Monday, December 28, 2020

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

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.

Friday, May 10, 2019

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.

Thursday, February 14, 2019

Project Kevin Part 1: Field and Lab Work

The astute social media observers among you may have noticed our new ceratopsian whose skull restoration was just finished in time for its debut at Tucson. Here's how we got it there in 2 parts. Today: the hot and nasty work.
Yep, that's hot
The site was originally discovered in the summer of 2017 by one of our landowners, rancher buddies and all around good guy Larry in the upper Judith River Formation of central Montana. We located a partial humerus, a lot of ribs and several vertebrae exposed on the erosional surface right away. The entire deposit was constricted to about 15cm (6 inches) of highly concreted sandstone, and from the exposed highly eroded elements we could tell it was from an ornithischian of some flavor. Odds were it was probably an incomplete scattered duckbill in fairly difficult to work matrix, so we decided to keep scouting and come back later.
The site is very remote but also gorgeous
That later turned out to be the summer of 2018. It was hot. Really hot. Continued scouting in that area turned up some pretty neat lag deposits but not a whole lot of good skeletal material. It was time to bite the bullet and see what the old duckbill site was going to give us. Who knows, there might be a skull in there.
Digging begins. We love our shade tents.

Sometimes we get visitors to the site

With 4 people digging we made some good progress on the first day of the dig. Around lunchtime I had moseyed on up to the top of a nearby bluff to get cell signal to call home to the boss and give him an update on how we weren't finding anything great out there and might relocate our scouting locality to somewhere closer to camp. Coming back to the site I ran into Jacob who was looking for me to let me know we had "the weirdest duckbill he's ever seen" in the quarry.
That ain't no duckbill horn.
Grace had found a brow horn.
Lainie demonstrates proper air hammer technique.
So, not a duckbill (though to be fair we did find some scattered hadrosaur material at the site). We dug more that week finding much more skull material, but had to come home for resupply and other projects. We got smart during trip #2 and brought out some diesel powered earth moving equipment as the overburden went from practically zero to nearly 3 meters very quickly. Again more skull material was found. There was some postcrania too but we all know that ceratopsian postcrania is pretty much worthless, right?
Bobcat good, getting hit by 2 dust devils in a row bad for shade tents
After the 3rd trip, the bone was very sparse along all edges of the excavation and we were pretty confident to call the dig finished.
Headed home with a load of jackets. Rock Chalk!
Lab work began right away. There were a few tricky bits getting the nasty concretion off the bones but for the most part they came out looking pretty good. Once cleaned up we got a much better idea of what parts of the skull we had (field identifications are always tentative). It also became pretty obvious the skeleton was trampled by other very inconsiderate dinosaurs way back in the cretaceous, as we had many broken bones with no parts to go back with them.
Right brow horn, missing some parts, but we can fix that.
Bone quality was pretty good and we ended up with most of the skull, quite a bit of the neck, some dorsal vertebrae and ribs, and curiously a random chunk of pubis.
Detail of jugal edge. Beautiful bone texture.
Stay tuned for the next installment where we show how we went from a pile of bones to a completed skull restoration in 100 easy steps!

Monday, December 3, 2018

Pete III Final Update: In Its Forever Home

This post has been a long time coming. A little over 13 years from when we first dug a hole in the ground for a toe fragment in Central Montana, our giant Daspletosaurus sp. "Pete III" is now on permanent display at the Cincinnati Museum Center! A photo of Pete's metatarsal was prominently featured in my first blog post here way back in 2010. We put over a decade into excavating, preparing, scanning, molding, casting and assembling this specimen (click these links to go directly to the older content). I'm happy that it's finally done, but I'm kinda sad to see it go all the same.

The original hole in the ground, field season 2005
The first ugly toe. It got better.
You can search all those old posts on the blog for progress, but now I'd like to share with you the finished product! We mounted all of the original bones (minus the skull, those bones are still loose and in the collections in Cincinnati) on an external steel armature with removable brackets so that anything that needs to be taken off of display for research can easily be done. Daspletosaurus is much more rare than "boring old" Tyrannosaurus rex so the research value of this specimen should be high.

Copies of this ungual can be purchased at
The mount itself is a fairly conservative pose, not really running, not really mouth-wide-open. Viewed from near the Allosaurus, it seems to tower over the city skyline (hold the Chili). The restored art deco hall that Pete III now calls home is an exhibit itself and was very well done.
I really like this shot

We tried to make the supporting steel as visually unobtrusive as possible while still being substantial enough to do its job of holding up hundreds of pounds of real bone (and quite a bit of super glue). There might just be as much steel by weight as original bone in this mount, but it really doesn't feel like it.
Every bone gets its own personal mounting steel support

We're really happy how this mount turned out and now all you tyrannosaur researchers out there know who to talk to about planning a visit and publishing. No more excuse to pretend it doesn't exist anymore! And if you notice, things look "unfinished" in the photographs. This is because I helped install it back in August, so if you have better pictures of the display from your next visit I'd love to see them! Here's to thousands and thousands of visitors liking this specimen just as much as we do!
The finished mount, curator for scale

An even better photo without the curator

Pete's huge (as far as tyrannosaurs go) arm

Wednesday, August 15, 2018

Bigfoot from Wyoming: The largest dinosaur foot found yet

Hey! I published on something, 18 years after I started the paper.

The awesome scientific article is here on PeerJ's website, open access for anyone to read and download. As far as I can tell, it's gotten almost 8000 reads so far, so not too shabby! I also did a companion blog post for them where you can read all kinds of information on why exactly it took 20 years from discovery to publication. Short version of the story: I got a job and it wasn't a huge priority to me.
KUVP 129716 "Annabelle". Bigfoot was found under the tail.

As someone that has to self-fund all my research projects, publication costs are a real issue. I wanted to go open-access as I think making another company richer by giving them the fruits of my labor (on a public specimen) is kinda wrong, but there are some expenses in order to publish it properly. I simply don't have the free cash to do that.
More brachiosaur material from the site, me for scale.

Then came February. I had already assembled a small team of experts to finally move the project along, as I was getting tired of constipating science. Emanuel Tschopp and Femke Holwerda were Team Europe, and David Burnham and Myself were Team Kansas. We had no idea where we would publish but we had already begun preparing measurements and basic text. PeerJ surprisingly had a special promotion for their 5th anniversary offering to waive publication costs for articles submitted during that month. That was an offer too hard to pass up, but could we do it?
Archaeopteryx gawks at the metatarsals

The writing crew huddled over Google Hangouts and assembled a pretty decent draft in just 2 weeks (!!!) complete with figures for submission. Femke referred to it as "Rambo Writing" and I don't think it's too far off the mark as a description. We submitted it and waited.
Making the model of the MT IV

In a few weeks we heard back: Accepted with minor revisions. Minor except we had to refigure all of the original bones. So off I went to Kansas with Triebold Paleontology Inc's Artec Spider scanner and 3D render rig. Not included in the paper (but existing) are complete 3D models of every bone on this foot. Contact KUVP if you need access for research, I think they came out pretty well.
Completed model of MT II

After that, things went pretty well! We resubmitted and it was just a very short time between then and it coming out to the world. Press was also pretty kind (though they kept referring to me as "Dr." and thought it was a footprint instead of an actual foot). Heck, I made it into Newsweek! Pretty wild.

In the news(week)!
Why didn't we say it's definitely from Brachiosaurus? Simple: No Morrison Formation Brachiosaurus specimen has ever had any pes material recovered with it, so we didn't have any overlapping elements to compare with. Could it be Brachiosaurus? Sure, even probably, but we simply don't have that smoking gun just yet.

Wednesday, January 24, 2018

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!