Wednesday, July 5, 2017

Digging a tyrannobutt

We're back from Montana waiting for the temperatures and fire danger to die down for a bit. Earlier this month though we were battling the gnats working on excavating a dinosaur I found late last summer.

Can you spot the site?

The site is pretty typical for how I find them: about halfway up a 30 foot cliff with a menacing hoodoo overhanging the specimen. I found this site about 2 days before we broke camp last year so I was only able to do the smallest of evaluation digs on it.
Bones on either side of an erosional notch: usually a good sign

 Using air tools I was able to notch out a few of the bones. These were clearly large theropod bones, one looked like a caudal vertebra and I couldn't tell what the one shooting straight into the cliff was. Big theropod in the Judith River formation means one thing: Tyrannosaur! I knew I'd be coming back for this site in 2017.
Duckbills. It had to be duckbills
Additionally at this site was a big wad of predepositionally broken ornithischian (most likely duckbill) bones under the tyrannosaur material. This gave the impression of a stream or oxbow lake bottom assemblage, but sometimes you find good skeletons mixed in with all this material. Unfortunately with fall closing in, I had to abandon the site till 2017.
Storms are no fun in vehicles that lack roofs and windshields
This year however we came out with our big jackhammer and managed to notch out a decent sized evaluation pit. I wanted to get a better feeling for what was present before I suggested getting a bulldozer out there to knock down the whole cliff.

The isolated tyrannobutt
Turns out, it appears it was just an isolated tyrannosaur sacrum with one dorsal vertebra still attached. Not pretty now, but once I prepare it we will see better the shape of the specimen. I'm thinking Albertosaurus, but it's hard to say from this element.
Closeup of the spines. Bonus duckbill chevron at top left

It's a bit of a bummer that there wasn't more of this skeleton. It was going in towards the head but it was just not meant to be. I'm happy to find this now before we invested time and resources removing 15 feet of really tough sandstone from the area though. Guess I'll just have to spend the rest of my summer looking for more dinosaurs. It's a tough job but somebody's got to do it!

Wednesday, May 3, 2017

First Kansas Trip in the Bag - 2017

For the first time in a few years, we've been able to hit the Niobrara outcrops in the spring! Holy crap was it cold. The last day out, I don't think it got above 50 degrees, not that the 40mph winds would make it feel any warmer. Perfectly miserable. And just like clockwork, on our last day, as the sun was setting behind a large row of thunderstorms on the horizon, we found the best skeleton of the trip! The rest of the time was staring at blank ground finding fossil poop.

Look at this swirly poop!
I entertained myself by finding a "nice" Xiphactinus tail. I was instructing a new hire on how to actually find fossils in pretty bleak badlands when I saw just a small fragment of tail fin coming out of the rock. I'm happy I found this one as since we have SO MANY Xiphactinus specimens in storage, we've implemented a "one in, one out" policy on these fish and I've somewhat jokingly insinuated firing anyone that finds another of these darn fish. Our newbies were safe.
Well, there's a fish tail

Jesse using a chainsaw to trench around the fossil
When you find weathered out fish tail chunks, you have to chase them in (even if they're "just" a Xiphactinus). Sometimes the rest of the tail is there. Sometimes there's the rest of a 15 foot long fish attached to it. Sometimes it just ends. In this case, we found a perfect lower lobe of the fin, but no body. As far as we were from the truck, I'm happy we didn't have to make a huge jacket, since those are heavy and I'm getting lazy in my old age.
Trenching complete, curatorial boot for scale

Jacketing complete and ready to flip, other curatorial boot for scale
Popping it out and prepping it was also quick. Measuring the vertebrae we found it's the exact same size to complete another Xiphactinus specimen we excavated 3 years ago (which just happened to be missing the tail). This will help us out tremendously when we panel mount the animal in the near future.
Not too shabby!
Other stuff was less plentiful on this first trip, but we were lucky enough to find parts of 3 sea turtles, which is always really nice.
Jesse and grace entrusted with power tools to get to a turtle
And of course at the very last minute, Jesse stumbled on a pretty complete Clidastes skull in an outcrop near where we discovered our gigantic 17 foot Xiphactinus specimen 20 years ago. We worked very hard to excavate the specimen with daylight fading and weather bearing down on us.
Jesse and grace getting Clidastes block ready for jacketing
The specimen was safely loaded in the truck by headlight, which also made for a really interesting drive through farm fields in the dark at the end of a 14 hour day. Prep is going on right now, so stay tuned to see how this cute little mosasaur turns out!





Friday, January 13, 2017

The Accidental Ichthyornis

Field identifications are problematic.

In mid October of this year the weather in Kansas was still warm enough to extend our dig season. That trip was pretty successful, finding a back half of a Protosphyraena and several small fish. Early on, Mike even thought he found another Pteranodon leg.
The drive to the site is a lot tougher when you can't see landmarks

We came out early in the morning. Man was it foggy. The entire day was supposed to be dedicated to finishing up excavation at several small sites. Since the "Pteranodon leg" site was so small, Mike and Jacob spearheaded the excavation there, while I wandered off to collect a Cimolichthys head and isolated Ichthyodectes site.
Several bones coming out at the site as discovered. Definitely not fish.

The "Pteranodon leg" showed some promising chunks of bone coming out, however inspection as they got down to the bone layer showed not a whole lot was there. Not like the large bones we were hoping to find for a Pterosaur.
That's a big hole for such a little block

Not a huge worry though, we perimeter the sites and very rarely expose the bone in the field, we will just find out what the "Pteranodon leg" looks like when we get back to the lab.
Jacob jackets and despairs as I tell him we have to go dig up another fish

Looking back at the video, just as Jacob began jacketing the specimen, I show up back at the site proudly announcing the discovery of the "Nia" Xiphactinus site that I blogged about last time. We all decided to drive over to the big fish and start work as the jacket cured. We were so stoked about the big fish that it was about a month later when we finally asked ourselves "Hey! Where did that jacket go?"

Turns out, we left it sitting there in the field, right next to a regularly visited oil well. Whoops! Over Christmas, Mike returned to the site to see if someone had poached it. Nope, the jacket was still exactly where we had left it. I guess you can say we got dang lucky. Let's never do that again.

Mike pulled it out and brought it back to the lab, where it sat for a week as I let it dry out (dry chalk behaves better than wet stuff when prepping, especially with small fossils). That's when the Eureka Moment happened: prepping down on the "Pteranodon leg" things weren't looking right. I immediately switched to my microscope, pin vise and very low pressure air abrasion (about 3psi with sodium bicarbonate blast media). My suspicions on the specimen's identity were confirmed when I found teeth. Pteranodon doesn't have teeth, but there's one small thing in the chalk with reptile-textured bone that does have it: a bird! Not only was it a bird, but the only complete articulated skull of Ichthyornis, who had been found only in fairly incomplete form since Marsh's days in the 1870s. This accidental and overlooked jacket suddenly turned into one of the rarest finds in the entire 160 year history of fossil hunting in the Niobrara.

Bird teeth, just a few milimeters long

Stay tuned for project updates as we work on this spectacular fossil.