A Q&A to the Diplodocus degree: HMNS skeletons still inspire after 110 years

Editor’s Note: Sometimes, you ask us questions on Facebook or Twitter that require a bit more than just a pithy response. So .. we wrangle the experts to get to the heart of the matter for you. You’re welcome.

Q: A write-up on another Diplodocus says that the forelimbs and hands on all the Carnegie casts are all based on a Diplodocus specimen from the Houston Museum of Natural Science. Is this the one known as “Dipsy,” first mounted in 1975? Or a different one? There’s a reference online to one excavated in 1902, but again, I don’t know if this is the same specimen. -Andrew Armstrong

bob.bakkerA: Yes indeed, our Dipsy has unusually fine feet.

Our skeleton is a composite of the two famous ones dug by Utterback near Hole in the Wall, Red Fork of the Powder River, Wyoming, way back in 1902-1903. Butch Cassidy and the Sundance Kid had their secret camp not far away. The Dipsy Duo skeletons were originally numbered as 307 and 662 in the Carnegie Museum catalog.

Not only are the forefeet and hind feet quite splendid, but the braincase — the biggest, most complicated unit in the entire skull — is still the most perfect one for all diplodocines. Matt Mossbrucker at the Morrison Museum and I are publishing a paper using the Dipsy Duo to re-think how long-necked dinos used their heads.

Here’s a close-up of our braincase, set on the first two neck vertebrae:

jm_dippy_carn_art_bcase-axis

And a shot of the excellent Denver skeleton with our entire neck and head, so you can see the proportions of skull and cervical vertebrae:

jm_dippy_carn_grey_neck_dnvr

Stay tuned: the Dipsy Duo head and neck are about to start a Diplodocus Renaissance.

-Dr. Bob Bakker

Nota bene: As of September 2013, our darling Dipsy the Diplodocus has been de-installed and is currently on vacation in Black Hills, being cleaned and repositioned. She will return to us and take up permanent residence in our Morian Hall of Paleontology in the next year or so.

Looking Back…

In case you were wondering about notable science events that occurred the week of July 4th…

ET christmas 2004
Creative Commons License photo credit: Lathyrus

Ready for the clone wars? On July 5th, 1996, Dolly the sheep was born. Dolly was the first mammal to be cloned from an adult somatic cell. Dolly lived her entire life at the Roslin Institute in Scotland. She had six lambs of her own, and lived to the age of six.

ET phone home… On July 6th, 2003, a message was sent out to five different stars. The message, Cosmic Call 2, was broadcasted from Eupatoria, a 70-meter radar. The message was sent to the stars Hip 4872, HD 245409, 55 Cancri, HD 10307, and 47 Ursae Majoris. The message should reach its destination in 2036, 2040, 2044, 2044, and 2049 respectively. Talk about your long distance phone calls.

Well I’ll be a monkey’s uncle. On July 10, 1925, in Dayton, Tennessee, the Scopes Trial began. John T. Scopes, a high school teacher, was accused of teaching evolution in the classroom in violation of Tennessee law.

Raw DNA Image
Creative Commons License photo credit: MASH DnArt

The law, which passed in January of 1925, stated that it was illegal for anyone to teach anything but the story of Divine Creation of man. After an eight day trial, Scopes was found guilty of teaching evolution and fined 100 dollars (approximately 1,165 dollars in today’s currency.)

On July 10, 1997, London scientists report their DNA analysis of a Neandertal skeleton, nicknamed African Eve, found in modern day Ethiopia. The results place her life at roughly 140,000 years ago, which supports the Out of Africa Theory. This theory states that all our ancestors originally came from Africa. An alternative theory is the Multiregional Origin Theory, which states that our ancestors developed independantly in different regions of the world.

Mystery Skeleton – Update 4

While I was waiting for the skull to dry I checked out the bits and pieces.  A few curious traits stood out and I may be a bit closer to the cause of death for our mystery Fido.

Item 1:plaque.JPG

A weird chalky white substance was on several of the teeth.  I noticed it first on the big back teeth dogs use to crack bones. At first I tried to figure out where the skull would have been that mortar could have gotten on the teeth.  Then it hit me.  Not mortar.  Tartar.  This is what old bleached tooth plaque looks like.  Who knew.  So, what does any good skeleton preparer do with tooth plaque?  She gets herself a dental pick to clean said teeth.  No joke.  It is in my car right now.  This is a significant build up.  You can also see where the gum-line ended as that is the highest place the plaque rests on the tooth.

Item 2:

The next item of question is the amount of wear on the teeth in such weird places.  Here you have a picture of Millie’s teeth.  I went to the vet at the end of June and she told me to get soft Frisbee for Millie as her teeth are really getting worn.  Compare her canine teeth (the pointy ones in front) to mystery skeleton’s.

Mystery skeleton upper jaw.Millie’s worn teeth. Broken bottom canine teeth.

Now, in the first picture, you can see mystery skeleton’s canine’s resting on my thumb.  The point is nice and sharp. Millie’s teeth are in the next picture. Her upper teeth are squared off, but still fairly long.  The lower teeth are flat and end at her gum line.  She is about six years old.  So comparing the two sets of teeth, I would say that the mystery skeleton is an adult – all the bones in the vat are completely fused – and probably about 2 or 3 years old.  NOW!  Look at the third picture closely.  This is where things get weird.  The lower canines are totally broken off, but have been worn smooth.  You can actually see the quick – look for the two tiny dark colored circles in the center of each tooth.  This means that the tooth was broken off and that the dog lived long enough to work the teeth on something to even out the rough bits.  It had to have been painful.  Think about an exposed tooth when you get a crown.

Item 3:

On the inside of the lower right jaw, I found an interesting spot.  Literally.  There is a huge cavity in one of the teeth.  Huge.  I have had a couple small ones in my life, but never one that big.  Once again.  Painful.  Cavity.

Conclusion:  This dog had serious issues with his teeth.  The pain from the teeth probably made it uncomfortable to eat and quite possibly contributed to his demise.

Mystery Skeleton – Update 3

Cavity

After a few days of soaking the bones in the hydrogen peroxide bath, I took the skull out and dried it off.  According to Lee Post, if a bone still has fats inside it, there will be spots on the bone that are darker and still look wet even after it is totally dry. Taking the skull out gave me the opportunity to identify the bones and see how much more of a soak it would need.

I picked the skull because it is the bone that most readily identifies an animal.  In this instance I began by asking Dr. Bakker what he thought.  From the pictures I showed him, he said dog. 

I already knew it was a canid, so it wasn’t surprising that it was a dog.  At first, I wanted to determine what type of dog it was, but I quickly realized that was kind of dumb on my part.  It was probably a wild dog.  I wanted to check it out anyway however, just to make sure.  It was going to be fairly crucial to the articulation to make sure I have the right critter, so I went to Skulls Unlimited to see what they had for comparison.  Except for specialty breeds, like pugs, my skulls and their skulls are a pretty close match.

As I said in the original post, my parents live on a ranch.  Around their ranch are several packs of wild dogs. It is not uncommon for people to shoot at the dogs because they will hunt livestock, fight with working dogs and are occasionally rabid.  To think that this was a wild dog that was shot isn’t too far fetched (no pun intended).

Broken Teeth

I took a look at my vat o’ bones and considered this theory.  All the major bones seem to be there – leg bones, pelvis, shoulder blades.  None of the spinal column bones or the ribs seem to be shattered like a bullet hit them.  So what this tells me is that this theory might be faulty.  The skull is smaller than Millie’s would be.  She is a 60 pound dog, so she is good sized but not huge.  I imagine this dog being more in the 35 to 45 pound range.  The dog would have been more compact, a small target.  It seems logical to conclude that the shooter would have gone for a body shot, and it seems nearly impossible that, from several yards away, he or she wouldn’t have hit the dog and shattered several bones.  So if it wasn’t a bullet, what was the cause of death?