Xiphactinus: The Inception Fossil

If you were to travel back 100 million years from where I live in Colorado, the face of a very, very different planet would emerge.  I suppose emerge isn't necessarily the best word in this context: submerged is more of an adequate description!  You see, unlike the mountains you would see in Colorado today, Late Cretaceous Colorado was even flatter than present-day Kansas....and a whole lot closer to sea level!  Between about 100 and 70 million years ago (MYA), an enormous seaway stretched northwards from the Gulf of Mexico, and southwards from the Arctic.  Within these waters, hundreds, perhaps thousands of animals flourished, many of which we have nothing like today.  Massive sea turtles like Archelon slowly swam through the waters, while the long-necked plesiosaurs cruised around, snapping up fish before they even knew they were there.  While sharks and mosasaurs were probably the most impressive denizens of the seaway, these massive carnivores fed on fish as well.  And the subject of today's post is one of those fish: a 17-foot long beastie called Xiphactinus.

Due to the numerous pictures uploaded to Pinterest by the Best Western Denver Southwest hotel (read more about it HERE), I'm going to be using a lot of pictures from this site!  Make sure you check it out by clicking HERE!  Unless otherwise noted, photo credit for all of the pictures in this post goes to that Pinterest page!

Why did I call Xiphactinus (pronounced zye-FACT-un-us) "The Inception Fossil?"  Well, that's a description that I came up with (don't ever let anyone tell you otherwise!) that has to do with one of the most interesting things about Xiphactinus: numerous specimens of the fish have been found with the remains of other fish in its stomach!  Just as the premise behind Inception is "a dream within a dream," so too are specimens of Xiphactinus sometimes "fish within a fish!"  The specimen below is a thirteen foot Xiphactinus that died with a fish known as Gillicus arcuatus in its stomach!

Unlike sharks, Xiphactinus would have been unable to bite off chunks of flesh from its prey, and instead would have had to swallow its prey whole, which is what makes the Inception Fossils so spectacular!  Some paleontologists propose that this lack of chewing may have been what killed some of these Xiphactinus specimens, and that they actually choked to death on their last meal!  I suppose it's possible, but I don't actually know enough about these specimens to be a very good authority on them!

The next three pictures below are pictures that I took of a specimen that I saw a week or so ago.  Long story short, my friends Isabel and Sam Lippincott and I had gone to a presentation given by paleontologist Dr. Ian Miller about the Snowmastodon Project a few months back, and he was impressed with Sam's paleo drawings when we showed him after the lecture.  He invited us to come on down to the Denver Museum of Nature and Science so that he could show us around behind the scenes, which he very kindly did a few weeks ago!  These are pictures I took of the 80 MY old Mancos Shale specimen of Xiphactinus, which was discovered in 1966 by some kids who had been hunting with their dad near Snowmass in Colorado.  They had stumbled across the rib cage of the animal, and had notified the Denver Museum.  The next summer, the museum excavated the remarkably complete, 13-foot specimen, taking it back to the museum, where it has been stored to this day!

Here are some more cool pictures from the Pinterest page!  This is a diorama of paleontologist Charles Sternberg caught in the act of discovering one of his "Inception fossils!"

And here are another pair of reconstructions of Xiphactinus!

Make sure to check out the Pinterest page of the Best Western Denver Southwest by clicking HERE!

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!

Otters of the Americas

Most scientists today accept that there are thirteen extant (still living, opposite of extinct) otters in the world.  Of these, five are native only to the Americas, while one, the sea otter, lives in both the Old World and the New World!  In this post, though, we are going to be only looking at the New World otters, the otters of the Americas!  Let's start up north and work our way downwards!

If we're starting up north, then that would mean that our first otter of the day is the North American river otter!  The diet of the river otter is primarily composed of slow moving, bottom feeding fish, but will eat many other different animals given the opportunity!  Reports of river otters catching and eating snowshoe hare have been recorded, as well!

When my friend Masaki Kleinkopf, my father and I were able to go on a behind the scenes tour at the Cheyenne Mountain Zoo with my grandparents, one of the keepers at the grizzly bear enclosure told us a very interesting and funny story!  A few years ago, the four river otters had managed to create a hole in their enclosure large enough for them to squeeze through, and some of them escaped.  One of the river otters was never found, and to this day is still probably roaming the mountainside (unless it got eaten).  If I remember correctly, another one of the otters was captured a few weeks later farther down the mountain, swimming around.  The final two otters were much easier to capture, however, and this is the funny part of the story!  If I remember correctly, the zookeepers figured out that the otters were missing because they went up and visited the nearby grizzly bear enclosure.  Instead of being greeted with the typical blue pond loaded with fish, they were met with a vision of a bloodbath: the waters were red with blood, and there were fish parts everywhere!  And there, on the side of the pond, were two fat and happy otters!

In other river otter news, one was recently captured on a camera trap in Boulder, Colorado, the first such sighting in the area for around 100 years!  Click HERE to be directed to an article to learn more!

Next up, we have the sea otter, the heaviest mustelid, and the only other otter native to North America!  Sea otters also have the thickest fur of any mammal, with around an astonishing ONE MILLION HAIRS PER SQUARE INCH!  Now THAT'S a lot of hairs!  This unfortunately has attracted many, many poachers over the years, and sea otter populations the world over took a serious tumble.  However, in recent years, they have recovered to around two thirds their historical numbers, making it one of the most successful marine conservation movements ever!  The sea otter will also hold hands with other sea otters to avoid floating away from each other, and sometime will form what scientists call "rafts" of around 2,000 individuals!  Click HERE to learn more about the hand holding and the rafts!

Let's take this trip south of the Equator to Mexico, Central, and South America!  The next otter is the neotropical otter and, as you can see by the range map below, is native to all three of those places!  A solitary animal, not a great deal is known about its behavior and habits.

Next up is the second largest mustelid in the world (after the sea otter, of course), the aptly named giant otter!  Although much longer than the sea otter, the giant otter is much more slim.  It is, however, the longest mustelid, growing to lengths of about five and a half feet!  Unlike most mustelids, the giant otter is a fairly social animal, living in groups generally numbering between around four and thirteen individuals, usually composed of one pair of breeding individuals and their offspring from one or more generations.

One of the most interesting things that I have learned about the giant otter is entirely and categorically false: according to one TV show (I am pretty sure it was Survivorman), the giant otter is a threat to people.  I can't remember the exact quote, but in one episode in which he was in the Amazon, he says something along the lines of "I definitely have to watch out for jaguars and insects here, but I've also been told to watch out for the highly aggressive giant otter."  Which is total crap.  The giant otter is often regarded as a nuisance to indigenous peoples, but nowhere have I been able to find anyone saying that they can be dangerous to humans!  I don't recommend that show.

The second to last otter of the Americas is the marine otter.  Much of the marine otter's time is spent out of water, and it rarely, if ever, ventures into rivers or estuaries.  The marine otter is the second smallest otter (the only smaller otter being the Asian small-clawed otter), and, like the neotropical otter, not a lot is known about it.

Finally, we have the southern river otter, another otter about which not a great deal is know.  Although called a river otter, the southern river otter spends a great deal of time in both fresh and salt water.  Some people believe the southern river otter simply to be a sub-species of the North American river otter.

This was the birthday post of Julie Neher! Happy birthday, Julie! Want to see some cute (or ugly) baby animals featured here on your birthday? Well, if you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in! And if you like what you are reading, please feel free to follow us here or via Facebook!

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!

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!

The Morrison Biota

Stegosaurus lived in western North America during the Late Jurassic Period, about 150 million years ago (MYA). Today, we find its remains in the Morrison Formation, named after the tiny town of Morrison in Colorado. What was going on in Colorado at that time? What was the depositional environment like, the environment that laid down the sediment that would one day become the famed Morrison Formation?

Well, according to paleontologist Dr. Robert Bakker in an article about the re-discovery in 2002 of some old paleontological quarries (CLICK HERE TO LEARN MORE) in the Smithsonian Magazine, the environment was very much like the kind of environment seen in Uganda today: a “hot tropical woodland that was dry for most of the year.”

What about the animals, though? Dr. Bakker also said in the article that to “understand the Late Jurassic, you need to understand the common animals, which means Apatosaurus.” Most people are familiar with this massive animal: about 100 feet long (around the length of three school buses put end to end to end), and weighing around as much as eight African elephants, Apatosaurus was definitely a heavyweight of the Morrison biota!

What other animals were running around though? There are a great many dinosaurs, as well as many other animals, that were living in this area at that time, but in this post we are only going to look at one more: Camptosaurus and Allosaurus. All right, I lied. We’ll look at two more.

First off, we have Camptosaurus. To be honest, Camptosaurus doesn’t really look all that special. A small- to mid-sized ornithopod, Camptosaurus was only about fifteen feet long, and didn’t really appear to have any obvious defenses. However, discoveries of articulated Camptosaurus skeletons (indicating that the bones were fossilized were they were deposited, i.e. where the animal died, and weren’t washed together in a big mumble-jumble like at Dinosaur National Monument) in close conjunction with articulated Stegosaurus skeletons seems to indicate that these two herbivores liked to hang out together. But why? Why would they open themselves up to competition and potential conflict like that? Well, analysis of the brains and skulls of these two animals suggests that perhaps by hanging out together, the dinosaurian duo could avoid much deadlier conflict. Studies have shown that the sensory organs of Camptosaurus and Stegosaurus would have differed in very critical ways. The sense of Stegosaurus would have been akin to a rhinoceros, or perhaps myself as well (at least without my contacts), in that it would have had a pretty good sense of smell, but not very good vision. Camptosaurus, on the other hand, appears to have had quite acute vision, which has led to an interesting proposition by researchers: that Camptosaurus acted as a lookout for herds of Camptosaurus and Stegosaurus. If a predator was spotted (say, an Allosaurus or a Ceratosaurus), then Camptosaurus would have been able to alert the herd, and Stegosaurus would have been able to move to the forefront to defend them all against attack.

The last dinosaur that we are going to look at today is Allosaurus, a large, meat-eating theropod dinosaur. It occurs to me as I type this that I have done a very thorough job on Allosaurus before, so instead of typing this all again, I am going to be lazy and redirect you to another post that I did awhile back, entitled “23-Fact Tueday: Allosaurus.” Hidden within the post (but not too hard to find) are 23 Facts about Allosaurus. Yeah. Pretty much says it in the title. Anyways, check out that post to learn more about Allosaurus, as well as the rest of the Morrison ecosystem! And make sure to check back tomorrow, as we learn about stegosaurs from the rest of the world!

Want to learn more about Stegosaurus?  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")

An Amur Leopard Upchucks

On Saturday, January 26th, my father and I drove down to Colorado Springs to see a few of my friends perform in the Colorado All State Jazz Band.  Before the concert, we met up with my grandma and grandpa, and went up to the Cheyenne Mountain Zoo for an hour or so.  We saw a few cool things, all of which I will share with you in the next post, but this post I wanted to devote to the "Critically Endangered" sub-species of the leopard, the elusive and mysterious Amur leopard.  Fewer than thirty of these amazing creatures are thought to be alive in the wilds of southeastern Russia and northeastern China, in the Primorye region.  Poachers have taken an immense toll on the numbers of this cat, as its pelt is highly prized.  Like that of the snow leopard, another fairly large cat that also lives in a very cold, harsh environment, the Amur leopard has a very soft and, for lack of a better term, floofy, coat.

The Amur leopard prior to its little....episode.

Since the number of people who see an Amur leopard in the wild per year could almost certainly be counted on one hand, you are very unlikely to see this animal lose its lunch.  For that, you would have to go to a zoo. Now, don't get me wrong, we didn't go to the zoo just to see animals throw up, but it was definitely an interesting addition to our day!  I do hope that the poor animal is feeling better, though.  If you want to see the video of the animal barfing, click on the link below.  It's not actually as gross as it sounds, trust me!  Also, please enjoy some pictures of the beautiful cat PRIOR to its cookie tossing.  

The leopard recovers after it loses its cool

Upcoming Lecture: Animal Adventures Part 2

So we have another lecture coming up, on March 14th!  4:00 PM at Fairview High School in Boulder, Colorado!  Here we have a bunch of fliers that you can save, print, and hang up if you want to help me out and raise awareness!  Thanks!