''Ultrasaurus'' (meaning "

ultra Ultra may refer to: Science and technology * Ultra (cryptography), the codename for cryptographic intelligence obtained from signal traffic in World War II * Adobe Ultra, a vector-keying application * Sun Ultra series, a brand of computer work ...

lizard") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...

dinosaur discovered by Haang Mook Kim in South Korea. However, the name was first used unofficially (as a ''

nomen nudum In Taxonomy (biology), taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published ...

'') in 1979 by Jim Jensen to describe a set of giant

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

bones he discovered in the United States. Because Kim published the name for his specimen before Jensen could do so officially, Jensen renamed his specimen ''

Ultrasauros ''Supersaurus'' (meaning "super lizard") is a genus of diplodocid sauropod dinosaur that lived in North America during the Late Jurassic period. The type species, ''S. vivianae'', was first discovered by Vivian Jones of Delta, Colorado, in the ...

''. Jensen's giant sauropod was later found to be a

chimera Chimera, Chimaera, or Chimaira (Greek for " she-goat") originally referred to: * Chimera (mythology), a fire-breathing monster of ancient Lycia said to combine parts from multiple animals * Mount Chimaera, a fire-spewing region of Lycia or Cilicia ...

, and the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

remains are now assigned to ''

Supersaurus ''Supersaurus'' (meaning "super lizard") is a genus of diplodocid sauropod dinosaur that lived in North America during the Late Jurassic period. The type species, ''S. vivianae'', was first discovered by Vivian Jones of Delta, Colorado, in the ...

''.

Mistaken assessments

A collection of bones discovered by Jim Jensen, of

Brigham Young University Brigham Young University (BYU) is a Private education, private research university in Provo, Utah, United States. It was founded in 1875 by religious leader Brigham Young and is the flagship university of the Church Educational System sponsore ...

, at the

Dry Mesa Quarry The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, United States, near the town of Delta Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fo ...

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

were originally believed to belong to the largest dinosaur ever. Jensen informally called this supposedly new dinosaur "Ultrasaurus", and this name was widely used by the press and in scientific literature as a ''nomen nudum'' (informal name lacking an actual scientific description). In 1983, Kim Hang-mook published a paper describing a different specimen representing a new dinosaur species, which he named ''Ultrasaurus tabriensis'', because he believed it was bigger than ''

''. However, Kim's assessment was incorrect. His dinosaur was much smaller than he believed, because he mistook a partial

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

for an

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

. However, since Kim was the first to publish the name ''Ultrasaurus'', the name officially applied to the small

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern half of the Korea, Korean Peninsula and borders North Korea along the Korean Demilitarized Zone, with the Yellow Sea to the west and t ...

n sauropod, and could no longer be used as an official name for Jensen's giant specimen. Jensen published a paper describing his original discovery in 1985, but since the name ''Ultrasaurus'' was already in use (or "preoccupied"), his discovery was renamed in 1991 to ''Ultrasaur''o''s''. However, Jensen also made a mistake. His discovery was a chimera; the collection of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s came from two different dinosaur species, both of which already had names. So his new name, ''Ultrasauros'', is now just an alternate name (''junior synonym'') for the dinosaur officially known as ''Supersaurus''.

Description

''Ultrasaurus'' lived 100 to 110

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

, during the

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

and

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

stages Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

of the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

. It is known from the holotype DGBU-1973, which consists of part of an upper forearm (

), and DGBU-1978-A, a single tailbone (

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e) from the Gugyedong Formation, belonging to the Hayang Group.

Classification

Kim's ''Ultrasaurus'' is currently a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

''. Not enough is known about the specimen to formally assign it to a specific

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of sauropods.

References

{{Taxonbar, from=Q277682 Sauropoda Dinosaur genera Albian dinosaurs Fossil taxa described in 1983 Dinosaurs of Asia