About Alioramus
| Scientific Name (Genus) | Alioramus |
| Meaning of Name |
Different branch
alius(different)[Latin]-rāmus(branch)[Latin] |
| Classification | Saurischia, Theropoda, Tyrannosauridae, Alioramini |
| Total Length | Approx. 5-6m |
| Diet | Carnivorous |
| Period | Late Cretaceous (approx. 70 million years ago) |
| Sub-classification / Species Name |
Alioramus remotus
Alioramus altai |
| Year of Paper Publication | 1976 |
| Genus Name Publication | Kurzanov, S. M. (1976). A new carnosaur from the Late Cretaceous of Nogon-Tsav, Mongolia. The Joint Soviet-Mongolian Paleontological Expedition Transactions, 3, 93-104. |
A Tyrannosaurid with a Unique Appearance
Alioramus was a carnivorous dinosaur that lived in what is now the Gobi Desert of Mongolia during the Late Cretaceous, about 70 million years ago. Although it belonged to the tyrannosaur family (Tyrannosauridae), its appearance was so different from its relatives that it was given a name meaning "different branch" in Latin.
Its most prominent features were a low, elongated head and five bumpy bony crests lined up along its snout. It also had about 76 to 78 thin, sharp teeth, the most of any tyrannosaurid.
Its overall build was very gracile and slender, and having long, thin legs, it is thought to have been a dinosaur that excelled in speed and agility.
New Discoveries That Cleared the "Juvenile" Misconception
For a long time after the first fossils were discovered in the 1970s, only fossils of young Alioramus individuals were found. Therefore, many researchers suspected that it might be the juvenile form of the giant Tarbosaurus that lived in the same region.
However, the situation completely changed in 2001 with the discovery of a new, well-preserved fossil (Alioramus altai). While the number of teeth in Tarbosaurus does not change as it grows, Alioramus already had far more teeth than Tarbosaurus at a young stage, proving clearly that it was a separate, independent dinosaur.
Source: Brusatte, S. L. et al. (2009). A long-snouted, multihorned tyrannosaurid from the Late Cretaceous of Mongolia. PNAS, 106(41).
Furthermore, in recent years, a dinosaur with a similarly long snout called "Qianzhousaurus" was discovered in China. This revealed that they formed their own unique group called "Alioramini" within the tyrannosaur family.
Typical giant tyrannosaurs underwent a change where their skulls became thicker and more robust as they grew. However, the dinosaurs of the Alioramini tribe underwent a unique evolution where their head shapes did not become robust even as they grew, maintaining their elongated shapes and extending their snouts even further.
Alioramini
A taxonomic name referring to a group within the Tyrannosauridae that has elongated snouts. Currently, it includes two genera: Alioramus and Qianzhousaurus. During the end of the Cretaceous in Asia, they took a unique evolutionary path completely different from the giant tyrannosaurs.
"Bite Force" and Hunting Style Revealed by Calculations
Was the elongated jaw of Alioramus strong enough to catch prey? Using the latest computer simulations, the strength of their jaws was calculated.
As a result, it was found that the gracile skull of Alioramus was not structured to withstand the intense force of crushing the prey's meat and bones together and tearing it off, like the giant Tyrannosaurus.
Having no robust jaws, they adopted a completely different hunting style. It is thought that they excelled at swift attacks to "slash" the prey's meat repeatedly, utilizing their elongated, specialized forward jaws and numerous sharp teeth.
Analysis via Biomechanics
A field that studies the structure and movement of living organisms' bodies from a mechanical perspective. By creating 3D models of dinosaur skulls on a computer and using a technique called "Finite Element Analysis (FEA)" to simulate how much stress is placed on which part of the bone when biting, it is possible to scientifically infer their past diets and hunting methods.
Clever Niche Partitioning with a Giant Rival
In the rich floodplains of Mongolia where Alioramus lived, the largest Asian tyrannosaurid, "Tarbosaurus", reigned supreme.
Normally, if there are similar large carnivorous dinosaurs in the same place, fierce conflicts over prey occur, and the loser of the competition goes extinct. However, they brilliantly solved this problem. While the overwhelmingly powerful Tarbosaurus overpowered slow-moving giant herbivorous dinosaurs with its strength, Alioramus specialized in targeting fast-running small dinosaurs (such as ornithomimids) using its slender body and speed as weapons.
Avoiding competition by changing target prey in this way is called "niche partitioning" in ecology. It can be said that the reason Alioramus did not develop a robust skull even as it grew was because it avoided competing with the giant Tarbosaurus and specialized in hunting small prey.
Furthermore, research examining the shape of the brain by CT scanning the inside of the Alioramus skull supports their excellent motor skills. The parts of the brain controlling balance, agility, and the movements of the eyes and head (such as the flocculus of the cerebellum) were highly developed, proving from a neuroscientific perspective that they were excellent hunters chasing fast prey.
Go See Alioramus
Fossils of Alioramus can be seen at the following museums.
However, the exhibits may have changed. Please check the latest information yourself.
Central Museum of Mongolian Dinosaurs (Ulaanbaatar, Mongolia)
Fossil parts to see: Actual fossils, full skeletal reconstructions
Highlights: Located in the capital of Mongolia, the homeland of Alioramus. It houses and exhibits extremely well-preserved Alioramus skull fossils returned from the United States, as well as specimens of multiple individuals. The overwhelming amount of material unique to the local area and comparative exhibits with dinosaurs from the same region, such as Tarbosaurus, are the highlights.
American Museum of Natural History (New York, USA)
Fossil parts to see: Full skeletal reconstructions, skull casts
Highlights: Exhibited as an important specimen showing the evolutionary lineage of tyrannosaurs. There is an exhibit based on the study of the historically famous type specimen of Alioramus remotus, positioning it as indispensable when discussing the diversity of the Tyrannosauridae.
Especially since the discovery of Alioramus altai, Alioramus has been exhibited more frequently in museums around the world due to its unique appearance. Be sure to enjoy its delicate silhouette in actual exhibits.