The Truth Behind the "Truth" Behind Megalodon

Today, the great white shark rules the seas and haunts our imaginations.  After the release of the 1975 movie "Jaws," the great white shark and other sharks were feared and loathed more than they already were, although much of this fear was unbiased.  Ever since Jaws, hundreds of books, movies, television programs, and more have all capitalized on the shark craze, producing everything from the fantastic Steve Irwin Crocodile Hunter specials to the recent TV movie Sharknado.  One of the most popular shark-related features in the media is Discovery Channels "Shark Week," an annual event that features a week of shark-related programs.  Although many of these programs, as is to be expected for television programs nowadays, push the limits of reality, I think that the premiere of this year's Shark Week went too far, and I'm not the only one who thinks that, either.

First off, let's meet the star of this program: megalodon.  Estimates of the size of megalodon have varied widely and wildly, with some older estimates as high as about 100 feet long.  Today, however, most scientists agree that the largest megalodon could grow to around 60 feet long.  Which is still pretty massive, given that most great white sharks don't exceed lengths of around 20 feet, and look at how much people are afraid of them!  megalodon would have easily been able to swallow the average human in one bite: just take a look at those reconstructed jaws, below!  Also, below that picture, make sure to check out the size of just one megalodon tooth.  Suffice it to say, this shark was one massive bruiser.  This shark WAS one massive bruiser.  Notice how I emphasized the "was?"  Well, that's because megalodon went extinct about two million years ago.

Pyg encounters a mid-sized megalodon tooth, graciously donated to my collection of fossils and things that I take to local schools by local paleontologist Wayne Itano

Megalodon sounds pretty awesome, right?  I mean, to be honest, it's one of those extinct animals that just doesn't need to be "sci-fied up," because it's already cool enough as is, on par with other animals such as Tyrannosaurus, Spinosaurus, and Utahraptor.  Well, just because it didn't NEED to be sci-fied up doesn't mean that television networks didn't do it anyways.  And this years Shark Week premiere was the culprit.  Discovery Channel aired a two hour "documentary" showing "biologists" on the hunt for a megalodon.  Today.  In the present.

One of those extinct animals that just doesn't need to be "Hollywoodized!"  Meet Stan, the resident Tyrannosaurus rex at the Morrison Natural History Museum!  You can see Pig seated in the bottom jaw for scale!  Yeah, this guy was huge.

We have no evidence to indicate that megalodon is alive and with us today, and the "evidence" included in the "documentary" was very clearly doctored.  For example, below is a picture of a whale that has supposedly been bitten in half by a megalodon:

And here is a photo "uncovered from Nazi archives" of a giant shark fin surfacing behind a pair of U-Boats:

The first picture just screams CG.  And the second one....really?  Nazi's? Very Indiana Jones-esque.  OK then, Discovery.

The "documentary" starts off with "found footage" of a "boat capsizing off the coast of South Africa and several people being eaten, but whose bodies were never recovered."  Already, this reeks of a typical television plot.  Especially given the fact that a quick Google search of this supposed incident, as well as any of the "biologists" in the "documentary," yields diddly-squat.  Apparently the prospect of a giant shark brutally attacking and destroying a fishing boat just wasn't exciting enough to make it to the news, despite the fact that every news story relating to sharks and shark attacks spreads like wildfire.  Perhaps the South African press was just busy that day?

People refute our naysaying by pointing out that "we know more about the surface of the moon than the ocean," and "the coelacanth (which you can learn more about by clicking HERE) and the giant squid were only discovered recently!"  Yeah, that's true.  But megalodon is very different from a giant cephalopod or a five or six foot long fish.  We are talking about an active, 60 foot long predator that's feeding on much, much bigger prey than the giant squid or coelacanth would.  The giant squid and coelacanth eat a lot of fish, and are considered to be primarily piscivorous.  The giant squid, although very large, is by no means at the top of its food chain, and is fed upon by the largest of the toothed whales, the 60 to 70 foot long sperm whale.  And two million years ago, megalodon would have made up the final link in this food chain, feeding on the 60 to 70 foot long sperm whale.

Am I saying that there is no possibility that more giant animals exist in the deepest depths of the ocean, just waiting to be discovered?  No, I most definitely am not.  I do, however, encourage you to consider the ecological resources that would be needed by such a massive animal.  With no evidence of mutilated whale carcasses that could be attributed to such a massive animal, and an equal amount of evidence from first-hand accounts....I think that the conclusion should speak for itself.

The biggest issue that I have with all of this is not that a television program was made that packages myths, untruths, and exaggerations: it was with the fact that they packaged it as a documentary, no quotations this time.  Discovery tried to balance out the fact that they blatantly made stuff up to appease some of their viewers by pointing out that they included disclaimers in the show.  Yeah, true, there were disclaimers: but click HERE to see how short and hazy these disclaimers really were.  The disclaimers read:

None of the institutions or agencies that appear in the film are affiliated with it in any way, nor have approved its contents. Though certain events and characters in this film have been dramatized, sightings of "Submarine" continue to this day. Megalodon was a real shark. Legends of giant sharks persist all over the world. There is still debate about what they might be.

Notice how they never really say that none of it was true.  When he gave a press release, the executive producer of Shark Week, Michael Sorensen, said that “With a whole week of Shark Week programming ahead of us, we wanted to explore the possibilities of megalodon.  It’s one of the most debated shark discussions of all time, can megalodon exist today? It’s Ultimate Shark Week fantasy. The stories have been out there for years and with 95 percent of the ocean unexplored, who really knows?”  The part that bugs me the very, very most about that statement is the line "It's one of the most debated shark discussions of all time."  It isn't, I promise you.  It really, really isn't.  I have never heard of any paleontologist who seriously believes that megalodon swims the oceans today.  There might be some paleontologists who won't discount the possibility, which is fine.  Science changes all the time.  But with a complete and total lack of evidence, no serious scientist will really debate that sort of thing.

There's many more issues that people have had with this presentation, varying from thousands of people on social media voicing their complaints, all the way to actor Wil Wheaton, who wrote about the megalodon fiasco on his blog, which you can read HERE.  Others, such as popular paleo writer Brian Switek, went to Twitter:

I do hope that this backlash will cause the people at Discovery, as well as at other television stations, to reconsider what they make into a television program, and consider the possibility that, just maybe, there's a significant chunk of people out there who don't want to be fed this garbage.  I do hope that this causes some changes in any future programming, and if we are all really lucky, this event might spawn a South Park episode.  You have to admit, it'd be pretty perfect.  Let's just cross our fingers, shall we?

Mr. Bones Visits the Morrison Natural History Museum!

Yesterday, Mr. Bones, a local dinosaur enthusiast who's created some amazing looking dinosaur skeleton suits, visited the Morrison Natural History Museum!  The museum was also visited by Greg and Meredith Tally and their children, the fantastic people who are renovating the Best Western Denver Southwest to be a dinosaur-themed hotel!  All of these folks were here to make a brief teaser sort of thing to promote both the dinosaur hotel and the Morrison Museum!  I took a little bit of video, as well as some pictures, so make sure to check them out here!

 Greg Tally is attacked by Mr. Bones!

 Running is useless!

 Just a little too big for the door!

Below, we have a picture of Greg Tally helping out with the cameraman and Mr. Bones!

If you want to see some video of the museum's encounter with Mr. Bones, check out the video below!

Here, we have some shots of Mr. Bones taking a swipe at the museum sign out on the road!

Kids LOVE Mr. Bones!

 One of his other suits, a Utahraptor!  All of the other shots are of him wearing his "Kindergarten Tyrannosaurus rex" suit!

 A size comparison between the two suits.

 Mr. Bones goes in for the kill!

Not Enough Bacteria, Too Many Allergies

If you were to hear someone say "by making our world more sterile, we're actually making ourselves sicker," you might think they were full of it: initially, it sure doesn't sound like it makes any sense. Interestingly, however, it seems as if this may, in fact, be true: our attempts to make our world a cleaner place, we are slowly and steadily weakening our own immune systems!

It all started yesterday as I was working at the Morrison Natural History Museum, watering and destroying the angiosperms from the Jurassic Garden with "extreme prejudice," as angiosperms do not appear to have inhabited Colorado during the Jurassic Period. I started wondering why there was so much dead plant material around the base of the plants in the garden, and, for lack of a better conclusion, decided that it was probably because the bacteria that would normally digest these plants didn't actually live here. (I still don't know whether that is true or not). The topic of bacteria triggered my brain to start thinking about digestive bacteria: I was quite hungry, you see. It had been brought to my attention in the past that, even if humans were somehow able to miraculously clone a dinosaur, we almost certainly couldn't keep them alive. Each animal on the planet has its own, unique set of bacteria that helps it to digest its food. With the extinction of the dinosaurs, it is almost certain that the bacteria that constantly accompanied them in their digest tracts went extinct, as well.

This line of thought made me think about the passing of bacteria from the parents to their offspring. How is it done? I assumed that they weren't born with it, but I wasn't sure. I ended up thinking that perhaps, in animals that regurgitate food into the mouths of their young (like penguins), perhaps this was how the bacteria was passed. With perfect timing, out came Matt Mossbrucker, the director and curator at the Morrison Museum. I asked him whether it was, indeed, regurgitation that passed the bacteria on, and he said yes: partially. You know how many animals (such as your dog and cat at home) will eat poop? That's at least part of the reason: they're trying to get bacteria from the poop to help them digest their food!

After thinking about it for a few seconds, I realized that humans (most of us, anyways) neither regurgitate our food for our young 'uns, nor do we eat each others poop. So I asked Matt whether humans get this bacteria through breast milk: turns out, we don't. So how do we get the bacteria?

According to recent research, humans aren't getting enough bacteria to digest their food. Much of this research seems to indicate that perhaps this is the reason why so many humans have digestive issues, allergies, and the like. Matt also said that, just like I said in the introduction, "by making our world more sterile, we're actually making ourselves sicker." Still sound paradoxical? Well, ultimately, humans are trying so dang hard to sterilize their world with hand sanitizer, bleach, alcohol, and soap, that we aren't being exposed to as many pathogens. While in some cases this is a good thing, in other cases, our immune systems, just like the six-pack of someone who doesn't exercise, slowly weaken.  And, of course, a weak immune system is good for no one!

So is the moral of the story to stop washing your hands?  No, of course not.  It's to go out there and eat poop.  See you later, everyone!

Stegosaurus at the Morrison Natural History Museum (Stegosaurus Week)

So as you probably know (at least if you've been following us here for Stegosaurus Week), the whole point of the special week was to celebrate Stegosaurus Day at the Morrison Natural History Museum in Morrison, Colorado!  But what Stegosaurus-related exhibits does the Morrison Natural History Museum even have?  Well.  I am so glad you asked.  Let's dive on in!  

The first Stegosaurus-related thing that you will see is just a small exhibit, whose size is not a good representation of its importance.  The four groups of bones that you see here are part of the holotype specimen of Stegosaurus!  It was with these bones, as well as the rest of the specimen (part of which is at the Morrison Museum, the rest in the collections at Yale in Connecticut)  that paleontologist Othniel Charles Marsh first named and described the genus Stegosaurus in 1877, during the famous (or rather, infamous) Bone Wars.  Below, we have a picture with the four different groups of bones highlighted in red. 

The first bone that we see below is part of one of the plates of Stegosaurus!  The entire specimen actually extends back several inches, but the fossil part of the specimen is only on the very top layer.

Next, we have part of the femur of Stegosaurus!

Here we have two different types of vertebrae of Stegosaurus, lumbar and caudal (back and tail) vertebrae.

The next picture is an illustration by paleoartist Fabio Pastori of what this animal would have looked like.  Meet Stegosaurus armatus, one of four species of Stegosaurus that are currently considered to be valid!

Next, we have some more VERY interesting Stegosaurus fossils, as well as a cute little baby Stegosaurus model!  This little guy below is about a foot long, and is a life-size representation of the animal that would have made that footprint.  Besides being the very first baby Stegosaurus footprint discovered anywhere in the world, this footprint is especially interesting because it shows that the baby Stegosaurus was walking on its back legs, without its front legs touching the ground!

Here we have another Stegosaurus footprint: or rather, a trio of footprints!  The main footprint on this slab of Jurassic-aged rock contains what is largely considered to be the best adult Stegosaurus hind foot track in the world!

This footprint-containing slab is of particular importance to the paleontological community for another reason other than preservation quality: not only does the slab contain a very well preserved hindfoot track of an adult Stegosaurus, it also contains a forefoot track, probably from the same individual, as well as a partially crushed juvenile Stegosaurus track.  This partially crushed juvenile Stegosaurus track is of particular importance, as it seems to be pretty strong evidence that the adult and the juvenile were traveling together! 

Next, we have a cast of a skull of Stegosaurus, next to a cast of the foot of the animal, as well as a reconstruction of the foot itself! 

Next, we have a VERY interesting block of fossil-containing rock!

It all started when the block was brought into the museum because of the dinosaur bones, like the rib bone you can see below from an unidentified dinosaur....

....and these bones, on the back of the block.  It wasn't until the block was brought inside the museum that researchers noticed something that they hadn't been able to see outside: some tiny dinosaur footprints!

Here are two of the footprints, below.  The one on the left, about the size of the palm of my hand, is thought to belong to a mid-sized ornithopod, likely a hypsilophodont or a heterodontosaur, we don't really know.  The much smaller one on the right (which isn't much larger than a house cats) is even harder to identify, and could belong to a wide variety of dinosaurs.

  

Here is another picture by Fabio Pastori, depicting the small ornithopod that might have made the tracks.

The other tracks on the slab are by and large considered to be much more interesting.  What you are looking at below are some more baby Stegosaurus footprints!  Remember the baby Stegosaurus footprint that we discussed below, and remember the model of the animal that was thought to have made it?  The model is about the size of the animal that is thought to have made the little tracks on the left in the picture below!  What's particularly interesting about these footprints, however, is that they show the footprints of at least two individual Stegosaurus, each probably just a few months old, superimposed on each other!  This seems like pretty good evidence that these guys were also moving in groups, just like the other slab of Stegosaurus footprints shows us with older individuals!  The smaller footprint on the right (again, around the size of a domestic cat's footprint) is from a much smaller individual, probably just a hatchling!  It is also possible that this hatchling was moving with the other juveniles, as well!  

This is a model of the hatchling Stegosaurus that made the footprint on the right in the three pictures that we have above.

Finally, we have a size comparison of footprints of Stegosaurus at different ages!  The bottom one is from an infant Stegosaurus, maybe an inch and a half or so in diameter.  The top one is from an adult, larger than your average dinner plate!

Want to learn more about Stegosaurus and it's relatives? Well, check out the Homebase for Stegosaurus Week HERE to partake in more of the festivities!

How Would Stegosaurus Have Sex? [FOR MATURE AUDIENCES ONLY] (Stegosaurus Week)

In the newest episode of "Animal Explorations With Zack Neher," we investigate (with Hugh Hefner) a very interesting dilemma that has puzzled paleontologists for a plethora of years: how would Stegosaurus and its relatives have had sex?

After I posted this video, Matthew Mossbrucker, the director of the Morrison Natural History Museum, commented on the post, with some very important and interesting information!  Here is what Mr. Mossbrucker had to say:

"Quite a few folks have pondered this through the years - myself included. Allow me to put on my Dr. Ruth field hat for a moment. Heinrich Mallison's concept of the African stegosaur Kentrosaurus mating seems plausible to me. I've assumed this myself as a default mating position for these animals. My read of the tail base in Stegosaurus is a bit different than Brian Switek's analysis. While it is true that our North American stegosaurs had limited up-down motion at the base of the tail, stegosaurs do something for ornithischian dinosaurs: they have the ability to twist their tails in a corkscrew-like fashion. I can envision a standing female Stegosaurus twisting her tail to one side and therefore removing obstacles for her mate. Unlike the boated models in your photo, a living Stegosaurus would have been able to stand and even walk on its hind-limbs with grace. So, therefore I see no barrier putting a male into mating position. So, there you have it."

There we have it indeed!  I hope you find that enlightening, as well as the video!  The dilemma definitely makes more sense after hearing what Mr. Mossbrucker has to say!

Want to learn more about Stegosaurus and it's relatives?  Well, check out the Homebase for Stegosaurus Week HERE to partake in more of the festivities! 

Bone Wars, Marsh and Cope: to the Tune of "Two Black Cadillacs" (Stegosaurus Week)

One of a pair of songs that I made especially for Stegosaurus Week!  "Bone Wars, Marsh and Cope" to the tune of "Two Black Cadillacs" by Carrie Underwood.  Below is the link to the song:

Here are the lyrics to the song:


Full Lyrics:

1800s, Morrison, a big find was made
"If Cope got a bone, Marsh lost," Dr. Bakker say
They devoted their life,
To get the most bones, each other they'd fight
Two rivals fighting over fossils in the dirt and grime

[Chorus:]

And the teacher, Lakes, he was a good man
And Marsh and Cope, they used to be friends
But then the two of them wanted the other to die
Bye, Bye bye, Bye
1,500 species they wrote down
Dug them all out of rock and from the deep ground
They both refused to work together on the same side
Bye bye, bye bye, bye bye

Bone Wars, Marsh and Cope

Eleven years ago researchers found some more fossil bone
123 years they'd been buried there for oh so long
Matthew Mossbrucker, from the Morrison Natural History Museum
The site had been reburied, waiting for the right time, right time

[Chorus:]

Even now some of the fossils in rocks and time are still encased
Mystries and new species found in the Quarry
Learning new secrets from the grave

[Chorus:]

Are you diggin' the songs?  Well, then check out our playlist below!

CLICK HERE TO BE DIRECTED TO A FUN-FILLED PLAYLIST OF AMAZING SONGS.

Want to learn more about Stegosaurus and it's relatives?  Well, check out the Homebase for Stegosaurus Week HERE to partake in more of the festivities!

Baby Stegos Galore (Stegosaurus Week)

In 2002, paleontologists from the Morrison Natural History Museum rediscovered an old paleontological dig site that had been missing since the late 1800s. One of many highly-contested sites of the so-called “Bone Wars” (a paleontological competition between rival paleontologists Othniel Charles Marsh and Edward Drinker Cope), this dig site, dubbed Quarry 10, has been the site of many very interesting discoveries, as has another Quarry nearby, Quarry 5.

Quarry 10 had long thought to have been destroyed. Fossil hunter Arthur Lakes had reportedly dynamited the dig site on Marsh’s orders, to prevent Cope from getting any fossil bones out of it. However, it looks like Arthur Lakes was a very good man, and did not actually dynamite the dig site. According to the MNHM paleontologists, it looks like Lakes, not wanting to destroy something that was potentially very valuable, decided to merely cover up the site with some rocks in order to prevent other people from coming across it.

Further excavations at the Quarrys have yielded a number of VERY interesting fossils, including, amongst others, some baby Stegosaurus footprints! Multiple blocks have been uncovered with the footprints of Stegosaurus at all different stages of development, everything from infants to adults. On some of the blocks, multiple age groups are found in close conjunction to each other, and sometimes are found going the same way. This seems to indicate that Stegosaurus would move in groups consisting on members of multiple ages, a very interesting discovery indeed!

Want to learn more about Stegosaurus?  Well, check out the Homebase for Stegosaurus Week HERE to partake in more of the festivities! You can also check out a song that I wrote to the tune of Carrie Underwood's "Two Black Cadillacs" to learn more about the Bone Wars, below!

The Thagomizer of Stegosaurus (Stegosaurus Week)

This Saturday at the Morrison Natural History Museum in Morrison, Colorado, we will be celebrating Stegosaurus Day, in honor of Colorado's state fossil!  (To learn more, click HERE to be redirected to the Facebook page of the Morrison Natural History Museum!)  So, in honor of Stegosaurus Day, The Natural World is going to have ourselves a little Stegosaurus Week!  Each day, we are going to be looking at a different aspect of Stegosaurus, and today, we are going to be looking at the tail spikes on the tail of Stegosaurus, nicknamed the thagomizer!  What were they used for?  Did they actually use their tail spikes for defense?  And how about that funky name: where did the term "thagomizer" come from?  Well, learn those answers and more in today's post for Stegosaurus Week!

Remember IN THE LAST POST OF STEGOSAURUS WEEK when we mentioned paleontologist Ken Carpenter and his very complete and articulated Stegosaurus skeleton?  Well, in 1993, when Carpenter was presenting his findings, he first used the term "thagomizer" to describe the tail and spikes of Stegosaurus.  Without even knowing its backstory, it seems like a fitting name: but its true origin is even more interesting!  For those of you who have enjoyed Gary Larson's fantastic "The Far Side" comic strip, then you may already know where we are heading with this!  One of my favorite "Far Side" strips is the one above, and, interestingly, it is from this strip that Ken Carpenter got the name "thagomizer!"

Now, one question that has stumped paleontologists for years is, how were the spikes arranged on the thagomizer?  Nowadays, we know that there were two sets of spikes, and they are thought to have been about 180 degrees from each other, forming a horizontal line.  (For a more complete discussion, see the last post in our Stegosaurus Week series, entitled THE GENUS STEGOSAURUS THROUGH TIME.)  But other questions stumped paleontologists, too.  For example: what was the thagomizer used for?  It definitely looks like a very apt defensive weapon, but for a long time, paleontologists had no clues to help them figure out whether defense was actually the answer.

One source of evidence that Stegosaurus and other stegosaurs were using their thagomizers to defend themselves is that many of the spikes have broken tips.  Now, just because a fossil is broken, doesn't necessarily mean that it was broken during the animals life.  Paleontologists can tell whether or not a bone was broken during the life of the animal by looking to see whether the bone shows any signs of healing.  If the fossilized bone shows signs of "remodeling," then the bone broke during the life of the animal, and then started to heal while the animal was still alive.  Following the death of an animal, if somehow a bone becomes broken, it's not going to heal: the animal is already dead!  In a study that examined 51 tail spikes of Stegosaurus, researchers found that about 10% of these spikes had broken tips whose bone had started to grow back.  So clearly, these spikes weren't just for show, and were actually being used for something.

The best evidence that paleontologists have right now that indicates that Stegosaurus was using its thagomizer to defend itself against predators is an Allosaurus tail vertebrae with a hole in it: a hole exactly matching the kind of hole that a thagomizer would have made!  What's very interesting about this fossil is that, while damaged bone in the vicinity of the hole shows signs of healing (indicating that the Allosaurus survived, at least for a little while, following its encounter with Stegosaurus, and that the damage to the vertebrae was not post-mortem), the hole itself doesn't seem to have healed at all.  This has caused some paleontologists to hypothesize that part of the tough outer sheath that would have surrounded the tail spikes in life, probably making them sharper and pointier, of a Stegosaurus became stuck in the tail vertebrae, remaining lodged within the tail vertebrae of that particular Allosaurus, until the animal died!

Another picture that I took at the Denver Museum of Nature and Science of an Allosaurus attacking a Stegosaurus adult and juvenile

Want to learn more about Stegosaurus and it's relatives? Well, check out the Homebase for Stegosaurus Week HERE to partake in more of the festivities!

The Genus Stegosaurus Through Time (Stegosaurus Week)

This Saturday at the Morrison Natural History Museum in Morrison, Colorado, we will be celebrating Stegosaurus Day, in honor of Colorado's state fossil!  (To learn more, click HERE to be redirected to the Facebook page of the Morrison Natural History Museum!)  So, in honor of Stegosaurus Day, The Natural World is going to have ourselves a little Stegosaurus Week!  Each day, we are going to be looking at a different aspect of Stegosaurus, and tonight, we are going to be looking at the genus Stegosaurus as a whole, and how our concept of Stegosaurus has changed over time!  Let's dive on in!

Stegosaurus was first discovered by famous paleontologist Othniel Charles Marsh during the Bone Wars (a paleontological competition from Marsh and rival paleontologist Edward Drinker Cope) in the late 1800s, and was first described by him in 1877.  When Stegosaurus was first described by Marsh, he wasn't really sure what it was: he actually thought that it might be a turtle-like creature, as you can see in his illustration from above!  This reconstruction explains why Stegosaurus has its name: covered, shingled, or roofed reptile.  It wasn't until Marsh and his crew found other, more complete specimens of Stegosaurus that he was able to figure out what the animal looked like with a greater degree of accuracy, which you can see in the reconstruction below.

The reconstruction above, while much closer to what we think Stegosaurus looks like today than the first reconstruction, nevertheless has several key differences from today's reconstructions.  One of the main issues that paleontologists face when reconstructing Stegosaurus and its relatives from fossils is that the plates aren't attached to any bones.  The plates are modified osteoderms, used in many different animals to protect themselves from attack (a more extreme example of which can be seen in the close relatives of stegosaurs, the ankylosaurs).  Like the osteoderms in other animals, such as the ankylosaurs, the osteoderms would sort of "float" in the skin, only attaching to the rest of the skeleton by means of softer tissues, softer tissues that don't typically fossilize.  What paleontologists really needed was an articulated specimen of Stegosaurus.

Well, that's exactly what paleontologist Ken Carpenter got in the 1990s!  Using this very complete and articulated specimen, Carpenter and his colleagues were able to solve a number of Stegosaurus mysteries.  For example: the exact placement of the plates.  In Marsh's 1890s reconstruction above, you can see that he had positioned the plates in a single row running down the back.  Later reconstructions by other scientists had been created with a double row of plates, which was proven to be correct by Carpenter's specimen.  It was also shown that the plates alternated down the back, as opposed to the side-by-side reconstructions sometimes seen.

Another mystery that Carpenter's specimen was able to solve is the number and placement of the tail spikes.  As you can see in Marsh's 1890s reconstruction above, he hypothesized that Stegosaurus had four pairs of spikes, and that they pointed upwards at around 10-15 degrees from the vertical.  Carpenter's specimen, coupled with further research, has shown that, to the best of our knowledge, no species of Stegosaurus had that many tail spikes: in fact, from what we know, all species of Stegosaurus had two sets of tail spikes, for a grand total of four.  We also now know that, instead of the spikes being about 10-15 degrees from the vertical, they were almost certainly horizontal to the ground!  This hypothesis is backed up by investigations into the flexibility of Stegosaurus's tail: to successfully bring its tail spikes into play in the 10-15 degree arrangement, Stegosaurus would have had to have a tail much like a scorpion, and all research done up to this point indicates that Stegosaurus had nowhere near that much vertical flexibility in the tail.  However, the horizontal reconstruction makes much more sense, as the tail seems like it would have had a great deal of side-to-side flexibility.

The final main difference between Marsh's 1890s reconstruction and our reconstructions of Stegosaurus today lies in the way it held its tail and its neck.  Due to the Dinosaur Renaissance in the 1960s and 1970s led by John Ostrom and his pupil Robert Bakker, the perception of dinosaurs as lumbering failures changed dramatically to what it is today: not failures of evolution, but instead, a remarkable success that shaped the evolutionary course of the Earth for millions of years.  This change in perception is reflected in how we think dinosaurs moved: we no longer think that they dragged their tails on the ground, barely able to keep their heads from dragging in the mud.  Instead, we view them as much more nimble than we once thought.  And while Stegosaurus may not have been the nimblest of them all, you can clearly see how our ideas of how we think this animal moved around have changed over the years.

Want to learn more about Stegosaurus and it's relatives? Well, check out the Homebase for Stegosaurus Week HERE to partake in more of the festivities!

Welcome to Stegosaurus Week!

This Saturday at the Morrison Natural History Museum in Morrison, Colorado, we will be celebrating Stegosaurus Day, in honor of Colorado's state fossil!  (To learn more, click HERE to be redirected to the Facebook page of the Morrison Natural History Museum!)  So, in honor of Stegosaurus Day, The Natural World is going to have ourselves a little Stegosaurus Week!  This post will serve as the Homebase for the weeks festivities!  Below, we have a schedule of what I hope to have us talk about this week: we'll see whether I end up sticking to it or not!  I am also going to be making a few videos, as well, so be on the lookout for those!

The Posts:

Sunday: Welcome to Stegosaurus Week!
             The Genus Stegosaurus Through Time
Monday: The Thagomizer of Stegosaurus
Tuesday: The Plates of Stegosaurus
Wednesday: Baby Stegos Galore
Thursday: The Morrison Biota
Friday: Stegosaurs of the World
           Part 1: China
           Part 2: England, France, and Portugal
           Part 3: South Africa and Tanzania
           Part 4: Wyoming, Colorado, and Utah
Saturday: Stegosaurus at the Morrison Natural History Museum

The Videos:

How Would Stegosaurus Have Sex? [FOR MATURE AUDIENCES ONLY]
8 Truths about the Stegosaurus

The Songs:

The Stegosaur Song
Bone Wars, Marsh and Cope (to the tune of "Two Black Cadillacs")