Dakota (fossil)
Encyclopedia
Dakota is the nickname given to a fossil
Edmontosaurus
from the Hell Creek Formation
in North Dakota
. It is about 67 million years old, placing it in the Maastrichtian
, the last stage
of the Cretaceous
period. It was about 11 m (35 ft) long and weighed about 3.5 ton
s.
The fossil is unusual and scientifically valuable because soft tissue
including skin
and muscle
have been fossilized, giving researchers the rare opportunity to study more than bone
s, as with most vertebrate
fossils. Preliminary research results indicate that hadrosaurs had heavier tails and were able to run faster than was previously thought.
s as well as degradation by the elements. The soft tissue must then be mineralized before it decomposes
. Finally, as with all fossils, the mineralized body must escape destruction by geological forces over millions of years.
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 to rock
through fossilization.
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 paleontologist Phillip Manning, and the site was excavated in summer 2006.
Manning's team used a large-scale CT scanner
, provided by NASA
and the Boeing Company, to generate high-resolution scans of the preserved muscles and tendons of the rear legs. Because the intervertebral disc
s 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 and tendon
s allow the calculation of its mass
. The results indicate the dinosaur could likely have run at 45 km/h (28 mph), faster than the estimated top speed of Tyrannosaurus rex
, at 32 km/h (20 mph).
The well-preserved integument has retained its texture, and researchers have mapped it in three dimensions. The scales
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.
This fossil's examination was the subject of a National Geographic documentary, Dino Autopsy.
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
Edmontosaurus
Edmontosaurus
Edmontosaurus is a genus of crestless hadrosaurid dinosaur. It contains two species: Edmontosaurus regalis and Edmontosaurus annectens. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian stage of the Cretaceous Period 73 million years ago,...
from the Hell Creek Formation
Hell Creek Formation
The Hell Creek Formation is an intensely-studied division of Upper Cretaceous to lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana...
in North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
. It is about 67 million years old, placing it in the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
, the last stage
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
of the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
period. It was about 11 m (35 ft) long and weighed about 3.5 ton
Ton
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
s.
The fossil is unusual and scientifically valuable because soft tissue
Tissue (biology)
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
including skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
and muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
have been fossilized, giving researchers the rare opportunity to study more than bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s, as with most vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
fossils. Preliminary research results indicate that hadrosaurs had heavier tails and were able to run faster than was previously thought.
Preservation
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 escape scavengerScavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
s as well as degradation by the elements. The soft tissue must then be mineralized before it decomposes
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
. Finally, as with all fossils, the mineralized body must escape destruction by geological forces over millions of years.
News reports have referred to Dakota as "mummified
Mummy
A mummy is a body, human or animal, whose skin and organs have been preserved by either intentional or incidental exposure to chemicals, extreme coldness , very low humidity, or lack of air when bodies are submerged in bogs, so that the recovered body will not decay further if kept in cool and dry...
"; however, it is actually a fossil of a mummified dinosaur, where the animal's dried tissues have been transformed to rock
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
through fossilization.
Discovery and analysis
Dakota was first discovered by paleontology student Tyler LysonTyler Lyson
Tyler Lyson is the discoverer of the dinosaur fossil Dakota, a fossilized mummified hadrosaur.Lyson received his bachelor's degree in biology from Swarthmore College in 2006, and received a scholarship to study for his PhD in paleontology at Yale University, where he remains as of 2011.In 1999,...
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 paleontologist Phillip Manning, and the site was excavated in summer 2006.
Manning's team used a large-scale CT scanner
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
, provided by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
and the Boeing Company, to generate high-resolution scans of the preserved muscles and tendons of the rear legs. Because the intervertebral disc
Intervertebral disc
Intervertebral discs lie between adjacent vertebrae in the spine. Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together.-Structure:...
s 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 and tendon
Tendon
A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments and fasciae as they are all made of collagen except that ligaments join one bone to another bone, and fasciae connect muscles to other...
s allow the calculation of its mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
. The results indicate the dinosaur could likely have run at 45 km/h (28 mph), faster than the estimated top speed of Tyrannosaurus rex
Tyrannosaurus
Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...
, at 32 km/h (20 mph).
The well-preserved integument has retained its texture, and researchers have mapped it in three dimensions. The scales
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
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.
This fossil's examination was the subject of a National Geographic documentary, Dino Autopsy.