Tuesday, December 17, 2013

Giant Oviraptor Tracks from the Hell Creek

It's been known for years that there are oviraptor-like dinosaurs found in the Hell Creek Formation. We find isolated elements mostly. A pubis here, a claw there. Small snapshots into their world, but they don't answer deeper questions like how big they got, how they moved, where they lived (instead of just where their remains ended up).
Skeleton of the new Hell Creek Ovi

In 1997 Mike Triebold was scouting on private land in Harding County, SD for dinosaurs. He came across a strange looking concretion. It looked a bit like a footprint, but as we know, concretions can take on all kinds of shapes. Looking closer, there was another concretion, in the same shape nearby. Then another and another, all in a line. A small excavation was started into the nearby outcrop, and the line of concretions continued. Though the overburden was getting too deep to chase them futher, it is likely there are even more still at the site. Mike recovered the specimens and made them available for research, which will be published on shortly.

Tracks in situ. The largest are nearly 60cm (2ft) across
Excavation of tracks
The concretions have now been identified as a preserved as the trackway of a giant North American oviraptorid, much larger than the specimens that we have skeletal remains for. The trackway shows how fast the animal was moving and even what kind of muck it was trudging through. We made molds and casts of the best ones, I'm thinking it may be a great addition to our ovi display in the exhibit hall.

Thursday, November 14, 2013

3d scanner and printer up and running

After several years of fighting with technology, our 3d laser scanning program is up and running here at the RMDRC. We're currently scanning original specimens that are in the restoration queue in order to generate mirror image parts for missing bones. We started with simple parts on the Avaceratops including cranial and limb material, and progressed to more complicated things like the dentary and maxilla. Not satisfied with the amount of punishment we dished out on ourselves, we then tried Enchodus bits like the super thin premaxilla and operculum. They all turned out extremely well.

One of our new printers which works surprisingly well
Now that we have more complete sets of replicas to work with, our restoration of these specimens will be not only much more accurate but also faster.

Avaceratops lower jaw, with white 3d prints of actual material

Avaceratops tibia, split in a computer so it could fit in the printer
Next on the docket is some of the cranial material of our Daspletosaurus specimens. Donor parts from other animals will be brought in and scaled to size. Surprisingly easy to do with the software and operators we now have here. If you are out there and need some items scanned, give us a call!

Thursday, October 10, 2013

Atractosteus from the Hell Creek

I feel a bit guilty. I found a gar specimen last year, in a soft sand, and I was afraid to prepare it. I had nightmares of thousands of bony scales floating loose in space. Well this week I finally took the plunge and started work. I've even been able to identify it to genus (I think). Let's start at the beginning.

June, 2012:
Hey look, a fossil! Toes for scale.
While prospecting in far western Harding County, SD for typical latest Cretaceous dinosaur fauna, Jacob and I climb a really high butte to GPS a Triceratops and see if it's on our landowner's property. No luck, it's a few dozen yards too far south. From up high we see a few very small low outcrops on our landowner's side of the fence that probably should be checked out. Jacob heads towards the pond, I trudge up to a sand blowout about 5 feet high at the most.
Scales in the field

The gar was just laying there in the flats. The scales caught my eye first, then I noticed the vertebrae, and the faint outline of a skull just barely coming to the surface.

Finishing the perimeter and consolidating
We treated the specimen like ones we dig up in Kansas: no need to expose any more, just find the perimeter. If you hit bone (or scales) just move on in a wider circle. The sand was so soft that we did all the work with mason's trowels. In about an hour or so, the site was perimetered.

Jacket's done!
I was fearful that no matter how good of a jacket we made, the thing in the loose sand would collapse out of it as we flipped the jacket, so I made the call to saturate the topside of the block with B-72 to harden it at least a bit. The hydrocal jacket was then applied directly to the rock, no separator being used. By lunchtime we had the jacket under control. Back in the lab, it sat under a workbench for over a year.

October 2013:
The specimen, now known as RMDRC 12-008, alternatively "ValDaGar" after my wife (plus it's really fun to shout), is brought out of storage. I figure it would be good to at least get the skull exposed, if it's there, before SVP. It'd suck to show up a second year in a row and tell researchers "no, we still haven't worked on it yet". After removing a few inches of sand (we dug deep JUST IN CASE) I finally hit something hard. Luckily it was bone, not the other side of the plaster jacket.

Here's where to start

Ok, I admit, it doesn't look pretty
Exposing the skull took surprisingly little time. I moved a bit further back to see if there was indeed articulated body. There was indeed. Every one of the hundreds of scales is getting prepared individually. I'll let the photos speak for themselves
Much better

The body slowly gets exposed

Side of face floated off a bit

Tuesday, September 24, 2013

Prepping the Avaceratops

It's long overdue for an update, and since the weather in Montana isn't cooperating with our plans to head up there today and finish our season in the Judith River, it's as good a time as any to show what we've gotten done in the lab.

Newer modification to Scott Hartman's illustration: now with no nose horn
Work is slow due to the fact that the bone of this juvenile animal is fairly soft and crumbly when not consolidated, and that many bones are jackstrawed together in larger blocks. Each bone is individually removed from its jacket and checked against the field inventory. When it's a new bone, not exposed in the field excavation, we give it a separate accession number to keep track of it in the lab.

Jacket disassembly with documentation

Typical multi bone jacket before removal
We're primarily using air scribes on the "firm" sanstone matrix, with air abrasion for the detailed work. In some cases, such as the extensive skin impressions over the left hip and rib area, we skip the abrasion in order to preserve the skin as best we can.

Skin texture preserved on the right ilium
Once out of the rock, we restore the cracks and missing bits with epoxy putty in order to get the bones ready for molding. Our current plan, due to the completeness of the skull and skeleton, is to mold everything and do a full skeletal restoration. The animal looks like it will be less than 1.5m tall at the hips - very manageable for a ceratopsian.
Molding jaw parts prior to laser scanning

Wednesday, August 28, 2013

Avaceratops now has skin!

Very large lambeosaur tibia on the east edge of the site

We've been so busy working the Avaceratops site in central Montana that I've hardly had a chance to think of this blog let alone update it. Luckily, that means we've found a lot of stuff, including most of the skeleton of this very rare animal.

Measuring a jacket before putting plaster over it
The site, which started out as a small hand dug pit at the bottom of a wash, ended up as a hole the size of a decent basement. Bobcat excavators, jackhammers and air tools (complete with 2 compressors running)made for a noisy and gritty dig site, but the work paid off.

That's a sizable hole

Using the bobcat to haul out heavy things

Prep is now starting in the lab with the ultimate goal of making a complete restored cast skeleton. We're slowly filling in our bone map, updating it weekly with the bones we're sure we have. Thanks to Scott Hartman for the base image. You can see more of his reconstructions here.
More bones to come as prep continues

Working the final jacket

As mentioned, the Avaceratops has a very faint set of skin impressions with it. Not extraordinarily spectacular, however it is the first time it's ever been found for this kind of dinosaur. I'm excited!
Flipped and getting lightened for transport

Can you see the skin pattern?

Thursday, July 25, 2013

Field season in full swing

Sorry for the lack of updates lately. We've been in South Dakota and Montana working the Hell Creek and Judith River Formations respectively.

Jacob for scale before we open a Triceratops site
South Dakota had seen its fair share of rain, where we got rained out more in two weeks there than in my entire previous decade of Hell Creek digging combined. We pulled a few Triceratops bones and finished evaluating a few sites before moving on north.

Nanotyrannus teeth collected from a single lag deposit
In Montana, our main focus has been opening the Avaceratops dig again and pulling out more of the animal. Lots of bobcat work The back wall of the quarry is nearing 10 feet tall now. Hopefully we're ending the dig soon so we can explore... Enjoy the photos!

Huge fault in the Hell Creek. Jacob somewhere to the left

It's the greenest I've ever seen in July for Montana in the JRF

I cut the steep part of the bobcat road. It's pretty scary to use. 

Duckbill butt I found a few years ago. Finally excavated this year.

After excavation and pedestaling

Part of the Avaceratops braincase

Ava site a few weeks back, before Bobcat work to push the wall back

Tuesday, June 18, 2013

Enchodus rears it's head!

Over the past few weeks, Jacob and I were out doing some scouting and excavation in the lower Niobrara chalk in western Kansas. With the recent drought in the area, not much erosion has happened and so specimens were a bit tough to come by. Though we were blessed with instructions to just record fish localities, secure them, and move on, sometimes the fish are just too good to pass up.

Enchodus palatine fang eroding out
One of our long term goals is to expand our 3 dimensional fish reproductions from Kansas. We've completed 4 so far (Xiphactinus, Ichthyodectes, Saurodon, Pachyrhizodus) and we're working on Megalocoelacanthus as our 5th. Enchodus has always been on our wish list (one of the most common fish in the WIS, and those fangs... people love pointy parts), however the large specimens of Enchodus petrosus are very rare, especially anything resembling a complete skeleton and not just isolated palatine bones with fangs.
RMDRC 13-001 fanf after prep
Jacob struck first with a very large Enchodus fang protruding from the grey chalk between MU 7 and 8 He took down the overburden and exposed a sizable disarticulated skull with pectoral fins and vertebrae. We prepared a good portion of it in the lab and have decided that this specimen is where we will mold the majority of the individual elements from.
RMDRC 13-001 digsite

A few days later I was working an outcrop slightly lower (just above MU 6) and was shocked to find an articulated skull weathering out of some seriously soft chalk. I hoped it was attached to the rest of an Enchodus.
RMDRC 13-005 as found

Originally we were going to "Sternberg" the specimen (pouring plaster directly over the exposed bones to stabilize everything in the jacket) assuming that there was more resent at the site. Unfortunately, sometimes all you get is a head. In this case a giant one (lower jaw 25cm long) indicating an overall length of about 1.25m. This will be the basis for our overall reconstruction.
RMDRC 13-005, bottom side prepared

We're hoping for the prototype to be completed and ready for SVP at the end of October. Fingers crossed.

Friday, May 24, 2013

Megalocoelacanthus restoration in progress

As many of you know, here in the lab we have a thing for rare stuff out of the Niobrara chalk. We've found the only articulated skeleton of Protosphyraena, described the giant filter-feeder Bonnerichthys, we make a habit of collecting excellent cephalopod mouthparts like Spinaptychus and Rugaptychus, and even discovered the only open coiled ammonite out of the whole formation. So when it comes to new giant coelacanths out of Kansas, yeah we're on that too!

The second specimen (left) with a cast of the left lower jaw of the first specimen
The first specimen of Megalocoelacanthus from Kansas was prepared by our lab in 2005. It was given the name "mystery fish" since the bones looked nothing like what we usually work with. The bone quality was pretty nice, and comprised a nearly complete skull. It was eventually identified by Dr. Ken Carpenter (at the Denver Museum at the time) as a coelacanth, and the specimen went off to a repository.

Sculpting a body with the Vienna Latimeria specimen  blown up to size
While preparing and molding the specimen, I discovered a second specimen in 2007 much higher in the chalk consisting of a left lower jaw. As far as we know, these are the only two specimens of Megalocoelacanthus ever discovered in 150 years of paleontological prospecting in the entire Niobrara.

Side fiew of the unpainted and almost finished prototype
From past projects, it is obvious that we are the only people crazy enough to do 3d restorations of Kansas fish. We had disarticulated casts of the whole head of this giant coelacanth, so why not attempt a restoration?

No teeth, but it could nearly swallow me whole with that maw
Well, here's our first stab at it. In the future we're going to have to un-flatten the mandibles so they better fit the floor of the mouth. One thing is for sure though: it's still a strange fish even when all put together.

Friday, May 17, 2013

More Mosasaur Fun, Complete With Spectators

Just finished a sort of long-term new project for us. Occasionally we get requests from museums and universities to come out in the field with us and collect specimens. Even more occasionally, we oblige. In 2011 a class from the University of Tennessee - Martin (actually 2 classes, one in geology, one in journalism) came out to our digsites in western Kansas to find and document fossils for a new museum project. TPI fieldcrews supervised and instructed, however we let the students do the finding. They came up with several neat little fossils (several Spinaptychus, a Chelosphargus partial skull, Martinichthys skulls) and lots of partial fish. On the second day, one student hit the jackpot: the tip of the lower jaw of a mosasaur poking out from just under the alluvium. 

Ever feel like you're being watched?

Here, Aaron (the discoverer) works to remove overburden from the specimen. TPI does the same thing, though usually with fewer spectators. He decided to name the mosasaur "Kimberly". I've named specimens worse things I suppose.
Digsite viewed from across the gully, right near MU 5
 The specimen was tentatively identified int he field as Platecarpus planifrons. Though reasonably well articulated, it was missing the front limbs and everything back behind the mid dorsal vertebrae. UTM students preimetered, stabilized and jacketed the specimen. Most importantly they also carried the slab across the badlands to the nearest truck, which was great for me!

Standard TPI field photo pose, before jacketing
Back in the lab, preperation was begun by UTM students under TPI guidance. Mosasaurs are usually pretty straightforward to work with, however this one presented a few challenges. The proximity to the alluvium meant that this specimen encountered some weathering back during the last ice age, and roots made matters worse. The prognosis was grim initially, as the bone and teeth looked to be in pretty rough shape. But careful consolidation and prep resulted in not only stable bone, but the discovery of the preserved remnants of tracheal rings, as well as extracollumnellar (ear) cartilage. At the rear of the left lower jaw, one of the scavenging sharks, Squalicorax falcatus, left its calling card.

Kimberly's skull
Next up the specimen will be delivered to the new museum in Tennessee, where it will go on display later this year. Luckily the whole process was documented by the journalism students, almost from the instant of discovery. If I see the video, I'll post a copy on the blog in the future.

Not a bad little mosasaur.