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Specimen of the Month #14: our new Stegosaurus

Posted by Amy Freeborn on Dec 17, 2014 9:34:41 AM

First things first - I know our new Stegosaurus is no longer behind the scenes, and now grandly stands at the Museum's Exhibition Road entrance. I know that a lot has already been written and reported about it, so there can't be much more left for me to reveal. But the opportunity to write about the acquisition of an internationally significant and scientifically invaluable new specimen doesn't come along every day. In fact, it rarely comes along for the Museum, with this being the first near complete dinosaur fossil to be acquired by us in the past 100 years. So for that reason, I had to pick our new fossil skeleton as December's Specimen of the Month.


However, there is a 'behind the scenes' aspect to this piece. I was one of the few members of staff lucky enough to actually get behind the hoarding which protected the view of the construction process from the public while the Stegosaurus was being assembled. On that Monday, 1 December, looking down from the first-floor balcony of the Earth galleries (where an interactive digital display, 3D printed touch objects and specimen interpretation now stand), it was impossible not to get excited by the magnitude of the occasion. It was momentous not just for the Museum, but for any human being with even a passing interest in nature and history.


Much to the varied amusement/excitement/jealousy of my friends and followers, I tweeted:

Today at work I'm watching the (re)construction of a dinosaur skeleton #standard #museumlife @NHM_London

— Amy Freeborn (@amyfreeborn) December 1, 2014


My view from the balcony before the (re)assembly commenced. Of course, I couldn't tweet this, or any subsequent pictures, until the 22.00 embargo on Wednesday 3 December had passed.


Things kicked off around 10.45, as senior conservator Lu Allington-Jones attached the dinosaur's feet. Then she was joined by our dinosaur expert Prof Paul Barrett and they both slipped the left tibia into place.


Lu and Paul install the first major Stegosaurus bone of the build - the tibia, or shin bone.


The bones are supported by a specially-designed steel armature. Surfaces of the armature in contact with the skeleton are cushioned to prevent vibration damage. The supporting plinth, which handsomely rises up under the dinosaur's tail, is also designed to dampen vibration from visitor footfall, as well as external traffic and building works.


Once the legs and pelvis were in place, it really was quite amazing to see how fast the neck, spine, ribs and tail then came together. The whole thing was complete - topped out with the final of the four tail spikes - in under four hours. But, Paul said, it wasn't their quickest time:

We did mount the skeleton on three earlier occasions behind the scenes, partly to test that the armature was strong enough in the right places. We can assemble the skeleton in about two hours, but the mounting in the Earth Hall took twice that time as the plinth made it a little more awkward to work around the frame and we needed the Genius lift to get to some parts that we could previously reach from the floor or a regular ladder.


Watch this time-lapse video created on 1 December to see just how impressive the build process was, as four hours becomes about 24 seconds:



Senior curator Tim Ewin, who was mostly responsible for mounting the large back plates and tail spikes, explained of his contribution:

The plates are both heavy and large but very thin and fragile. It was like trying to stack bone china on its thinnest point!


Owing to the way the armature was constructed, it was not as simple as just plonking the bones in place either. Each plate almost invariably had its own unique technique to getting into the right position so it was properly supported and could not jump out and smash itself, other remains, or onto the viewing public. This involved trying a variety of approach directions, rotations and physically moving some of the supports out of the way for each element.


This was not so bad for the more robust, smaller and lighter elements, such as the vertebrae, but was really butt-clenching when it came to trying to install the largest plates at full stretch whilst 12 feet off the ground. Fortunately, there were no breakages, although several took a few goes and a little rest! I was, however, very relieved when we had finished.


Indeed, the whole team in the Earth Hall was relieved when that final fossil bone was put into place, and a spontaneous round of applause broke out. For me, and everyone else, it really was a proud moment to be part of the Museum.



Tim affixing the final Stegosaurus bone, seconds before applause broke out at the completion of the assembly.


Lu told me that the tail spikes are known collectively as the 'thagomizer' that, Tim revealed, is actually a term that originated from a Far Side cartoon. He directed me to Wikipedia, where it says:

The term "thagomizer" was coined by Gary Larson  in a 1982 Far Side comic strip, in which a group of cavemen in a faux-modern lecture hall are taught by their caveman professor that the spikes on a Stegosaur's tail are so named 'after the late Thag Simmons'.


The term was picked up initially by Ken Carpenter, a paleontologist at the Denver Museum of Nature and Science, who used the term when describing a fossil at the Society of Vertebrate Paleontology Annual Meeting in 1993. Thagomizer has since been adopted as an informal anatomical term.


Vital Stegosaurus statistics:
  • Our specimen is a Stegosaurus stenops.
  • It is the first complete dinosaur specimen to go on display at the Museum in about 100 years.
  • It is 560cm long, 290cm tall, and composed of around 300 bones.
  • Its 19 back plates and four tail spikes form the most complete set ever discovered.
  • It is nearly complete, missing only the left arm and base of the tail, as well as a few smaller bones from the hands, toes and tail.
  • It is the best preserved and most complete of only about six Stegosaurus skeletons in the world.
  • It's the only Stegosaurus in a public collection outside the USA.



Following the assembly, I was finally able to tweet at 22.01 on Wednesday 3 December:

We got a new dinosaur at work! @NHM_London #Stegosaurus

— Amy Freeborn (@amyfreeborn) December 3, 2014


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