About Guanlong
| Scientific Name (Genus) | Guanlong |
| Meaning of Name |
Crown dragon
Guan [Chinese] - long [Chinese] |
| Classification | Saurischia, Theropoda, Tyrannosauroidea (Proceratosauridae) |
| Total Length | Approx. 3-3.5m |
| Weight | Approx. 125kg |
| Diet | Carnivorous |
| Period | Late Jurassic (approx. 163.5 to 157.3 million years ago) |
| Sub-classification / Species Name | Guanlong wucaii |
| Year of Paper Publication | 2006 |
Characteristics of Guanlong
The most striking feature of Guanlong, which is also the origin of its scientific name, is the large crest that rises from the premaxilla to the nasal bone. Although this crest was 5 to 6 cm high, its thinnest part was only about 1.5 mm thick, and it was hollow inside.
Therefore, it has been concluded that this crest was not used as a weapon or armor for attacking prey or defense, but rather as a "visual display organ" for identifying members of the same species or attracting mates.
Guanlong was a small carnivorous dinosaur belonging to the early lineage that led to Tyrannosaurus, and it possesses features different from the Tyrannosaurus that grew huge in the Cretaceous. For example, its arms (forelimbs) were long and had three fingers for grasping objects (later Tyrannosaurus had short arms with two fingers).
On the other hand, it also possesses new features characteristic of tyrannosauroids, such as D-shaped teeth suitable for scraping off meat.
It was once thought to be a direct ancestor of the Tyrannosauridae, but it is currently classified into an early diverging relative group.
This is a phenomenon in the process of biological evolution where old ancestral features remain in one part of the body while new evolved features appear in another. In the case of Guanlong, "old features (3 fingers)" remain in its hands, while "new features (teeth unique to tyrannosaurs)" appear in its head.
It is an early group of the lineage leading to Tyrannosaurus (Tyrannosauroidea). Unlike the giant tyrannosaurs that appeared later, they are characterized by having a crest on their snout.
Also, although there is no direct evidence from fossils, since traces of feathers have been found in closely related dinosaurs, it is considered certain that Guanlong was also covered with fluffy feathers like a down jacket.
Excellent Senses and Tooth Mechanism
In recent years, non-destructive testing using high-resolution CT scans has revealed the ecology of Guanlong in more detail.
What is particularly noteworthy is the mechanism of tooth replacement. When juvenile fossils were examined, it was confirmed that "second-generation spare teeth" were waiting inside the jawbone. It was found that such a tooth replacement system was already established in the Jurassic stage.
Also, investigations of the space where the brain was housed (braincase) indicate that they possessed the ability to hear low-frequency sounds, reflexes to follow fast-moving prey with their eyes, and a keen sense of smell. Guanlong was a sophisticated hunter that cornered its prey using its excellent senses.
Two Fossils Left in a "Death Trap"
Two Guanlongs were buried here.
Guanlong fossils were discovered in a Late Jurassic stratum in the Xinjiang Uygur Autonomous Region of China, with two individuals overlapping each other. As a result of the investigation, it was found that the one underneath was a 6-year-old juvenile, and the one on top was a 12-year-old adult.
It is known that this location was a "death trap" where the footprints left by giant sauropods (large herbivorous dinosaurs) walking at the time turned into a quagmire.
A chain reaction occurred where small dinosaurs caught in the mud sank deeper the more they struggled, and other dinosaurs attracted by the smell of death fell into the trap as well. It is thought that the adult Guanlong also approached aiming for prey such as trapped herbivorous dinosaurs and juveniles, and ended up unable to get out of the mud itself.
Research examining the internal tissue of fossilized bones (bone histology) has also revealed the growth speed of Guanlong. The 6-year-old juvenile was still in the middle of growing and had a small crest, whereas the adult had already stopped growing and had a largely developed crest. It is known that Guanlong reached adulthood at about 7 years of age and rapidly grew its crest.
Guanlong Stamp and Fossil Gallery
