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Ultrasaurus is a genus of gigantic dinosaurs that lived about 100 to 110 million years ago.


Scientific Classification

Kingdom Animalia
Phylum Chordata
Class Reptilia
Clade Dinosauria
Suborder Sauropodomorpha
Clade Neosauropoda
Genus Ultrasaurus
Species U. tabriensis

Quick Facts file

Name Meaning Ultra lizard
Geological Time Period Aptian/Albian stages of early Cretaceous
Size 82 – 100 ft (25-30 m) long
50 ft (15 m) high
Weight 55 – 130 tons
Location South Korea (Asia)
Diet Herbivorous
Birth type Eggs
Locomotion Quadrupedal

Physical Description

Their front legs reached a height of nearly 25 feet while their neck measured 60 feet in length. They had a relatively short tail.

History and Discovery

Ultrasaurus was discovered by Kim Haang Mook in South Korea in the year 1983. However, in 1979, Jim Jensen of Brigham Young University used this name to unofficially describe dinosaur fossils, which he found at Dry Mesa Quarry, Colorado.

But before Jensen could officially declare his discovery, Kim Haang published the name “Ultrasaurus,” and thus Jensen had to rename his specimen to “Ultrasauros.”

However, Jensen’s findings were considered a “chimera” since the fossil he found belonged to two distinct dinosaurs – Brachiosaurus and Supersaurus.

Comparison with Other Dinosaurs

Like Ultrasaurus, Diplodocus and Argentinosaurus too were plant-eating dinosaurs with similar body structure.  Diplodocus was a native of North America during the late Jurassic period while Argentinosaurus inhabited Argentina during the Late Cretaceous Period.

Among the three Sauropods, Diplodocus is considered the largest with an approximate length of 25 meters.


They were terrestrial animals living in herds, migrating from one place to another in search of food. Fossil studies have revealed that they laid their eggs in a linear pattern. It is believed that the parent Ultrasaurus did not care for their young ones.


No substantial data exists but it is assumed that the Cretaceous- Tertiary mass extinction event might have wiped them out.


Natural enemies like Allosaurus and its relative Ceratosaurus used to prey upon the baby as well as the old and sick Ultrasaurus.

Interesting Facts

  • When Jensen unofficially named his dinosaur “Ultrasaurus,” the scientific community called it a nomen nudum because of its inadequate scientific description.
  • It was believed that the Ultrasaurus had a second brain like the other Sauropods, but later it was found that it was an enlargement of the spinal cord.

Published on December 26th 2016 by under Reptiles.
Article was last reviewed on 16th September 2019.

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