Dakota (specimen NDGS 2000) is the nickname given to an importantEdmontosaurusfossil found in theHell Creek Formation inNorth Dakota. It is about 67 million years old,[1] placing it in theMaastrichtian, the laststage of theCretaceousperiod. It was about 12 m (40 ft) long and weighed about 7-8 tons.[1][dubious –discuss]
The fossil is unusual and scientifically valuable because softtissue includingskin andmuscle have been fossilized, giving researchers the rare opportunity to study more thanbones, as with mostvertebrate fossils. Some structures "retains soft-tissue replacement structures and associated organic compounds."[1] Preliminary research results indicate that hadrosaurs had heavier tails and were able to run faster than was previously thought.
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Dakota was first discovered by paleontology studentTyler Lyson on his family's North Dakota property in 1999 while he was a high school student, but he did not investigate the site in detail until 2004, when he discovered the soft tissue preservation. Lyson teamed with British paleontologistPhillip Manning, and the site was excavated in summer 2006.[2]
Manning's team used a large-scaleCT scanner, provided byNASA and theBoeing Company, to generate high-resolution scans of the preserved muscles and tendons of the rear legs. Because theintervertebral discs which space out the spinal column of the tail have been fossilized, researchers have been able to calculate its length more accurately. The preservation of its muscles andtendons allow the calculation of itsmass. The results indicate the dinosaur could likely have run at 45 km/h (28 mph), faster than the estimated top speed ofTyrannosaurus rex, at 27 km/h (17 mph).[1]
The well-preservedintegument has retained its texture, and researchers have mapped it in three dimensions. Thescales are of different sizes, and researchers speculate that their pattern may reflect the animal's coloration in life. For example, areas of an arm's joints are textured in what resembles a striped pattern.[1] This fossil's examination was the subject ofDino Autopsy, a documentary aired onNational Geographic Channel on December 9, 2007.[1]
The specimen was previously housed at theMarmarth Research Foundation (MRF) under the catalog number MRF-3, but now it is permanently part of the collection of theNorth Dakota Geological Survey located at theState of North Dakota, under the specimen number/catalogue NDGS 2000.[3]
Dinosaur fossils with Dakota's degree of preservation are extremely rare because many different factors must come together to allow it to occur. The carcass first must escapescavengers as well as degradation by the elements. The soft tissue must then be mineralized before itdecomposes. Finally, as with all fossils, the mineralized body must escape destruction by geological forces over millions of years.[1] News reports have referred to Dakota as "mummified"; however, it is actually a fossil of a mummified dinosaur, where the animal's dried tissues have been transformed torock through fossilization.[2]
Stephanie K. Drumheller and team in 2022 proposed that Dakota was exceptionally preserved because of several identified scavenging marks to the carcass, which helped to escape the gases, fluids, and microbes that develop during decomposition. This may have likely allowed soft tissues to withstand the weeks and/or months required fordesiccation prior to burial and eventualfossilization.[3]
Media related toDakota at Wikimedia Commons
Data related toEdmontosaurus at Wikispecies
