Dakota Goes Digital: Replicating a Mummy Arm

Reonstruction by Natee Puttapipat from Drumheller et al., PLoS One, 2022

Confession time: I love giving nicknames to the specimens that I find. It makes them really easy to recall compared to listing off a specimen number. Valerie? Yeah that's a Tyrannosaurus rex. Cap'n Chuck, yeah that's a Platecarpus I found in 2006. So much simpler than remembering RMDRC 22-014 and RMDRC 06-009 respectively. And we're of course not the only ones to follow this practice.

The frill of Princess Lumpybumps, how it got its nickname

Way back in 1999, a teenager named Tyler Lyson found a dinosaur on a ranch owned by his uncle in North Dakota. The specimen was impressive, and was recognized early on to be a "mummy" of a duck-billed dinosaur, Edmontosaurus, that had lots of fossilized skin surrounding its bones. Of course a specimen like this was going to need a nickname so Tyler called it "Dakota". The specimen was excavated by the Marmath Research Foundation in 2004. Fast forward a few more years and Tyler is now Dr. Tyler Lyson, who we work collaboratively with from time to time at the Denver Museum of Nature and Science. Dakota has now made it to the North Dakota Heritage Center and State Museum in Bismarck, reposited with the North Dakota Geological Survey. More information is available on the ND State Museum Blog.

Denver Museum crew excavating a Triceratops that I discovered

In the museum in North Dakota, Dakota the Edmontosaurus has recently gone on display showcasing the original fossils, new artwork by the incredibly talented Natee Puttapipat, and more importantly replicas of many of the skin impressions. Replicating a dinosaur mummy is a tough thing to do, since so much research down to the molecular level is going on with Dakota and nobody wants to risk contaminating it. Traditional silicone molds were determined to be too risky for the safety of the specimen, so everything was scanned at 25 micron level of detail. To put that into perspective, a human hair is usually 50-75 microns in diameter, so this scanning preserves even the finest structures digitally.

Dr. Clint Boyd and crew supervising the move of Dakota, from ND State Museum Blog.

We at Triebold Paleontology Inc. are world leaders in making digital things physical again. Our 3D department was able to print the 3D file full-sized, separated mostly on crack lines going through the real specimen. We then took those parts and assembled them into the full arm. The detail is so precise that you can see the marks where researchers cut away a sample of the skin on the original fossil to analyze. 

Prototype copy being painted with the original arm in the background

Why am I mentioning this now? TPI has recently completed an agreement with the Heritage Center in North Dakota to offer replicas of this amazing fossil arm for the very first time! You may have seen the first (and up to that point only) copy of the replica on display at SVP this past year in Minneapolis. We are now the only authorized company that can make these exquisitely detailed and painted copies for museum exhibits across the world. Contact Jacob Jett for pricing and delivery timelines 

Prototype copy at the NDGS display during SVP 2024

The little Thescelosaurus that could

The Hell Creek Formation is so much more than just Triceratops and Edmontosaurus and Tyrannosaurus rex. There, I said it. I head out there to swelter and dig nearly every summer, and it's truly not the big famous dinosaurs I'm interested in. This is where Jonathan comes in. This specimen, RMDRC 06-007, was collected over a decade ago and sat in our collections partially prepared for most of that time. Coincidentally it's a specimen of Thescelosaurus neglectus, the "neglected marvelous lizard" and the name sure fits. 

Partly prepared in the jacket, tail and right leg in other places

In the spring of 2017 we decided we needed to do something with the specimen. Jonathan was mostly articulated in a large heavy field jacket. The first step was to get all the parts into a state where we could mold them, so lots of careful preparation, and lots of consolidant was required. Jonathan was a large (by Thescelosaurus standards) and old animal, but the bones were still preserved with the insides like coffee grounds, ready to pour out in a pile of disappointment if the bones were even looked at the wrong way.

Right foot after prep and restoration

Any damage was stabilized and repaired as we worked. Missing parts were scanned with an Artec Spider structured light unit and we printed them out using our Form2 SLA printer and the usual PLA filament scribblebots. Molding was quick and straightforward for the most part, though the chest cavity posed a special problem for us. The chest cavity preserved a series of calcified intercostal plates between the ribs, which only start to solidify when the animal hits a ripe old age. These super delicate features prevented us from molding a set of ribs that could be immediately used on the cast, so instead we molded them all as a whole unit, cast them, then modified the casts to fit on the mount, then remolded them. Straightforward, right?

Posterior dorsal vertebrae

Assembly was pretty easy as well, though at nearly 14 feet long we were always remarking on how surprisingly big this animal was. It's huge clod-stomper feet came out very well, and since we had calcified cartilage with the specimen, we thought it would be dumb not to include it on the finished mount. In the end we came up with what I think is the very best and most scientifically accurate reconstruction of this poor neglected animal ever attempted. I hope you all like it as much as I do.

Finished mount, Grace for scale

An unusual view highlighting the cartilage

He just looks so dang HAPPY!

More on Gil

Show prep is continuing on our duckbill! Time for a little background information. Gil, AKA RMDRC 04-001, was discovered in 2004 by and is named in memory of "JC" John Cully Gilpatric, who sadly passed away 2 years ago. It comes from the upper Judith River Formation, putting its age somewhere around 75 million years old. Excavation began on June 26, 2004 and had been completed by July 2nd. Gil wad found in a fairly soft sandstone with low overburden, which greatly sped up the recovery.

Above is a sketch of the site when TPI field crews excavated it that summer. As you can see it is highly articulated but missing the skull and lower legs. Unfortunately for hadrosaurine hadrosaurs those also happen to be the most distinctive parts, so identification down to genus is still a little tentative. We have been considering Gil to beling to Miasaura, however there exists the possibility that It could belong to two other non-crested duckbills that existed at the same time: Gryposaurus or Prosaurolophus. Below is a photo of the 54cm long right humerus, which may or may not be distinctive. In any case it's pretty, and also slightly longer than the radius.Prep work is ongoing to find more distinctive skeletal elements, so that we may get a better idea of the true identity of this critter. Special thanks goes out to Dr. James Kirkland for providing PDF reprints so that I may attempt to clear this up!

Duckbill tails from the past!

We've been able to do a slight bit of preparation on a Maiasaura that was collected by TPI crews in 2004 from the upper Judith River Fm of Montana. Unfortunately no skin was discovered preserved in this jacket, however there were a few surprises.

The anterior 6 vertebrae show pathological neural spines, perhaps an old bite wound that healed. The chevrons (Y-shaped bones under the tail) are tiny, much smaller than what would normally be expected on a dukbill of this size.

This jacket contains 32 articulated caudal vertebrae in a string nearly 8 feet long. Strangely the chevrons are all nearly gone and the ossified ligaments normally found in ornithischian dinosaurs are completely missing.

Fossil of the week: 5/29/09

This past week I was attending the 8th Conference on Fossil Resources in St. George, UT. The second group of talks all focused on the Campanian aged flora and fauna of the western interior. A few brief mentions of the poor neglected duckbill dinosaur fauna were made, but I wanted to share with you an image of one that I'd love to find: "The duckbill that ate Manhattan!" Paleo Tech Jacob Jett (6'4" tall, shown back in his younger days) is shown for scale.

This isolated rib bone was discovered in the upper Judith River Formation (Campanian aged) in the summer of 2004 while excavating a centrosaurine horned dinosaur called "UTC". Isolated duckbill skeletal remains are not uncommon at dig sites. In fact, juvenile hadrosaur jaws have been found at both our  "Joyce" and "Pete 3" sites in the same area.

Unfortunately, isolated postcranial remains on hadrosaurs aren't very diagnostic, so it is impossible to say which critter this rib belongs to. It is a good deal longer than our longest rib on "Big Ed", the 34 foot long Edmontosaurus annectens that is now on display in Korea. I'd estimate the body length of this duckbill to be at least 40 feet.