ExtinctZoo - Prehistoric Animals Scientists Got Horribly Wrong

Episode Date: June 14, 2025

To figure out what animals millions and millions of years old were like through some bones, is breathtakingly difficult, which is why it may not be surprising, that a few times, paleontologist have gotten things really wrong.

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At First Citizens Bank, we roll with your goals, because we're built for what you're building. Fit for your ambition for Citizens Bank. Paleontology is a notoriously difficult science. It basically tries to figure out what extinct animals are like, just going off of their bones, which sometimes are barely intact, other times hundreds of millions of years old, and many times, both of these things. So to say this line of work is hard is an understatement. Therefore, it's not hard to comprehend how paleontologists have made a few mistakes over the years.

Many times, these errors are rather small and common, like perhaps they slightly exaggerate the size of an animal. However, once in a while, a mistake is made that is neither small nor unimportant, being big enough to change our entire perception of an animal and leaving many scratching their heads, which is nicely demonstrated by these seven creatures. The first example is a rather understandable slip-up, and it was pretty much almost guaranteed to happen, as it involves the very first dinosaur ever described by paleontologists, the megalosaurus.

This Jurassic Theropod was first described all the way back in 1824, when people knew next to nothing about dinosaurs. In fact, at the time, the word dinosaur wasn't even invented yet, and as a result, the first ideas on what megalosaurus was like were, uh, let's just say pretty rough. The holotype had consisted of a femur bone, some bits of vertebrae and part of a lower jaw, which were studied by the English paleontologist William Buckland, who concluded that he had stumbled upon a giant carnivorous lizard, which walked on all fours. Reason being, it was massive, and to him all massive lizards must walk on all fours, obviously.

Additionally, he reckoned that this strange creature was probably amphibious too, showing more preference for water than land, acting kind of like a crocodile. And he estimated that with flesh, it would have measured longer than 40 feet or 12.2 meters. But then a rival paleontologist found an even larger dinosaur bone, which seemingly caused him insecurities, as he really did emphasize the massive part. And he soon decided that 40 feet was not nearly big enough for his little, not-so-little lizard. And thus he increased his estimate to a whopping 70 feet or 21 meters. What's more is that megalosaurus was discovered during a time when many scientists were

still heavily religious, and they would often try to reconcile their finds with their beliefs, In this case, Christianity. And this particular find was a major problem for Buckland, as traditionally it was thought that death and suffering only appeared after Adam and Eve's original sin. But from the bones it was clear that Megalosaurus was a predator, i.e. a killer, and one that seemed to him as living before Adam and Eve. And therefore, he came up with a rather interesting solution by stating that Megalosaurus was not a killer, but rather an animal specialized to end the lives of the old and ill,

order to lower total suffering, and thus preserving the idea of the original sin. And yes, I am serious. And of course, this was a bit off, as was honestly most of its description of the megalosaurus. And slowly but surely the true nature of this theropod was revealed. But what's interesting is that the revelations actually came mostly from the discovery of other theropods that were often quite intact, leading to the realization that megal was not quadrupedal, but rather a biped. And it was not an amphibian, but rather fully terrestrial. We've also since come to know that it wasn't as giant as Buckland claimed, being about half

the original estimate and weighing just slightly over one ton, which was still big for its day, though, and allowed it to be the undisputed apex predator of Middle Jurassic England. But it wasn't just megalosaurus that was misunderstood back in the early days of paleontology. Many dinosaurs ultimately were, but things did get better as time progressed. However, this doesn't mean the mistakes disappeared entirely, as they still did happen and still do happen, and even with non-dinosaurs as well, including animals that as a whole are still living, like spiders. Back in the 1980s, an Argentinian scientist came across a rather peculiar fossil in Argentina's

Bajo de Valiz formation, which dated all the way back to the Carboniferous period. It involved a rather large carapace, three appendages, and turgites, all things you can find in certain groups of animals today, including. arthropods. And given just the general shape of the fossil, the paleontologist realized that he must have found an ancient spider, one that threw everything we knew about spiders out the window, as it was a complete monster, measuring 34 centimeters or 13.3 inches long, which is greater than the maximum size seen in the Goliath bird eater, who up until then had held the title of the largest spider to ever live. And the timing of this new arachnid made

a lot of sense to people, as it existed during the Carboniferous period, a time famous for producing giant creepy crawlies. And what do you do when you discover the largest spider of all time? Well, you give it a fitting name. And this new fossil was dubbed Megarachnay, meaning the great spider. And seeing how many of us are scared of spiders, this creature quickly turned into a fan favorite, and the Megarachnay soon found itself in museums, documentaries, and even stores. But despite all of its fanfare, there were a few skeptics, as Megarachnay did possess

some rather unusual features, even besides its size. For one, its carapace was divided into a front and rear section by a suture, and it also had a spatulate chelisere, a trait never seen before in other spiders. However, these concerns were swept under the rug, with people justifying that these differences were simply because it represented a new order of arachnid, or potentially just that it was simply one-of-a-kind. In either way, clarifying its details proved to be difficult, as the holotype had been stored away in a vault for safekeeping, and thus leaving skeptics with only plastercasts to study.

And so over 25 years it remained how it was, until in 2005 that by chance a second specimen was found that had to be a megarachnate as well, considering the identicalness of its carapace and appendages. This new fossil was also much more complete, which was great news, or so you'd think, as it instead just caused a lot of headaches. For when they were analyzing this specimen, they noticed as turgites and appendages were spitting images of those that belonged to another extinct genus. Only this genus was not a spider, but rather a sea score point.

To be exact, mega-arachnate was virtually identical in some areas to the Woodward Opterus, a permo-carboniferous Eryptorid of similar size. And so then it finally dawned upon everyone that all along, the world's favorite spider hadn't been a spider at all. Quite the fumble, especially seeing that sea scorpions aren't even arachnids. But to be honest, it's not the worst guess, as even though sea scorpions aren't arachnids, they're actually not that distantly related as far as extinct animals go. And I mean, the holotype does superficially look like a spider, kind of.

Now, digesting this news of its real identification wasn't exactly the easiest thing, especially for museums, seeing that many of them had paid some pretty good money for giant spider exhibits. And even today, you can still find this creature being represented as one in certain museums, because again, they paid for it. Nowadays, we imagine the Megarachne was a fair-sized Euripterid that lived in an expansive freshwater floodplain, where it spent its day sifting through substrate with a rake-like arms and feasting on small invertebrates, as opposed to the original belief of prowling dense forests

looking for its next meal. And it's not every day we get the whole ecosystem where an animal lived wrong, on top of its identity itself. But honestly, I'd argue that Megarachnase case is not the worst out there. As a better contender, yet again evolves a dinosaur, but a much more iconic one than megalosaurus, the Therazenosaurus. Thanks to Jurassic World, a lot of people know what this dinosaur looks like from its name alone. I mean, it's kind of hard to forget thanks to those whopping claws. Yet, it wasn't always thought of as the Wolverine dinosaur, nor was it even originally classified as a dinosaur period, but rather a turtle of all things. Now, it makes you wonder how we go from this to this, and to understand that

we'll have to travel back to the 1940s, when dino knowledge, while better than the 1800s, was still lacking. At the time, the Soviet Union had been sponsoring many expeditions, as they were seeking to increase their scientific prowess, with the Gobi Desert, and the Gobi Desert, being a particular hotbed for expiration due to its high number of fossils. And in 1948, a group had made a huge discovery there. As among a trove of dinosaur and turtle bones, they had located massive claw bones that were unlike anything discovered previously, being literally the largest claws ever found at that point.

With each one being some three feet or one meter in length, and were located in the same vicinity as the body of a large theropod, plus some fragmentary ribs and vertebrae of unknown origins. But oddly enough, the paleontologist believed that the theropod's body was unrelated to the claws, while for the fragmentary bones, they were unsure of who they belonged to. And so with just the massive claws, they were left a bit clueless. However, because the Nemek formation was home to a large amount of turtles and was composed in many river systems, one scientist, Evgenli Mali, Malive, came up with a rather interesting idea that these claws

had actually belonged to a giant aquatic turtle, one that measured 4.5 meters or 15 feet long, and weighed over a ton. So definitely quite the sight once you throw in those nails. But thankfully, we were not talking about a killer turtle, as his hypothesis was that this Titan had evolved a very specific way of obtaining food, utilizing its massive claws to rake in huge amounts of scrumptious seaweed. And while this turtly aspect might be news to some of you, this strange path to the Therazenosaurus isn't exactly hidden, as if you didn't know, it's species named to this day, Therazinosaurus, Klonoformis, means scyth lizard turtle, not dinosaur. Yet obviously we know this creature is no turtle, so what happened?

Well, after some time the bones were re-examined by another paleontologist, who noticed that some other extinct animals had very similar claws, albeit many times smaller. However, what was odd to him was that he remarked that the animal with the closest claws weren't turtles, but large theropods, with the paleontologists specifically comparing it to, Chilentysaurus. a possible Chinese neo-venatorid, and thus leading to the new idea that Therazenosaurus was a dinosaur. And sure enough, this was eventually confirmed as other giant claws were located, just this time with additional material, which included part of this mysterious dinosaur's legs, arms, and ribs, among other parts, and thus cementing its identification as a theropod.

Though, despite its fame, even to this day, we have some questions, as not everyone can agree on how it used as giant claws, with ideas ranging from self-defense, and digging for food to hooking food, climbing, and even the hypothesis that they held no purpose, and were just there for show, relatively speaking. But anyways, at least we know it's not a turtle. But it is fun to imagine animals that are iconic for their appearance in different forms. And it wasn't just there as Xenosaurus that this happened to, seeing that it also occurred to an animal even more iconic in some ways, the pterodactylos.

Now, while most won't know this genus specifically, they'd probably gather it was a pterosaur given its name. The group of flying reptiles so iconic to the age of dinosaurs that even people with no interest in paleontology have heard of them. And if you didn't know, it was actually the pterodactylous that the order was named after, seeing that it was the first terrosaur to ever be discovered, with the oldest fossils first being found in the late 1700s. In other words, before even dinosaurs were. And this specific fossil had come from limestone out of Bavaria, and it was for all things considered in quite good shape, with most of the body intact. which is almost a miracle for pterosaurs whose light hollow skeletons rarely fossilized well. And yet, despite the completeness of this find, the first scientist to study it, Cosimo Kalini, still got a lot wrong, to say the least, essentially being so weirded out by this new creature

that he reckoned that it had to be a marine animal, seeing that in his mind, the depths are well known for harboring very freaky creatures, which is kind of true. And because of his assumption, he tried his best to explain how the terasor's features would have aided in aquatic locomotion, despite kind of being able to tell that it really wasn't adapted for the water at all. But he persevered, and his biggest reasoning ended up being that what seemed to be its wings were in reality large and elongated flippers, that it would flap underwater in order to generate propulsion. He further assumed that it would have been fully aquatic, yet others thought it was amphibious, splitting its time between land and water, living kind of like a seal. But beyond this,

he really couldn't say much, and didn't even distinguish if it was a reptile, mammal, or something else. though ironically, he did specifically reject it as having any affinity to bats or birds. Now, because the fossil is quite complete, it didn't actually take long for people to start doubting this aquatic idea. And in the early 1800s, some started pointing out that this new creature had elongated bones to which a wing membrane may have been supported, comparing it to the elongated finger bones we see in bats, and also marking the first-time pterosaurs were regarded as possibly flying animals. Yet, as you can see by this reconstruction, their vision was still some ways off. However, this image would still prove pivotal as it was sent to another

scientist, Georges Cuvier, who was fascinated enough by it to take a peek at the fossil, and ultimately leading him to officially describe the animal in 1809, giving it a name that roughly means winged finger. A fair start, but still mistakes remained, with no one agreeing on what it was, with some speculating that it was in fact a bat, or some type of animal in between a mammal and a bird, while others like Cuvier were unknowingly correct calling it a reptile. This would only be confirmed later on as more specimens of it and other terosaurs were found, but while its flying lifestyle was cleared up much earlier, its original aquatic past would keep haunting it for quite some time, as it wasn't until the 1830s that basically every paleontologist

caved in and antaroptilus in general were flyers, not sea creatures. Though for what it's worth, it does seem that this group did have some species that were a surprisingly good swimmers. And today we know that pterodactylos was really a rather small terrosaur that primarily lived in Jurassic Europe, where it sustained itself on small animals. And while the depths were not its home, it did actually like the water, living near highly salinated lagoons, where life was rich and abundant. Now, confusing one animal for another can definitely be viewed as a big oopsie by some, but at least it was confused for just one creature, not multiple, which is something that sometimes happens. Case in point, Exhibit A, the Anomolo Karris.

Even today, with everything we know about this guy, it's still seen as an odd creature. I mean, come on, just look at it. And you won't probably be surprised to hear it came out of a very strange time for life, the Cambrian, where it was actually a very important animal, being one of the largest animals of the era and presumably one of Earth's first apex predators, given both its unusual size for the time and features that indicated a carnivorous diet. But when the first fossil was unearthed in 1892, it wasn't known as being an apex predator, or even an animal, but rather, animal's, plural.

In this case, three. Like many other odd creatures we know of, its holotype came out of the Burgess shell in Canada, where researchers originally found a piece of its mouth, multiple front appendages, and a trunk. And obviously, having come from one animal, all three parts were found next to each other. And considering how strange looking this guy is, even when completed, it's not hard to see why the researchers first could entail that these fossils represented not three, but one creature, them instead believing that the trunk represented a new type of sea cucumber, the appendages of shrimp, and the mouth, some kind of jellyfish. And funnily enough, originally, they were quite confident

about their classifications, seeing this to be the only logical answer. So imagine their surprise when they started finding more of these fossils in the vicinity, which was obviously confusing, because why would a jellyfish, shrimp, and sea cucumber keep hanging out and dying in the same spot? And the answer? Well, obviously, because it was just one animal. And though I'm sure their guesses are pretty interesting, one anomaloceros is still much cooler in the end, as it is one of the strangest animals known to date, representing a member of the Radiodonta, who in themselves are an extinct order of stem group arthropods. And as a result, the anomal charyis is not really a shrimp, jellyfish, or cucumber, but its odd appearance still has kept it tied to one of these animals,

as it often being described as looking like a very strange shrimp. And sure enough, it was even given a name meaning, the abnormal shrimp. And honestly, it's not the worst name, considering that radiodonto would at least be a distant cousin to them, and that is definitely held true to the abnormal part of its name. But the anomalacharis isn't the only animal that was mistaken for multiple, as there is another, a dinosaur, that for a long time went down as just about the strangest dino in existence. While most mistakes I mentioned have come from misinterpreting what was found, this mistake occurred with what wasn't found, and it has to do with the one-of-a-kind dinochiris. Like some of the others on this list, dinochiris is today a hard to miss

creature, given its strange, giant duck-like appearance, and of course those frightening arms. But back in the day, it was rather easy to miss, as originally only a small fraction of its body was found. Similar to Therazinosaurus, this dinosaur came straight out of the Nemeckd formation, where it was found after a researcher stumbled upon some pretty messed up forelims, a shoulder girdle, vertebrae, and some ribs, all of which were of immense proportions, so big in fact that at the time they represented the largest arms of any bipedal animal ever discovered. And, uh, they also had some pretty metal claws to match. But besides this, nothing else was found, leaving the paleontologist utterly confused and mysticized,

because honestly, who wouldn't be after finding some massive arms and claws in the middle of the desert? And with this little information, all they could report to the world was that back in Cretaceous, there had been a huge dinosaur, presumably a theropod, who rummed about wielding some pretty crazy claws and extraordinarily large arms and hands, which led to its name, Dinochiris, meaning horrible hands. Now, it was by no means the first time that an incomplete fossil been found, but rarely has the found fossil been so tantalizing. And more importantly, it's not often that the incompleteness remains for so long. In immediate subsequent excavations, they weren't able to locate any additional materials. And it became something of a legend, being described as one of the most etymatic, mysterious, and bizarre dinosaurs,

eventually even finding itself literally part of a traveling show. In this lasted for decades, during all of which, many ideas about what it was were floated around, of which the most captivating and terrifying was that it was a giant carnivorous theropod the size of a T-Rex, that undoubtedly terrorized all of the lands. And then another idea posed that it was really just a sloth-like dinosaur, who fed on plants and animals that lived in trees. Meanwhile, a third hypothesis claimed it was a slender man-like entity, in that its arms were supercharged overpowered weapons that allowed it to grab and smash various animals,

for consumption. Pretty wild. But the bottom line remained the same. No one was sure what it was, and thus many errors were made on it. Finally, though, nearly 50 years after its original discovery, researchers caught a break in 2013 when an additional, more complete specimen have been dug up, finally breaking the Mysterium around this creature. Yet, as you know by just looking at this thing, its reality was just as strange, for it turned out to be a giant ornithymosaur, with a duck-like face, horrific limbs, and a large hump, giving it quite the striking appearance. And though it still looks a bit unnerving, it has turned out that despite the presence of large claws, Dinochiris is something of a gentle giant, seeing that its nails were actually blunt,

leading to the idea that they were used to dig and gather plants, not kill animals. Furthermore, its skull was more specialized for eating vegetation, not meat. But at the same time, one specimen found later on did contain fish scales within its stomach region, creating the new assumption that this dinosaur is an omnivore, and a big one at that. And it's now regarded as the largest anathymimosaur ever, and even among the largest theropods, period, with specimens measuring 11 meters or 36 feet long, and weighing 6.5 tons, with some people even thinking it cracked 10 tons in certain cases. So as you can tell by now, paleontology is not perfect, and fossil finds can lead to mistakes,

especially if they are lacking or sufficiently confused whoever found them. But sometimes we also make mistakes when we don't find fossils. In fact, there's a whole term that kind of describes this, Lazarus Taxa, which simply put occurs when an animal disappears and then reappears in the fossil record, causing some confusion, with perhaps the most striking case of this involving a fish, one that's actually still alive. And yes, this does deviate from the whole extinct animal thing, but I think it's an interesting story and still relevant, as the whole problem stems from the fact that we thought it was extinct. and for 66 million years at that.

In the 18th century, paleontologists started to unearth a brand new kind of fish in various formations. The first specimen came out of Europe and was dated all the way back to the late Permian, so over 250 million years ago. It was a medium-sized fish, one which they believe represented an entire new group, which they called the celicants. Now, this original specimen wasn't the most interesting to look at, but it did catch the attention of some researchers, given one, its extreme age, and two, because it's a single. seemed to represent a transitional species between fish and tetrapods.

And what they also noted was that this fish seemed to have managed to survive for a very long time. As others belonging to this group were also found in Devonian formations, Jurassic ones, and so on. And while the public wasn't super engaged in these new finds, some did draw a bit of attention, like the Jurassic date in Mausonia, a giant fish, which could measure 5.3 meters or 17.4 feet in length, and either fed on hard-shelled prey, or any animal that can be. could be suctioned up. And this behemoth, along with the rest, were seemingly a common part to prehistoric life. But then all of a sudden, they abruptly disappeared, and at an interesting point too, 66 million years ago, right when the KT extinction event had occurred, which was seemingly

clear evidence that celacanths and non-avian dinosaurs shared the same fate. But then something crazy happened. In 1938, off the east coast of South Africa, local fishermen have been, well, fishing, and after a hard day of work they returned to shore where the boss of the fisherman ringed up a museum curator, saying that his men had caught a lot of things that would make for good museum exhibits. And so the curator drove out to take a look at the pile,

which consisted mainly of sharks. But among the fish, she noticed a strange blue fin, and as she grabbed and pulled it, she revealed a relatively large five-foot or 1.5 meter long fish, which was unlike anything she had ever seen. And really, anything the fisherman had ever seen either, with them stating that in the 30 years of work,

none had come across a fish like it. And so sensing that it was significant, she bagged it and wrote a letter to a well-seasoned scientist describing her find, stating that the fish was coated in heavy scales, almost armor-like, in fact, while the fins resembled limbs and were scaled right up to a fringe of filament. And then besides the description, she also included a drawing. Then, almost two weeks later, the recipient, J.L.B. Smith, finally saw this sketch, and essentially did the paleontologist version of pooping his pants. As to him, it resembled not a living thing.

fish, but a prehistoric one. But he calmed himself and tried not to get too excited, instead just telling her in all caps to preserve what she could. Eventually, she was also able to send him some small scale samples, which to him confirmed his wildest dreams. It was a silicant, an animal presumably dead for 66 million years, which now had seemingly come back from extinction. And when he finally got to see the specimen in person, he recalled a sensation of being hit by a white, hot blast that just made him feel shaky and happy, with his whole body tingling an afterglow. Kind of odd, but maybe it makes sense for paleontologists as what stood before him was no doubt a celicant, now known as Latimeria.

Unsurprisingly, this was an international sensation and triggered numerous expeditions which not only found more specimens, but also a second kind, and together they're colloquially known as the West Indian Ocean and Indonesian Silicantth. Like some of their ancient relatives, living celiacants can get quite big, clocking in at two meters or 6.6 feet, and weighing around 90 kilograms or 200 pounds. And then on top of this, they also live for extended periods of time, even up to 100 years. And because of course they're still living, we did end up getting to better study them, even sequencing their genome, leading scientists to discover that opposed to the original belief that silicants might be the youngest diverging

non-tetropod sarcopterigian, that title actually goes to lungfish. And surprisingly, or perhaps unsurprisingly, if you understand how evolution works, they also found that celacanths were still evolving to this day though superficially they do resemble their ancestors quite a bit especially in considering their hundreds and millions of years of existence thanks for watching and until next time on extinct zoo