Revised as of May 6, 2008.
*Medical Writer, SciMantis Communications, Inc, Pen Argyl, Pennsylvania.
Address correspondence to: Kristina Woodworth, Medical Writer, SciMantis Communications, Inc, PO Box 3, Pen Argyl, PA 18072. E-mail: firstname.lastname@example.org.
A 67-million-year-old mummified hadrosaur has been found with intact skin, tissue, and bones, raising hopes for groundbreaking research and insight into the anatomy of dinosaurs. The research team, led by British paleontologist Phillip Manning of the University of Manchester, knew that viewing the internal structure of the specimen would be a challenge, and identified computed tomography (CT) imaging as their best option. But how would they scan, let alone rotate, the 3.5-ton, 35 foot-long creature? The solution resided with a large-scale CT scanner used by the Boeing Company to inspect space shuttle and aircraft parts for structural integrity.
Paleontologist Tyler Lyson, now a graduate student in geology and geophysics at Yale University, first discovered the unique fossil as a teenager on his family property in the Badlands of North Dakota. The mummified specimen is a hadrosaur, or duck-billed dinosaur, and has been named Dakota after its place of origin.
Although Mr Lyson first noticed the fossil as a teenager in 1999, it was not until 2004 that he began to realize the magnitude of his discovery. Most fossils are of just bone and teeth, but this specimen is a 3-dimensional package of skin encasing bones, tissue, and possibly organs in their original anatomic locations.1
Mummified specimens are rare, as the bodies of most animals are degraded by predators and scavengers, and are weathered by nature with time.2 Furthermore, a chemical process must occur to preserve the tissue and prevent natural microbial degradation. In the case of this specimen, the animal must have been exposed to the ideal conditions that favored mummification over decomposition, according to Dr Manning. The researchers have hypothesized that the animal was swept away and buried by mineral-rich flood waters shortly after its death, and was thereby protected from the normal decomposition process.
Enlisting CT Technology
Dr Manning and his team soon recognized the need for advanced imaging technologies to view the interior of this unique specimen. Fortunately, the Boeing Company was willing to enlist the world's largest CT scanner, typically used by NASA to analyze the structural makeup of space shuttle parts, in the Dakota research.
So while ongoing excavation and analyses were being performed on a portion of the specimen at the North Dakota State Heritage Center Museum in Bismarck, North Dakota, the team prepared the specimen's back section for transport to a Boeing facility north of Los Angeles. The specimen, and some of the surrounding rock in which it rested, were encased in plaster for the 1300-mile journey.
The dimensions of the specimen initially challenged Dr Manning and the Boeing group because Dakota was the largest, heaviest item ever analyzed by the scanner. Unlike medical CT scanners that spin around the patient, the Boeing scanner is designed to have the specimen spin around the machine. After making the necessary adjustments to accommodate Dakota, they were still unsure if the scanner would be powerful enough to penetrate the plaster and rock surrounding the mummy.
Jeff Anders led the Boeing CT team and described some of the challenges they faced. He explained that the Boeing CT device "starts its life as a medical machine" and is modified by an independent contractor to Boeing's specifications. Penetrating the plaster and rock was a challenge to even a machine of this magnitude, and the mineral content of the rock made the scan even more difficult, which the team did not initially anticipate. Scans of the tail were generally 6 MeV in strength, and the bulk of the body specimen required scans of 9 MeV. Despite the greater strength of the radiation used in the body analysis, the 9 MeV scans resulted in images of lesser clarity than those obtained with 6 MeV scans.
The bulk of the specimen required nonstop scanning, 24 hours a day for 3 weeks. In total, the project logged up to 500 hours of scan time between the body and the tail over the 6 months that the specimens were kept at the Boeing facility.
Mr Anders cited important challenges in running and maintaining a machine that generates constant scans over the course of its life. Above all, "we have to choose materials carefully" for things such as wiring insulation. Although Teflon, nylon, and certain plastics can degrade quickly under constant radiation exposure, "polyethylenes work beautifully" and may be considered by CT manufacturers working to extend the life of their machines, said Mr Anders.
Data Management Poses the Greatest Challenge
Mr Anders stressed that although the logistics of scanning Dakota were challenging, data management posed the greatest hurdle. He said, "Trying to manage this amount of data is a nightmare," and Boeing is building new computers to manage the data, with a target image resolution of 0.007 of an inch. "We threw the kitchen sink at [Dakota], knowing that we could go back [to data analysis] as the technology improves," explained Mr Anders.
In tackling ongoing data storage challenges at Boeing, Mr Anders and his team are using a PowerFile system (PowerFile, Inc, Santa Clara, CA), which Mr Anders described as stand-alone servers, housed onsite, that resemble "racks of DVDs." Each rack holds up to 20 terabytes of data, and the system is scalable. In discussing the benefits of the current system, Mr Anders said, "we finally have something that is seamless," unlike previous data storage methods.
Although Boeing and Mr Anders' team generously offered their services in this project, he stressed the value of working on something aside from their usual contract work with NASA and other government entities. Working on a project like this "takes us out of our comfort zone and helps us work through a challenge," which has always been his team's key to innovation, said Mr Anders.
Findings Change Previous Assumptions About Dinosaur Anatomy
The team's initial findings have the potential to impact the entire field of paleontology. Among the remarkable findings initially revealed in the Dakota specimen were intact scales and markings on the skin that suggested a camouflage pattern as opposed to one solid color (Figure 1), which is almost unheard of in specimens from other archaeological digs.3
Figure 1. Hadrosaur Skin and Markings
Reprinted with permission from National Geographic Society. "Mummified" Dinosaur Unveiled. December 3, 2007. Available at: http://news.nationalgeographic.com/news/2007/12/photogalleries/dinosaur-pictures/. Accessed April 14, 2008.3
Meanwhile, one of the findings that may have larger implications for many of the fossilized currently displayed in museums is the spacing of the vertebrae in the Dakota specimen. Whereas most museums space the vertebrae closer together, Dr Manning and his team discovered that the spacing of the Dakota vertebrae were approximately 1 cm apart (Figure 2).4 This could mean that most dinosaurs are longer, many at least by 1 meter, than paleontologists had previously assumed.
Figure 2. CT Scan of Hadrosaur Vertebrae
CT = computed tomography.
Reprinted with permission from National Geographic Society. Wired News. Rare Mummified Dinosaur Unearthed: Contains Skin, and Maybe Organs, Muscle. Available at: http://www.wired.com/science/discoveries/news/2007/12/dino_mummy. Accessed April 14, 2008.4
The CT scan also was able to accomplish an analysis of the soft tissue of the animal, including the musculature of the tail. The scans revealed that these muscle groups, responsible for the animal's locomotion, were much larger than previously assumed. The research team noted that the estimated size of the muscles would mean that Dakota could run at speeds of up to 28 miles/hour, which is faster than previously thought for these animals.3 Dr Manning noted that this would make the hadrosaur faster than one of its predators, the Tyrannosaurus rex, which would make sense from a survival standpoint.
Aside from these important findings, the initial CT scans will act as "a roadmap" as the research team works to recover the animal from the surrounding sediment, according to Dr Manning. Although Dr Manning and his team have not yet allowed outside experts to analyze the specimen, he conceded that Dakota could represent decades of research.
Those interested in additional information about Dakota or advanced imaging techniques for dinosaur fossils can access the following web-based resources:
1. National Geographic Society. Dinosaur Mummy Found With Fossilized Skin And Soft Tissues. ScienceDaily. December 3, 2007. Available at: http://www.sciencedaily.com/releases/2007/12/071203103349.htm. Accessed April 14, 2008.
2. National Geographic News. "Dinosaur Mummy" Found; Has Intact Skin, Tissue. Available at: http://news.nationalgeographic.com/news/2007/12/071203-dino-mummy.html. Accessed April 14, 2008.
3. National Geographic Society. "Mummified" Dinosaur Unveiled. December 3, 2007. Available at: http://news.nationalgeographic.com/news/2007/12/photogalleries/dinosaur-pictures/. Accessed April 14, 2008.
4. Wired News. Rare Mummified Dinosaur Unearthed: Contains Skin, and Maybe Organs, Muscle. Available at: http://www.wired.com/science/discoveries/news/2007/12/dino_mummy. Accessed April 14, 2008.