Crocs in South Dakota: Bad Footwear, Good Fossils!

Our first Hell Creek fieldwork trip is in the books, and boy did we find some neat specimens! Recently Mike Triebold and I set out for South Dakota to check in with our landowners and scout for new fossils eroding out of the Hell Creek Formation. You never know what might be hiding out in the badlands, heck in 2022 I even found a Tyrannosaurus rex that I named "Valerie".

Mike Triebold at work in the field

We spent the first few days finding some small specimens and I even located a site that may produce a small disarticulated Triceratops skull, but the rocks were being unusually stingy with fossils. We kept pushing on though, sometimes for 22,000 steps a day if my Fitbit can be believed, because you never know what might be hiding around the next corner.

Part of a Triceratops jugal with the distinctive bone texture below the eye socket

One morning I met up with a crew from the Denver Museum of Nature and Science who were based in nearby North Dakota this summer. There's a lot of federal land in these parts, however there's no way to access some of these outcrops legally without getting permissions to cross the private lands that typically surround them. Nobody likes trespassers. When a museum wants to visit some of these landlocked outcrops, I work with them and the surrounding landowners to make sure everyone can cross safely and in a way that doesn't interfere with the ranching activities or destroy their property. It works well and keeps science happening!

Edmontosaurus annectens hoof from a microsite

The Denver crew wanted to collect some rock samples on various parts of an outcrop, and I was also showing them some microsites that I had found in previous years. I check them yearly becauseyou never know what little thing might be exposed at the surface of a microsite after each year's rains (and what might be destroyed by erosion if left for another winter) and plenty of croc, dinosaur and mammal fossils were found. After breaking for lunch, I was contacted by Mike to FIND HIM NOW. I made sure the Denver crew was safe and set for departure and then went to meet the boss.

Sometimes great looking outcrops are disappointing

Mike drives me out to a low outcrop on the side by side. Coming out of the outcrop are croc osteoderms (or Crocsteoderms as I mutter to myself in the 120+ degree heat). These bones, embedded in the skin of the living crocodilians, are super common in the Hell Creek. What's uncommon about this site was the osteoderms were ARTICULATED: together as in life. I've never seen that in the wild before.

Sites that you can drive right up to are rare

I documented the site and Mike started digging. We scraped ironstone concretion pebbles off the surface, collected any fragments, then started excavating the rock around the exposed bones. It became immediately clear that the skeleton of this crocodilian was there and almost complete.

The croc: skull near my toe, the "panhandle" is the tail

We excavated the specimen much like we do Kansas fossils, where we find the maximum extent of the specimen, jacket the whole area, and worry about the small delicate things that are in the rock back in the lab where we aren't roasting in the sun and getting eaten alive by bugs. The sandstone matrix was fairly hard and difficult to work with, but the jacket split free and flipped very well. 

Mike with the flipped jacket

And what a specimen we think this will be. The entire skeleton looks to be about 3 1/2 feet long, or a little over a meter. From what I could see of the shape of the skull, it looks similar to Stangerochampsa, a croc that we at TPI helped to restore a few years back. Stick with us this year as we get to preparing this jacket hopefully exposing the best example of tiny Hell Creek crocodilian found so far!

Stangerochampsa replica made by Triebold Paleontology Inc.

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

Hell Creek Gar Reproduction Now Available

ValDaGar in initial stages of preparation

Back in the summer of 2012, known as the summer of "Lake Dakota" in the lab due to how much it rained that year keeping us at our soggy campsite, I was lucky enough to discover an articulated gar in the Hell Creek Formation. In the previous decade of Hell Creek fieldwork, I had found hundreds of scales and isolated bones from gar but hadn't given them much thought. 

Hell Creek gar scales

Perhaps it was because of all the rain that year, but late on our first trip out to South Dakota for that season on a low, soft, sandy outcrop I found vertebrae, articulated scales and the outline of a skull just beginning to erode out. I had no idea at the time just how special that discovery would be. It turns out this specimen - RMDRC 12-008 - which I nicknamed "ValDaGar" after my wife giving it a bit of Nordic sounding flair, was the most complete articulated gar fossil out of the entire Mesozoic of North America. 

RMDRC 12-008 ValDaGar as originally found, with beautiful articulated scales

The excavation was pretty straightforward. Our now Executive VP Jacob Jett and I managed to perimeter around the specimen through the soft sand and jacketed the gar all in one day. Unfortunately there were no sizeable outcrops immediately adjacent to the dig to help place us in section, however a butte a short distance away had a Triceratops skeleton eroding out approximately 60 feet above our dig, indicating we were definitely working on a Cretaceous gar, not a later one from the post-asteroid Fort Union Formation. 

Jacob Jett cleaning out the trench before jacketing

I'm not going to lie, I was a bit nervous when it came time to prepare the specimen. The matrix was very soft, which poses quite a few challenges, especially when you're set to work on an animal that is basically a tube sock made of 10,000 scales floating in loose formation in the sand. Since this specimen was extremely rare and scientifically important, I went very slowly.

Initial prep of the skull area in the lab

Much of the initial work was done with just an X-acto knife and chip brushes, slowly working down to the specimen until you feel and hear the "thunk" of the underlying bone or scale. Once the bulk of the matrix was moved off a section, I stabilized it with Paraloid B72 and came back with low pressure air abrasion to finish cleaning the surface. All this was done one section at a time so that the air abrasion wouldn't blow away any adjacent patch of scales that may not have been consolidated yet. 

Skull area after basic consolidation and air abrasion

In the end, prep took me about a solid week. After the specimen was cleaned, we wondered how to replicate this rare (and likely new taxon) gar. Traditional silicone molding techniques were rejected right away due to the danger the demolding process might pose to such a soft and delicate specimen. It would be a shame to rip it apart after all of this work so we turned to technology.

Skeleton after prep, Senior Curator for scale

We were curious how the specimen looked hidden under the surface of scales and sand, and what might be present for the lower jaws that were spun under the skull. For this we took it to a local animal hospital, Powers Pet Emergency in Colorado springs to have it CT scanned in between patients. There were concerns that the metal poles used in stabilizing the field jacket might interfere with the scans however no problems were noted and the images they turned out just fine. 

Image taken of the skull area at Powers Pet Emergency

Luckily though 3d scanning was very much still in its infancy at the time, we at TPI had the equipment and skill to create a very high fidelity surface scan and model of ValDaGar. Turning the digital model into something physical would take a bit more time though, as we thought the resolution of the printers used in making such a large print was insufficient for what we wanted the final product to be. Fast forward about a decade. Luckily for us, technology has caught up enough to allow a high fidelity physical replica to be made. 

Scanning of ValDaGar in our collections area

We were able to print it out, though not all in one piece. That's where I came in, reassembling the parts and getting it ready for our skilled artists to detail and paint up. The detail was fantastic, especially with the diamond plate skin resolution.

With this step finished, we are now able to offer reproductions of this Mesozoic gar for museums across the world. Contact Jacob Jett jacob@rmdrc.com for specifics and to make your order.

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!

Digging the middle half of a Triceratops

We've finished the Triceratops dig that I announced in my last blog post. We got pretty much everything from the rear of the neck to the back of the hips, minus the limbs. It looks like the specimen was well laid out in order, unfortunately with the head end going off the edge of the cliff. Just a couple thousand years too late, but oh well. There was an unconformity at the top of the site that destroyed the higher bones, including shearing the bottom 4/5 of the femur away. Sometimes nature isn't nice to us. Enjoy the pics!

Scary bobcat driving to get rid of overburden

Mike not finding anything, Jacob on the hips

Naptime in the shade while employees roast

Hips isolated

Cap jacket on hips and attempting to recover a whole rib

Big jacket done after a seriously long day

Prep on the main hips block is going slowly, but we hope to have this monster chunk of bone out on display later this week.

Progress on the jacket but still lots to go

Hell Creek: What I found on my summer "vacation"

We've just returned to the lab from a 2 week expedition to the Hell Creek Formation in South Dakota. The weather was very hot, the bugs were out in force, and I had a grand total of one shower during our stint in the wilds. Here's a bit of what we found.

Thescelosaurus claw

Theropod tibia

partial triceratops skull before excavation

Finds were a bit sparse in week one. Lots of hiking and lots of incredibly bare outcrops. Occasionally I founds some Champsosaurus bones or gar scales, but for the most part it was just a bit depressing. Then I made my big "find" of the first half of the trip: a Pachycephalosaurus dome!

Not a pretty dome

but they're so rare

Just when things were starting to look bleak, I found 2 Triceratops sites a few days apart. The first so far is just a pile of ribs (we will expand the dig later to see if more is present) but was in a great location where we could drive the truck to, no overburden, really ideal.

We can always use more parts

The second one, in true Anthony fashion, I found by tracing a bone fragment to the top of a 50-60 foot cliff that had bones sticking out of it. I knocked out a very small excavation the first day and kept running into more bones. Jacob and I returned for a few more very hot (120 degree plus) excavation days and found over 20 bones so far. A few were recovered, and we will return to the site in a few weeks with a bobcat to move some serious dirt and continue the excavation. So far it's mostly really big vertebrae, ribs, and girdle elements, though there is some skull and rooted teeth too. Fingers crossed for a complete-ish specimen!

Looking down from the site. Part of the humerus can be seen poking out

Looks like quite a climb up to the site

Dorsal vertebra awaiting excavation

Giant Oviraptor Tracks from the Hell Creek

It's been known for years that there are oviraptor-like dinosaurs found in the Hell Creek Formation. We find isolated elements mostly. A pubis here, a claw there. Small snapshots into their world, but they don't answer deeper questions like how big they got, how they moved, where they lived (instead of just where their remains ended up).

Skeleton of the new Hell Creek Ovi

In 1997 Mike Triebold was scouting on private land in Harding County, SD for dinosaurs. He came across a strange looking concretion. It looked a bit like a footprint, but as we know, concretions can take on all kinds of shapes. Looking closer, there was another concretion, in the same shape nearby. Then another and another, all in a line. A small excavation was started into the nearby outcrop, and the line of concretions continued. Though the overburden was getting too deep to chase them futher, it is likely there are even more still at the site. Mike recovered the specimens and made them available for research, which will be published on shortly.

Tracks in situ. The largest are nearly 60cm (2ft) across

Excavation of tracks

The concretions have now been identified as a preserved as the trackway of a giant North American oviraptorid, much larger than the specimens that we have skeletal remains for. The trackway shows how fast the animal was moving and even what kind of muck it was trudging through. We made molds and casts of the best ones, I'm thinking it may be a great addition to our ovi display in the exhibit hall.

Atractosteus from the Hell Creek

I feel a bit guilty. I found a gar specimen last year, in a soft sand, and I was afraid to prepare it. I had nightmares of thousands of bony scales floating loose in space. Well this week I finally took the plunge and started work. I've even been able to identify it to genus (I think). Let's start at the beginning.

June, 2012:

Hey look, a fossil! Toes for scale.

While prospecting in far western Harding County, SD for typical latest Cretaceous dinosaur fauna, Jacob and I climb a really high butte to GPS a Triceratops and see if it's on our landowner's property. No luck, it's a few dozen yards too far south. From up high we see a few very small low outcrops on our landowner's side of the fence that probably should be checked out. Jacob heads towards the pond, I trudge up to a sand blowout about 5 feet high at the most.

Scales in the field

The gar was just laying there in the flats. The scales caught my eye first, then I noticed the vertebrae, and the faint outline of a skull just barely coming to the surface.

Finishing the perimeter and consolidating

We treated the specimen like ones we dig up in Kansas: no need to expose any more, just find the perimeter. If you hit bone (or scales) just move on in a wider circle. The sand was so soft that we did all the work with mason's trowels. In about an hour or so, the site was perimetered.

Jacket's done!

I was fearful that no matter how good of a jacket we made, the thing in the loose sand would collapse out of it as we flipped the jacket, so I made the call to saturate the topside of the block with B-72 to harden it at least a bit. The hydrocal jacket was then applied directly to the rock, no separator being used. By lunchtime we had the jacket under control. Back in the lab, it sat under a workbench for over a year.

October 2013:
The specimen, now known as RMDRC 12-008, alternatively "ValDaGar" after my wife (plus it's really fun to shout), is brought out of storage. I figure it would be good to at least get the skull exposed, if it's there, before SVP. It'd suck to show up a second year in a row and tell researchers "no, we still haven't worked on it yet". After removing a few inches of sand (we dug deep JUST IN CASE) I finally hit something hard. Luckily it was bone, not the other side of the plaster jacket.

Here's where to start

Ok, I admit, it doesn't look pretty

Exposing the skull took surprisingly little time. I moved a bit further back to see if there was indeed articulated body. There was indeed. Every one of the hundreds of scales is getting prepared individually. I'll let the photos speak for themselves

Much better

The body slowly gets exposed

Side of face floated off a bit