No I Did Not Mean Triceratops, I Meant Ceratops

Recently, the folks over at the Best Western Denver Southwest purchased yet another fossil cast for their amazing hotel!*  This time, the cast is of a skull nicknamed "Judith," a specimen that is referred by some paleontologists to the dinosaur genus Ceratops.  And, no, I didn't mean to say Triceratops.  Don't feel bad if you haven't heard of Ceratops montanus: as a matter of fact, I hadn't really heard of it either until several weeks ago, when Greg Tally informed me that the Morrison Natural History Museum would soon be receiving a very large box in the mail!  Judith is still in the Cretaceous Room here at the MNHM, where she will stay for at least a few more weeks.  I really didn't know much at all about this dinosaur, and was eager to learn more.  Unfortunately, there's not much out there, as Ceratops is based on just a few bones that were discovered in the late 1800s.  Despite the lack of material, Ceratops does have a pretty fascinating history, and is an incredibly important dinosaur; not because of what has been discovered about the fossils themselves, so much as what these fossils resulted in.

Greg Tally peers through one of the fenestrae (literally means "window" in Latin) in the skull of Judith, the Ceratops montanus skull for the hotel that is temporarily on display at the Morrison Museum.  Photo Credit: Greg and Meredith Tally

When it comes to giving an animal or a group of animals a scientific classification, there are a lot of hoops you have to jump through, and a bunch of rules you have to follow.  Sometimes, groups of animals are named after the best known and understood animal in that group.  For example, Stegosaurus is the genus of dinosaur that defined the group of animals called the stegosaurs, and Tyrannosaurus is the genus of dinosaur that defined the group of animals called the tyrannosaurs.  Sometimes, it isn't quite as simple.  Think about it this way: Las Vegas is easily the most famous city in Nevada, and I'm sure I'm not the only one who spent a significant portion of their childhood thinking that Las Vegas was the capital of Nevada.  However, it is Carson City that holds the official title of capital.  Even though Las Vegas receives much more attention than Carson City, the state of Nevada isn't simply going to change where its capital is, and to the best of my knowledge, a change like that never really happens.

Although that comparison was a bit of a stretch and had about as many holes as the skull of Chasmosaurus, I think you get my point.  The same thing goes for scientific names.  Although Triceratops is the best known individual of the dinosaurian group called the ceratopsians, this group is still called the ceratopsians, as opposed to being called the triceratopsians.  That's because it was Ceratops, and not Triceratops, that was described by scientists first.

Ceratops montanus, temporarily on display at the Morrison Natural History Museum.  Photo Credit: Greg and Meredith Tally

The year was 1888, and paleontology in western North America was still going strong.  We've talked about the Bone Wars between paleontologists Othniel Charles Marsh and Edward Drinker Cope before, and we are going to revisit Marsh in this post.  To maximize the number of fossils he could describe, Marsh called upon the talents of a large number of fossil collectors, including the always brilliant Arthur Lakes in Morrison, Colorado.  Another of these collectors was a man named John Bell Hatcher.  Although Hatcher should also be remembered for a large number of his contributions to paleontology, for our purposes here we remember Hatcher as the man who discovered Ceratops.  On a trip to a known dinosaur fossil site near the Judith River in Montana, Hatcher discovered a number of fossils.  One of these fossil discoveries was composed only of a pair of horn cores.

Doesn't sound like much, does it?  Well, truth be told, it wasn't, though it was enough for Marsh to realize that he had something new.  If you click HERE, you can view the two page paper that Marsh published in 1888 that briefly described this new discovery as an animal called "Ceratops montanus."  There are several things of interest that we should take away from this paper, some of which are:

1. Marsh originally suspected that this new creature was "nearly allied to Stegosaurus of the Jurassic, but differs especially in having had a pair of large horns on the upper part of the head."  Marsh got the location of the horns right, but the close relation to Stegosaurus.....not so much.  Given the enormously tiny sampling of bones he had to work with though, it's not a surprise that Marsh compared this new animal to something that he already knew a good deal about.  Keep in mind that this is the very first scientific description of a ceratopsian dinosaur, so Marsh just had to go off of what had already been discovered.  Which was nothing.
2. Marsh notes that the "position and direction" of the horns could be likened to the enormous Meiolania, an extinct turtle from Australia, as well as the lizards in the genus Phrynosomax, the horned lizards.  He also notes that amongst the dinosaurs, the "only known example of a similar structure....is the single median horn-core on the nasals of Ceratosaurus," a mid-sized theropod dinosaur from the Late Jurassic Morrison Formation.   
3. In 1887, the year before this paper was published, geologist Whitman Cross sent Marsh a pair of horn cores about two feet in length and six inches across at their widest point.  Discovered right smack dab in the middle of where Denver, Colorado is today, Cross relayed to Marsh that they had been discovered in beds of Cretaceous rock.  Marsh, however, decided that these horns must have belonged to some sort of enormous bison, and gave the horns the name "Bison alticornis."  Perhaps Marsh was still suffering from the misconception that the 1887 discovery was, indeed, an enormous extinct bison, as these 1887 Denver horn cores are not mentioned in the brief Ceratops paper.  It is mentioned, however, that if the horns were discovered "detached," their "resemblance in form and position of the posterior horn-cores to those of some of the ungulate mammals is very striking," and the horns would "naturally be referred to that group."  I have no evidence to support my hypothesis, but I wonder whether this comparison to the mammalian ungulates is insurance on the part of Marsh, as perhaps at this point he had recognized the true nature of the 1887 horn cores.  This is pure conjecture on my part, and is mostly irrelevant anyways, as in 1889 Marsh recognized the dinosaurian nature of the Denver cores, and referred them to the genus Ceratops.  Today, these horn cores are regarded as belonging to Triceratops.
4. Marsh mentions that several limb bones, vertebrae, and teeth were also found in the Ceratops horizon, as well as several bits of dermal armor, and states that he believes they also belonged to Ceratops.  Whether this is true or not I do not know, but what I do know to be false is Marsh's next sentence, in which he states that the bones "indicate a close affinity with Stegosaurus, which was probably the Jurassic ancestor of Ceratops."  The specimen is housed in the Smithsonian today, under the catalogue number USNM 2411.  A search through the online records of the Smithosonian shows that 2411 consists only of a partial skull, which seems to be consistent with what I've read in other sources.  I'm not sure whether these other skeletal elements mentioned above have found a definitive dinosaurian home, or whether their true owner is uncertain.  
5. The final paragraph is, in my opinion, inarguably the most important.  The paragraph reads as follows: "The remains at present referred to this genus, while resembling Stegosaurus in various important characters, appear to represent a distinct and highly specialized family, that may be called the Ceratopsidae."  In this paragraph, Marsh has created the group of dinosaurs that, more colloquially, we refer to as the ceratopsians.  Or, more colloquially than that, "those dinosaurs that look like Triceratops with those horns."

Ceratops was discovered in what scientists now call the Judith River Formation.  Several other ceratopsians have been discovered in this formation, and due to the small amount and fragmentary nature of the material that was originally described as Ceratops, most paleontologists consider the dinosaur to be a nomen dubium.  Nomen dubium pretty much means that the material is too fragmentary for it to be diagnostic, and can't really be used in the future to determine whether new specimens are the same as the original or not.  Whether or not the newly discovered Judith specimen currently on display at the Morrison Museum is, indeed, Ceratops is still up in the air, as the paper has not been published yet.  Almost all of my Ceratops knowledge is out on the table for all to see, so I am not going to speculate or attempt to draw conclusions about something that I don't really know enough about to have an informed opinion on.  Guess we will just have to wait and see!  In the meantime, come on by the Morrison Natural History Museum and the Best Western Denver Southwest to see Judith, and much more!

*If you've been living underground amongst worms and fossils for the last few months, you might not have heard of the hotel, so you can check out some incredible pictures of the best Best Western by clicking HERE and HERE.

Works Cited:

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!

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 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!