UCMP Profiles
Mark Goodwin: Research (cont.)

Goodwin's work on bone preservation has added important data to his work on dinosaur bone development, including that of "bone headed" pachycephalosaurs. For many years, literature about pachycephalosaurs speculated that their thick domed heads were used as "battering rams," much like modern-day big-horned sheep. This was based on an assumption that the domes, much like the skulls of big-horned sheep, were constructed to absorb the shock of the collision and protect the brain. In fact, they are quite different.

Goodwin believes that this speculation is not well supported by the evidence. Not only is the shape of the head wrong for head-to-head contact, but analysis of the bone itself is not consistent with that interpretation. It seems likely that the dome was related to some sort of display, used in competition or mate selection, and that any physical contact was more likely to have been lateral rather than head-on.

Coneheaded pachycephalosaur

Coneheaded pachycephalosaurs? Goodwin says, "We do know that there was something covering the domes, because we can see collagen fibers where a structure would have been attached. But what did it look like? We just don't know." (Slide courtesy of J.R. Horner, Museum of the Rockies)

STIM microprobe image

Above is a microprobe image from a thin-section of a hadrosaur bone from Alaska's North Slope. Preliminary analysis indicates that the bone surrounding the Haversian canal is significantly enriched with trace elements such as iron and manganese compared with the neighboring areas. Modern bird and crocodile bone contains relatively little iron and manganese. This data, in addition to sediment samples, supports Goodwin's interpretation that the enrichment was caused by the burial environment.

What advice would you give to scientists who use biochemical techniques to draw conclusions from fossilized bone material?
“I’d like scientists to search for better sampling techniques to identify which areas of the bone to examine. We can increase resolution by sampling areas of the bone that are not affected by geochemical changes. One way is to isolate areas not enriched by trace element from the burial environment. Through microsampling, we can extract samples from multiple locations in the bone and see if the isotope signals differ.

“Another way to approach this problem is to look at bones from different burial environments in the fossil record of animals, say dinosaurs, that lived in similar environments during life. I'm asking, will their chemical composition be significantly different?

“I’m also interested in increasing the resolution of bone sampling techniques. I still think we might be able to identify areas of the bone that are unaffected by diagenesis, and I now have some techniques for investigating these questions.”

Browse the Interview:    Profile  |   Interview intro  |   Research  |   Path to UCMP  |   Life in UCMP
Home  |   What’s new  |   About UCMP  |   History of life  |   Fossil collections  |   Other resources

Credits button UCMP logo Copyright symbol