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

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.

What's the Bag Limit on Xiphactinus?

October has a lot of opportunities for hunting big game such as deer and elk. Some people use muzzleloader firearms or bows and arrows. I prefer to use my trusty walking shovel, Winona.

Fishing for the biggest toothiest one out there

This October I led a small field crew out to the Niobrara Chalk of Western Kansas, squeezing a week of scouting in between seminars and the Society of Vertebrate Paleontology meeting in Minneapolis. Due to injury, this was my first time out on the rocks since August. The Kansas chalk is full of some amazing fossils like Pteranodon, Tylosaurus, and my personal favorite, Martinichthys. It also has Xiphactinus.

Finding a piece of Bonnerichthys while wearing a Bonnerichthys shirt

By Wednesday morning of the trip, we had found a few cool specimens like a pathological tail fin from an ichthyodectid fish, but nothing large or truly impressive. As my crew packed up some of their gear at the truck, I struck out for a distant outcrop that I could see the distinctive Marker Unit 5 layer (home to Martinichthys). Less than half of the way there, I looked down and froze.

Fish face as found, curatorial hand for scale

Eroding out of the small exposure of chalk is the perfectly articulated face and pectoral fin of a moderate sized Xiphactinus. The amazing thing is the up side of the fossil was all still articulated. Usually when the animal decays on the seafloor, the top side gets stirred around a bit by scavengers. The bottom part, pressed into the seafloor ooze, is usually even better.

Evan and Jordan opening the site to see what's there

Before touching it I grabbed the team. They were from our 3D department and were getting some well deserved away-from-screen time. This past year I worked with them on so many excellent dinosaur, mosasaur and crocodilian reconstructions that some fresh air and exercise seemed like a great respite. And what better way to get fresh air and exercise than with digging up a giant fish? I told them I found another Xiphactinus and they only groaned a little. When they got to the untouched site, I think they got a little excited. It's not every day you have the chance to work on a beautiful fossil like this one.

Undercutting process begins

When you're big and dead and bloated floating at the surface of the Western Interior Seaway, you make a really nice meal for all kinds of predators in the late Cretaceous. After a little excavation (the site had maybe 3 inches of overburden on it), we determined that all that remained of this fish was the disembodied head, fins, and a few vertebrae. The rest of the fish was long ago consumed by some lucky shark I think. That made our jacketing job so much easier, as this was originally a 12 foot long fish.

The jacket is finished!

I was very nervous about the flip of this large jacket in very loose and friable chalk. I broke out every trick I could think of to ensure success but the lift and flip was extremely stressful. Luckily, 27 years of experience paid off and the flip went perfectly! We lightened the jacket by removing a little of the extra chalk, then loaded it into the back of the field truck to bring back to Colorado. The naming scheme this year is due to a song I had stuck in my head, so they all flow from a stream of consciousness rant during the song "A Shogun Named Marcus" by the band Clutch. This being the 4th good fish I found this year, it gets the name "Spitfire", which I think suits it just fine.

I managed to get 2.5 out of the 3 of us in this shot. Successful flip!

All in all, it was a very successful expedition to the Niobrara. No pterosaurs or giant lizards, but a big fish head and another specimen worthy of publication is still a good haul. Stay tuned for more updates as we get to preparing Spitfire's fish face back in the lab. 

Walhalla's Sea Snake: Welcome Jormungandr!

Believe it or not, I don't spend all of my time in the field (though it still does tend to be A LOT). In the winter and spring I have time to work on some fossils we find during the year, as well as work on projects for other museums. This past spring, Dr. Clint Boyd approached us about restoring a brand new mosasaur that he and a crew were describing from northeastern North Dakota. He called the critter "Eustace", nicknamed after the BEST character from the Cartoon Network classic "Courage the Cowardly Dog".

Eustace is famous for various disagreements

The specimen was found in the Pembina member of the Pierre Shale and an underlying bentonite was dated to 80 million years old. This is pretty similar in age to our "Walker" Mosasaurus specimen that we excavated from Western Kansas in 2015. I suspected we were in for a very fun project, and something that we at TPI are very capable of doing well.

Walker's reconstructed skeleton

The first step was getting the scan files of the specimen sent over and opened up in the computer. The specimen was fairly complete but missing a few bones. Evan Sonnenberg and I teamed up to reassemble the parts, and remove some of the distortion to make the individual elements fit back together like before they were crushed by 80 million years of rock and geologic processes. Some elements were completed using mirror images of bones from the opposite side of the skull in order to keep Eustace as Eustace as possible. 

Eustace's skull (right) and after restoration (left)

Once that part was completed, we used mosasaur specimens from our digital bone bank to come up with plausible shapes for the bones that were completely missing. When working on the parietal/braincase, lead author Amelia Zietlow kept urging us to make it more Clidastes-ey in overall appearance. And indeed, the paper that came out today does make a case for the new mosasaur being very closely related to Clidastes. Amelia and crew decided to name the specimen Jormungander walhallensis, which is a pretty clever name. The species name indicated it came from near Walhalla, ND, while the genus name plays off of the Norse mythology of the place name, with the name shared with the legendary snake that ends the world in the sagas. 

Once all the parts were there, we printed out two copies of the skull at full size so that they could go on display in museums in North Dakota. While not a huge mosasaur like the Bunker Tylosaurus, the skulls still had to be printed in pieces that were later assembled.

Parts for the top of the skull

Top of skull assembled

Easy enough! Lastly the specimens needed to be painted mounted. There's an external steel armature under the skull and each lower jaw on the copies so that the parts can be removed for closer inspection. One Easter egg that we included in the mount was that each base is a silhouette of Eustace's skull as seen from above. BTW the mini skulls were sent to the authors so they could evaluate it while finishing the manuscript.

The two reproductions were sent to North Dakota this June. One is on display at the Walhalla Library, which is nice having it on display so close to where the original specimen was discovered. The second is due to go on display at the Pembina State Museum in the near future.

Come find and prepare fossils for TPI

We are hiring a preparator to help me and our crew in the lab and the field!

Preparator and Field Collector

Triebold Paleontology Inc. is searching for a dependable full time preparator and field

collections technician to join our team. The position will be based out of the

Rocky Mountain Dinosaur Resource Center in Woodland Park, Colorado (15 miles west

of Colorado Springs). Field localities require up to 2 weeks at a time of field/travel time and

are located in Kansas, Montana and South Dakota. Our specimens primarily focus on marine

and terrestrial late Cretaceous animals. Compensation depends on experience, qualifications

and skills.

Required qualifications:

Excellent written and verbal communication skills, organizational skills and attention to detail

Basic anatomical knowledge of tetrapods

Use and maintenance of a variety of air scribes, glues, consolidants, and hand tools for

preparation and collection

Valid Colorado driver's license or the ability to procure one

Knowledge and experience of current best practices and techniques in collection and

documentation of fossil specimens

Ability to safely conduct field work for extended periods of time in remote or primitive locations

Ability to lift and carry heavy (at least 50 pound) objects, equipment and supplies.

Preferred qualifications:

Knowledge of operation and maintenance of COMCO brand (Microblaster and Accuflo) air

abrasion units

Molding and casting experience

2D and 3D digitization experience

Experience using heavier equipment in field work (jackhammers, Bobcat, mini excavators)

Experience constructing well-made archival jackets and housings

This position is intended to be full time, permanent, with the candidate beginning work at our

Colorado facility as soon as feasible. If you are interested in applying for this position please

provide the following 3 items via email to Anthony Maltese at anthony@rmdrc.com .

No phone calls please.

At this time candidates from outside the US or that lack permission to work in the US

cannot be considered.

1: Cover letter briefly describing your qualifications, experience and interest

2: Resume or CV with 3 professional references

3: A brief portfolio document (PDF or similar format) visually showing past projects that

demonstrate experience and quality of work.

Compensation:

Starting at $13-16/hr plus overtime when needed

retirement plan after 2 years

paid vacation after first year

Per diem for days spent away from home in field

The deadline for applications is April 21

Ashley: The cannibal Xiphactinus

 If you're following me on the twitters I'm sure you all know about my absolute and undying love for the giant ugly predatory fish from Kansas, Xiphactinus audax. We spend a lot of time in normal years in Kansas during the spring and fall (when the weather and bugs aren't too miserable) and we tend to find a good number of at least partial skeletons, some exceeding 18 feet in length.

Random Xiphactinus verts in the wild

It's easy to think of them as just another boring fossil, as if they were the hadrosaurs of the ocean, but every once in a while something about them makes them interesting.Sometimes because they are found inside something interesting, other times because something interesting is found in them.

Xiphactinus as stomach contents of a large shark, Cretoxyrhina
Photo taken at University of Kansas Natural History Museum

Xiphactinus is well know for its gluttony. The famous "Fish Within a Fish" at the Sternberg Museum of Natural History, where a 13 foot long Xiphactinus semi-successfully ingested a nearly 6 foot long Gillicus is a prime example of this. I claim it to be semi-successful as the Gillicus is completely articulated and not digested, indicating that trying to swallow this meal likely killed the Xiphactinus. Other times smaller remains of a fishy meal in the body cavity of a Xiphactinus are found, we see this in a little less than half of our specimens.

Photo courtesy of Mike Everhart www.oceansofkansas.com

Fast forward to the spring of 2018. I was scouting the lower Niobrara Chalk in Gove County, Kansas. The chalk is defined stratigraphically by 23 distinctive easily traced (usually) bentonite layers laid out by Hattin in his 1982 work. These outcrops were around Hattin's Marker Unit 6, so the upper limit of where I could possibly find my dream fish , an articulated specimen of the ram-snouted Martinichthys ziphoides. No luck on that front however I did find this fine pile of bone eroding out, seemingly face-first. A small pile of bones is always a good sign!

The bones are the kinda grey things on the yellow chalk

Unfortunately it looked like it was headed into the base of a big cliff. After initial evaluation, we decided to GPS and cover up the site to protect it until we could come back at a later date. That date came the next spring.After a long morning of removing overbruden, we were relieved to see the fish had actually folded in half back on itself about 4 feet from the erosional edge and the balk half pointed back out that direction. We didn't have a tail fin, but we also didn't have to move a mountain of rock chasing this Xiphactinus either. I gave it the nickname "Ashley" after one of my trivia teammates (remember when we could go to bars and do that? Wear a mask and maybe we can soon).

Can you see the digsite?

One of the strange things we noticed while exposing the bones in the field was a large bulky bone near the belly. It looked like a cliethrum, one of the bones that the pectoral fin hangs off of. The skeleton itself was mildly disarticulated in parts, and any Xiphactinus will have 2 of them, so maybe this was just a bit of Ashley that was pulled off the carcass when scavengers like the shark Squalicorax came to strip off all the flesh.

Typical Kansas fish dig

Preparation showed the skeleton was in much better condition than we had imagines, with decent articulation and a beautiful pelvic fin. It also showed both cliethra that were supposed to be present on a Xiphactinus wee in fact there in place. So what does that mean with our now THIRD cliethrum?

2 very nice looking jackets all cleaned up

One way to be sure is to prepare it as well. Free from all of its matrix two things were readily apparent: One: the acid-etched texture of the surface of the bone meaning it was stomach contents and Two: based on the shape, it also belonged to Xiphactinus.

The smoking gun, so to speak. Acid-etched Xiphactinus cliethrum

With that shocking knowledge in hand with al of the bad things Xiphactinus could be (common, boring ugly, a lot of work to dig up and prepare) we can also add cannibalism to that ever growing list.

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.