Episode 297: Dinosaur Mummies

This week we have a two-ghost rating for our episode about dinosaur mummies! It’s a little spooky because we talk about mummies, but it’s mostly an episode about dinosaurs, which are not spooky.

Further reading:

The lost Tarbosaurus mummy

Dinosaur Mummy Found with Fossilized Skin and Soft Tissues

Dakota the Dinomummy: Millenniums in the Making

Spectacularly Detailed Armored Dinosaur “Mummy” Makes Its Debut

Was a Dinosaur Mummy Dubbed ‘Appalachiosaurus’ Found in Tennessee?

An Edmontosaurus mummy found in 1908:

A 3D model of Dakota’s skin [photo from third link above]:

The Nodosaurid ankylosaur mummy:

Show transcript:

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

It’s monster month and this week we’ve got a monster from ancient times—really ancient times. We’re talking about mummies today, DINOSAUR mummies! On our spooky scale, this one rates two ghosts out of five since we do talk about mummies, but it’s not too spooky because we mostly talk about dinosaurs!

A dinosaur named Tarbosaurus lived around 70 million years ago in what is now Mongolia. It was probably closely related to Tyrannosaurus rex and would have looked very similar, with a big strong body but teeny-tiny front legs. Its front legs were even smaller than T. rex’s in relation to its body. It grew up to about 33 feet long, or 10 meters, and probably stood about 10 feet high at the hip, or 3 meters, and its big head had a big mouth full of really big teeth. It probably killed and ate hadrosaurs, sauropods, and other big dinosaurs. Some scientists think it was so closely related to T. rex that it should be classified as another species in the genus Tyrannosaurus.

We have quite a few Tarbosaurus fossils, including some very well-preserved skulls, so we know quite a bit about it. It had a good sense of smell and good hearing, but its vision wasn’t all that great. Some paleontologists think it might have been nocturnal. We’ve also found lots of bones of big dinosaurs with bite marks from teeth the size and shape of Tarbosaurus’s.

In 1991, though, a team of scientists found something even more incredible. They found a partial skeleton of a Tarbosaurus with lots of skin impressions. In short, they’d sort of found a mummified dinosaur. (It’s not really a mummy.)

The mummy consisted of the back end of the dinosaur, including the pelvis, tail, and hind legs. It had fallen onto sandy sediment that was especially fine-grained, so when the sediment transformed into sandstone over many millennia, it retained an exceptionally clear impression of the skin, including every small pebbly scale.

The expedition members took pictures and measurements, but they didn’t collect the specimen. Another expedition returned to the area to do so in 1993, but by then the specimen was gone. It was probably stolen by fossil poachers, who probably didn’t even realize the skin impressions were far more valuable than the bones and may have destroyed them while removing the skeleton.

The lost Tarbosaurus specimen is called a fossilized mummy since a dead animal’s skeleton with skin is sort of like a mummy. When the soft tissues of a dead animal or person are preserved in some way that causes them to stop decaying, that’s considered a mummy, and there are a lot of causes.

The most famous mummies, of course, are from ancient Egypt. It was important in Egyptian culture at the time to preserve a dead person’s body, and dead animals were also mummified sometimes, especially cats. The body was treated with salt and spices that helped dry the tissues and preserve them from bacteria, and once it was fully dehydrated the body was wrapped in linen bandages, covered with a natural waterproofing material made from plant resins, and placed in a wooden coffin. Sometimes the coffin was then put into a stone sarcophagus to keep it extra safe.

Other cultures across the world have practiced mummification too, and sometimes mummification happens naturally. This mostly happens in deserts and other dry areas, or in places where it’s very cold and the body freezes before it can decay, then dries out slowly. Sometimes a body is preserved after it’s buried, when the soil of the grave or the conditions in an underground crypt are just right, although bodies found in bogs are mummified too since bogs lack oxygen and that stops the decay of soft tissues.

Another dinosaur mummy was found in 1910 in the western United States, in Wyoming. It’s an Edmontosaurus specimen that’s remarkably well preserved and nearly complete, including skin impressions and even the horny beak. Initially the scientists who studied the animal thought the stomach contents had been preserved too, but more modern studies have concluded that the plant material was probably deposited in the body cavity after death. The dinosaur died near water and flooding may have washed plants into the partially decomposed carcass. There was even a little fish among the plant material, which was probably already dead when it was washed into the body cavity.

Edmontosaurus lived in what is now North America around 67 million years ago, surviving right up to the extinction event that killed off the non-avian dinosaurs. It’s one of many species of hadrosaurid, which are often called duck-billed dinosaurs. It could grow up to 39 feet long, or 12 meters, and possibly larger, and it was relatively common throughout its range. It probably walked on all fours most of the time but could stand or walk on its hind legs only, when it wanted to. It ate plants and may have migrated long distances to find food. It probably lived in groups.

The skin impressions of the 1910 specimen were impressive, but it isn’t the only edmontosaurus mummy ever found. We have several, in fact. The earliest was found in 1908, known as specimen AMNH 5060, and it was discovered by a man named Charles Sternberg and his three sons, who all three became paleontologists later in life. They were hoping to find a good triceratops skull to sell to a museum, but they found something even better when one of the sons realized the dinosaur they were uncovering was wrapped in skin impressions.

AMNH 5060 had died in an area that was very dry, so instead of rotting away, all the moisture in the body dried out and the skin remained stretched across the bones. It was essentially a natural mummy at that point. Then, as in the 1910 specimen, flooding probably covered the dead animal with sediment that preserved it in fine detail. Not only is the skeleton mostly intact, it’s also articulated so that the fossilized body parts are in the same places they were when the animal died, instead of having been scattered around after death.

More edmontosaurus mummies were found later, too, but it wasn’t until 2006 when the most important find so far was discovered in North Dakota, part of the United States. It isn’t just skin impressions we have from this specimen, which is nicknamed Dakota. We have actual fossilized skin and muscles and tendons, along with bones.

Dakota was discovered by Tyler Lyson on his uncle’s ranch when he was still in high school. He knew the dinosaur was there but he didn’t realize how important the find was until five years later when he was a paleontology student. The specimen was excavated in 2006 and was identified as an adolescent edmontosaurus that died about 67 million years ago. It was recently given a new 3D scan and results will hopefully be published soon, letting us all know if there are any fossilized organs inside the body.

Because so much of the soft tissues were preserved in place, we know a lot about how edmontosaurus looked when it was alive. For instance, the intervertebral discs that act as little shock absorbers between vertebrae are still in place, which means we know exactly how long Dakota was when it was alive, about 40 feet long, or 12 meters. Because so many of its tendons and muscles are preserved, scientists can calculate how fast it could run. Dakota could probably run 28 mph, or 45 km/hour. We even have a clue about Dakota’s pattern, if not its coloration. Differences in scale size and texture suggest that the dinosaur might have had stripes on at least part of its body.

Edmontosaurus fossils aren’t the only dinosaur mummies, though. In 2011, an amazing ankylosaur fossil was discovered in a Canadian mine. Ankylosaurs had short legs and wide bodies covered in armor, and while some had club-like tails, Nodosaurids had regular tails but spikes on their backs that pointed sideways. The Canadian ankylosaur mummy is a nodosaurid.

Researchers think the dinosaur was probably caught in a flash flood, which swept it out to sea. It probably swam as long as it could, but its armored body made it heavy and it eventually drowned. Its body sank into the bottom sediment, which protected it from decay, scavengers, weathering, and other things that might have destroyed it. 110 million years later, an equipment operator fortunately noticed how weird the rock was that he’d just uncovered, and the world now has an amazing idea of what a living ankylosaur looked like.

The animal’s armored plates from the front of its body, some skin, and even its stomach contents are beautifully preserved, and the body is still articulated. It looks like it lay down to sleep and turned to stone. Some chemical pigments called melanosomes were discovered during study of the skin, which suggests that its skin was probably reddish-brown in color with a lighter-colored belly. It had massive spikes on its shoulders and along the sides of its neck, along with the smaller osteoderms that made up its armor on the rest of its body.

We know it mostly ate ferns because that was mostly what was in its stomach when it died. There was also some charcoal in its stomach, and researchers think it was probably eating ferns that had grown in an area where a wildfire had been recently. The ferns are so well preserved that scientists can determine their stage of growth, which means the dinosaur probably died in early to mid-summer.

Another dinosaur mummy is a Brachylophosaurus nicknamed Leonardo. Leonardo was found in July 2000 and wasn’t full grown when it died, only maybe three or four years old. Its skin and some of its internal organs are fossilized, and 3D scans have allowed scientists to learn a lot about it.

Brachylophosaurus was a hadrosaurid that lived around 80 million years ago in North America, and it could grow up to around 36 feet long, or 11 meters. It may have lived and migrated in groups. It had a flat crest on its head and a frill down the back, although some individuals had big crests and some had small ones. Paleontologists think big crests might have been a trait found only in males or only in females, we’re not sure which.

It ate plants, and we know from studies of Leonardo’s fossilized digestive system that it had eaten a lot of ferns right before it died, as well as leaves and other material from ancient relatives of conifers and magnolias. It also had worms. That’s right, even the parasites in Leonardo’s digestive system were fossilized. They were needle-like bristly worms who left more than 200 tiny burrows in the digestive lining, fossilized for eternity. Leonardo also had an internal pouch in its neck that was similar to a modern bird’s crop, where food was stored immediately after swallowing and where the digestive process may have started.

We’ll finish by talking about a story from April 2022, which discusses a dinosaur mummy found in my own state of Tennessee. The dinosaur was called Appalachiosaurus and was at least 77 million years old, and its skin and even some of its internal organs were reportedly intact—so much so that DNA was able to be extracted from them. The problem is that this particular story was posted to Facebook on April 1, also known as April Fool’s Day, and yes, it was a hoax. But Appalachiosaurus is a real species of dinosaur, a theropod that grew at least 21 feet long, or 6.5 meters, and probably quite a bit longer since the most complete specimen found so far is a juvenile. We don’t know a lot about Appalachiosaurus since only a few partial remains have ever been discovered. It would be fantastic if a fossilized mummy of one really did turn up one day.

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 107: Ankylosaurus and Stegosaurus

This week we’re going to learn about some armored dinosaurs, a suggestion by Damian!

I love that there’s a stock picture of an ankylosaurus:

Stegosaurus displaying its thagomizer:

Thagomizer explained:

Show transcript:

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

This week’s episode is another suggestion, this one from Damian, who wants to learn about armored dinosaurs like stegosaurus. It turns out that stegosaurus and its relatives are really interesting, so thanks to Damian for the suggestion!

We’ll start with ankylosaurus, which lived near the end of the Cretaceous period, right before all the non-avian dinosaurs went extinct, about 65 million years ago. A lot of paleontologists pronounce it ANKillosaurus, but it’s properly pronounced anKYlosaurus and for once, I’m finding the correct pronunciation easier, probably because it has the name Kylo right in the middle, like Kylo Ren of Star Wars.

There are a lot of species in the ankylosauridae family, but ankylosaurus was the biggest and is probably the one you would recognize since it’s a popular dinosaur. It’s the one with a big club on the end of its tail, but its leathery skin was studded with armored plates called osteoderms or scutes that made it look something like a modern crocodile. It also had spikes along its sides, although they weren’t as long or as impressive as some of the other ankylosaurids’ spikes.

We don’t know exactly how big ankylosaurus could get because we’re still missing some key bones like the pelvis, but paleontologists estimate it could grow around 33 feet long, or ten meters. Is legs were relatively short and its body wide, something like a turtle. When it felt threatened, it may have just dropped to the ground to protect its unarmored belly and laid there like a huge spiky tank.

Because we only have a few fossil specimens of ankylosaurus, there’s actually a lot we don’t know about it. Much of what we do know is actually mostly from ankylosaurus relatives. Researchers think ankylosaurus actually may not have been a typical ankylosaurid. They aren’t sure if the few fossils found mean it was a rare animal or if it just lived inland, away from water, since fossilization is much more common when water is involved. It lived in what is now North America, although it had relatives that lived throughout much of the world.

Ankylosaurus had a beak something like a turtle’s but it also had teeth that it probably used to strip leaves from stems before swallowing them whole. It probably ate ferns and low-growing shrubs. It had a massive gut where plant material would have been fermented and broken down in what was probably a long digestive process. But some researchers think it may have mostly eaten grubs, worms, and roots that it dug up with its powerful forelegs or its beak, sort of like a rooting hog. Its nostrils are smaller and higher on its nose than in other ankylosaurids, which could be an adaptation to keep dirt out. This might also explain why ankylosaurus appears different from other ankylosaurids, which definitely ate plants.

Ankylosaurus had a remarkably small brain for its size. Paleontologists think it may have used its massive tail club as a defensive weapon, but they don’t know for sure. The tail might just have been for display, or maybe males used their tail clubs to fight during mating season. It probably couldn’t walk very fast and was probably cold-blooded, which allowed it to survive after other dinosaurs went extinct after the big meteor struck. Eventually the plants it ate started going extinct, and since it was a big animal that needed a lot of food, it finally went extinct too. Researchers think bird ancestors survived because they were small and could live by eating plant seeds.

One interesting thing about ankylosaurs of all kinds is how they kept from overheating. Large bodies retain heat better than small bodies, which is why polar bears and mammoths are such chonks. Ankylosaurs were massive animals that lived in warm climates. New research published in late 2018 shows that they kept their brains cool by having extremely convoluted nasal passages with blood vessels alongside them. This helped cool the blood before it reached the brain, keeping it from overheating.

Ankylosaurus was related to stegosaurus. Stegasaurus lived in North America around 150 million years ago, during the Jurassic, but its ancestors were found in many other parts of the world. Like its cousin, stegosaurus had a small brain but grew to enormous size, as much as 30 feet long, or 9 meters. You definitely know what a stegosaurus looks like, since next to T rex it’s probably the most recognizable dinosaur. It had big dermal plates that stood up in rows along its spine and four spikes on the end of its tail, called a thagomizer. I’m not even making that name up, it really is called a thagomizer and the term really is from the Far Side cartoon. Its forelegs were shorter than its hind legs, and researchers think it probably stood with its head down to browse on low-growing vegetation, with its tail sticking up as a warning to any predator foolish enough to get too close.

The thagomizer spikes were probably used for defense. Not only do a lot of the spikes show injuries, we have a fossilized tail vertebra from an Allosaurus with a hole punched right through it. The hole matches the size and shape of a stegosaurus’s tail spike.

Paleontologists aren’t as sure about what the plates were for. They were made of bone covered with a keratin sheath that might have been brightly colored or patterned. There are signs that the plates contained a lot of blood vessels for their size, which suggests they helped with thermoregulation—that is, they might have helped the animal absorb and shed heat. Then again, new studies also suggest that the males had larger, broader plates while females had smaller, sharper ones. This argues that the plates might have been for display. Of course, they could be for both display and for thermoregulation.

Sometimes you’ll hear that stegosaurus had such a small brain that it had a second brain in the hip to help it control its tail. This isn’t the case, though. There is a canal in the stegosaurus’s hip near the spinal cord, but this is something found in other dinosaurs and in modern birds. In birds it’s where a structure called the glycogen body is, but researchers don’t actually know what the glycogen body is for. That’s right, something present in all birds, even chickens and pigeons, is more or less still a mystery to scientists. But whatever it is, it’s not a second brain.

There are other mysteries associated with the stegosaurus, like how it ate. It had a tiny head for its size, about the size of a dog’s head, with peglike teeth that seem to have been used for chewing or shearing plant material. But because the head was so small, and the teeth weren’t shaped for grinding, it probably couldn’t have chewed its food up like modern grazing mammals do. But it also doesn’t seem to have ingested gastroliths, small stones used for grinding up food in the stomach.

There were lots of other armored dinosaurs, generally related to stegosaurus and ankylosaurus. I was going to talk about triceratops too, but technically it didn’t have armor, just head frills and horns. Besides, I think triceratops and its relations need their own episode pretty soon. So we’ll finish up with another ankylosaurid, Akainacephalus.

The only fossil we have of akainacephalus was discovered in 2008 in Utah. It’s a remarkably complete fossil, including the skull and jaws, and has been dated to around 76 million years old. It had a spiky ridge over its eyes and short triangular horns on its cheeks that pointed downward. It also had a tail club that ankylosaurids are known for.

Akainacephalus was formally described in 2018 as not just a new species of ankylosaurid, but one in its own genus. Even though it was found in North America, researchers have determined that it’s more closely related to the ankylosaurids that lived in Asia.

Before Akainacephalus evolved, Asia and North America were connected with a land bridge due to low sea levels. This land bridge is called Beringia, and while it’s currently underwater, at different times in the past it’s been exposed and allowed animals to cross from Asia to North America and from North America to Asia. Beringia is about 600 miles wide, or around 1,000 km, when it’s above water. At the moment, it’s represented by a couple of little islands in the shallow Bering Strait, since it’s been underwater for the last 11,000 years.

Previously researchers thought this land bridge had only been open once during the Cretaceous, but that was before paleontologists examined akainacephalus. Since akainacephalus is related to ankylosaurids that lived in Asia after the land bridge was submerged, it’s possible there was a second opening of Beringia that allowed akainacephalus’s ancestor to migrate from Asia to North America.

That’s one of the really neat things about science. You start by looking at a cool spiky fossil skull, and you end up learning something new about how deep the oceans were 80-some million years ago.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!