Supersaurus
Encyclopedia
Supersaurus is a genus
of diplodocid
sauropod
dinosaur
discovered by Vivian Jones of Delta, Colorado, in the Upper Jurassic Morrison Formation
of Colorado
in 1972. The fossil remains came from the Brushy Basin Member of the formation, dating to about 153 million years ago. It is among the largest dinosaurs
known from good remains, possibly reaching 33 to 34 meters (108 to 112 ft) in length, and a weight of 35 to 40 tons. Recent discoveries show Supersaurus to be a large relative of the familiar Apatosaurus
.
The original fossil
remains of Supersaurus, discovered in the Dry Mesa Quarry
, yielded only a few bones: the shoulder girdle (type specimen
BYU
12962, earlier BYU 5500), an ischium (BYU 12946) and a few neck vertebrae. This shoulder girdle (or scapulocoracoid
) stood some 2.4 meters (8 ft) tall, if placed on end.
A new and much more complete specimen of Supersaurus, nicknamed 'Jimbo', WDC DMJ-021, was found in Converse County, Wyoming
in 1996. It is currently being prepared and was described in 2007. Its bones are being held at the Wyoming Dinosaur Center
. By comparing the two specimens, it could be established that a series of tail vertebrae referred to Supersaurus by Jensen may have belonged to some other form. Originally, it was thought that Supersaurus was related to the long-necked diplodocid Barosaurus
, and therefore a member of the subfamily Diplodocinae. Study of the new specimen indicated that Supersaurus may actually more closely related to Apatosaurus
, and a member of the subfamily Apatosaurinae. However, more thorough phylogenetic analyses show that Supersaurus may in fact be more closely related to the diplodocines than to Apatosaurus. In most respects, Supersaurus has the same morphology
as Apatosaurus but it is less robustly built with especially elongated cervical vertebrae, resulting into one of the longest known sauropod necks. Supersaurus is present in stratigraphic zone 5 of the Morrison, dating from the Tithonian
.
Paleontologist James A. Jensen
, who described the original Supersaurus specimen, simultaneously reported the discovery of another gigantic sauropod, which would later be named "Ultrasaurus" macintoshi (later re-named Ultrasauros macintoshi). The type specimen (the specimen used to define a new species
) of Ultrasauros, being a backbone (dorsal vertebra, labeled BYU 9044), was later found to have come from Supersaurus. In fact, it probably belonged to the original Supersaurus specimen, which was discovered in the same quarry in 1972. Therefore, Ultrasauros became a junior objective synonym of Supersaurus, which had been named first and thus retains priority, and the name Ultrasauros was abandoned.
Other bones that were found at the same location and originally thought to belong to Ultrasauros, like a shoulder girdle (scapulocoracoid
, BYU 9462), actually belonged to Brachiosaurus
, possibly a large specimen of Brachiosaurus altithorax. The Brachiosaurus bones indicate a large, but not record-breaking individual, a little larger than the "Brachiosaurus" brancai (Giraffatitan
brancai) mount in the Humboldt Museum
of Berlin. Larger specimens of Brachiosaurus are known from the Tendaguru
beds of Tanzania
, in east Africa
.
Originally, these Supersaurus and Brachiosaurus bones were believed to represent a single dinosaur that was estimated to reach about 25 to 30 meters (80 to 100 ft) long, 8 meters (25 ft) high at the shoulder, 15 meters (50 ft) in total height, and weighing maybe 70 metric tons (75 short ton
s). At the time, mass estimates ranged up to 180 tons, which placed it in the same category as the blue whale
and the equally problematic Bruhathkayosaurus
.
The naming of the chimeric
Ultrasauros has a similarly complicated history. Ultrasaurus was the original choice, and was widely used by the media after the discovery in 1979. However, the name of a new species
must be published with a description to become official.
Before Jim Jensen published his discovery in 1985, another paleontologist, Kim Haang Mook, used the name Ultrasaurus
in a 1983 publication to describe what he believed was a giant dinosaur in South Korea
. This was a different, much smaller dinosaur than Jensen's find, but Kim thought it represented a similarly gigantic animal because he confused a femur
(leg bone) for a humerus
(arm bone). While the logic of naming was incorrect, the Ultrasaurus from Kim's find fulfilled the requirements for naming and became regarded as a legitimate, if dubious genus. Thus, because Jensen did not publish his own "Ultrasaurus" find until 1985, Kim's use retained its official priority of name, and Jensen was forced to choose a new name (in technical terms, his original choice was "preoccupied" by Kim's sauropod). In 1991, at his suggestion, George Olshevsky
changed one letter, and renamed Jensen's sauropod Ultrasauros.
When it was later discovered that the new name referred to bones from two separate, and already known species, the name Ultrasauros became a junior synonym for Supersaurus. Since the bones from the Brachiosaurus were only used as a secondary reference for the new species, Ultrasauros is not a junior synonym for Brachiosaurus. Since Supersaurus was named slightly earlier, the name Ultrasauros has been discarded in favor of Supersaurus.
dinosaur found near the original Supersaurus quarry, known from a backbone (dorsal vertebra type specimen BYU 5750), was named Dystylosaurus edwini and is now also considered to be a specimen of Supersaurus vivianae. Hence, Dystylosaurus has also become a junior synonym of Supersaurus.
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...
of diplodocid
Diplodocid
Diplodocids, or members of the family Diplodocidae , are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including Diplodocus and Supersaurus, which may have reached lengths of up to .-Description:While still massive, when compared to the...
sauropod
Sauropoda
Sauropoda , or the sauropods , are an infraorder of saurischian dinosaurs. They had long necks, long tails, small heads , and thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land...
dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
discovered by Vivian Jones of Delta, Colorado, in the Upper Jurassic Morrison Formation
Morrison Formation
The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...
of Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
in 1972. The fossil remains came from the Brushy Basin Member of the formation, dating to about 153 million years ago. It is among the largest dinosaurs
Dinosaur size
Size has been one of the most interesting aspects of dinosaur science to the general public. This article lists the largest and smallest dinosaurs from various groups, sorted in order of weight and length....
known from good remains, possibly reaching 33 to 34 meters (108 to 112 ft) in length, and a weight of 35 to 40 tons. Recent discoveries show Supersaurus to be a large relative of the familiar Apatosaurus
Apatosaurus
Apatosaurus , also known by the popular but scientifically deprecated synonym Brontosaurus, is a genus of sauropod dinosaur that lived from about 154 to 150 million years ago, during the Jurassic Period . It was one of the largest land animals that ever existed, with an average length of and a...
.
History
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains of Supersaurus, discovered in the Dry Mesa Quarry
Dry Mesa Quarry
The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, USA, near the town of Delta. Its geology forms a part of the Morrison Formation and has famously yielded a great diversity of animal remains from the Jurassic Period, among them Ceratosaurus, Supersaurus, and Torvosaurus...
, yielded only a few bones: the shoulder girdle (type specimen
Holotype
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...
BYU
Brigham Young University
Brigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...
12962, earlier BYU 5500), an ischium (BYU 12946) and a few neck vertebrae. This shoulder girdle (or scapulocoracoid
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
) stood some 2.4 meters (8 ft) tall, if placed on end.
A new and much more complete specimen of Supersaurus, nicknamed 'Jimbo', WDC DMJ-021, was found in Converse County, Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
in 1996. It is currently being prepared and was described in 2007. Its bones are being held at the Wyoming Dinosaur Center
Wyoming Dinosaur Center
right|290px|thumb|Wyoming Dinosaur CenterThe Wyoming Dinosaur Center is located in Thermopolis, Wyoming and is one of the few dinosaur museums in the world to have its own excavation within driving distance...
. By comparing the two specimens, it could be established that a series of tail vertebrae referred to Supersaurus by Jensen may have belonged to some other form. Originally, it was thought that Supersaurus was related to the long-necked diplodocid Barosaurus
Barosaurus
Barosaurus ; Greek barys/βαρυς meaning 'heavy' and saurus/σαυρος meaning 'lizard', 'heavy lizard') was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar Diplodocus...
, and therefore a member of the subfamily Diplodocinae. Study of the new specimen indicated that Supersaurus may actually more closely related to Apatosaurus
Apatosaurus
Apatosaurus , also known by the popular but scientifically deprecated synonym Brontosaurus, is a genus of sauropod dinosaur that lived from about 154 to 150 million years ago, during the Jurassic Period . It was one of the largest land animals that ever existed, with an average length of and a...
, and a member of the subfamily Apatosaurinae. However, more thorough phylogenetic analyses show that Supersaurus may in fact be more closely related to the diplodocines than to Apatosaurus. In most respects, Supersaurus has the same morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
as Apatosaurus but it is less robustly built with especially elongated cervical vertebrae, resulting into one of the longest known sauropod necks. Supersaurus is present in stratigraphic zone 5 of the Morrison, dating from the Tithonian
Tithonian
In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...
.
Ultrasauros
James A. Jensen
James A. Jensen , was an American paleontologist. His extensive collecting program at BYU in the Utah-Colorado region which spanned 23 years was comparable in terms of the number of specimens collected to that of Barnum Brown during the early 20th century. He was given the name "Dinosaur Jim"...
, who described the original Supersaurus specimen, simultaneously reported the discovery of another gigantic sauropod, which would later be named "Ultrasaurus" macintoshi (later re-named Ultrasauros macintoshi). The type specimen (the specimen used to define a new species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
) of Ultrasauros, being a backbone (dorsal vertebra, labeled BYU 9044), was later found to have come from Supersaurus. In fact, it probably belonged to the original Supersaurus specimen, which was discovered in the same quarry in 1972. Therefore, Ultrasauros became a junior objective synonym of Supersaurus, which had been named first and thus retains priority, and the name Ultrasauros was abandoned.
Other bones that were found at the same location and originally thought to belong to Ultrasauros, like a shoulder girdle (scapulocoracoid
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
, BYU 9462), actually belonged to Brachiosaurus
Brachiosaurus
Brachiosaurus is a genus of sauropod dinosaur from the Jurassic Morrison Formation of North America. It was first described by Elmer S. Riggs in 1903 from fossils found in the Grand River Canyon of western Colorado, in the United States. Riggs named the dinosaur Brachiosaurus altithorax,...
, possibly a large specimen of Brachiosaurus altithorax. The Brachiosaurus bones indicate a large, but not record-breaking individual, a little larger than the "Brachiosaurus" brancai (Giraffatitan
Giraffatitan
Giraffatitan, meaning "giraffe titan", is a genus of sauropod dinosaur that lived during the late Jurassic Period . It was originally named as an African species of Brachiosaurus...
brancai) mount in the Humboldt Museum
Humboldt Museum
The Museum für Naturkunde, officially the ' or Naturkundemuseum , occasionally known as the Humboldt Museum, is a natural history museum in Berlin, Germany. Usually the museum's name is abbreviated MFN...
of Berlin. Larger specimens of Brachiosaurus are known from the Tendaguru
Tendaguru
The Tendaguru Beds are a fossil-rich formation in Tanzania. It has been considered the richest of Late Jurassic strata in Africa. Continental reconstructions show Tendaguru to have been in the southern hemisphere during the Late Jurassic. Tendaguru is similar to the Morrison Formation except in...
beds of Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
, in east Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
.
Originally, these Supersaurus and Brachiosaurus bones were believed to represent a single dinosaur that was estimated to reach about 25 to 30 meters (80 to 100 ft) long, 8 meters (25 ft) high at the shoulder, 15 meters (50 ft) in total height, and weighing maybe 70 metric tons (75 short ton
Short ton
The short ton is a unit of mass equal to . In the United States it is often called simply ton without distinguishing it from the metric ton or the long ton ; rather, the other two are specifically noted. There are, however, some U.S...
s). At the time, mass estimates ranged up to 180 tons, which placed it in the same category as the blue whale
Blue Whale
The blue whale is a marine mammal belonging to the suborder of baleen whales . At in length and or more in weight, it is the largest known animal to have ever existed....
and the equally problematic Bruhathkayosaurus
Bruhathkayosaurus
Bruhathkayosaurus might have been the largest dinosaur that ever lived. The accuracy of this claim, however, has been mired in controversy and debate...
.
Naming of Ultrasauros
Chimera (paleontology)
In paleontology, a chimera is a fossil which was reconstructed with elements coming from more than a single species of animal. A now classic example of chimera is Protoavis.-List of paleontological chimeras:*Brontosaurus*Lametasaurus...
Ultrasauros has a similarly complicated history. Ultrasaurus was the original choice, and was widely used by the media after the discovery in 1979. However, the name of a new species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
must be published with a description to become official.
Ultrasaurus
Ultrasaurus is a genus of sauropod dinosaur discovered by Haang Mook Kim in South Korea. However, the name was first used unofficially in 1979 by Jim Jensen to describe a set of giant dinosaur bones he discovered in the United States...
in a 1983 publication to describe what he believed was a giant dinosaur in South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
. This was a different, much smaller dinosaur than Jensen's find, but Kim thought it represented a similarly gigantic animal because he confused a femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
(leg bone) for a humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
(arm bone). While the logic of naming was incorrect, the Ultrasaurus from Kim's find fulfilled the requirements for naming and became regarded as a legitimate, if dubious genus. Thus, because Jensen did not publish his own "Ultrasaurus" find until 1985, Kim's use retained its official priority of name, and Jensen was forced to choose a new name (in technical terms, his original choice was "preoccupied" by Kim's sauropod). In 1991, at his suggestion, George Olshevsky
George Olshevsky
George Olshevsky is a freelance editor, writer, publisher, amateur paleontologist, and mathematician living in San Diego, California.Olshevsky maintains the comprehensive online Dinosaur Genera List...
changed one letter, and renamed Jensen's sauropod Ultrasauros.
When it was later discovered that the new name referred to bones from two separate, and already known species, the name Ultrasauros became a junior synonym for Supersaurus. Since the bones from the Brachiosaurus were only used as a secondary reference for the new species, Ultrasauros is not a junior synonym for Brachiosaurus. Since Supersaurus was named slightly earlier, the name Ultrasauros has been discarded in favor of Supersaurus.
Additional synonyms
Another diplodocidDiplodocid
Diplodocids, or members of the family Diplodocidae , are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including Diplodocus and Supersaurus, which may have reached lengths of up to .-Description:While still massive, when compared to the...
dinosaur found near the original Supersaurus quarry, known from a backbone (dorsal vertebra type specimen BYU 5750), was named Dystylosaurus edwini and is now also considered to be a specimen of Supersaurus vivianae. Hence, Dystylosaurus has also become a junior synonym of Supersaurus.
External links
- "Whatever happened to 'Ultrasauros?, by Brian Curtice.
- "Why do mass estimates vary so much?", by Mike Taylor, 27 August 2002. (see footnote)