King of the Crocs: Rebuilding Deinosuchus schwimmweri

The year is coming to an end soon, but we are still busy developing new skeletal mounts for museums all across the world. Recently, while I was away in England for the SVP Annual Meeting, our founder Mike Triebold led a crew to the Tellus Science Museum in Cartersville, Georgia to install the very first reconstructed skeleton of the humongous Cretaceous crocodilian Deinosuchus schwimmeri.

Deinosuchus osteoderms mounted on the skeleton

Deinosuchus fossils are found all over North America in Campanian aged sediments. D. riograndensis is known from the Big Bend region of Texas, D. hatcheri from Montana and Utah, and to the east there is D. rugosus originally discovered in North Carolina. In 2020, Chris Brochu described a new species from Appalachia, Deinosuchus schwimmeri, named after David Schwimmer.

This David Schwimmer doesn't have a fossil named after him

No, not THAT David Schwimmer. The one in this case is an accomplished paleontologist from Georgia who has worked extensively with fossils of this giant crocodilian. It is a great coincidence that the actor that played a paleontologist (sorta) on Friends shares the same name, but this species is definitely not named after him.

Assembling the skull prints 

In 2024, TPI crews visited several museums to scan and digitize as much Deinosuchus material as possible. Digitally, we reconstructed the bones to take out distortion or complete missing parts. Basing the skeleton off of modern animals helped us come up with an accurate skeleton, and we sized it up to the largest known material. We even dissected an alligator and used a dermestid beetle colony to clean the skeleton for reference. This was very handy because it enabled us to make a complete set of osteoderms for our reconstruction. The skull was a unique challenge since printing out in one giant piece would take a long time on FDM printers, with poor detail. We ended up making it in many smaller pieces in SLA printers, which then had to be assembled before molding.

If it were alive today, I wouldn't go near the water

TPI crew laying out parts before assembly begins

Building the specimen was tricky as the entire thing ended up being about 9 meters long. The Tellus Museum wanted it portrayed in a "high walk" pose, which gave us a good opportunity to show off the details we put into the gastralia and sternal elements. 

The assembled skeleton in our atrium

The pose also demanded a tight curvature to the tail to fit into the exhibit area, which was already built and partially occupied by an Appalachiosaurus skeleton that we had provided when the museum first opened many years ago. That poor theropod had to move a little bit to make room, but it worked out well. The team did an amazing job on all parts of the process, and the installed specimen looks fantastic. 

Mike, Krieg and John after completing the delivery in Georgia

Restoring the skull of Texas Nessie

It's not just your imagination, we have been EXTREMELY busy in the lab and 3D department working on all sorts of new reconstructions of animals. I'm very proud of this next one, which debuted at the TPI booth during the Society of Vertebrate Paleontology annual meeting in Minneapolis this past fall.

The completed polycotylid skull

This skull belongs to a fantastic specimen of polycotylid plesiosaur excavated in 1991 by Mike Donovan, a collector working in the Eagle Ford Shale of Texas. After Donovan passed away, this specimen was donated to the Heard Museum in McKinney, just outside of Dallas. Shortly thereafter we were contracted to mount the original skeleton for display. You should really check it out, my friend Pamela Riddle made the custom mural that's the background for it and I think it looks spectacular. Several paleontologists are working on the description of this animal, and I hope to see the finished paper out soon.

Photo of the display from www.nbcdfw.com

Fast forward to November 2023: Evan, our 3D Director, drove with me down to Dallas for a few projects. In addition to getting to meet up with Pamela at the Perot Museum prep lab we also were able to visit the Heard in order to work on the skull. Darlene Summerfelt was gracious in accommodating us even though she had a touch of a cold a the time. Taking the specimen off of display was a stressful experience, since the real skull bones were mounted individually around a steel armature and plastic casts filling in the reconstruction. 

Darlene (L) and Evan (C) working on the skull as museum visitors observe

We scanned all of the original material and carefully reassembled the skull onto the mount in just one day. That, it turns out, was the easy part. Once back in Colorado we consulted with plesiosaur experts as well as with our own virtual 3D library of plesiosaur material to digitally reconstruct the skull of the animal. Special thanks to Mike Polcyn for letting me pick his brain.

Evan scanning reconstructed jaw parts in the Heard Museum

As you can see, even when the skull is completed, there was a lot of distortion from being buried under Texas for nearly 90 million years. Luckily we were able to remove this deformation. In the old days, during the 2004/5 reconstruction of the Martinectes (formerly Dolichorhynchops bonneri skull, this was done by making plastic casts and then heating and bending them, with lots of manual sculpting, to get them to resemble what they looked like in life, a difficult and time consuming process. 

Early reconstruction work showing the crushed-down top of skull

Once done with that we were able to print out a copy of the completed skull, which I got the privilege to assemble. Working with these highly detailed prints isn't the easiest thing to do, but I've had some pretty good experience with this reconstructing the BCT Teratophoneus skull, the mosasaur Jormungandr, as well as quite a few secret upcoming projects that you'll have to stay tuned for. 

The assembled print of the top of the skull, with me for scale

This one has made it back to Texas for the Heard Museum to put onto display (the Heard's Darlene Summerfelt for scale in this photo). She says she loves the reconstruction. Now that it's available through the www.trieboldpaleontology.com we hope other museums are just as impressed and order one today!

Darlene Summerfelt with the full size (and mini) skull reconstructions

Project Kevin Part 2: The Kevining

Project Kevin is complete (for now, we have to invent a body and that might be... interesting)! The last time I updated this, I had left you at "We dug stuff up and were making it as pretty as it could be" in the lab. That left us with a pile of neat looking bones, but of course we wanted more. Did we have enough to make a skull? And if so, what did it look like? We sure thought we did based on what we identified, though since the site was trampled int he Cretaceous most bones were missing chunks.

One of the mostly complete brow horns

First things first though. Let's laser scan (alright not a laser, but an Artec Spider structured light scanner) all the things! This gives us a good baseline to record what we have. These scans can also be shared with interested researchers across the planet. Researchers are usually pretty happy giving opinions of things and many helped us with details on how this thing might come back together.

Right maxilla in digital form

We can also try out new things with the scans. I came up with an interesting idea to print a 30% scale model of all the parts (using mirrored parts if one side was missing or just incomplete/really ugly). We popped off the parts on our Formlabs Form2 (the 30% scale was determined by the size of the build plate of the printer, these SLA printers can be pretty small) and tried to put together a model to guide us. We goofed though.

The first draft, complete with all our errors

Turns out we had the brow horns on backwards. Also the fits between the bones weren't as accurate as we would have liked. So we fixed them on a small scale before committing on the casts and prints of the full scale stuff. It also gave us the ability to try out things like a scaled and computationally-squished rostrum to make a part that we were completely missing. In this case we printed out a bunch of different possibilities and fit them on until we had a result that looked plausible.

Second draft of scale model, now we get to try out different beaks

With this information in hand, 4 binders of papers as references and a pile of casts, we were ready to take a stab at reconstructing the skull. Lainie and Grace really did a heck of a job learning these techniques. Printing out full size mirrored parts make the skull more accurate and easier to reassemble than if we were to sculpt the missing bits from scratch.

3D prints, casts, lots of epoxy putty and Bondo. Lainie for scale

Things went pretty smoothly till someone (who shall remain nameless) suggested our minimum length conservative frill was probably much too short. The first draft was based only on the length of the frill parts that were preserved. Chasmosaurines like this have seriously long frills though so we took their advice and busted out the sawzall. It was only plastic after all.

OK, let's move this frill about a foot to the back I really think it looks better this way.

We also had to make teeth. Hydrospan 100 was wonderful for this. We poured it into a mold of Ava (RMDRC 12-020)'s dentary and made a floppy cast. This material was then soaked in water until it expanded enough to fit the tooth rows for Kevin. Then we molded it, poured a bunch of plastic copies and played dinosaur dentist for a few days getting over 100 rows of teeth in all the jaws.

We molded all the finished parts and made casts. The skull was cut apart to make the molding process easier. A single mold for the top of the skull would have been huge, complicated and really heavy.

This is what a Kevin skull kit would contain if you bought one

Grace and Lainie making a huge mold for the frill

We put the prototype together in just a few days. It was a lot bigger than we expected. But after paint and finishing, I thought it went together pretty well! Technology really helped us out on this one, saving us materials, time and most importantly effort. I don't think we could have gotten it done by the deadline without it. Now it's time to figure out where this belongs in the family tree.

The prototype is done!

And the obligatory "Curator for scale" photo. I forgot to suck in my gut.

Here's what we put together for the left side, and where we got it from.

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!

Everyone loves a little tail

Or even a huge one. Just wanted to share some cool pics we took of Pete III's 5.1m long (17 foot) tail. Caudal 1 is missing from this layout (it was still in the pelvis jacket), so add on another 18cm or so.

Not too shabby

Jacob, our living 2m scalebar

The Fossil Brewing Company shirt is apt

A day in the life of a Daspletosaurus bone

Some people asked me not too long ago about what we do in order to get some of these bones ready for molding. In the case of Pete III, our Daspletosaurus from Montana, the condition of the bone gave us some additional problems. All specimens of course get excavated and painstakingly prepared by our expert staff, but in Pete III's case, even the prep necessitated the invention of new techniques which I published on a few years back. The entire specimen was pixelated, with some bones made up of hundreds of thousands of fragments. Lots of glue was needed to even expose the bone, which is huge, literally Tyrannosaurus rex sized. Once done the left ilium looked kind of like this:

Next up is reconstruction of any major missing bits and holes with epoxy putty like Aves Apoxie Sculpt. That's the grey stuff.

We then apply a barrier layer of B-72 to hold everything together for the next steps. Shiny!

Then we take our gorgeous bone and smear the whole thing with tinted Hydrocal.

 Yuck. OK now it doesn't even look like a fossil. Never fear, most of it will be gone soon. The main aim is to work the Hydrocal into all the seriously tiny cracks in the surface to better hold the bone together. This also reduces the amount of the relief in the specimen so molding goes much faster. The excess on the surface is removed with air abrasion.

Doesn't look so shiny anymore, but we can fix that with a wee bit more of very thin B-72.

And there you have it, one half of a bone restored in a few days time. Now we just make a support jacket so the entire thing can be flipped over and the process repeated.

Actual Mosasaurus from Kansas

Mosasaurs in Kansas, no big deal, there are thousands of specimens known. But what about the actual genus "Mosasaurus"? As recently as 1967, Dale Russell's excellent mosasaur book claimed "Mosasaurus ivoensis" was present in the Niobrara. Since then, Johan Lindgren has moved the holotype of that species (from Sweden) into Tylosaurus. The lone Kansas specimen originally described by Williston in 1902 looks to be attributable (to my eye) to existing known Niobrara mosasaurs, most likely Platecarpus and Clidastes.With the loss of the one possible chalk specimen we're left with a sort of sad thought: Mosasaurus didn't exist in Kansas.

Until now.

Excavating the skull parts

This spring a TPI field crew accompanied by famed Kansas Cretaceous expert Mike Everhart came out to Wallace County in far western Kansas at the request of a private landowner. We were investigating a report of a mosasaur eroding out of the Weskan member of the Pierre Shale, immediately above the much better known Sharon Springs member. Hardly any people work on collecting fossils out of the Weskan, so we were excited for this opportunity in virtually unexplored country. The critter, RMDRC 14-015, got the nickname "Wally" after Wallace County, and was brought back to the lab this spring.

Nice flipper

After recovery and prep it was obvious we were dealing with a pretty darn big mosasaur with a skull about 4 feet long, but what could it be? The only reported specimens this size out of the Pierre in Kansas could be Tylosaurus or Globidens. Prognathodon crassartus from "Eagle Tail, Kansas (now known as Sharon Springs) turned out to just be Plioplatecarpus. the premaxilla lacked a substantial rostrum so that excludes Tylosaurus, though its slight nub of one also excludes Prognathodon (known from other Pierre deposits). The teeth are all sharp and pointy, so not Globidens (yes they are pointy in juvenile Globidens, but with a 4 foot long head, it's silly to consider this critter a juvenile). In the end, with the characters we saw, there was only one logical conclusion.

Bite mark on frontal

Yes Virginia, there really is Mosasaurus in Kansas.

Bulky snout

In fact now there are two: We started recovery of another even larger and more massive specimen from the same ranch at the end of October, RMDRC 14-050. More on that this spring when we return to finish the site. The coolest thing is how the specimens display both advanced and primitive features usually assigned to one or another species of Mosasaurus, but not all in one. It's probably a brand new species, which is really exciting for us.

We are currently restoring and molding the complete skull of RMDRC 14-015 for debut at the Tucson Gem and Mineral show this January, in fact the palate it being installed as I type. The rest of the specimen may take a bit longer to restore, but the world always needs more 30 foot long water lizards. And you can quote me on that.

Newest digsite, mainly concretion

Daspletosaurus reconstruction progressing: Pete III

You know, I think I'm just going to share some pictures as an update to my last blog post. We'll keep the reading part short and sweet. Restoration is coming along well. The skull is up next, and in the meantime we have the leg finished and the arms almost there. Lots more to come over the next few months. It's always good to have new tyrannosaur stuff to play with.

Pete III's scaps and arms

The scapulae were remarkably well preserved in 3D

Left leg before paint

After paint, left leg from the rear

Side view, the leg is HUGE!