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.

Stangerochampsa: Weird Hell Creek Croc

Last thanksgiving when I was in Illinois visiting family, I got to take a day to visit the Burpee Museum in Rockford, IL. While there I got to pick up molds and original bones from one of their discoveries from the Hell Creek Formation of eastern Montana. Ernie is a small alligatoroid, apparently related to the much more common Brachychampsa. I never seem to be able to complete any vacation without becoming some sot of fossil transporter, however it gives me a chance to see a lot of new places along the way.

In any case, we've spent the past few months working on the specimen. It was pretty complete as far as Hell Creek crocs go (which isn't saying much, though if you saw the poster on the specimen at SVP last year, you have a pretty good idea) but it needed some parts badly.

Skull bones getting molded

The first thing we did was remold the individual skull bones and any other originals. Using the molds provided by Burpee we poured casts of the postcranial elements as well. In the end we had a nice skull and less than half of a body. How do we improve on that?

Donor gator, tail skilfully removed for shipping

Donor gator of course! Dr. Ray Wilhite from Auburn University was able to get us a 49 inch long frozen Alligator mississippiensis. It was a great day in the lab when the package arrived, not even oozing at all! Jacob and I did a dissection on it to see how things move on recent animals, then stripped most of the muscles and skin off of it before sending it to the dermestid beetle colony for final cleaning. The skin, especially the osteoderms were a lot more difficult to remove than we had originally planned.

Processing through, those jaw muscles give me nightmares

While the beetles were chewing away at the smelliest part of the gator, Jacob restored the missing bits of the casts of the original material. Missing neural spines and transverse processes were sculpted. When we got the modern bones back, they were disassembled and molded. Where possible we incorporated any part of Ernie into the restored bones.

Ernie's coming for you!

I especially like the shadow

Once remolded, assembly was pretty straightforward. The prototype was completed this week and will be headed back to Rockford for display in the upcoming brand new "Homer's Odyssey" exhibit in a very shortly!

Termonaris: Now with skull... sorta

Assembly of the body of the first cast is done! Just detailing and the skull to go. Today we decided to see what it looks like with the skull on the body. Let's just say we were a bit surprised with the size of the animal that resulted. Here April and Todd do the honors!

Terminonaris restoration project

For the past month or so we've been working hard on restoring a specimen of the extinct crocodilian Terminonaris, in collaboration with the Royal Saskatchewan Museum (RSM) in Regina. We were supplied molds of the original slightly crushed specimen, which provide the basis for our restoration. It's been a long but fun process. As of today, restoration and molding of all postcranial elements have been completed. Casts are nearly finished being poured and trimmed... now for the good part - a sneak peek.

We've moved on to the exciting assembly portion of the project. Cast #1 is intended for a travelling exhibit and is being built to the exact specifications provided by the RSM. The animal is pretty dang big, at over 18 feet long. As you can see, the dorsal, sacral and caudal vertebrae are finished, the ribs and pelvis are hung and the chevrons are being attached. Nearly 100 individual elements so far! I'll be updating our progress as the projects progress. Stay tuned.