Tuesday 26 April 2022

Behind the scenes of the Sauriermuseum, with Victoria the Hesperosaurus

It has been a while here, and this time for a good reason: I got a job now. How is another story, but I am now a research assistant to Dr. Dennis Marinus Hansen, who is the exhibit manager of the Zoological and Paleontological Museum of Z├╝rich (come visit us if you are ever close, the entry is free!). And Dennis probably needs all the help he can get right now, because the museum is undergoing some radical changes that he is in charge of. One of these is the addition of at least four new, genuine dinosaur skeletons for a new exhibit in 2023. But where will those skeletons come from? The Sauriermuseum Aathal of course, which you hopefully still remember from last year on this blog. Because it is a private museum, Kirby Siber, not being the most youthful anymore, has decided to not burden his children with the ownership of some of the massive dinosaurs and is instead donating the scientifically most valuable finds his team made in the Morrison Formation to the Zoological Museum. For now this includes Big Al II, an Allosaurus jimmadseni more complete than the first Big Al, the Diplodocus carnegii HQ1, the Nanosaurus Barbara, baby-sauropod Toni and the Hesperosaurus Victoria (later down the line we will also get the Camarasaurus E.T., Arky the Camptosaurus and the so-far-indeterminate diplodocid Arapahoe). However, these skeletons will not directly come to us now, but will instead go on a little tour over half the globe to a special event in Hong Kong. Two weeks ago there was therefore a test-assembly of the skeletons going on at the Sauriermuseum for the HK-correspondents, and since this was a good opportunity for our museum to make some assessment for our own future exhibit as well, Dennis took me with him.

The skeleton in question was the aforementioned Victoria (SMA 0018), a specimen of Hesperosaurus mjosi, which you can see here above how it stood in the museum last year in its old mounting. It was found by the Aathal team in 1997 at the Howe-Stephens Quarry in Wyoming, alongside two other Hesperosaurus-specimens, Moritz (SMA M04) and Lily (SMA L02). All three of them are mostly complete, even including their skulls. Victoria and her siblings were originally classified as Stegosaurus (and some material you might encounter still labels them as such), which is because the genus Hesperosaurus would not be described until 2001 and Victoria was not recognized as belonging to that genus until 2010 (Christiansen & Tschopp 2010). Victoria stands out in two ways: first, she is very massive compared to her siblings, which I only realized after standing right next to the specimens. While Moritz is about the size of a donkey (not counting the backplates), Victoria has dimensions comparable to a rhinoceros. You definitely would not have wanted to meet her in an angry mood. Second: Victoria preserves integument-impressions, not just of the skin but also the surface of the iconic backplates. These show pretty conclusively that at least in some stegosaurs, these plates were covered in a keratinous sheath (Christiansen & Tschopp 2010).

Apart from that I do not have much to tell you apart from what happened that day. First off, we had to section off the pterosaur-exhibit of the museum so we had enough room to assemble the skeleton. The barriers we put up were unfortunately not always enough to restrict the area, as over the course of the day at least one pair of children accidentally got in before we had to kindly tell them to leave. After restricting the area we went out to the parking lot, where fossil-preparator Ben Pabst (the one with the beautiful white mane after whom Galeamopus pabsti is named) had arrived with the back of his car loaded with Victoria’s pelvic girdle (mostly made of real bone, partly 3D-printed). After helping with loading the massive pelvis onto a wooden lift, we drove the bones back into the museum, where construction could now begin. 

First the pelvis was pulleyed onto a scaffold and the leg bones were attached.

Then the tail was assembled. This was probably one of the most fun parts for me, as I was able to personally help with arranging the vertebrae (though this was admittedly pretty easy, as the caudals were already labelled with numbers). The spinal column of Victoria is pretty much complete, as far as I am aware only the very tip of the tail that you see on the table had to be 3D-printed.

Then came the rest of the spine and the ribs, where I could also help out a bit. Interestingly, one of Victoria’s ribs close to the hindlegs (the second-to-last one at the back in the upper image) had a weirdly flattened bit. The corresponding rib on the other side is not known and no other rib had that feature, so one has to wonder if this was perhaps an injury the animal had acquired in life.

Between the assembly of the ribcage and the shoulder-girdle, Dennis, his other assistant David, Esben Horn and Me had to make a quick detour and pay another dinosaur a visit, Barbara (SMA 0010) the Nanosaurus agilis. As mentioned, Barbara will also eventually come to our museum and we have some pretty big plans for her. Not only will her original fossil be beautifully exhibited in a Lenin-esque glass-sarcophagus, but she will also be accompanied by a full-size life-reconstruction. This is why Esben Horn, founder of the model-manufacturer 10TONS was there with us in the first place, as we had to show him the fossil and our plans with it. The clear specifications for the model are still being decided on, but in general we want her to lean down and look at her own fossil because it makes for a nice aesthetic. We also want her integument to be some form of dino-fuzz. The latter is justified, as, among a few other reasons (I wrote a 10-page document for Dennis where I weighed our options), in most current models Nanosaurus is actually surprisingly close to Kulindadromeus zabaikalicus on the family tree. In order to make potential 3D-scans of the dinosaur we also quickly borrowed a smaller skeletal model of it from the fossil plant exhibit and tried to photograph it in the parking lot. The school classes who were at the museum that day seemed obviously quite surprised, as it looked like Dennis was stealing the specimen.

After that we went back to Victoria. Now came the shoulder-girdle and the front-limbs. Here you can see me laying hands on Victoria’s thicc thighs.

Lastly Ben laid out the backplates and discussed the arrangement of the them (these were copies of the original bones or else they would have been too heavy for the mounting). An interesting thing he pointed out was that one of the tail-vertebrae was badly squished and the plate that was likely associated with that vertebra was also noticeably malformed. While both things could be attributed to compaction during fossilisation, one again wonders if this could have been an injury or an illness in life. 

I unfortunately could not stay long enough to see the mounting of the head and neck, but I at least got to photograph a replica of Victoria’s skull (the actual skull will remain in the Sauriermuseum’s Howe-Quarry-exhibit for now). If you want to see a lot more pictures from that day, I made a long collection of images and videos on my Intstagram. In the end, it really was a great time. It was a lot of fun and I got to meet and see many interesting people. I definitely hope I can give you more posts like these in the future.

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