Strange Animals Podcast

Further reading:

Pterosaur melanosomes support signalling functions for early feathers

Show transcript:

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

This month we have a small mystery from Australia, which as far as I can find is still unsolved.

In 1950, a man named George Gray started hearing bellowing from the gum swamp near his house. His adult son, Ted, heard it too and reported it was loud enough to hear half a mile away, or about 800 meters.

The bellowing sounded like a crocodile. The problem is, the Grays lived just outside of the small town of Wee Waa in New South Wales, Australia. Very, very rarely a saltwater crocodile wanders down the coast as far as New South Wales, but Wee Waa is a five or six hour drive inland. It’s not crocodile country. It gets cold in winter and it’s surrounded by farmland.

Ted Gray found tracks in the swamp where a large animal had flattened tall grass, although the footprints didn’t have claw marks. He estimated that if the animal was a crocodile, it was only about 6 feet long, or 1.8 meters, although he did note that none of the trails seemed to lead to the water. The bellowing mostly occurred in early morning and around sundown and continued for several months.

Attempts to search the wetlands were unsuccessful, mostly because of heavy rain that spring and summer. The water was ordinarily no more than 3 feet deep, or about a meter [actually about 92 cm, got this wrong], but was much deeper that year. Hundreds of people came to listen to the bellowing, though, and one constable perched in a tree for most of a day hoping to shoot the animal. He never saw it.

Seven years earlier, during World War II, an armored division of troops stayed in the area. The troops had been based in northwest Australia for a time and were supposed to have brought some baby crocodiles with them as mascots. The soldiers were told to kill the crocodiles, but newspapers in 1950 suggested they’d been released instead and that one had found its way to George Gray’s swamp. That doesn’t explain how it survived seven winters or why no one had seen or heard it until then.

Then again, one man named Ross Tuckey claimed he’d seen a crocodile several years before about 20 miles away, or 32 kilometers. He’d first thought it was a goanna, which is a type of monitor lizard that lives in Australia. Some species of goanna can grow more than 8 feet long, or about 2.5 meters. When Tuckey’s dog rushed at the animal, it bowled the dog away with its tail and slid into a dammed stream. Tuckey watched it float in the water with only its nostrils visible.

The Wee Waa monster was never identified.

That’s all there is! I tried to find out more but if anyone ever found what animal was bellowing in George Gray’s swamp, the newspapers didn’t report about it. I actually only learned about this animal mystery when I was searching for something else, which is always a lot of fun.

***

115 million years ago a colony of strange flying animals lived in what is now northeastern Brazil in South America. It was a reptile that lived at the same time as dinosaurs, but it wasn’t a dinosaur. It wasn’t a bird either. Its wingspan might have been as much as 13 feet across, or 4 meters, which was big for a pterosaur, which of course is what it was. Specifically, it’s Tupandactylus imperator [too-pan-DAK-tillus imper-AH-ter], and it is a complete weirdo.

Tupandactylus was only described in 1997, but we have several really well preserved specimens, including nearly complete skulls. And it’s the skull that makes it so bizarre. Many pterosaurs had large crests that were probably brightly colored and probably used to attract mates, but Tupandactylus had what may be the largest crest ever found. It was just ridiculously large, nearly as big as its whole body, not counting its wings, of course.

Tupandactylus’s skull is hard to describe. I’m going to do my best, but you might want to click through to the show notes and look at the picture.

First, imagine a pelican’s bill. It’s long and has a pouch underneath. But in your mental picture, push that pouch forward so that it’s at the base of the lower jaw like a chin, and made of bone instead of soft tissue. Tupandactylus had a sort of keel on the underside of the end of its lower jaw that was probably for display.

Next, the upper jaw is tall but narrow. Maybe it will help to picture a toucan’s bill, but unlike a toucan, Tupandactylus’s upper jaw had a projection at the top that formed the base of the crest. This projection is a big triangular piece of bone that tops the upper jaw, and at the upper point of the triangle there’s a long, thin spur of bone that points upward and bends back. It’s ridiculously long.

Finally, the rear of the skull has another projection that points straight back to form the back of the crest. The tall rod of bone on top of the upper jaw forms the front of the crest. The crest itself was mostly made of soft tissue and keratin stretched between the two bony rods.

To finish our description of the skull, Tupandactylus had no teeth and probably also had a keratin beak at the very tips of its jaws, especially its lower jaw. We don’t know what it ate, but some paleontologists hypothesize it might have mostly eaten fruit and other plant material. It probably spent a lot of time on the ground looking for food and hanging out in its flock, sort of like geese do today.

We have a pretty good idea of what the crest looked like because a few specimens have soft tissue impressions left by the crest when the animal died and fell into mud. The complete crest was like a big sail, although there’s no evidence that it helped the animal fly.

What we don’t know is what color the crest was, but researchers have long assumed it was brightly colored and probably patterned to attract a mate.

In an article published in Nature in April of 2022, a team of paleontologists from Brazil and Belgium announced that they’ve found some amazing details in a newly discovered Tupandactylus skull. Tupandactylus had feathers.

They discovered the feathers at the bottom of the crest, some of them fluffy and some of them longer and more like modern bird feathers. And that’s not all. The feathers are so well preserved that under electron microscopes, the team found preserved melanosomes, which are pigment granules. We still don’t know what colors the feathers were, but they were definitely different colors because the melanosomes are different shapes, and in bird feathers different melanosome shapes correspond to different colors. Simple feather fibers have also been found on the jaws, which suggests that Tupandactylus might have had feathers over much of its body. That means other pterosaurs probably did too.

There are actually two species of Tupandactylus known, T. imperator and T. navigans. T. navigans is smaller and has a smaller, less extravagant crest. Some researchers suggest the two species might actually be the same species, with sexually dimorphic males and females (meaning they look different). Maybe one day we’ll find out for sure.

Thanks for your support, and thanks for listening!

It’s our 500th episode! Wow!

Thanks to Rosie, Remy and Julien, and Dylan, Emily, and Michelle for their suggestions this week!

Further reading:

Crikey! Newly Discovered Snake Species Named After Steve Irwin

Steve Irwin’s Treesnail

A young Steve Irwin’s tree snail [photo taken from link above]:

A marbled lungfish:

A fennec, smallest and cutest of all foxes:

Show transcript:

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

This week we have a brand new episode, because it’s episode 500! Congratulations to me and to you too, listening to the 500th episode of a podcast! That doesn’t happen very often!

Despite the big 5-0-0, I’m going to treat this like a regular episode. Thanks to Dylan, Emily, and Michelle, Remy and Julien, and Rosie for their suggestions this week!

We’ll start with Dylan, Emily, and Michelle, who live in Australia. A while back now they got to visit the Australia Zoo, which is run by the Irwin family. Steve Irwin was a conservationist, science educator, and wildlife rehabilitator, also known as the Crocodile Hunter for his work relocating crocodiles who were endangering people, and vice versa. He died tragically young in 2006 but his wife and children continue his work.

Michelle pointed out that Irwin has been honored by scientists who have named newly discovered animals for him, so let’s learn about a few of them!

The most recent one is a type of wolf snake discovered on the Great Nicobar Island off the coast of India and described in 2025, Lycodon irwini. It’s mostly black in color with a slender body, and can grow as much as 47 inches long, or 119 cm. That’s almost four feet long! Luckily it’s non-venomous, plus it has only been found on that one island in evergreen forests, so you’re not likely to run across one by accident. It probably eats small animals like frogs, but we don’t know a whole lot about it yet.

Back in 1990, Steve Irwin caught a strange turtle while fishing with his father, Bob, who was also a conservationist. Between them, the two men knew a whole lot about Australian wildlife but they didn’t know what the turtle was. They sent pictures to a turtle expert, who determined that yes, it was a species new to science. It was described in 1997 and named Irwin’s turtle, Elseya irwini.

Irwin’s turtle has a black and yellow carapace and lives in the lower part of the Burdekin River in northern Queensland. The female also has a light-colored head and other pale spots on the body.

Like some other turtles, it can absorb oxygen from the water through its cloaca, which is often referred to as its butt. A chamber at the end of the cloaca contains structures that act like gills and absorb oxygen. This allows it to stay underwater longer, and in fact it can’t survive in water that doesn’t contain enough oxygen.

As a result, Irwin’s turtle is endangered due to habitat loss, especially from pollution and the damming of its river home. It used to be common but its numbers are in decline. The Australia Zoo started a captive breeding program to help conserve the species, and in 2023 they succeeded in hatching the very first Irwin’s turtle babies ever bred in captivity.

The last one is my favorite, a land snail named after Steve Irwin. It was described as a new species in 2009, only a few years after Irwin died, and was named Crikey steveirwini. It’s the only species in the genus Crikey. It only lives in high altitudes in the tropical rainforests of northeastern Queensland. It’s rare and not much is known about it, because it’s so hard to find and so small. It has a cone-shaped shell that’s striped with spiral bands of brown, yellow-brown, and white, and it only grows 15 mm long at most.

Next, brothers Remy and Julien wanted to learn about the African lungfish. Lungfish are fascinating fish, because as you can probably guess from the name, they have gills but they also have lungs, and the fish needs both to get enough oxygen.

Four species of lungfish live in Africa, all belonging to the family Protopteridae. They’re eel-like in shape although they’re not closely related to eels at all, with soft scales, and a dorsal fin that continues down the fish’s back and continues around the end of the tail, since the dorsal fin and tail fin are actually fused into one big fin. Its only other fins are the pectoral and pelvic, which are very thin and are more like flexible legs than actual fins. The lungfish can actually crawl along the bottom of the swamp or lake with its fins, although it can also swim like an eel.

While the African lungfish does have gills, they’re small and are mostly associated with eliminating carbon dioxide instead of absorbing oxygen. The lungs do most of the work. The fish surfaces periodically to gulp fresh air into its lungs. It’s one of the few fish that can drown if it can’t surface for air.

African lungfish eat insect larvae, especially of aquatic insects, crustaceans, mollusks, small fish, and frogs, but it can also sometimes eat seeds and other plant material. It usually lives in shallow water like swamps and small rivers, where there’s not a lot of oxygen in the water. In many cases, its waterways dry up periodically, but the fish can still survive. As its water gets lower and lower, the lungfish digs into the mud and curls up, then secretes a thick mucus that helps retain moisture and stops its body from drying out. Its metabolism slows way down so it doesn’t need to breathe very often, and it doesn’t need to eat. It can survive this way for up to four years, although it usually only has to stay in its cocoon for a few months, until the rains return and its waterways fill up again.

The smallest species of African lungfish is the East African lungfish, which only grows about 17 inches long, or 44 cm, while the largest is the marbled lungfish that can grow a whopping six and a half feet long, or two meters.

Lastly, Rosie suggested we learn about the fennec fox, which lives in northern Africa. It’s the smallest fox in the world, barely eight inches tall at the shoulder, or 20 cm, but it has incredibly large ears. Its ears can be as much as six inches long, or 15 cm.

Part of the reason its ears are so big is so it can hear insects and other small animals moving around underground, but they’re also big because they help dissipate heat from the fox’s body into the air. Since the fennec lives in deserts, that’s only one of many adaptations it has to the heat and lack of water.

For instance, the fennec gets most of its water through the food it eats. It’s also a nocturnal animal. The pads of its paws are protected by long, coarse hairs that grow between the pads, so hot sand won’t burn its toe beans. The hair also gives the fox better traction in loose sand.

The fennec’s fur is a pale sandy color with a black tip to the tail, and it has dark eyes. It eats rodents, birds and their eggs, insects, scorpions, and other small animals, as well as fruit and other plant material. It can jump really far, some four feet in one bound, or 120 cm. Not only can it run really fast, it can change directions really quickly too. This helps it escape predators and catch prey.

Fennecs can be social animals and like to play, even as adults. Pairs mate for life and both parents take care of the babies. A fennec’s burrow can be very large and may even link up to neighboring fennec family burrow, so neighbors can visit each other without going out into the heat of the day.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s.

Thanks for listening!

Thanks to those of you who backed my recent crowdfunding campaign! Right now the Small Mysteries book isn’t available yet, but in the Halloween episode in October, I’ll make sure to put a link where you can buy the ebook.

Further reading:

Cambrian Explosion Month #18: Stem-Gnathifera

Ambiguous Amiskwia

Amiskwia, possibly [picture taken from above link]:

Show transcript:

Welcome to the Patreon bonus episode of Strange Animals Podcast for May 2025!

We’ve talked about a lot of strange and mysterious animals from the Cambrian in past episodes, especially episode 69, but I don’t think we’ve learned about Amiskwia yet. For a long time it was another mystery animal from the Burgess Shale and a few other places, dating back as much as 518 million years ago, but as of only a few years ago the mystery seems to be solved, at least mostly.

Amiskwia grew about an inch long, or 2.5 cm, which actually made it one of the larger animals that lived in the Cambrian. It probably looked superficially like a slug, with a slightly flattened body and a pair of short tentacles on its head. It had a paddle-shaped tail and two flaps on its sides that probably acted as fins to help it swim. Its mouth was on the underside of its head and was surprisingly complicated, with two pairs of plates with little spikes on them. We even know about its internal anatomy, since some of the Amiskwia fossils are so well preserved that its insides can be studied too. It had a brain and a simple digestive tract.

Amiskwia was described in 1911 by Charles Walcott, who described a lot of the Burgess Shale fossils. Walcott classified it as a type of arrow worm. When scientists gave it a closer look later, not everyone agreed it was related to modern arrow worms. Some suggested it might be a type of ribbon worm, or maybe an early mollusk, while others argued that it was so different from known animals that it belonged in its own phylum.

A 2019 study suggested that Amiskwia’s weird mouth plates matched up with the mouth plates in a living animal, and a 2022 follow-up study confirmed the 2019 findings. Not everyone agrees, but as of now, Amiskwia is considered an ancestral gnathiferan.

There! Mystery solved! Wait, what do you mean you don’t know what a gnathiferan is?

As everyone knows, especially me, I definitely didn’t just learn about this type of animal myself just now, gnathiferans include a lot of different animals with complex jaws—not like your own jaws, but with little plates and spikes and moving parts made of chitin. Most gnathiferans are tiny, microscopic or barely a few millimeters long, so Amiskwia was a giant in comparison.

Arrow worms are also generally considered to be gnathiferans, so Wolcott wasn’t too far off in his description of Amiskwia. We don’t know what Amiskwia ate, but it could probably swim pretty well and most likely hunted other animals or scavenged already dead ones. Scientists think it probably spent most of its time swimming well above the sea floor, which is why it’s a relatively rare fossil.

Another Cambrian mystery animal that lived even earlier than Amiskwia, around 520 million years ago, and which is probably related to it, is Timorebestia. Its fossils were discovered in Greenland and only described in 2024. It had a pair of long tentacles or antennae, a rounded paddle-like tail, and fins on each side of its wide, flattened body. Its tentacles were around half the length of its body–and if Amiskwia was a giant compared to modern gnathiferans, Timorebestia was a colossus! It grew almost 8 inches long, or over 20 cm, not even counting its tentacles!

Some Timorebestia specimens are so well preserved that scientists can identify what they ate right before they died, and it looks like they mostly ate small arthropods. Timorebestia was probably the biggest and strongest predator in the area when it was alive, one of the earliest apex predators discovered.

Another similar animal was Nectocaris, which has been discovered in the Burgess Shale of Canada and other Cambrian fossil sites in China and Australia. It was flattened and had a pair of tentacles on its head, and a fin on both sides of its body–but it had a lot of features not found in Amiskwia and Timorebestia, including eyes. It also seems to have had a tube or funnel of some kind that emerged from the underside of the body near the head. It might have been a proboscis of some kind, but some scientists think it was a funnel like the ones found in modern squid, used to jet through the water quickly. Many scientists even think Nectocaris was a precursor to squid and other cephalopods, but other scientists disagree. Some specimens are about one inch long, or around 3 cm, while others are around 4 inches long, or about 10 cm. This might mean there were two species, or that the small ones were juveniles, or that males and females were different sizes. We just don’t know.

Small animals, especially ones with mostly soft bodies, don’t fossilize as often as larger and more robust animals. We’re very lucky that we have so many beautifully detailed Cambrian fossils, since so many modern gnathiferans and their close relations aren’t otherwise found in the fossil record at all.

Thanks for your support, and thanks for listening!

Further reading:

https://sharonahill.substack.com/

https://metazoan.net/54-octlantis/

https://metazoan.net/109-octopolis-and-octlantis/

Scientists discover an underwater city full of gloomy octopuses

The gloomy octopus [photo by Niki Hubbard – https://www.inaturalist.org/photos/118664956, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=123044473]:

Show transcript:

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

As I’ve mentioned before, I really don’t like April Fools Day, which is April first. I especially don’t like it when someone makes an April fools day post online and just leaves it there afterwards. It’s too easy for other people to stumble across it and think it’s real. This goes double for strange animal and cryptid reports.

I subscribe to geologist Sharon Hill’s Pop Goes the Cryptid articles, and on March 31 she talked about a hoax called the North American Pine Squid. It got popular around Halloween of 2024. It’s said to be a black squid or octopus that lives in pine trees in remote, heavily forested places like the Pacific northwest and the Appalachian mountains. Most of the time it eats small animals like birds and squirrels, along with pine cones, but if someone walks underneath its tree, the pine squid grabs the person, pulls them up into the tree, and they’re never seen again.

But you don’t have to worry, because the pine squid isn’t a real animal. It’s also not even a new story. It’s based on another hoax called the Pacific Northwest tree octopus, which dates back to 1998. In the case of the tree octopus, it wasn’t created as a hoax or an April fool’s joke but as a study about whether children can tell if a website is reliable or not. The researchers made a page with information about a type of octopus that lived in the ocean but that also climbed trees. Then they asked several classrooms of children around age 11, from different schools in different countries, to read the page, look at the pictures provided, and answer some questions.

The study found that most of the children thought the page contained reliable information. Only a few figured out that the tree octopus wasn’t real. The study has been used repeatedly to argue that children need more lessons in how to evaluate a website to know if it contains reliable information, and of course that’s always a good thing. But it makes me a little angry too, because how were the kids supposed to know that octopuses can’t climb trees? There are so many amazing and strange animals out there, a tree octopus sounds perfectly normal if you don’t know very much about octopuses. So I argue that kids should be taught about everything, and taught in as interesting a way as possible so that they remember it better. The same goes for adults.

But this episode isn’t actually about April fools day, tree octopuses, or pine squids. It is about a type of octopus, and what I’m going to tell you is so weird that I have to reassure you that it’s actually true. It’s not a hoax or an April fools joke or anything like that. It’s about the gloomy octopus and the underwater cities some populations have created, referred to as Octopolis and Octlantis. I swear I’m not making this up!

The gloomy octopus lives off the eastern coast of Australia and the northern coast of New Zealand. It’s mainly brown and gray, but it has orange on the undersides of its arms, and it’s covered in little bumps that help camouflage it. Its eyes are white. On average, it has an armspan of about 6 ½ feet, or 2 meters, with females generally larger than males. Like many other octopuses, when the female lays her eggs, she stops eating completely and protects the eggs until they hatch. After they hatch, she dies.

The gloomy octopus lives in shallow warm water and especially likes places with lots of rocks, seagrass, reefs, and other places where it can hide. It spends a lot of time in a den it digs into the sea floor, only coming out at night to hunt. It especially likes scallops, but it will eat pretty much anything it can catch, including sea snails, crabs, seahorses, and even other gloomy octopuses. It usually brings its food back to its den to eat.

The gloomy octopus was thought to be a solitary animal until 2009. That’s when a biologist named Matt Lawrence was exploring Jervis Bay in New South Wales. In this particular part of the bay, the sand is silty and there are a lot of predators, so it’s not great for the gloomy octopus. But not only did Lawrence find a gloomy octopus there, he found 16 of them living in close proximity.

The octopuses’ dens were very close to each other, surrounding a human-made object that’s so encrusted with sea life that it can’t be identified. Scientists think it was a piece that fell off a boat at some point. Even more interesting, there are so many shells around, especially scallop shells, that instead of making dens in the sand, the octopuses are basically making dens in huge piles of scallop shells. The octopuses spend time moving the shells to improve their dens.

In other words, Lawrence had found an octopus city. Admittedly, it’s a very small city by human standards, with only 16 residents identified at any given time, but for a supposedly solitary animal, that’s pretty amazing.

The site was nicknamed Octopolis, and scientists think the presence of the piece of boat actually started the site. When it fell into the sand, it provided a great place for a gloomy octopus to hide. Since gloomy octopuses bring mollusks back to the den to eat, naturally they discard the shells near their dens. Once enough discarded shells had piled up, it provided better building material for another den. Another octopus moved in as the first one’s neighbor, which meant twice as many shells being discarded. Pretty soon another octopus joined the first ones, and eventually there were 16 separate dens in a little community.

Then, in 2017, another octopus city was discovered not far from Octopolis. Instead of a human-made object at its center, it has a few rocks sticking up in the middle of the city, which has been nicknamed Octlantis.

Observations of the octopuses living in these communities are surprising. The octopuses come out during the day even though ordinarily the gloomy octopus is most active at night, especially around dawn and dusk. They interact with each other in various ways, sometimes fighting, sometimes pairing off to mate, sometimes sneaking into another octopus’s den and trying to take it over. It might not be full of underwater skyscrapers and underwater scallop vendors on busy corners, but there’s a lot of hustle and bustle in these cities.

When biologists revisited Octopolis in 2023, they only found three octopuses. Octlantis had a little more activity and a few more octopuses, but nothing like its busy 2017 numbers. But this doesn’t mean that the cities are deserted. Low Octopolis populations were also discovered in 2010 and 2013, but a high population in between. The biologists also noted that the presence of sharks caused the octopuses to move, and in 2023 a shark was hanging around Octopolis.

Another reason for the changing population sizes at the sites is that gloomy octopuses don’t live very long. A three-year-old gloomy octopus is really old, since most die before they reach their first birthday. The octopuses spotted in Octopolis and Octlantis in 2023 might be as much as 14 generations removed from the ones seen in 2009. Young octopuses have to continually repopulate the cities as the older ones die off, and that might take longer some years than others.

Just because we know about Octopolis and Octlantis doesn’t mean those are the only two octopus cities in existence. There are probably a lot more. Scientists just haven’t noticed them yet. In years where sharks are spending too much time in Octopolis, the octopuses might just move to a city we don’t know about. Octopolis and Octlantis might even be really small in comparison to some cities. If you’re a diver around Australia or New Zealand, keep a sharp eye out for an octopus city. You might be the first human to visit New Octleans.

Thanks for your support, and thanks for listening!

Megarachne as we know it now:

Show transcript:

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

Megarachne is only known from two specimens, neither of which is complete, which adds to the confusion. It lived around 300 million years ago in what is now South America. It was described in 1980 from the first specimen discovered and was named Megarachne, which means big spider. The scientist who described it thought it was a type of primitive spider related to modern tarantulas, but much bigger. He estimated its legspan was 20 inches, or 50 cm, with a body length of just over 13 inches, or 34 cm. That made it the largest spider ever known by a lot.

Other palaeontologists, especially arachnologists who specialize in spiders and their relations, weren’t convinced Megarachne was a spider. But it wasn’t until 2005 when a more complete specimen was discovered that anyone could say for sure what it was. The second specimen made it clear that it wasn’t a spider at all but a sea scorpion, or eurypterid, and not an especially large one compared to some. It probably grew to 21 inches long, or 54 cm.

But by then, Megarachne had gotten really popular as a giant spider. It was in the BBC documentary Walking with Monsters, although the producers changed its name to Mesothelae right before it aired, which was just after the new findings about Megarachne came out. Mesothelae is a suborder of big spiders from parts of Asia that retain many traits of ancestral spiders. It was a valiant attempt by the BBC to make the documentary less incorrect, but of course the spider they were talking about still wasn’t a spider and no spider known has ever grown that large.

But while Megarachne isn’t a giant spider, and isn’t even a very big eurypterid, it is important since not very many eurypterids are known from South America. It also appears to be closely related to Mycterops and Woodwardopterus, similar-looking euripterids from North America and Europe. But some researchers think it’s not as cut and dried as it sounds. Instead of three similar creatures living in different areas, they think there’s something else going on.

Eurypterids were arthropods, the phylum that includes insects, arachnids, and crustaceans, among others. Arthropods have an exoskeleton that they molt periodically as they grow, and many arthropods have complicated life stages compared to other animals. When a shark hatches, it looks like a miniature adult and just grows larger as it gets older, but when an arthropod hatches, it usually doesn’t look anything like its adult form. Some arthropods go through many stages of life before reaching the adult body plan. Crustaceans have numerous larval stages, for instance, that often look very different from the adult. Some researchers think that Megarachne, Mycterops, and Woodwardopterus were all the same animal, and that the differences are due to it being in three different stages of development when it died and was preserved.

We don’t have any way to know if this was correct, of course, not until we hopefully find more fossil remains. Other eurypterids did appear to go through some physical changes during maturation, as far as researchers can tell with the remains we have, but Megarachne, Mycterops, and Woodwardopterus belonged to a different family from other eurypterids and are much rarer. They might have been quite different developmentally.

We can also look at the living relations to see how likely it is that eurypterids had different larval stages where they looked different from the adult form. Eurypterids were probably most closely related to horseshoe crabs, although not everyone agrees. Horseshoe crabs have been around for 445 million years and are really neat animals that we’re lucky to still have in the world. The horseshoe crab hatches into a larva that looks a lot like a trilobite. It does indeed go through physical changes as it grows and molts over the course of three years, so it’s reasonable to assume that eurypterids did too.

On the other hand, some researchers think eurypterids were more closely related to modern scorpions. Scorpions actually give birth to live babies instead of laying eggs, and the female carries the babies on her back for several days up to several weeks, depending on the species. Once the babies have their first molt they look a lot more like miniature adults and pretty soon are able to leave their mother and hunt on their own. So again, it’s possible that eurypterids had a system more like this instead of like the horseshoe crab’s.

While we’re talking about scorpions, did you know that scorpions glow blue-green in ultraviolet light? The scorpion’s exoskeleton contains fluorescent chemicals, but we’re not sure why. Scorpions do have incredibly light sensitive eyes, and can navigate at night using only starlight. Their eyes can’t form sharp images like ours can, though. And scorpions have a lot of eyes. Spiders have four pairs of eyes, but some scorpions have more than that. All species have a pair on top of the cephalothorax, which corresponds to the head, and more on the sides of the cephalothorax. Some species have up to five pairs of eyes in addition to the ones on top of the head. Twelve eyes seems like overkill but it works for the scorpion. Eurypterids had both compound eyes and simple eyes.

That’s all we know about Megarachne right now, at least until we find more fossilized specimens. Let’s hope we do, and while we’re at it, let’s hope we find some more fossilized giant spiders because that would be cool.

Thanks for your support, and thanks for listening!