Specimens of Tyrannosaurus
Encyclopedia
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...
for more information on the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
itself.
Early discoveries
The holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
of Tyrannosaurus rex, a partial skull and skeleton originally called AMNH 973 (AMNH stands for American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
), was discovered in the U.S. state of Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
in 1902 and excavated over the next three years. Another specimen (AMNH 5866), found in Wyoming in 1900, was described in the same paper under the name Dynamosaurus imperiosus. At the time of their initial description and naming, these specimens had not been fully prepared and the type specimen of T. rex had not even been fully recovered. In 1906, after further preparation and examination, Henry Fairfield Osborn
Henry Fairfield Osborn
Henry Fairfield Osborn, Sr. ForMemRS was an American geologist, paleontologist, and eugenicist.-Early life and career:...
recognized both skeletons as belonging to the same species. Because the name Tyrannosaurus rex had appeared just one page earlier than Dynamosaurus in Osborn's 1905 work, it was considered the older name and has been used since. Had it not been for page order, Dynamosaurus would have become the official name.
Holotype: CM 9380
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...
. Fragments of (then) AMNH 973 were first found in 1902 by Barnum Brown
Barnum Brown
Barnum Brown , a paleontologist born in Carbondale, Kansas, and named after the circus showman P.T. Barnum, discovered the second fossil of Tyrannosaurus rex during a career that made him one of the most famous fossil hunters working from the late Victorian era into the early 20th century.Sponsored...
, assistant curator of the American Museum of Natural History and a famous paleontologist in his own right. He forwarded news of it to Osborn; it would be three years before they found the rest of it.
In 1905 when the type was described by Osborn, previous knowledge of dinosaur predators at the time were based on Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
carnosaurs
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
, so the short fore-arms of the Tyrannosaurus were treated with extreme caution, with suspicion that bones of a smaller theropod had become jumbled with the remains of the bigger fossil. Following the 1941 entry of the United States into World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, the holotype was sold to the Carnegie Museum of Natural History
Carnegie Museum of Natural History
Carnegie Museum of Natural History, located at 4400 Forbes Avenue in the Oakland neighborhood of Pittsburgh, Pennsylvania, USA, was founded by the Pittsburgh-based industrialist Andrew Carnegie in 1896...
in Pittsburgh for protection against possible bombing raids. The specimen, now labeled CM 9380, is still mounted in Pittsburgh, at first with the tail acting as a tripod in the old fashioned kangaroo pose. It has since received a modernization of its posture and can now be found balancing with tail outstretched.
AMNH 5027
AMNH 5027 was found in 1907 by Barnum BrownBarnum Brown
Barnum Brown , a paleontologist born in Carbondale, Kansas, and named after the circus showman P.T. Barnum, discovered the second fossil of Tyrannosaurus rex during a career that made him one of the most famous fossil hunters working from the late Victorian era into the early 20th century.Sponsored...
in Montana, and described by Brown the following year. At the time of discovery, a complete cervical
Cervical vertebrae
In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also...
(neck vertebrae) series for Tyrannosaurus was not previously known, so it was this specimen that brought the short, stocky tyrannosaur neck to light. Compared to later specimens (BMNH R7994 and FMNH
Field Museum of Natural History
The Field Museum of Natural History is located in Chicago, Illinois, USA. It sits on Lake Shore Drive next to Lake Michigan, part of a scenic complex known as the Museum Campus Chicago...
PR2081, for instance) the cervical series of AMNH 5027 is much more gracile, so with later discoveries the distinction between tyrannosaurid necks and the necks of carnosaurs
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
became more obvious. This specimen also provided the first complete skull of Tyrannosaurus rex. In total, Brown found five partial Tyrannosaurus skeletons.
Famous mount
Osborn planned to mount the similarly-sized AMNH 5027 and AMNH 973 together in dynamic poses. Designed by E.S. Christman, the scene was to depict a rearing Tyrannosaurus (AMNH 5027) snapping at another cowering one (AMNH 973), as they fought over the remains of a hadrosaur, described at the time as TrachodonTrachodon
Trachodon is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-age Upper Cretaceous Judith River Formation of Montana, U.S.A...
:
"It is early morning along the shore of a Cretaceous lake four [we now know to be sixty five] million years ago. A herbivorous dinosaur Trachodon venturing from the water for a breakfast of succulent vegetation has been caught and partly devoured by a giant flesh eating Tyrannosaurus. As this monster crouches over the carcass, busy dismembering it, another Tyrannosaurus is attracted to the scene. Approaching, it rises nearly to its full height to grapple the more fortunate hunter and dispute the prey. The crouching figure reluctantly stops eating and accepts the challenge, partly rising to spring on its adversary. The psychological moment of tense inertia before the combat was chosen to best show positions of the limbs and bodies, as well as to picture an incident in the life history of these giant reptiles."
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
(the more allosaur-like arms were replaced several years later when better fossils of tyrannosaurid arms were found). The mount retained a rearing pose similar to the initial proposal. By the 1980s it was generally accepted that such a pose would have been anatomically impossible in life, and the skeleton was re-mounted in a more accurate, horizontal pose during a renovation of the museum's dinosaur halls in the early 1990s. The mount can still be seen on display on the fourth floor of the American Museum.
After the war, the holotype of Dynamosaurus imperiosus and a second specimen (AMNH 5881) were also sold and now reside in the collections of the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
, London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
(formerly the British Museum of Natural History), where they are known as BMNH R7994 and BMNH R7995, respectively. The American Museum of Natural History features AMNH 5027 in its famed Hall of Saurischian Dinosaurs to this day.
1940s-1990s
Very few other Tyrannosaurus rex skeletons were discovered until the late 1980s. The skull of Nanotyrannus, frequently considered to be a juvenile T. rex, was recovered from Montana in 1942. In 1966, a crew working for the Natural History Museum of Los Angeles CountyNatural History Museum of Los Angeles County
The Natural History Museum of Los Angeles County opened in Exposition Park, Los Angeles, California, USA in 1913 as the Museum of History, Science, and Art. The moving force behind it was a museum association founded in 1910. Its distinctive main building, with fitted marble walls and domed and...
under the direction of Harley Garbani discovered another T. rex (LACM 23844) which included most of the skull of a very large, mature animal. When it was put on display in Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
, LACM 23844 was the largest T. rex skull on exhibit anywhere. Garbani also discovered several other partial skeletons over the next decade (including LACM 23845, the holotype of "Albertosaurus" megagracilis), some of which are maintained in the collections of the University of California
University of California
The University of California is a public university system in the U.S. state of California. Under the California Master Plan for Higher Education, the University of California is a part of the state's three-tier public higher education system, which also includes the California State University...
Museum of Paleontology in Berkeley, California
Berkeley, California
Berkeley is a city on the east shore of the San Francisco Bay in Northern California, United States. Its neighbors to the south are the cities of Oakland and Emeryville. To the north is the city of Albany and the unincorporated community of Kensington...
. Other skulls and partial skeletons were discovered in South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
and Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
in the early 1980s.
Before 1987, Tyrannosaurus rex was thought to be rare. However, the last two decades have seen the discovery and description of over a dozen additional specimens. The first, nicknamed "Stan" in honor of its discoverer, amateur paleontologist Stan Sacrison, was found in 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...
near Buffalo, South Dakota
Buffalo, South Dakota
Buffalo is a town in Harding County, South Dakota, United States. The population was 330 at the 2010 census. It is the county seat of Harding County.-History:Buffalo was established in 1909...
, in the spring of 1987. After 30,000 hours of digging and preparation by the Black Hills Institute, beginning in 1992, 65% of a skeleton emerged, including a complete skull. Stan (BHI 3033) is currently on display in the Black Hills Museum of Natural History in Hill City, South Dakota
Hill City, South Dakota
Hill City is the oldest existing city in Pennington County, South Dakota, United States. The population was 948 at the 2010 census. Hill City is located southwest of Rapid City on State Highway 16 and on U.S. Route 385 that connects Deadwood to Hot Springs...
following an extensive world tour, and replicas
Casting
In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process...
sold by the Black Hills Institute are also found in museum exhibit halls around the world. This specimen exhibits many bone pathologies
Pathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
, including broken and healed ribs, a broken and healed neck and a spectacular hole in the back of its head, about the size of a Tyrannosaurus tooth.
"Wankel Rex or Devil Rex": MOR 555
Charles M. Russell National Wildlife Refuge
Charles M. Russell National Wildlife Refuge surrounds Fort Peck Reservoir and at 1,100,000 acres is the largest refuge in Montana, United States. Created in 1936, the refuge was named after famed painter of the American West, Charles M. Russell...
of Montana. This specimen was excavated by a team from the Museum of the Rockies
Museum of the Rockies
The Museum of the Rockies, is located in Bozeman, Montana. The museum, originally affiliated with Montana State University in Bozeman, and now, also the Smithsonian Institution, is known for its paleontological collections, although these are not its sole focus...
led by paleontologist Jack Horner
Jack Horner (paleontologist)
John "Jack" R. Horner is an American paleontologist who discovered and named Maiasaura, providing the first clear evidence that some dinosaurs cared for their young. He is one of the best-known paleontologists in the United States...
, with assistance from the U.S. Army Corps of Engineers. The specimen, given the number MOR 555 but informally called the "Wankel rex," includes approximately 90% of the skeleton, including the skull, as well as what at the time was the first complete T. rex forelimb. It is now on exhibit at the Museum of the Rockies in Bozeman, Montana
Bozeman, Montana
Bozeman is a city in and the county seat of Gallatin County, Montana, United States, in the southwestern part of the state. The 2010 census put Bozeman's population at 37,280 making it the fourth largest city in the state. It is the principal city of the Bozeman micropolitan area, which consists...
. A cast of MOR 555 is on display at the National Museum of Scotland
National Museum of Scotland
The National Museum of Scotland, Edinburgh, Scotland, was formed in 2006 with the merger of the Museum of Scotland, with collections relating to Scottish antiquities, culture and history, and the Royal Museum next door, with collections covering science and technology, natural history, and world...
.
"Black Beauty": RTMP 81.6.1
Black Beauty was found in the lower region of Crowsnest passCrowsnest Pass
Crowsnest Pass is a high mountain pass across the Continental Divide of the Canadian Rockies on the Alberta/British Columbia border.-Geography:...
, Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
in 1980 and excavated in 1982. The nickname comes from the shiny dark color of the original fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
, which likely was caused by mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s in the surrounding rock. The fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
is now at Royal Tyrrell Museum, but casts of it can be seen at many exhibitions around the world. As example, a complete cast of the skeleton can be found at Naturhistoriska riksmuseet in Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. Many skullcasts are also exhibited.
"Sue": FMNH PR2081
Black Hills Institute of Geological Research, Inc.
The Black Hills Institute of Geological Research, Inc. is a private corporation specializing in the excavation and preparation of fossils, as well as the sale of both original fossil material and museum-quality replicas...
discovered the best-preserved Tyrannosaurus currently known, in the Hell Creek Formation near Faith, South Dakota
Faith, South Dakota
Faith is a city in Meade County, South Dakota, United States. The population was 421 at the 2010 census. Sue, the most complete Tyrannosaurus rex skeleton known, was discovered about 15 miles north and east of Faith in December 1990.-Geography:...
, on August 12, 1990. This specimen, named "Sue" in honor of its discoverer, soon became embroiled in a legal battle over its ownership. The land on which the fossil was discovered was found to lie within the Cheyenne River Indian Reservation
Cheyenne River Indian Reservation
The Cheyenne River Indian Reservation was created by the United States in 1889 by breaking up the Great Sioux Reservation, following its victory over the Lakota in a series of wars in the 1870s. The reservation covers almost all of Dewey and Ziebach counties in South Dakota...
and is occupied by the family of Maurice Williams, a Native American
Native Americans in the United States
Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...
of the Sioux
Sioux
The Sioux are Native American and First Nations people in North America. The term can refer to any ethnic group within the Great Sioux Nation or any of the nation's many language dialects...
tribe
Tribe
A tribe, viewed historically or developmentally, consists of a social group existing before the development of, or outside of, states.Many anthropologists use the term tribal society to refer to societies organized largely on the basis of kinship, especially corporate descent groups .Some theorists...
. In 1992, Williams claimed he still owned the fossil, for which the Black Hills Institute had paid him USD 5,000. The local Cheyenne River Sioux Tribe, of which Williams is a member, also claimed ownership. The fossil, as well as many thousands of pages of field notes and business records, were confiscated by the Federal Bureau of Investigation
Federal Bureau of Investigation
The Federal Bureau of Investigation is an agency of the United States Department of Justice that serves as both a federal criminal investigative body and an internal intelligence agency . The FBI has investigative jurisdiction over violations of more than 200 categories of federal crime...
in 1992 and held throughout the ensuing court proceedings. In 1997, the suit was settled in favor of Maurice Williams because his land is technically held in trust
Trust law
In common law legal systems, a trust is a relationship whereby property is held by one party for the benefit of another...
for him by the United States government. Therefore, although the Black Hills Institute had paid Williams for the fossil, it was judged that the fossil could be considered "land" which Williams owned but could not legally sell without government permission. The fossil was returned to Williams' ownership and Pete Larson
Pete Larson
Peter Larson is an American paleontologist from the Black Hills Institute of Geological Research that led the team that excavated "Sue", one of the most complete specimens of Tyrannosaurus rex found to date. He also co-authored the book "Rex Appeal" which relates the story of how the U.S....
, vice-president of the Black Hills Institute, was sentenced to two years in federal prison for an unrelated customs violation discovered by the FBI while searching through his business records. Williams quickly offered up "Sue" for auction by Sotheby's
Sotheby's
Sotheby's is the world's fourth oldest auction house in continuous operation.-History:The oldest auction house in operation is the Stockholms Auktionsverk founded in 1674, the second oldest is Göteborgs Auktionsverk founded in 1681 and third oldest being founded in 1731, all Swedish...
in New York, where it was sold to the Field Museum of Natural History
Field Museum of Natural History
The Field Museum of Natural History is located in Chicago, Illinois, USA. It sits on Lake Shore Drive next to Lake Michigan, part of a scenic complex known as the Museum Campus Chicago...
in Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
for USD 8.4 million — the highest price ever paid for a fossil. Preparation of "Sue" (FMNH PR2081) was completed at the Field Museum and her skeleton was placed on exhibit on May 17, 2000. Over 90% of the skeleton was recovered, allowing the first complete description of a Tyrannosaurus rex skeleton.
"Samson"
Following the sale of "Sue," another Tyrannosaurus rex skeleton, dubbed "Z-rex", was put up for auction on eBayEBay
eBay Inc. is an American internet consumer-to-consumer corporation that manages eBay.com, an online auction and shopping website in which people and businesses buy and sell a broad variety of goods and services worldwide...
in 2000 with an asking price of over USD 8 million. It failed to sell online but was purchased for an undisclosed price in 2001 by British
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
millionaire Graham Ferguson Lacey, who renamed the skeleton "Samson" after the Biblical
Bible
The Bible refers to any one of the collections of the primary religious texts of Judaism and Christianity. There is no common version of the Bible, as the individual books , their contents and their order vary among denominations...
figure of the same name
Samson
Samson, Shimshon ; Shamshoun or Sampson is the third to last of the Judges of the ancient Israelites mentioned in the Tanakh ....
. This specimen, discovered on private land in South Dakota in 1992, includes a complete and undistorted skull, which was prepared by the Carnegie Museum starting in May 2004. After preparation was complete in March 2006, the specimen was returned to its owner, who plans to put it on an educational tour. "Samson" along with some other dinosaur skeletons was sold at auction on October 3, 2009, exhibited in early 2011 at the Embedded Systems Conference Silicon Valley.
"Stan": BHI 3033
Buffalo, South Dakota
Buffalo is a town in Harding County, South Dakota, United States. The population was 330 at the 2010 census. It is the county seat of Harding County.-History:Buffalo was established in 1909...
by Stan Sacrison. When Pete Larson
Pete Larson
Peter Larson is an American paleontologist from the Black Hills Institute of Geological Research that led the team that excavated "Sue", one of the most complete specimens of Tyrannosaurus rex found to date. He also co-authored the book "Rex Appeal" which relates the story of how the U.S....
and his team at the Black Hills Institute began extracting the fossil, they nicknamed it "Stan", after its discoverer, and from then on, the name stuck.
While examining this fossil, Larson made a number of observations which were consistent with non-fatal injuries sustained during life. These include several broken ribs with signs of bone regrowth; scarring on the ribs; two fused cervical vertebrae, suggesting that "Stan" healed a broken neck; cheeks showing signs of healed injuries; and a hole in the braincase 1 inch in diameter (it is a leap, but a Tyrannosaurus tooth is the right size to inflict such an injury). A thin layer of bone resealed the hole, suggesting this injury fell just short of fatal.
"Jane": BMRP 2002.4.1
Tyrannosauridae
Tyrannosauridae is a family of coelurosaurian theropod dinosaurs which comprises two subfamilies containing up to six genera, including the eponymous Tyrannosaurus. The exact number of genera is controversial, with some experts recognizing as few as three...
specimen nicknamed "Jane" was excavated. Now residing at the Burpee Museum of Natural History
Burpee Museum of Natural History
The Burpee Museum of Natural History is located along the Rock River in downtown Rockford, Illinois at 737 North Main Street.-Museum History:...
as BMRP 2002.4.1, "Jane" is at the center of a debate about whether the small tyrannosaurid genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Nanotyrannus
Nanotyrannus
Nanotyrannus is a genus of tyrannosaurid dinosaur, known only from two juvenile specimens, which may in fact represent juvenile specimens of the contemporary species Tyrannosaurus rex.-History:...
is valid or a juvenile Tyrannosaurus, as "Jane" compares favorably with the original specimen of Nanotyrannus. Although there are dissenters, the majority of paleontologists who have looked at the specimens consider them to be juvenile individuals of Tyrannosaurus rex.
Soft tissue in MOR 1125 (B-rex)
In the March 2005 Science magazineScience (journal)
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....
, Mary Higby Schweitzer
Mary Higby Schweitzer
Mary Higby Schweitzer is a paleontologist at North Carolina State University known for leading the groups which discovered the remains of blood cells in dinosaur fossils and later discovered soft tissue remains in the Tyrannosaurus rex specimen MOR 1125, as well as evidence that the specimen was a...
of North Carolina State University
North Carolina State University
North Carolina State University at Raleigh is a public, coeducational, extensive research university located in Raleigh, North Carolina, United States. Commonly known as NC State, the university is part of the University of North Carolina system and is a land, sea, and space grant institution...
and colleagues announced the recovery of soft tissue from the marrow cavity of a fossilized leg bone, from a 68 million-year-old Tyrannosaurus. The bone had been intentionally, though reluctantly, broken for shipping and then not preserved in the normal manner, specifically because Schweitzer was hoping to test it for soft tissue. Designated MOR
Museum of the Rockies
The Museum of the Rockies, is located in Bozeman, Montana. The museum, originally affiliated with Montana State University in Bozeman, and now, also the Smithsonian Institution, is known for its paleontological collections, although these are not its sole focus...
1125 (and known informally as B-rex), the dinosaur had been excavated from the Hell Creek Formation. Flexible, bifurcating blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s and fibrous but elastic 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...
matrix tissue were recognized. In addition, microstructures resembling blood cell
Blood cell
A blood cell, also called a hematocyte, is a cell normally found in blood. In mammals, these fall into three general categories:* red blood cells — Erythrocytes* white blood cells — Leukocytes* platelets — Thrombocytes...
s were found inside the matrix and vessels. The structures bear resemblance to ostrich
Ostrich
The Ostrich is one or two species of large flightless birds native to Africa, the only living member of the genus Struthio. Some analyses indicate that the Somali Ostrich may be better considered a full species apart from the Common Ostrich, but most taxonomists consider it to be a...
blood cells and vessels. However, since an unknown process distinct from normal fossilization seems to have preserved the material, the researchers are being careful not to claim that it is original material from the dinosaur. If it is found to be original material, any surviving proteins may be used as a means of indirectly guessing some of the DNA content of the dinosaurs involved, because each protein is typically created by a specific gene. The absence of previous finds may merely be the result of assumptions that soft tissue could not be preserved, so that nobody had looked for it. Since the first, two more tyrannosaurs and a hadrosaur have also been found to have such tissue-like structures.
Paleontologist Thomas Kaye of the University of Washington in Seattle has also hypothesized that the soft-tissue is permineralized
Permineralization
Permineralization is a process of fossilization in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue...
biofilm created by bacteria while digesting and breaking down the original specimen. He has discovered this to be true in many specimens from the same area.