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!