Wednesday, June 29, 2011

Well, I was told to find a Pteranodon

So I did. Jacob and I were scouting a few weeks back in some nasty hard more vertical than not yellow chalk between Marker Units 5 and 7. We were finding a whole lot of nothing except for blown out Cimolichthys bodies and some random Xiphactinus/Ichthyodectes parts. Not even a shark tooth to be seen. We were getting frustrated and I was busy entertaining myself picking up Martinichthys coprolites.

We had shifted into "Don't look where you don't want to collect" mode in the really steep stuff to avoid having to excavate 7-12 feet of chalk overburden like when I found the Platecarpus "Cap'n Chuck". Walking up a narrow gully it expanded and flattened out a bit, and I mustered the gumption to check out the outcrops closely. Nothing... Nothing... Martinichthys poop... weathered Cretoxyrhina tooth... Oooh Pterosaur wingtip!
Mmmm bones

I checked out the face of the outcrop and saw bones poking out on a single horizon for 4 1/2 feet. It was definitely a dig. Unfortunately it was a dig in the hard vertical yellow chalk, with 6 feet of overburden, located about 200 feet away from the nearest place we could pack in heavy tools and equipment.
Looks crunchy, but the bone is in beautiful condition

Jacob and I decided if we wanted to get this out of the ground sometime this year, we'd have to get the handy-dandy electric jackhammer down to the site. We set the generator up near the truck and daisy chained every single extension cord we could find together. Stretching them all out, we made it to the dig site, with only about 6 feet to spare.

A whole lot of topography
We used the power equipment to dig down to within 2 inches of the bone horizon. There was no splitting layer at the fossil so we had to carefully explore the perimeter of the excavation with chipper hammers and xacto knives. We found fingers and toes, legs and wings, and even some hints of super delicate skull material. We jacketed the slab and spent the better part of an hour climbing and hauling the 200 pound jacket out of the badlands.

After prep. Lower jaw running l to r under humerus. Lower unprepared area is full of metatarsals/toes
Back at the lab I began preparing the critter.Everything came out well, and it turns out we have about 50% of the skeleton, including a mostly complete lower jaw. The humerus measures 19cm, putting the total wingspan at 4.56m, or 15 feet. This size puts it in the range of a medium sized male of Pteranodon sternbergi. No giant, but still an exciting fossil

Quickie bone map of what is present

I decided to give it the nickname "Val" after my wife, since she pretty much made it clear I had to. A pretty hellish dig and packout, but the specimen is well worth it.

Tuesday, June 21, 2011

Catching a poacher (sorta). Kansas trip #3

Back again after another week of baking my brains out in the chalk in search of long dead marine critters. We were focusing on a strip of outcrops that exposed MU 4 to MU 6 in the lower Niobrara chalk. Found some good stuff too, a nice Pteranodon sternbergi (which will be the focus of another post once prep starts), a partial Xiphactinus audax skull, a small Pachyrhizodus caninus tail, some Martinichthys rostra, and a whole bag of Martinichthys poop! If anyone has any research interest in this poop, let me know, I'd be happy to provide samples.

Pteranodon site
The Pteranodon took up most of our time on till Wednesday, but late that afternoon, Jacob and I finished up and moved on to some outcrops that our crews hadn't explored for a few years. Erosion in the chalk is surprisingly quick, so searching the same spots every 2-4 years is extremely productive. We drove the truck over next to an outcrop and decided to take a quick snack break. While chewing on a small bunch of Red Vines, I look over and notice something blue on the face of the outcrop. "what the hell is that?" I ask Jacob, thinking it is probably just a piece of garbage from the oil rigs in the field.

We go over and investigate, since we had to scout the outcrop anyway. Upon inspection we discover this:
Peek A Boo

A pachychormid fin eroding out with a layer of blue plastic over it. The chalk above the layer was obviously disturbed, and there were small plants growing out of it. Someone tried to poach this fossil!
It's like christmas

We reopened the hole and followed the fossil in. The blue plastic extended quite a ways in. To the end of the fin in fact! Someone excavated the entire thing, then left it! Amazing. We pulled back the plastic and to my surprise it revealed the longest Protosphyraena perniciosa pectoral fin I'd ever seen, 2'8" (82cm) from tip to erosional edge. There were a few fragments in the float and a piece of a radial, but I'm fairly confident we recovered pretty much all of the specimen. Good thing too, we finished up just as another severe thunderstorm was bearing down on us. Also: DON'T STEAL FOSSILS!

The monster storm a few hours later
Back in the lab our summer intern, Lisa, had the job of preparing the specimen . She did a beautiful job! Now to find an interesting way to display the specimen in the museum.

Big fishie

With nasty pointy fins

Monday, June 6, 2011

Collecting a Xiphactinus: Kansas trip 2

Last week we went on a short trip to our Niobrara sites to collect a large specimen of Xiphactinus that was located by a 4H club member. Unfortunately the member had her boundaries confused, and found it on private property that she did not have permission to scout or collect on. Luckily though, we did. We still decided to nickname this fish "Lois" after the lady that discovered it.

Mike and Jacob in the hole, early in the morning
There was a lot of overburden to remove (volume-wise) because though the specimen wasn't deeply buried, it was spread 3 feet deep into the outcrop, along an exposure 9 feet long. A stirred up 15-17 foot fish is going to require a big hole, there's just no two ways about it. Hand tool digging was difficult, and we quickly escalated the equipment, first to an electric jackhammer (BTW I firmly believe everyone needs one of these things, they're awesome) and later to a bobcat excavator to knock down the bulk if the overburden.

The hole from another angle. Notice back-saving jackhammer!
We did this while it was still cool. Keep in mind this was one of the hottest days of the year. We awoke at 4:30 to get an early start. Funny thing: it doesn't get light this time of year in Gove County till 6:00 or so. Oops. No worries, we were pretty sure we could still get it out in one long day of work.

After bobcat work, expanding the hole to find the perimeter of the specimen

The fish itself was stirred up pretty severely, with the caudal fin exploded, spines everywhere, and the skull and pectoral girdle spread across the length of the excavation. On the bright side, this pile of bones will be a great basis for the restoration of the entire skeleton in a nice panel mount.
Dirty chainsaw work, with Jacob for scale

The stable pieces were removed and 2 jackets were carved out of the chalk with a chainsaw. 8:00 pm and we had it done. Only hit 95 degrees too. Much better than the 108 for a high the next day. I'm still exhausted from the experience.
Cleaning the undercuts in preparation for jacketing