Oryctodromeus exhibit at the Museum of the Rockies

After roughly a year of work the exhibit on Oryctodromeus, and aspects of the fauna and flora of the Wayan Formation of Idaho and Vaughn member of the Blackleaf Formation, is on public display at the Museum of the Rockies in Bozeman. Since my research includes providing a thorough osteological description of Oryctodromeus, I was asked to choose all the bones that were cast and molded for the skeletal mount, and to help make sure that the skeletal mount represented our best knowledge of the animal. Having worked on the animal for about a decade (collecting a lot of specimens before the species was described and describing the osteology of Idaho specimens in my Masters thesis), it is awesome to finally see a skeletal mount of the animal, and an exhibit describing some of the fauna and flora of the Wayan and Vaughn! I also love how the work of everyone involved in researching the Wayan and Blackleaf (Jamie Fearon, Steve Robison, Jade Simon, Cary Woodruff ) is described. Here I don't want to give away the whole exhibit, but I would like to share the Oryctodromeus mounts.

I love the Lull Mount that Matt Smith of Livingston did. A Lull Mount is a mount were one side is skeletal and the other side is fleshed out. Of course we have no idea about what integument Oryctodromeus had but I like the scheme used here. One of the things that took some people by surprise as the skeleton took shape is the length of the tail in Oryctodromeus. The tail on this mount is over seven feet long, roughly two-thirds of the whole length of the animal, a condition similar in Tenontosaurus. I based the length of the tail on a Wayan Formation specimen which represents (as far as I can tell) one individual, this specimen has 57 caudal vertebrae. I measured the length of each caudal and just used that to give a minimum length for a tail. Interestingly, the tail vertebrae of Oryctodromeus very quickly loose their long processes and the tail becomes thin and whip-like.
Another interesting aspect of the tail not indicated on the mount is the extreme abundance of ossified tendons found in many of the specimens. In these specimens the ossified tendons begin near the base of the neck and occur on the tops of the transverse processes of the vertebrae, and the tail vertebrae are entirely encased in a thick lattice of tendons (see Krumenacker, 2010). This could definitely complicate getting around in a burrow if these tendons were as stiffening as believed. But we have ideas that may help solve this problem...

Of course one of the most important aspects of Oryctodromeus, is it's burrowing behavior. As described originally (Varricchio et al., 2007), the bones of an adult and two juveniles were found in a fossilized burrow. Matt Smith did a great job again creating a replica of the burrow with two kiddos and the adult in the burrow. The original description also discusses smaller burrows that extend off the main body of the Oryctodromeus burrow, these could possibly belong to a small mammal (look carefully at the burrow in the exhibit).

As I said, I don't want to give away everything about the new exhibit, so I'll leave off there.

A few useful references as discussed above:

Krumenacker, L.J., 2010. Chronostratigraphy and paleontology of the mid-Cretaceous Wayan Formation of eastern Idaho, with a description of the first Oryctodromeus specimens from Idaho. BYU Provo MS.

Varricchio, D. J., A. J. Martin, and Y. Katsura. 2007. First trace and body fossil evidence of a burrowing, denning dinosaur. Proceedings of the Royal Society B: Biological Sciences 274: 1361–1368.

Faunal update

I've heard in regard to blogging that "Never has so much been written by so many that will be read by so few", and seeing as it's not dissertation or family related it has been a while since I updated this blog. However, I've given a few talks at conferences the past month detailing new Wayan/Idaho Cretaceous discoveries, so it's a good time to share this new information here.

My talks this spring were at the Mid-Mesozoic conference in Utah and Colorado (http://www.utahpaleo.org/mid-mesozoic-conference.html), and the regional GSA meetings here in Bozman (https://gsa.confex.com/gsa/2014RM/webprogram/Paper238289.html). The former talk outlined Wayan fauna and taphonomy, and the latter the fauna and taphonomy of the bonebed found last year that I have termed the Robison Bonebed, after my friend and mentor Steve Robison. Between the Robison bonebed, another site yet to be discussed, and other Wayan localities we are just starting to finally get real diversity (albeit very fragmentary fossils) for the Wayan fauna. So here is an updated listing of all the critters we now know about:

• Oryctodromeus: A small burrowing ornithopod. This animal heavily dominates the Wayan fossil assemblage, >12 partial to near complete skeletons and lots of isolated bits and pieces.
• Hadrosaur: Known from a tooth from the Robison Bonebed. These large ornithopods were fairly new arrivals on the Cretaceous scene at this time and would be dominant in later Late Cretaceous faunas.
• Iguanodont: Known from a few isolated teeth and bones from various localities.
• Nodosaurs: Known from isolated teeth, a partial skeleton currently under research, and arguably common scutes, teeth, and vertebrae from the Robison Bonebed.
• Giant oviraptorosaur: Represented by very common isolated eggshell, eggshell concentrations, and rare large eggs.
• Tyrannosaurid: Known from isolated teeth. These are small animals that have not yet achieved the giant size that tyrannosaurs would gain in the later Late Cretaceous.
• Cf. Neovenatorid allosauroid: This animal is represented by a small vertebra from a young animal.
• Dromaeosaurs: Known from rare teeth from various localities.
• Coelurosaurs/indeterminate small theropod(s): Known from teeth and bones from a few localities. I'm hoping to get better identifications on these and more material.
• Large, maybe Allosaurus-sized, possible fish-eating theropod: This animal is known from teeth from the Robison Bonebed. The teeth are distinctive and I can't seem to find anything that matches them.
• Triconodontid mammals: Known from isolated teeth from two localites.
• Non-cimolodontan multituberculate mammal: Known from a jaw with teeth found at the Robison Bonebed.
• Cimolodontan mammal: Known from teeth from one site.
• Eutriconodontid mammal: Known from teeth from one site.
• Metatherian mammal: Known from teeth from one site.
• Indeterminate mammals: Known from teeth from the Robison Bonebed.
• Deinosuchus-like/Large goniopholid crocodylian: Partial skull currently under research.
• Small crocodylians: Known from teeth from a number of sites.
• Turtles: Fairly common shell fragments from a number of sites.
• Semionotid fish: Known from hundreds of large crushing teeth and a few scales from a few sites. The size of one scale indicates maybe close to a meter in length at least for some of these fish.

And here's a figure that generally summarizes the fauna of the Wayan, made in this case to represent the fauna from the bonebed.

Once work is completed on these sites and specimens a number of publications will come out on all these bits and pieces. Hopefully in the interim we can find some more complete material of all these animals.

A few useful references:

Dorr, J.A. 1985. Newfound Early Cretaceous Dinosaurs and Other Fossils in Southeastern Idaho and Westernmost Wyoming, Contributions from the Museum of Paleontology, University of Michigan 27(3):73- 85.  Link: http://deepblue.lib.umich.edu/bitstream/handle/2027.42/48524/ID377.pdf

Krumenacker, L. J.; 2010. Chronostratigraphy and paleontology of the mid-Cretaceous Wayan Formation   of eastern Idaho, with a description of the first Oryctodromeus specimens from Idaho (MS), Brigham Young University. Link: http://contentdm.lib.byu.edu/cdm/ref/collection/ETD/id/2317

 

Simon, J. D., D. J. Varricchio, F. D. Jackson, and S. R. Robison, 2012. Giant theropod eggs from the Albian-Cenomanian Wayan Formation of Idaho: Taxonomic, paleogeographic, and reproductive implications. Journal of Vertebrate Paleontology 32 (3, supplement):174.