Ancient Grecians came across the bizarre one-holed skulls of long-dead Atlas elephants, and the mythological Cyclops was born. Accounts from China, in 300 BCE, attest to “dragon bones,” which we now know to have been dinosaur fossils. The mythical half-lion, half-eagle gryphon may have been an interpretation of unearthed fossils in Mongolia.

The science of paleontology is, by necessity, one of educated guesses and oft-revised assumptions. Even today, our assumptions are constantly changing. We now know that almost all of the Therapoda (the dinosaur family that contains both Tyrannosaurus rex and all modern birds) were feathered, something that’s still not represented in most paleo-art. Many extinct creatures are so outside our familiar world that it’s not unexpected to produce completely wrong interpretations of these ancient beasts.

But some representations of ancient creatures are more than just wrong—they’re straight up bizarre, or curious and wonderful. Here are some of the notable, odd, and amazingly incorrect interpretations of fossils.

1. Brontosaurus

Ah, the brontosaurus! Not only did the “Thunder Lizard” not exist—it was simply an apatosaurus (the aptly named “deceptive lizard”) skeleton with an incorrect head attached during the rushed competition of the Bone Wars—it certainly wouldn’t have looked like this depiction. The apatosaurus body was built like those of the other Diplodocae (giant plant eaters), with a mostly-level topline, and a tapered, non-dragging tail for balance. It also had a single large nail on its front feet, and three nails on its hind feet, unlike the many-phalanged beast shown here.

Because of the significant publicity of the initial “discovery,” and the almost non-existent publicity of the 1903 realization that the brontosaurus was simply another apatosaurus, the misinformation about this genus persisted in both grade school texts and the public’s imagination for decades after the official corrections. Below is a modern interpretation of “Brontosaurus.”

2. Hump-backed Megalosaurus

The first named dinosaur fossil was Megalosaurus, and as one can imagine, being the first meant that we had very little idea how dinosaurs were related to today’s animals, how they were built, and what parts went where. Given that the remains we had to work with were fragmentary at best, it’s understandable how wrong Samuel Goodrich was in his 1857 interpretation of the species. Here's a modern interpretation of Megalosaurus.

3. Squat Iguanodon

Another one of the three “original dinosaurs” that Victorian biologist Richard Owen used to describe the order (now the clade) Dinosauria, Iguanadon fared no better than Megalosaurus in its reconstruction. Instead of the bipedal, toothless plant eater that we know it as today, Iguanadon was shown as a quadrupedal, stout, snout-horned, mammal-like creature that Owen thought was the epitome of “transmutation” (a forerunner to evolutionary theory). Below you can see the modern interpretation of Iguanodon.

4. Spiny Tripod Stegosaurus

Though he eventually illustrated a much more accurate version of the stegosaurus, this bizarre depiction was O.C. Marsh’s first take on the fossils that his team dug up in Como Bluff, Wyoming. With its tail spikes on its back, its back plates on its tail, a long neck, and a tripodal pose, the image that ran in an 1884 issue of Scientific American was unrecognizable as a stegosaurus.

Marsh also briefly believed that, since it was perplexing how such a huge lizard had such a tiny brain (as evidenced by their miniscule brain cases), stegosauruses had an additional brain at the base of their tail.

5. Stegosaurus, Take 2

Those tail spikes! In another early interpretation of the Stegosaurus from 1914, Frank Bond assumed that the tail spikes of the thagomizer were scattered throughout the back, and the back plates served as osteoderms (hard protective scales) instead of the alternating ridge pattern that we know them to have been in today. Though the Stegosaurus was probably more flexible than it looked, it’s quite unlikely that it would have browsed so high up in trees, either.

By the way, the “thagomizer”—that spiky tail-end weapon on stegosaurids—didn’t have a name back when paleontologists first realized where those spikes belonged. The name came from a 1982 Far Side comic panel, and was first used in a professional setting in 1993. Though not “formal” terminology, it’s now widely known enough that it can be found in textbooks, at the Smithsonian Institution, and on the BBC series Planet Dinosaur. Here's the modern interpretation of Stegosaurus.

6. Tail-headed Elasmosaurus

When the elasmosaurus was discovered by E.D. Cope’s team in 1868, the bones were sent East, where Cope re-assembled them according to his notions of what he thought it should look like. Previously an expert on lizards, which regularly have short necks and long tails, Cope reconstructed the newly-discovered creature with its head placed on what we now know to be the tail (short end). Like the brontosaurus, the publicity surrounding the initial discovery (and initial assumptions) was far more wide-reaching than the announcement of the correction, in 1870. As can be seen in this ca. 1900 trade card for Cacao Suchard, the public image of the elasmosaurus was still that of a short-necked, long-tailed creature, decades after we knew that was incorrect.

7. Snake-necked Elasmosaurus

On the other end of the spectrum, Cope’s eventual rival, O.C. Marsh, had the head on the correct end of the body, but was still incredibly wrong in his depiction of its anatomy as “snake-like.” Due to the structure of the 71 cervical (neck) vertebrae, we now know that the elasmosaurus would have had an extremely limited range of motion for its neck. The head could move side-to-side and up-and-down, but any depiction of this creature with a “swan neck” (or this more extreme snake neck) is incorrect.

With the neck being so heavy and the center of gravity being just behind the front flippers, the elasmosaurus and its relatives also would not have been able to significantly lift their heads out of the water, except where its body was resting on the bottom. Along with this fact, the fairly weak muscles and odd center of gravity for these creatures means that, despite depictions in childrens’ books and television programs, they would not have been able to crawl onto land to give birth or lay eggs; elasmosaurus most likely gave birth to live young in the open ocean. Here's a modern interpretation of the elasmosaurus.

8. Sprawl-legged Diplodocus

Heinrich Harder created some of the most pervasive and captivating paleo-art and prehistoric landscape paintings of the early 20th century. He also created this diplodocus. At least its head is correct. The early assumption that the giant leaf-eaters had sprawled legs was disproven shortly after this 1920 illustration was created, when William Jacob Holland demonstrated that, thanks to their massive girth, a sprawling diplodocus would have needed a trench to drag its body through. You can see a modern interpretation of diplodocus below.

9. Aquatic brontosaurus

After scientists realized that the Sauropoda weren’t sprawl-legged, they discovered a new “problem” on their hands. The calculations that they made seemed to show that Brontosaurus (Apatosaurus) and other sauropods would not be able to support their own weight on land, or at least would not be able to sustain supporting their own weight on a regular basis. Given that, they assumed that the giant plant-eaters were semi-aquatic, and used buoyancy to maintain their great heft.

This assumption was, as we now know, incorrect. All known sauropods lived exclusively on dry land, and were able to support their own mass. They also had a significantly different posture, as shown with the Brontosaurus above.

Even though it’s not pictured, it’s also notable that syphilis isn’t “as old as creation,” nor was it around in the time of the dinosaurs. Genome sequencing of known strains of Treponema pallidum (the bacteria that causes syphilis, yaws, bejel, and pinta) and analysis of human remains and medical documents currently show that the syphilis we know today is less than 800 years old, and definitely less than 2000 years old. It is treatable, though, and you should definitely see a doctor if you think you have it, so at least the important parts of this 1936 WPA poster are correct!

10. Tyrannosaurus rex is not a sad tripod

This poor dewlapped fellow has many reasons to look so downtrodden—his arms are twisted the wrong way, his head is the wrong shape, and his tail is dragging on the ground like a kangaroo. Though it was demonstrated by the 1970s that a living animal could not maintain a tripodal posture like this—it would dislocate his hips, and likely fracture his vertebrae—museum fossil poses and popular culture kept the notion of the “upright T. rex” alive. The first major influence to dissuade that notion was actually another facet of pop culture: the Jurassic Park movie.

Even so, Jurassic Park’s Therapoda (the clade that includes Tyrannosaurus, Allosaurus, Velociraptor, and all modern birds) were missing one thing that is also missing on Mr. Sad Tripod: feathers! The quill knobs and pygostyles found on fossils throughout that clade, from large dinosaurs to raptors the size of chickens, show that there were species that had  feathering or proto-feathering in almost all known Therapod families. Of course, there is no direct evidence of feathering in the largest of the Therapoda, so T. rex might still have been the scaly beast we know it as. Here's a modern interpretation of Tyrannosaurus rex.

But who knows? In 20 or 30 years, we may be laughing at how goofy we were to ever think any of the clade was without feathers, or perhaps how absurd we were to think that Velociraptors weren’t master swimmers! Of course, the more knowledge we gather, and the more fossils and evidence we find to deduce the truth, the less likely it is that there will be a massive shake-up in the hypotheses and assumptions we make, just like in any field of science.

Back in the early 20th century, we didn’t have enough physical evidence or knowledge of the limits of certain types of joints, bones, and body structures to hypothesize what an ancient creature, unlike any on earth today, would look like. Today, with computer modeling, millions of fossils, and new knowledge of evolution and comparative anatomy, we can be far more accurate, and are likely fairly close to “accurate,” as far as knowing what creatures we’ve never seen (and, might I add, hopefully never will see) would look like.

All images courtesy of Wikimedia Commons.