Coelophysis biomechanics and the early part of a '"career"

In sticking with a theme of some of my papers that have come out recently, I would like to briefly talk about Coelophysis biomechanics. Coelophysis, in case some of you aren't aware, is, at least in my knowledge, a fairly well known early theropod dinosaur from the Late Triassic of New Mexico (and Arizona). With that said, I started my college career looking to follow in the footsteps of my father and uncle and become a chemist. I learned, after a little over two years (yes, it probably shouldn't have taken me quite that long) that I didn't really want to spend the rest of my life being a chemist. I bounced around for a semester or two before I took a gen ed course regarding dinosaurs and mass extinctions. As almost all young boys do, I was fascinated with dinosaurs and extinct animals. I never thought of pursuing a career till I took that course and talked things over with the instructor, a paleobotanist (Peter Wilf). He managed to convince me to pursue paleontology (geology mainly). Luckily, a vertebrate paleontologist had started there not long before (Russel Graham), and he was very accommodating with me on whatever I wanted to work on. So, for my senior thesis I conducted a project on the biomechanics of Coelophysis.

Coelophysis bauri

Coelophysis is so "famous" because of the sheer number of fossils of this animal that have been found. Almost all (if not all) of them are from a single locality, Ghost Ranch in northern New Mexico. Hundreds of individuals have been recovered, but many more are still there. The quarry has been closed, at least for the time being, but there is always hope that it may be re-opened. I suppose that looking at more of Coelophysis is not that interesting to many people, but a huge accumulation of individuals could help with paleobiologic studies and community structure, or perhaps tell us innumerable other things of this interesting little meat eater.

For my study though, I was looking for complete, or nearly complete, lower jaws. I treated the jaws as a lever, and the amount of bone at any one point in that lever can allow someone to see how strong the jaw is. The more bone present, the stronger the jaw. Of course, length and position also play a factor. I won't go into the methods too much, for that you can look at the paper itself (Jasinski, 2011).

Varanus komodoensis (Komodo dragon)

Dromaeosaurus skull

What was found though, was that the mandible of Coelophysis was most similar to Varanus komodoensis (Komodo Dragon) and dromaeosaurids. This suggests that Coelophysis may have hunted in ways similar to both the Komodo dragon and dromaeosaurids.

This is interesting by itself, but I was also able to look at the skull of a juvenile. While it may bot be especially surprising, the juvenile showed a strength profile incredibly similar to the adult Coelophysis. This suggests that juvenile Coelophysis were hunting in ways similar to the adults. This doesn't mean that they would be taking the exact same prey, but both parents and adults would have been hunting things (and these things would have been larger than insects).

The thought is then, if juveniles had to hunt on their own and take their own prey, that Coelophysis was probably not a precoccial animal and was mainly solitary. Others have thought this, but this is another method of showing it. Other techniques and studies are needed to confirm or deny this idea.  Coelophysis may be more deadly then previously expected though.

Coelophysis bauri skull and lower jaws

Take a look at the Beasts Evolved blog page as well to get another brief look at this paper and bit of different information on it and the paleobiology of Coelophysis.

So, that was my senior thesis, and, with a few add-ons, was recently published in the New Mexico Mexico Museum of Natural History and Science Bulletin. If you would like a copy, feel free to email me (sej139@yahoo.com). Otherwise, I am still early in my potential paleo career, so there should be plenty more to write about as I go.

Reference
Jasinski, Steven E. 2011. Biomechanical modeling of Coelophysis bauri: Possible feeding methods and behavior of a Late Triassic theropod. New Mexico Museum of Natural History and Science Bulletin 53: 195-201.