|Name Meaning||Feather tyrant||Height||2.2-2.7 meters (7.2-8.8 feet)|
|Pronunciation||Yoo-ti-ran-us||Length||7.5-9 meters (24.6-29.5 feet)|
|Era||Mesozoic – Early Cretaceous||Weight||1,100-1,414 kilograms (2,425-3,117 pounds)|
|Classification||Dinosauria, Saurischia & Theropoda||Location||China, Asia|
The Yutyrannus is known from three almost complete skeletons thought to have belonged to an adult, a subadult, and a juvenile.
These creatures were tyrannosauroid theropods and likely roamed the Earth about 125 million years ago, during the Early Cretaceous.
Since the fossils were recovered from the Yixian Formation, specialists agree that the only species in the genus, Yutyrannus huali, inhabited China’s Liaoning Province.
The discovery of Yutyrannus marked the discovery of the largest feathered dinosaurs.
Before this, the Beipiaosaurus was considered the heaviest dinosaur that featured feathers.
The Yutyrannus weighs forty times as much as the Beipiaosaurus, so the genus now has major significance in paleontology!
The Yutyrannus huali, also known as the feathered tyrant, was a bipedal carnivore thought to have hunted in packs.
It likely fed on sauropods, but there’s not enough evidence to support this.
It lived in an unusually cold environment, which could be one of the reasons it had feathers.
Keep reading to discover more about the species’ appearance, behavior, diet, and reproduction!
You’ll learn some incredible facts today!
The Yutyrannus was a large theropod, although scientists aren’t entirely sure how large it was because its size is just an estimation based on the discovered fossils.
The holotype is thought to have been an adult, while the paratypes are believed to have been at least eight years younger than the holotype.
The holotype had a femur length of 85 centimeters (33.4 inches), making Yutyrannus larger than some other large tyrannosauroids.
The Dryptosaurus, for instance, had a femoral length of 77 centimeters (30.3 inches), while the Appalachiosaurus had a femoral length of 79 centimeters (31.1 inches).
As such, some specialists estimate that the holotype dinosaur measured approximately 7.5-9 meters (24.6-29.5 feet) long.
Its weight is thought to have been between 1,100 and 1,414 kilograms (2,425 and 3,117 pounds).
The smaller, younger dinosaurs probably weighed between 493 and 596 kilograms (1,086 and 1,313 pounds).
As for height – Yutyrannus was probably 2.2-2.7 meters (7.2-8.8 feet) tall at the hips.
One thing you might’ve already known about this colossal predator is that its body was covered in feathers.
Specialists confirmed that the Yutyrannus had long feathers, measuring around 20 centimeters (7.9 inches) long.
However, not all body parts were feathered.
The dinosaurs whose fossils were discovered likely had feathers on the pelvis, on the tail, on the neck, on the upper arms, and near the feet.
Yutyrannus is among the few dinosaur species known to have feathers; there’s enough paleontological evidence to support this.
Some studies even call it the largest dinosaur, showing direct evidence of a feathered body.
Specialists consider this trait very interesting in large animals because they’re generally considered to lack the need for feathers.
Since they have low surface-to-volume ratios, they do not require a feathered body to retain metabolic heat.
The lack of feathers in large dinosaurs is suspected to have the same physiological explanation.
Moreover, since there’s no evidence showing that any tyrannosauroids living during the Cretaceous had feathers, paleontologists dropped this possibility; that is, up until the discovery of the Yutyrannus.
This proved that the lack of feathers isn’t necessarily linked to the animal’s size.
Besides the extensive research on Yutyrannus feathers, specialists also focused on outlining the dinosaur’s overall appearance.
It was a bipedal dinosaur and had a large and elongated head. Its hindlimbs were strong and long, but its feet were short.
The forelimbs were shorter than the hindlimbs and possessed three fingers.
The skull was large and deep. The snout had a high midline crest distinguishing this feathered tyrant from its relatives.
This midline crest resembles those of Concavenator and Guanlong.
Habitat and Distribution
The Yutyrannus fossils were discovered in China’s Liaoning Province.
More precisely, they were found at Batuyingzi, Beipiao, in the Lower Cretaceous Yixian Formation.
While the Cretaceous is considered a warm period overall, the age the Yutyrannus lived in (the Barremian) was colder than the others, having wet, humid periods that alternated with dry seasons.
As such, scientists estimate that western Liaoning’s mean annual air temperature was only 10 degrees Celsius (50 degrees Fahrenheit).
The same location registered roughly 18 degrees Celsius (64.4 degrees Fahrenheit) during the Late Cretaceous.
The studies that suggest this temperature also indicate that the climate was probably temperate and the region had unusually cold winters.
This cold environment might also explain why the Yutyrannus had feathers while other tyrannosaurids didn’t.
This bipedal dinosaur likely lived in forested habitats filled with coniferous plants and bodies of water, especially freshwater lakes.
Moreover, some scientists believe forest fires and volcanic eruptions were common there.
The Yixin Formation was home to the following plants:
- Three Archaefructus species (herbaceous aquatic seed plants)
- One Archaeamphora species
- Various horsetails (vascular plants reproducing by spores)
- Seed Fern
Behavior and Diet
Paleontologists believe that Yutyrannus dinosaurs hunted in packs.
This is suggested by the fact that the fossils belonging to the three specimens were found in the same place.
This could be further backed up by the fact that the species likely couldn’t run.
Specialists believe that their short feet were not specialized for this activity. As such, hunting in packs might have been useful to stay safe and catch prey.
The Yutyrannus was a carnivorous dinosaur, although it’s unknown what exactly it fed on.
Some sources suggest they preyed on sauropods. However, this has yet to be scientifically proven.
Like all dinosaurs, Yutyrannus reproduced by laying eggs. Since it was a theropod, it had a specific theropod reproductive system.
Males had testes and a retractable penis, while females had paired ovaries and oviducts.
Unlike modern birds, which have only one functional oviduct, dinosaurs, including Yutyrannus, had two and, thus, laid two eggs at a time.
Another unique characteristic of dinosaurs is that females probably grew a distinctive medullary bone rich in calcium, which was used in making eggshells.
This was first discovered in a Tyrannosaurus, which was also a theropod, thus indicating that Yutyrannus females grew it too.
Later research concluded that all dinosaurs likely possessed it.
The newly hatched babies might have been precocial because most baby dinosaurs were born this way.
Besides this, thanks to the discovered fossils, which likely belonged to an adult, a subadult, and a juvenile, scientists were able to agree on specific characteristics related to Yutyrannus ontogeny, or, in common terms, how these dinosaurs changed while growing.
More precisely, they discovered that their skulls became deeper and more robust while the forelimbs, ilia, lower legs, and feet grew smaller, as odd as it might sound.
Evolution and History
Since Yutyrannus is part of the Tyrannosauroidea subfamily, it’s essential to start our discussion there.
The ancestry of the Tyrannosauroidea has long been questioned.
At times, the members of this superfamily were thought to have been carnosaurs.
This theory suggests that the ancestors of tyrannosaurids were allosaurids.
Then, these creatures were placed in the Coelurosauria clade and remained so until today, but the debates didn’t end there.
Tyrannosauroids were subsequently placed in a clade called Arctometatarsalia alongside troodontids and ornithomimosaurs, but the clade was later dismantled.
In 1990, a paleontologist suggested that tyrannosaurs should form a group called Tyrannoraptora, which would’ve been equal to Maniraptora, as they were closer to birds than ornithomimosaurs.
Many other debates followed, but what concerns us the most is that the ancestry of the Yutyrannus and the relationship it had with other dinosaurs have long been debated.
However, most paleontologists are certain that it is an unquestionable member of the Tyrannosauroidea group.
It is now also part of the Proceratosauridae family, being a close relative to Guanlong, Kileskus, Proceratosaurus, and Sinotyrannus.
Interactions with Other Species
The Yutyrannus is thought to have lived among a very diverse fauna, especially because the habitats in the surrounding regions were diverse as well.
Moreover, the fact that the region was periodically destroyed and regrown because of wildfires and volcanic eruptions further contributed to its animal and plant diversity.
Here’s a list of animals that likely shared their habitats with the Yutyrannus:
- Dinosaurs like Beipiaosaurus, Bolong, Dongbetitian, Psittacosaurus, Mei, Dilong, Sinornithosaurus, and Graciliraptor
- Various ostracods
- Clam shrimps
- Snails and slugs
- Various fish, including Lycoptera
The Yutyrannus is thought to have hunted Dongbeititan sauropods, who were quadrupedal herbivores, although this requires further evidence.
Other prey might’ve included Psittacosaurus and Mei, which were herbivorous.
The discovery of Yutyrannus represents a major turning point in outlining our world’s evolutionary history.
Over the years, the species has been the subject of multiple research papers that primarily focus on feathered dinosaurs, but not only.
The feathered tyrant is also somewhat popular in entertainment, although probably not as famous as other renowned dinosaurs.
Players of ARK: Survival Evolved already know the creature, which is called Yuty, in the game.
Yutyrannus is depicted as a large predator feeding on other herbivorous and carnivorous dinosaurs.
The feathered dinosaur was planned to appear in Jurassic World: Camp Cretaceous, but it was later cut from the movie and replaced by an Ankylosaurus.
However, it can still be seen in Jurassic Park: Builder, Jurassic World: The Game, and Jurassic World Evolution 2.
The feathered tyrant is one of the most important dinosaurs in the universe of paleontology!
The Yutyrannus huali, or simply Yutyrannus, lived in what we now call China around 125 million years ago.
It was a large bipedal theropod with a carnivorous diet.
The creature lived in a somewhat unstable habitat, as forest fires and volcanic eruptions continuously destroyed it.
That’s why the ecosystem’s fauna and flora were diverse – in short, the Yutyrannus probably never got bored, as it had many creatures around it!
Since the species is so important in studying feathered dinosaurs, we’ll be on the lookout for new research and fossil discoveries!
What does Yutyrannus mean?
The generic name Yutyrannus comes from the Mandarin Chinese word for feather and the Latinized Greek word for tyrant, so the dinosaur is often called the feather tyrant.
Huali, the specific name, is a Mandarin word that can be translated as beautiful and refers to the beauty of the species’ plumage.
Was Yutyrannus bigger than T-Rex?
The Yutyrannus was smaller than the T-Rex. While the former measures 7.5-9 meters (24.6-29.5 feet), T-Rex can reach lengths of over 12 meters (39.3 feet) and is almost twice the feathered tyrant’s height.
Furthermore, while the Yutyrannus measures roughly one metric ton, the Tyrannosaurus rex can reach a body mass of 8.87 metric tons (9.78 short tons).