Our newest little turtle: Jubal

Apparently TPI is the new home for the small turtles of the Niobrara chalk. We've already prepared, molded and cast our tiny Chelosphargis advena, Prepared a new Prionochelys matutina, and show prepped a nice Toxochelys latiremis that we discovered this past spring, all with nice skulls.

Our Prionochelys matutina specimen from MU5 (Coniacian)

You'd think that we would be content with our fossil turtle stash, but no. You can never have enough of these little guys. This week we prepared from start to finish another new specimen of a tiny protostegid from Kansas.

Box o rocks and bones

Preservation of the bones was beautiful, in nice hard yellow chalk so prep was an absolute joy. We didn't collect this specimen ourselves, which might explain the slightly unorthodox packing method employed in shipping the bones.

Plastron during preparation

While prepping the slabs we discovered many bones that were not apparent when work started. many of these surprise elements were adhered to adjacent bones by a thin layer of the oyster Pseudoperna congesta, making separation much more difficult.

Detail showing much of the pelvis in place

Amazingly, we are 4 for 4 this year for beautiful turtle heads. The skull block on this specimen contained not only all the major head bones, but also most of the hyoid apparatus. A very rare find in animals this small in the chalk.

Skull block before prep

Partly in thanks for helping us determine the identity of this turtle (the uber rare Chelosphargis advena), and partly just because we like him so dang much, we nicknamed RMDRC 15-001 "Jubal" in honor of Dr. Kraig Derstler of the University of New Orleans. For the back story, well you're just going to have to ask him about it.

Profile view of skull after prep

When finished with the prep, we did a layout and were shocked how complete this specimen really is. Next up is restoration, molding and casting so copies can be exhibited in museums and homes worldwide. The specimen is currently displayed in our lab viewing area, so come by soon and check it out before we put it all back together.

This is what a turtle looks like if you crack it open and pull everything out

The Little Protostega is Restored!

A final follow-up on the project that I had mentioned in the last update. The project is "finished" for now, all molding is complete and the first two prototypes have been assembles and packed.

Cast bones and skull restoration before assembly

We molded hundreds of individual bones for this project. Those cast parts were restored, put into subassemblies, then remolded to produce the final cast. The cast preserves all the pathologic and taphonomic detail, including what appears to be puncture wounds from predation by one of the many mosasaurs in the Niobrara. I blame it on Tylosaurus.

Prototype #2 flying by the green screen

Prototype #1

Prototype #1 with curator for scale

Amazingly, the whole animal now goes together from a trimmed cast to a final project in less than a week. The first specimen was given to the Sternberg Museum at Fort Hays State University to accompany the original specimen now safely in their collections. The second cast will be on display beginning next week at the Tucson gem and mineral show, at the 22nd street show. Come by and check it out!

Restoring a Protostega

Back in October of 2011, the lovable TPI field crew was brought out to a ranch in western Kansas (very near the site of Sternberg's famous "fish within a fish" specimen) to help with the recovery of giant sea turtle. This turtle skeleton will be reposited in the Sternberg Museum of Natural History at Fort Hays State University. The term giant is used loosely here, since the actual turtle was only about a meter in shell length, nowhere near the car-sized members of its genus that would later cruise the oceans. Field photos shamelessly borrowed from Mike Everhart's wonderful Oceans of Kansas website.

Making the hole bigger with power tools. Also shovels.

The turtle site was located fairly low stratigraphically, and was entombed in a fairly hard grey chalk. Our first order of business was to identify the bone layer and then break out the power tools to remove the overburden from a wide area. I'll say it again, that cute little green jackhammer is a backsaver!

Mike Everhart and I jacketing the slab, with the finger hair saving nitrile gloves

Once down to the bone level we perimitered the specimen, cut around with the chainsaw, and jacketed the whole slab.

Perimitering in the quarry

Exposing more of the bones

That was the easy part! Back in the lab we began by using air abrasion and pneumatic scribes to remove the matrix from the fossil, first the individual bones that were collected before TPI arrived.

Individual bone before prep in the lab...

...and after air abrasion, scribe and glue work

A few interesting surprises popped up once I started removing the chalk. Abrasions on the ventral side of the plastron seem to indicate this turtle pulled itself up some distant beach, possibly suggesting it was a female getting to dry land to lay its eggs, though some modern male sea turtles also come out of the water occasionally. The carapace and especially plastron were covered by what look a heck of a lot like puncture wounds, all unhealed. The front flippers were totally lacking any parts below the elbow, in fact one humerus was bitten completely in half. It sure looks like the turtle was a partial meal for a mosasaur like Tylosaurus before it finally sank to the sea bottom.

Abrasion and puncture marks on the plastron

Once the bones were prepared they were all molded individually (when possible). The casts were then manipulated into larger assemblies, where we filled in missing parts and took out some crushing distortion. These assemblies are then used to make production molds for cast copies.

Carapace subassembly in a thixotropic mold

Original bone pile being molded for parts. 

We should have the project done in the next few weeks, just in time to display at the Tucson Gem and Mineral Show this January. Stop on by to check it out!

Basilemys reconstruction

In 2007, a friend of Dr. Kraig Derstler accompanied TPI crews doing field recon in the Judith River Formation of central Montana. In one gully he discovered some very large turtle shell parts coming out, and we traced them to their source. Though obviously belonging to the "emperor turtle" Basilemys, this turtle looks as if it had swallowed a hand grenade, where all parts were disarticulated and spread through the outcrop.

Excavation was conducted in 2007 and 2008 (and even a bit in 2009), and about 50% of the animal was recovered. Since the specimen, now nicknamed "Doug" after the discoverer, is disarticulated, this gives us a great opportunity to reconstruct the specimen in inflated form, as opposed to the crushed articulated specimens found until now.

This specimen is also remarkable because it preserves several non-shell skeletal elements, which is rare for this type. These include both pelvis assemblies, scapula, dorsal vertebra #1 and toes. An isolated Basilemys humerus found on a nearby ranch will also be used in the reconstruction. Stop on by the museum to see how the project is coming over the next few months!

Kansas Field Season Commences

Well we're heading out again for a quickie recon before my trip to Korea. Hopefully it will be more productive then the last trip, which was a lot of uphill and downhill walking and very little in return. We recovered a partial Xiphactinus skull that I found accidentally last spring, and I found another skull and partial skeleton (so far, it's still going into the outcrop) that we'll be puling out later this spring. Above the first Xiphactinus, I also found and recovered a small turtle, probably Ctenochelys, that even had limb material. This next trip will not have a film crew, so things should go pretty quick!

This turtle was recovered in 2006 from the Hell Creek Formation of southwestern North Dakota. Anyone have a guess to it's identity?