More Cephalopod Fun

Throwing a bone to the invertebrate guys out there, here's new images of RMDRC 10-018 Spinaptychus sp. that yours truly found earlier this spring in Gove Co., Kansas. Ammonite remains are fairly rare in the chalk since the aragonitic shells do not readily preserve. These jaw parts however are calcitic in nature, and are occasionally found. We lent this specimen to Neal Larson of Black Hills Institute for detailed preparation and a bit of restoration before molding. He and his staff did an absolutely phenomenal job. Thanks again, neal!

The specimen is fairly large at over 5 inches wide, 4 inches long. The next project is determining what ammonite this specimen belongs to. Hopefully a paper will be coming out soon!

The Disassembly of Dillon

Back in April of this year Paleotech Jacob Jett discovered a small mosasaur in the upper Niobrara Chalk of Logan County, Kansas. This critter, a Platecarpus (RMDRC 10-007) consisted of a skull and 5 cervical vertebrae. Part of the upper jaws were exposed at the surface, and there was extensive calciteAbove, Jacob works on preliminary excavation immediately after locating the specimen. Luckily there was little present in the way of overburden.
A few hours later, Jacob has found the perimeter of the specimen (he finally discovered something, so I went to search other areas of the outcrop, finding the big Clidastes Tony II RMDRC 10-008). The entire exposed area will be covered with a plaster and burlap jacket to transport back to the lab. Unfortunately, after the jacket was made, the area was hit with torrential rains (6 inches in 24 hours) and we were not able to get back to the jacket to bring it home. It had to sit out exposed to the elements for 2 weeks.
The jacket was "show prepped" (prepared to expose what is present) once it returned to the lab. As you can see, most of the skull is there, missing only parts of the left maxilla and for some strange reason, the braincase! I am currently in the process of getting these heavily concreted bones separated so that Dillon can be reassembled as a 3d skull and neck mount. As you can guess, it is a time-consuming and delicate process, and the results will be shown in the next blog update.

More on Gil

Show prep is continuing on our duckbill! Time for a little background information. Gil, AKA RMDRC 04-001, was discovered in 2004 by and is named in memory of "JC" John Cully Gilpatric, who sadly passed away 2 years ago. It comes from the upper Judith River Formation, putting its age somewhere around 75 million years old. Excavation began on June 26, 2004 and had been completed by July 2nd. Gil wad found in a fairly soft sandstone with low overburden, which greatly sped up the recovery.

Above is a sketch of the site when TPI field crews excavated it that summer. As you can see it is highly articulated but missing the skull and lower legs. Unfortunately for hadrosaurine hadrosaurs those also happen to be the most distinctive parts, so identification down to genus is still a little tentative. We have been considering Gil to beling to Miasaura, however there exists the possibility that It could belong to two other non-crested duckbills that existed at the same time: Gryposaurus or Prosaurolophus. Below is a photo of the 54cm long right humerus, which may or may not be distinctive. In any case it's pretty, and also slightly longer than the radius.Prep work is ongoing to find more distinctive skeletal elements, so that we may get a better idea of the true identity of this critter. Special thanks goes out to Dr. James Kirkland for providing PDF reprints so that I may attempt to clear this up!

Duckbill tails from the past!

We've been able to do a slight bit of preparation on a Maiasaura that was collected by TPI crews in 2004 from the upper Judith River Fm of Montana. Unfortunately no skin was discovered preserved in this jacket, however there were a few surprises.

The anterior 6 vertebrae show pathological neural spines, perhaps an old bite wound that healed. The chevrons (Y-shaped bones under the tail) are tiny, much smaller than what would normally be expected on a dukbill of this size.

This jacket contains 32 articulated caudal vertebrae in a string nearly 8 feet long. Strangely the chevrons are all nearly gone and the ossified ligaments normally found in ornithischian dinosaurs are completely missing.

And now for a rare one: Martinichthys

Even though the past two (hot) expeditions to Kansas have been primarily aimed at recovering various Xiphactinus skeletons that we have discovered over the years, we did have a little time to scout some outcrops low in the Niobrara chalk. Last Monday, I stumbled across some fish skull parts on an outcrop and followed them up to their source. This is what was coming out:

The rostrum of this rare fish is the most commonly discovered part recovered, mostly because it is the densest and most durable bit, and most likely to be found after weathering out of the outcrop. The teeth are tiny and resemble small barbs, though they number in the thousands. We may have found postcranial material with this fish as well, and a recovery operation at the site will be attempted next time we go to Kansas, though that may be a few months.

Martinichtys seems to have gone extinct between Marker units 5 and 6 (this specimen is the highest one I can find data for, about 1m below MU 6), as do several other animals int he Niobrara (such as Thryptodus, Tylosaurus kansasensis, and several invertebrates). I am curious what happened to wipe these species out.

Meet Tony II!

Well, field season started off with a bang this year. The little mosasaur snout I found in late April turned out to be a nearly complete specimen of Clidastes c.f. moorevillensis, which isn't really supposed to be in the chalk. The critter measures 4.8m long (16 feet), and is so well preserved that it retains cartilage in the ear, sternum, sternal ribs and above the scapulas.
Above, Mike Triebold uses a chainsaw with a special blade to separate the block away from the outcrop prior to jacketing. This chalk was the hardest we've ever encounterred in nearly 3 decades of collecting in the Niobrara.

The site as seen from the top of an adjacent bluff. Luckily we could drive up to the site to dropp off air compressors and generators!

Below is the prepared front half of the animal. 45cm (18 inches) of backbone was lost in the mid dorsal section due to erosion years ago. The tail section was taken out in another large jacket. Come see the specimen, now on display in our marine hall at the RMDRC!

RMDRC gets published!

A small project that I've been involved in for a few years, the discovery of the first heteromorph (open coiled) ammonite from the Niobrara Chalk.

Citation:

Everhart, M.J. and Maltese, A. 2010. First report of a heteromorph ammonite, cf. Glyptoxoceras, from the Smoky Hill Chalk (Santonian) of western Kansas, and a brief review of Niobrara cephalopods. Kansas Academy of Science, Transactions 113:(1-2):64-70.

We discovered the specimen while excavating the "Tracie" Tylosaurus nepaeolicus specimen in June 2008. Triebold Paleontology Inc. donated the ammonite to the Sternberg Museum at Fort Hays State University in 2009 after it became clear this was a scientifically important critter.

Email me if you need a PDF copy of the paper.