercontinent for hundreds of millions of years, and only started separating around 150 million years ago. Gualicho looked a lot like a pocket-sized Tyrannosaurus rex. It grew up to 23 feet long, or 7 meters, and had teeny arms. Deltadromeus’s arms are more in proportion to the rest of its body, though.

Some of the biggest dinosaurs found in the Kem Kem beds are the shark-toothed dinosaurs, Carcharodontosaurus, nearly as big as Spinosaurus and probably much heavier. It grew up to 40 or 45 feet long, or 12 to almost 14 meters, and probably stood about 12 feet tall, or 3 ½ meters. It had massive teeth that were flattened with serrations along the edges like steak knives. The teeth were some eight inches long, or 20 cm.

Researchers think that Carcharodontosaurus used it massive teeth to inflict huge wounds on its prey, possibly by ambushing it. The prey would run away but Carcharodontosaurus could take its time catching up, following the blood trail and waiting until its prey was too weak from blood loss to fight back. This is different from other big theropod carnivores like T. rex, which had conical teeth to crush bone.

Dinosaurs weren’t the only big animals that lived in and around the River of Giants, of course. Lots of pterosaur fossils have been found around the river, including one species with an estimated wingspan of as much as 23 feet, or 7 meters. There were turtles large and small, a few lizards, early snakes, frogs and salamanders, and of course fish. Oh my goodness, were there fish.

The river was a large one, possibly similar to the Amazon River. In the rainy season, the Amazon can be 30 miles wide, or 48 km, and even in the dry season it’s still two to six miles wide, or 3 to 9 km. The Amazon is home to enormous fish like the arapaima, which can grow up to 10 feet long, or 3 m. Spinosaurus lived in the River of Giants, and that 50-foot swimming dinosaur was eating something. You better bet there were big fish.

The problem is that most of the fish fossils are incomplete, so paleontologists have to estimate how big the fish was. There were lungfish that might have been six and a half feet long, or 2 meters, a type of freshwater coelacanth that could grow 13 feet long, or 4 meters, and a type of primitive polypterid fish that might have been as big as the modern arapaima. Polypterids are still around today, although they only grow a little over three feet long these days, or 100 cm. It’s a long, thin fish with a pair of lungs as well as gills, and like the lungfish it uses its lungs to breathe air when the water where it lives is low in oxygen. It also has a row of small dorsal fins that make its back look like it has little spikes all the way down. It’s a pretty neat-looking fish, in fact. They’re called bichirs and reedfish and still live in parts of Africa, including the Nile River.

There were even sharks in the river of giants, including a type of mackerel shark although we don’t know how big it grew since all we have of it are some teeth. Another was a type of hybodont shark with no modern descendants, although again, we don’t know how big it was.

The biggest fish that lived in the River of Giants, at least that we know of so far, is a type of ray that looked like a sawfish. It’s called Onchopristis numidus and it could probably grow over 26 feet long, or 8 meters. Its snout, or rostrum, was elongated and spiked on both sides with sharp denticles. It was probably also packed with electroreceptors that allowed it to detect prey even in murky water. When it sensed prey, it would whip its head back and forth, hacking the animal to death with the sharp denticles and possibly even cutting it into pieces. Modern sawfish hunt this way, and although Onchopristis isn’t very closely related to sawfish, it looked so similar due to convergent evolution that it probably had very similar habits.

The modern sawfish mostly swallows its prey whole after injuring or killing it with its rostrum, although it will sometimes eat surprisingly large fish for its size, up to a quarter of its own length. A 26-foot long Onchopristis could probably eat fish over five feet long, or 1.5 meters. It wouldn’t have attacked animals much larger than that, though. It wasn’t eating fully grown Spinosauruses, let’s put it that way, although it might have eaten a baby spinosaurus from time to time. Spinosaurus might have eaten Onchopristis, though, although it would have to be pretty fast to avoid getting injured.

But there was one other type of animal in the River of Giants that could have tangled with a fully grown spinosaurus and come out on top. The river was full of various types of crocodylomorphs, some small, some large, some lightly built, some robust. Kemkemia, for instance, might have grown up to 16 feet long, or 5 meters, but it was lightly built. Laganosuchus might have grown 20 feet long, or 6 meters, but while it was robust, it wasn’t very strong or fast. It’s sometimes called the pancake crocodile because its jaws were long, wide, and flattened like long pancakes. Unlike most pancakes, though, its jaws were lined with lots and lots of small teeth that fit together so closely that when it closed its mouth, the teeth formed a cage that not even the tiniest fish could escape. Researchers think it lay on the bottom of the river with its jaws open, and when a fish swam too close, it snapped it jaws closed and gulped down the fish. But obviously, the pancake crocodile did not worry spinosaurus in the least.

Aegisuchus, on the other hand, was simply enormous. We don’t know exactly how big it is and estimates vary widely, but it probably grew nearly 50 feet long, or 15 meters. It might have been much longer, possibly up to 72 feet long, or 22 meters. It’s sometimes called the shield crocodile because of the shape of its skull.

We don’t have a complete specimen of the shield crocodile, just part of one skull, but that skull is weird. It has a circular raised portion called a boss made of rough bone, and the bone around it shows channels for a number of blood vessels. This is unique among all the crocodilians known, living and extinct, and researchers aren’t sure what it means. One suggestion is that the boss was covered with a sheath that was brightly colored during the mating season, or maybe its shape alone attracted a mate. Modern crocodilians raise their heads up out of the water during mating displays.

The shield crocodile had a flattened head other than this boss, and its eyes may have pointed upward instead of forward. If so, it might have rested on the bottom of the river, looking upward to spot anything that passed overhead. Then again, it might have floated just under the surface of the water near shore, looking up to spot any dinosaurs or other land animals that came down to drink. Watch out, dinosaur! There’s a crocodilian!

Could the shield crocodile really have taken down a fully grown spinosaurus, though? If it was built like modern crocodiles, yes. Spinosaurus was a dinosaur, and dinosaurs had to breathe air. If the shield crocodile hunted like modern crocs, it was some form of ambush predator that could kill large animals by drowning them. You’ve probably seen nature shows where a croc bursts up out of the water, grabs a zebra or something by the nose, and drags it into the water, quick as a blink. The croc can hold its breath for up to an hour, while most land animals have to breathe within a few minutes or die. The shield crocodile and spinosaurus also lived at the same time so undoubtedly would have encountered each other.

Then again, there’s a possibility that the shield crocodile wasn’t actually very fearsome, no matter how big it was. It might have been more lightly built with lots of short teeth like the pancake crocodile’s to trap fish in its broad, flattened snout. Until we have more fossils of Aegisuchus, we can only guess.

Fortunately, palaeontologists are still exploring the Kem Kem beds for more fossils from the river of giants. Hopefully one day soon they’ll find more shield crocodile bones and can answer that all-important question of who would win in a fight, a giant crocodile or a giant swimming dinosaur?

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way and get twice-monthly bonus episodes as well as stickers and things.

Thanks for listening!