Khankhuuluu

Name Origin

Prince's Dragon

Family

Tyrannosauroidea

Classification

Reptilia, Saurischia, Theropoda

Habitat (Discovery Location)

Mongolia

Period

Approximately 90–86 million years ago (Late Cretaceous)

Length

Approximately 4 meters

Weight

Approximately 500–750 kg

Diet

Carnivore (Meat-eater)

Description

In June 2025, a shockwave ran through the world of paleontology.
A new species of dinosaur was announced that overturned established theories regarding the origins of the “strongest dinosaur,” Tyrannosaurus rex.

Its name is “Khankhuulu mongoliensis.”

Meaning “Prince’s Dragon” in Mongolian, this dinosaur is a critically important existence that fills the “missing link” in Tyrannosaurus evolution, a mystery that had persisted for many years.

Discovered After 50 Years! The Meaning of the “Mongolian Prince”

There is a long history behind the discovery of Khankhuulu.

Unidentified Fossils Sleeping in a Museum

The fossils themselves were excavated in the Gobi Desert by a joint Soviet-Mongolian expedition in the 1970s.
However, at the time, they were presumed to be “a type of Alectrosaurus,” and without a detailed classification, they lay dormant in a museum storage room for half a century.

Identified as a New Species in a 2023 Re-investigation

The turning point came in 2023.
When Jared Voris, a graduate student at the University of Calgary, conducted a re-investigation, he spotted features distinct from Alectrosaurus (such as the shape of the nasal bone and its hollows).
Detailed analysis confirmed it as a new genus and species. As a “Prince” in the lineage leading to the “King” known as T. rex, it was named Khankhuulu (Prince’s Dragon).

Appearance Like an “Eternal Juvenile” and the Key to Evolution

Khankhuulu lived during the Late Cretaceous, approximately 90 to 86 million years ago.
Its appearance bore little resemblance to the later Tyrannosaurus.

A Slender, Small Speedster

Size

Estimated total length of about 4 meters, weighing 500–750 kg.
This is less than one-tenth the weight of a Tyrannosaurus.

Characteristics

Instead of thick, bone-crushing teeth, it possessed “blade-like teeth for slicing meat” and had “speed-type” legs where the tibia was longer than the femur.

Evolution via Heterochrony

These features actually closely resemble the “juveniles” of large tyrannosaurs.
It is believed that Khankhuulu adopted a strategy called “paedomorphosis” (juvenile maturity), retaining slender, juvenile-like characteristics even as an adult.
Unlike the Tyrannosaurus which grew massive to stand at the top, Khankhuulu established a status as an “intermediate predator” that hunted prey with agile movements.

Three Round Trips Between Asia and North America? The Drama of Intercontinental Migration

The discovery of Khankhuulu also unraveled the mystery of how tyrannosaurs spread across the world.
They made at least three major migrations between Asia and North America.